Tamoxifen and weight loss

What Might Cause Me to Gain Weight?

Many things can play a role.

Chemotherapy can bring on premature menopause. And with it comes a slowing of the metabolism. That makes it harder to keep weight off. Menopause also causes you to gain more body fat and lose lean muscle.

It’s common for women who have chemotherapy to gain about 5 to 14 pounds over a year. Some gain less, while others put on as many as 25 pounds.

Another reason for weight gain is the use of corticosteroids. These medications help with nausea and swelling, or to stop reactions to chemotherapy. These drugs can boost your appetite. Corticosteroids are hormones that can also cause an increase in fatty tissue. They can make you lose muscle mass in your arms and legs, and gain belly fat, too. You may also have a fullness of the neck or face. Loss of muscle makes weight gain more apparent.

Women treated with steroids may also put on pounds, but the weight gain is usually seen only after weeks of continuous use.

Some research suggests that weight gain is also related to lack of exercise . When you get your cancer treatment, it’s common to feel stress and have some fatigue, nausea, or pain. That can lead to a drop in how much physical activity you get.

Weight gain may also be related to intense food cravings. Some women crave sweets and carbohydrates during chemotherapy. Too much of these foods can lead to added pounds.

The Weight Battle

Dietitians offer strategies for controlling weight after cancer treatment

Michelle Churches plans ahead to make sure the easiest food to prepare is the healthiest.

Michelle Churches walks 11,000 steps during her 10-hour nursing shift at an outpatient surgery center in Trenton.

She knows this because she wears a pedometer. After walking those 11,000 steps, she comes home and pulls together a homemade dinner in about 30 minutes. She chats with her husband and kids, cleans up the kitchen and heads out to walk the dog. Some weeks, depending on her work schedule, she’ll fit in an extra 12-hour shift to help fund a gift she wants to give her three children: a debtfree ride through college.

To say that Churches is active would draw an affectionate chuckle from her friends. When the season is right, Churches has been known to work from dawn to dusk in her herb garden, stopping only long enough for occasional water breaks. So when she was diagnosed in 2005 with breast cancer, weight wasn’t a concern for her. She was 5 feet 7 inches and 138 pounds. But after a mastectomy, chemotherapy, radiation and hormone therapy, Churches has found it’s more difficult to maintain her weight.

“I work my butt off so that now when I look at a Reese’s Peanut Butter Cup, I have a little calculator in my head: How much will it take to burn this off? Is it worth it?” she says.

At the University of Michigan Rogel Cancer Center, dietitians Joan Daniels and Nancy Burke spend a lot of time helping people prevent weight loss during treatment. But they also see patients who struggle to lose weight after cancer treatment. This is particularly true of breast and prostate cancer patients who receive hormone therapy. Certain chemotherapy regimens also may cause patients to lose muscle and gain fat tissue.

It may be more difficult to lose weight, but Daniels and Burke stress that it’s still important to try to control what you can: diet and exercise.

Weight-Loss Tips

  • Keep a food log. You may be eating more than you think.
  • Pay attention to what you drink. Sodas and sugary coffee drinks often contain a lot of calories.
  • Cut back on butter and oil. Use herbs to flavor foods instead.
  • Make meat secondary. Fill your plate with vegetables, fruits and whole grains. Think of lean meats and low-fat dairy products as side dishes.
  • Consider strength-building exercises if you have lost muscle or gained fat tissue.

“The bottom line is that you can manage your weight, but it takes a lot more effort,” Daniels said. “You have to exercise more and you have to cut back your food more.”

Depression may also be an underlying factor that needs to be addressed, Daniels said. Sometimes the full psychological impact of cancer doesn’t hit until a patient is into post-treatment survivorship. This can interfere with exercise regimens or cause people to binge.

Exercise can help reduce depression and anxiety as well as lower the risk of recurrence. One strategy Burke recommends for patients seeking to lose weight is to find an activity they enjoy to boost their commitment to exercising. For Churches, gardening is a great workout and also keeps her kitchen stocked during part of the year with healthy fruits, vegetables and herbs. Late last fall, as the season was ending, Churches was preparing to dry herbs to season foods during the winter months.

Churches uses herbs as a way to boost flavors without adding fat. Staying organized also makes eating healthier easier: Churches stocks the pantry with good choices so healthy snacks are always within reach. S he prepares meals ahead of time so that there’s very little work to do to get the meal on the table after work. The Churcheses limit take-out to Wednesday nights when they splurge on a pizza or Mexican food.

“All the women in my family cook like this. My mom always said, ‘Fast food is nothing but poison,'” Churches said, pausing to admit her guilty pleasure: Diet Coke. “My mom always had stuff she could throw together simply, and I do, too. I practice what I preach.”

Michelle Churches’s Chenin Blanc Chicken

Print the Chenin Blank Chicken recipe.


  • 1/4 c. olive oil
  • 1/4c. Chenin Blanc white wine
  • zest of one lemon
  • juice from ½ lemon
  • 2 cloves of pressed garlic
  • 1/2 tsp. dried oregano
  • 1/2 tsp. sea salt
  • pinch of pepper

1 to 2 lbs chicken, cubed
red or black seedless grapes
Minced flat-leaf parsley
Skewers, soaked in water 30 minutes

In a non-reactive bowl, whisk together the marinade ingredients until well emulsified. Toss the chicken with the marinade and refrigerate overnight.

Skewer chicken, alternating with grapes. Heat grill or grill pan over medium heat. Cook skewers until chicken juices run clear, about 3 minutes on each side. Grapes should puff and caramelize.

Sprinkle with parsley and serve.

Get more weight-loss tips and healthy eating ideas:

  • Comfort Foods
  • Fads Fade Fast, But Healthy Eating Sticks
  • Bounty of the Mediterranean
  • Plant-based Diets: Why all the Hype?

Learn more about the side effects of cancer treatment:

  • Keeping Up Appearances (lymphedema, hair loss)
  • Clearing the Mind: Coping with Chemobrain
  • When to Ask for Help (pain, numbness)
  • Life After Treatment (anxiety)

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Adverse reactions to NOLVADEX (tamoxifen citrate) are relatively mild and rarely severe enough to require discontinuation of treatment in breast cancer patients.

Continued clinical studies have resulted in further information which better indicates the incidence of adverse reactions with NOLVADEX (tamoxifen citrate) as compared to placebo.

Metastatic Breast Cancer

Increased bone and tumor pain and, also, local disease flare have occurred, which are sometimes associated with a good tumor response. Patients with increased bone pain may require additional analgesics. Patients with soft tissue disease may have sudden increases in the size of preexisting lesions, sometimes associated with marked erythema within and surrounding the lesions and/or the development of new lesions. When they occur, the bone pain or disease flare are seen shortly after starting NOLVADEX (tamoxifen citrate) and generally subside rapidly.

In patients treated with NOLVADEX (tamoxifen citrate) for metastatic breast cancer, the most frequent adverse reaction to NOLVADEX (tamoxifen citrate) is hot flashes.

Other adverse reactions which are seen infrequently are hypercalcemia, peripheral edema, distaste for food, pruritus vulvae, depression, dizziness, light-headedness, headache, hair thinning and/or partial hair loss, and vaginal dryness.

Premenopausal Women

The following table summarizes the incidence of adverse reactions reported at a frequency of 2% or greater from clinical trials (Ingle, Pritchard, Buchanan) which compared NOLVADEX (tamoxifen citrate) therapy to ovarian ablation in premenopausal patients with metastatic breast cancer.

Adverse Reactions* NOLVADEX (tamoxifen citrate)
All Effects % of
All Effects
% of Women
n =100
Flush 33 46
Amenorrhea 16 69
Altered Menses 13 5
Oligomenorrhea 9 1
Bone Pain 6 6
Menstrual Disorder 6 4
Nausea 5 4
Cough/Coughing 4 1
Edema 4 1
Fatigue 4 1
Muscoloskeletal Pain 3 0
Pain 3 4
Ovarian Cyst(s) 3 2
Depression 2 2
Abdominal Cramps 1 2
Anorexia 1 2
*Some women had more than one adverse reaction.

Male Breast Cancer

NOLVADEX (tamoxifen citrate) is well tolerated in males with breast cancer. Reports from the literature and case reports suggest that the safety profile of NOLVADEX (tamoxifen citrate) in males is similar to that seen in women. Loss of libido and impotence have resulted in discontinuation of tamoxifen therapy in male patients. Also, in oligospermic males treated with tamoxifen, LH, FSH, testosterone and estrogen levels were elevated. No significant clinical changes were reported.

Adjuvant Breast Cancer

In the NSABP B-14 study, women with axillary node-negative breast cancer were randomized to 5 years of NOLVADEX (tamoxifen citrate) 20 mg/day or placebo following primary surgery. The reported adverse effects are tabulated below (mean follow-up of approximately 6.8 years) showing adverse events more common on NOLVADEX (tamoxifen citrate) than on placebo. The incidence of hot flashes (64% vs. 48%), vaginal discharge (30% vs. 15%), and irregular menses (25% vs. 19%) were higher with NOLVADEX (tamoxifen citrate) compared with placebo. All other adverse effects occurred with similar frequency in the 2 treatment groups, with the exception of thrombotic events; a higher incidence was seen in NOLVADEX (tamoxifen citrate) -treated patients (through 5 years, 1.7% vs. 0.4%). Two of the patients treated with NOLVADEX (tamoxifen citrate) who had thrombotic events died.

NSABP B-14 Study
Adverse Effect % of Women
Hot Flashes 64 48
Fluid Retention 32 30
Vaginal Discharge 30 15
Nausea 26 24
Irregular Menses 25 19
Weight Loss ( > 5%) 23 18
Skin Changes 19 15
Increased SGOT 5 3
Increased Bilirubin 2 1
Increased Creatinine 2 1
Thrombocytopenia* 2 1
Thrombotic Events
Deep Vein Thrombosis 0.8 0.2
Pulmonary Embolism 0.5 0.2
Superficial Phlebitis 0.4 0.0
*Defined as a platelet count of < 100,000/mm3

In the Eastern Cooperative Oncology Group (ECOG) adjuvant breast cancer trial, NOLVADEX (tamoxifen citrate) or placebo was administered for 2 years to women following mastectomy. When compared to placebo, NOLVADEX (tamoxifen citrate) showed a significantly higher incidence of hot flashes (19% vs. 8% for placebo). The incidence of all other adverse reactions was similar in the 2 treatment groups with the exception of thrombocytopenia where the incidence for NOLVADEX (tamoxifen citrate) was 10% vs. 3% for placebo, an observation of borderline statistical significance.

In other adjuvant studies, Toronto and NOLVADEX (tamoxifen citrate) Adjuvant Trial Organization (NATO), women received either NOLVADEX (tamoxifen citrate) or no therapy. In the Toronto study, hot flashes were observed in 29% of patients for NOLVADEX (tamoxifen citrate) vs. 1% in the untreated group. In the NATO trial, hot flashes and vaginal bleeding were reported in 2.8% and 2.0% of women, respectively, for NOLVADEX (tamoxifen citrate) vs. 0.2% for each in the untreated group.

Anastrozole Adjuvant Trial – Study of Anastrozole compared to NOLVADEX (tamoxifen citrate) for Adjuvant Treatment of Early Breast Cancer (see CLINICAL PHARMACOLOGY – Clinical Studies).

At a median follow-up of 33 months, the combination of anastrozole and NOLVADEX (tamoxifen citrate) did not demonstrate any efficacy benefit when compared to NOLVADEX (tamoxifen citrate) therapy given alone in all patients as well as in the hormone receptor positive subpopulation. This treatment arm was discontinued from the trial. The median duration of adjuvant treatment for safety evaluation was 59.8 months and 59.6 months for patients receiving anastrozole 1 mg and NOLVADEX (tamoxifen citrate) 20 mg, respectively.

Adverse events occurring with an incidence of at least 5% in either treatment group during treatment or within 14 days of the end of treatment are presented in the following table.

Adverse events occurring with an incidence of at least 5% in either treatment group during treatment, or within 14 days of the end of treatment

Certain adverse events and combinations of adverse events were prospectively specified for analysis, based on the known pharmacologic properties and side effect profiles of the two drugs (see the following table).

Number (%) of Patients with Pre-Specified Adverse Event in the Anastrozole Adjuvant Trial1

Patients receiving anastrozole had an increase in joint disorders (including arthritis, arthrosis and arthralgia) compared with patients receiving NOLVADEX (tamoxifen citrate) . Patients receiving anastrozole had an increase in the incidence of all fractures (specifically fractures of spine, hip and wrist) compared with patients receiving NOLVADEX (tamoxifen citrate) . Patients receiving anastrozole had a decrease in hot flashes, vaginal bleeding, vaginal discharge, endometrial cancer, venous thromboembolic events and ischemic cerebrovascular events compared with patients receiving NOLVADEX (tamoxifen citrate) .

Results from the adjuvant trial bone substudy, at 12 and 24 months demonstrated that patients receiving anastrozole had a mean decrease in both lumbar spine and total hip bone mineral density (BMD) compared to baseline. Patients receiving NOLVADEX (tamoxifen citrate) had a mean increase in both lumbar spine and total hip BMD compared to baseline.

Ductal Carcinoma in Situ (DCIS)

The type and frequency of adverse events in the NSABP B-24 trial were consistent with those observed in the other adjuvant trials conducted with NOLVADEX (tamoxifen citrate) .

Reduction in Breast Cancer Incidence in High Risk Women

In the NSABP P-1 Trial, there was an increase in five serious adverse effects in the NOLVADEX (tamoxifen citrate) group: endometrial cancer (33 cases in the NOLVADEX (tamoxifen citrate) group vs. 14 in the placebo group); pulmonary embolism (18 cases in the NOLVADEX (tamoxifen citrate) group vs. 6 in the placebo group); deep vein thrombosis (30 cases in the NOLVADEX (tamoxifen citrate) group vs. 19 in the placebo group); stroke (34 cases in the NOLVADEX (tamoxifen citrate) group vs. 24 in the placebo group); cataract formation (540 cases in the NOLVADEX (tamoxifen citrate) group vs. 483 in the placebo group) and cataract surgery (101 cases in the NOLVADEX (tamoxifen citrate) group vs. 63 in the placebo group) (See WARNINGS and Table 3 in CLINICAL PHARMACOLOGY).

The following table presents the adverse events observed in NSABP P-1 by treatment arm. Only adverse events more common on NOLVADEX (tamoxifen citrate) than placebo are shown.

NSABP P-1 Trial: All Adverse Events % of Women
Self Reported Symptoms N=64411 N=64691
Hot Flashes 80 68
Vaginal Discharges 55 35
Vaginal Bleeding 23 22
Laboratory Abnormalities N=65202 N=65352
Platelets decreased 0.7 0.3
Adverse Effects N=64923 N=64843
Other Toxicities
Mood 11.6 10.8
Infection/Sepsis 6.0 5.1
Constipation 4.4 3.2
Alopecia 5.2 4.4
Skin 5.6 4.7
Allergy 2.5 2.1
1Number with Quality of Life Questionnaires
2Number with Treatment Follow-up Forms
3Number with Adverse Drug Reaction Forms

In the NSABP P-1 trial, 8.7% and 9.6% of participants receiving NOLVADEX (tamoxifen citrate) and placebo therapy, respectively withdrew for non-medical reasons.

On the NSABP P-1 trial, hot flashes of any severity occurred in 68% of women on placebo and in 80% of women on NOLVADEX (tamoxifen citrate) . Severe hot flashes occurred in 28% of women on placebo and 45% of women on NOLVADEX (tamoxifen citrate) . Vaginal discharge occurred in 35% and 55% of women on placebo and NOLVADEX (tamoxifen citrate) respectively; and was severe in 4.5% and 12.3% respectively. There was no difference in the incidence of vaginal bleeding between treatment arms.

Pediatric Patients – McCune-Albright Syndrome

Mean uterine volume increased after 6 months of treatment and doubled at the end of the one-year study. A causal relationship has not been established; however, as an increase in the incidence of endometrial adenocarcinoma and uterine sarcoma has been noted in adults treated with NOLVADEX (see BOXED WARNING), continued monitoring of McCune-Albright patients treated with NOLVADEX (tamoxifen citrate) for long-term effects is recommended. The safety and efficacy of NOLVADEX (tamoxifen citrate) for girls aged two to 10 years with McCune-Albright Syndrome and precocious puberty have not been studied beyond one year of treatment. The long-term effects of NOLVADEX (tamoxifen citrate) therapy in girls have not been established.

Postmarketing experience

Less frequently reported adverse reactions are vaginal bleeding, vaginal discharge, menstrual irregularities, skin rash and headaches. Usually these have not been of sufficient severity to require dosage reduction or discontinuation of treatment. Very rare reports of erythema multiforme, Stevens-Johnson syndrome, bullous pemphigoid, interstitial pneumonitis, and rare reports of hypersensitivity reactions including angioedema have been reported with NOLVADEX (tamoxifen citrate) therapy. In some of these cases, the time to onset was more than one year. Rarely, elevation of serum triglyceride levels, in some cases with pancreatitis, may be associated with the use of NOLVADEX (tamoxifen citrate) (see PRECAUTIONS- Drug/Laboratory Testing Interactions section).

Read the entire FDA prescribing information for Nolvadex (Tamoxifen Citrate)

Novel Study of Endocrine Therapy-Induced Hair Loss

It’s not only chemotherapy that causes breast cancer patients to lose their hair. Treatment with endocrine therapy (ie, tamoxifen or an aromatase inhibitor) can also cause hair loss and have a negative impact on quality of life, even when the loss is only mild in severity, a novel study suggests.

On the other hand, treatment with topical minoxidil (Rogaine, Johnson & Johnson) can restore hair growth, so the loss is potentially treatable, the investigators add.

“There are tens of thousands of breast cancer survivors on endocrine therapies, and the remarkable improvements in patient survival that have been achieved through their care have led to patients now being concerned about quality of life issues, like partial hair loss,” senior author Mario Lacouture, MD, Memorial Sloan Kettering Cancer Center (MSKCC), New York City, told Medscape Medical News in an email.

The study is the first to characterize endocrine therapy–induced alopecia (EIA) in patients with breast cancer. EIA has been anecdotally reported but never systematically described. The study was published online April 11 in JAMA Dermatology.

The investigators retrospectively identified a cohort of 112 female patients seen at MSKCC, all of whom had EIA.

“Those who either previously received cytotoxic chemotherapy or had a previous diagnosis of alopecia or any scalp condition were excluded from the study,” the investigators note.

Standardized clinical photographs of the scalp were taken from several angles with the hair parted and combed in the center. Responses to a questionnaire concerning hair were collected in order to assess the effect that alopecia had on patients’ quality of life. At baseline, the prevailing trichoscopic feature was the presence of vellus hairs as well as intermediate- and thick-density terminal hair shafts, the researchers report.

Patients were treated with topical minoxidil 5%. The effects of treatment were measured by a single investigator at 3 and 6 months.

The researchers note that vellus hairs may be present as a result of unsynchronized miniaturization of hair follicles, one of the hallmarks of so-called androgenetic alopecia. As Lacouture explained, androgenetic alopecia is a pattern of hair loss similar to that which occurs in men and women with age. It is characterized by a thinning of hair on the temples, a receding hairline, and loss of hair at the top of the head.

In the current study, evaluation of the standardized clinical photographs, available for 93% of the group, showed that there was a more prominent recession of hair in the frontotemporal area in 76% of patients than in the midanterior hairline, the investigators note.

“Also, the specific type of alopecia seen in 86 patients (83%) was mild to moderate alopecia on the crown area of the scalp,” they add.

Moreover, 92% of patients developed grade 1 alopecia; only 8% of the group developed grade 2 alopecia. Alopecia severity was graded using the Common Terminology Criteria for Adverse Events scale.

Data on alopecia-related quality of life were available for slightly fewer than half of the group (46%). For those patients, the mean score on the hair questionnaire was 25.6.

This score includes measures of emotions, functioning, symptoms, stigmatization, and self-confidence. The highest negative score on the hair questionnaire was in the emotional domain (P < .001).

Grade 1 alopecia represents hair loss of less than 50% that does not require camouflage.

Patients appeared to be negatively affected by even grade 1 hair loss, suggesting, Lacouture indicated, that “not only complete hair loss as seen with chemotherapy is affecting women but also hair thinning or partial hair loss will result in a negative psychosocial impact.”

Minoxidil Response

The investigators were able to assess response to topical minoxidil 5% in 41% of the group. Topical minoxidil 2% and 5% is the only agent approved by the US Food and Drug Administration for the treatment of androgenetic alopecia in women.

The investigators determined that 80% of patients who were treated with topical minoxidil experienced either moderate to significant improvement in alopecia.

The researchers explain that both estrogens and androgens are important modulators of hair growth.

“When endocrine receptor activation and pathway signaling are blocked, dihydrotestosterone levels increase, and this action may contribute to the induction of alopecia in susceptible women receiving ET ,” they observe.

This mechanism of action suggests that alopecia induced by endocrine therapy may be “physiologically similar” to androgenetic alopecia; as such, the investigators hypothesize that women with EIA may benefit from other potential treatments for androgenetic alopecia, such as spironolactone (multiple brands).

“Alopecia is often cited as one of the most negative effects on quality of life in patients with cancer, and it has been reported that 8% of patients with cancer would rescind lifesaving therapy had they known they were going to have alopecia,” the study authors state.

“Therefore, it should be important for oncology health care professionals treating patients with breast cancer to consider the distress that grade 1 alopecia may have on patients’ QoL ,” they add, especially given the long duration of treatment required with endocrine therapy.

Lacouture added that no randomized studies have investigated whether topical minoxidil should be given prophylactically to women about to receive endocrine therapy, so they cannot recommend that physicians treat women to prevent hair loss.

“However, they should refer women to a dermatologist or initiate minoxidil at the first sign or symptom of hair thinning, until we have better treatments,” Lacouture recommended.

Higher Incidence

In an accompanying editorial, Ralph Trueb, MD, Center for Dermatology and Hair Diseases, Zurich, Switzerland, suggests that the reported incidence of EIA may be significantly higher than the oft-cited 4.4%; it may affect as many as one quarter of patients treated with tamoxifen and approximately one third of women who are treated with an aromatase inhibitor. “Not unexpectedly, this would correspond to the estimated prevalence of androgenetic alopecia in the general population of women,” Trueb told Medscape Medical News in an email.

Trueb says that female androgenetic alopecia differs from male androgenetic alopecia in that it has a more complex etiology. “Topical minoxidil is as yet the single agent with proven effectiveness for treatment of female androgenetic alopecia,” Trueb points out.

“Because its mode of action does not affect estrogen metabolism, it is safe for use in women with hormone-sensitive tumors, as well as for long-term use in women with alopecia at risk for hormone-sensitive tumors,” he indicates.

Importantly, however, Trueb also notes that alopecia caused by endocrine therapy may eventually be irreversible if left untreated for a long time.

Early treatment of endocrine therapy–induced hair loss is mandatory. Dr Ralph Trueb

“Therefore, early treatment of endocrine therapy–induced hair loss is mandatory,” he said. Alternatively, physicians should prescribe minoxidil prophylactically in women with a history of androgenetic alopecia who are about to undergo endocrine therapy.

“Once hormonal treatment is stopped, there is a chance for preserved hair to remain, even after tapering of minoxidil,” Trueb said.

“Therefore, minoxidil treatment should be continued for the total duration of endocrine therapy,” he added. “Once the hair is lost, it will not regrow, even after cessation of endocrine therapy,” Trueb emphasized.

Chemotherapy-induced hair loss is different from endocrine therapy–induced hair loss; the only way to prevent chemotherapy-induced hair loss — at least to some extent — is through the use of scalp cooling during treatment, he also pointed out.

The study was supported in part by grants from the National Institutes of Health/National Cancer Institute Cancer Center and by Beca Excelencia. Dr Lacouture has received research funding from Berg and Bristol-Myers Squibb and has served as a consultant to Quintiles, AstraZeneca, Legacy, Foamix, Adgero Bio Pharmaceuticals, Janssen Research & Development, and Novocure. Dr Trueb has disclosed no relevant financial relationships.

JAMA Dermatol. Published online April 11, 2018. Full text, Editorial

For more from Medscape Oncology, follow us on Twitter: @MedscapeOnc

How To Beat Weight Gain On Tamoxifen (A Success Story!)

If you are taking tamoxifen, you have A LOT of questions. And when it comes to weight loss, these two probably rank near the top:

  1. Will I gain weight on tamoxifen? And,
  2. If I do, is there anything I can do to stop it—and actually lose weight?

Both of these are valid questions. You’ve heard so many women talk about how they put on weight while on tamoxifen.

Kathy, a MyBodyTutor success story, said, “My oncologist told me he’d never seen any women on tamoxifen lose weight.”

Luckily, that wasn’t the case. She has a happy and powerful story!

(Keeping reading, we’ll pick Kathy’s story back up soon.)

Is weight gain something you’re struggling with now?

If so, we’re going to talk about how you can challenge your beliefs and assumptions and beat this extra weight.

But first, let’s start with:

What is Tamoxifen?

Tamoxifen is a medication prescribed for breast cancer treatment. And, as a preventative measure for women at high risk of developing breast cancer.

It works by attaching to estrogen receptors and blocking the effects of estrogen on the breast tissue. So it helps prevent the growth of breast tumors that need estrogen; which, according to the National Cancer Institute, is about 80%.

The benefits of tamoxifen are tremendous, but it’s not without risk of side effects.

Is Weight Gain A Side Effect?

A major concern among women on tamoxifen is if they will gain weight. And whether we’re talking about tamoxifen (or a countless number of other medications), weight gain is possible.

Here are just a few potential side effects from Breastcancer.org:

  • Hot flashes
  • Blood clots
  • Mood swings
  • Depression, and
  • Weight gain

The Mayo Clinic also details weight gain or loss as a possible side effect.

So the risk of gaining weight is very real.

But how common is it?

To answer that, we’ll dive into the research. And, the study we’re going to look at is one of the most comprehensive out there.

This women’s healthy eating and living (WHEL) study spanned a six-year period and included more than 3,000 breast cancer survivors—ranging in age from 27 to 74.

Among the study’s goals, one was to determine if tamoxifen had an effect on weight change after a breast cancer diagnosis.

The study had two key conclusions:

  1. That there was no link between weight gain and tamoxifen.
  2. However, chemotherapy is significantly associated with weight gain.

So, to answer the question: Should I worry about gaining weight on tamoxifen?

The answer is:

Weight gain is a potential side effect of tamoxifen. However, most studies suggest there is no direct link.


An unfortunate fact remains. Many women will gain weight after diagnosis.

In fact, according to an article published in the World Journal of Clinical Oncology, you can expect to gain anywhere from 2 to 11 pounds.

Right now, you may be asking…

If there is no link between tamoxifen and weight gain, why am I gaining weight?

And the answer is…there is no single aspect we can put our finger on. It is a combination of many, many reasons.

1.) Chemotherapy

In the WHEL study we looked at earlier, we learned that chemotherapy has a significant association with weight gain. But, there are other reasons to consider as well.

2.) Emotional Stress

Beyond the initial shock of a cancer diagnosis, there is the inevitable stress, anxiety, and worry that go with that kind of life-changing news.

  • How will I take care of my family during treatment?
  • What will I do about my job?
  • How will I pay for all this?
  • What happens if cancer returns?

Your life just got turned upside down, and there are a million worries you have today that you didn’t have yesterday. Emotional stress can play a huge role in contributing to weight gain.

3.) Metabolism

Your metabolism (the rate at which you burn calories) slows as you age. So naturally, losing weight becomes much more difficult than it once was. Luckily, there are ways, like exercise, that can help you battle a slowing metabolism.

Which brings us to the next factor…

4.) A Lack Of Physical Activity

Studies show that physical activity will decline after a breast cancer diagnosis, which is completely natural. You are recovering from surgery or chemotherapy.

However, less activity means fewer calories burned, which can easily translate into increased weight.

If we consider the magnitude of the situation, combining:

  • A cancer diagnosis,
  • An intensely emotional situation (worry, anxiety, and fear),
  • A lack of physical activity, and
  • The treatment itself.

It is entirely understandable why one would gain weight.

But, what can we do about it?

How To Beat Weight Gain Following A Breast Cancer Diagnosis.

Make no mistake, losing weight is a challenge even under normal circumstances. And it can be even harder after breast cancer.

But it is possible, and you CAN do it.

And where we need to start is with challenging our assumptions.

1.) Challenge Your Assumptions

When you hear you will gain weight after a diagnosis and not many women will ever lose weight enough times, that belief starts to solidify.

Remember when I mentioned earlier that Kathy said, “My oncologist told me he’d never seen any women on tamoxifen lose weight.”

It’s easy to start believing that is true, especially when you keep trying to lose weight without seeing any results.

So we have got to expect a different result. Kathy didn’t believe she could lose weight…


So if you’re thinking, “There is no way I am going to lose this weight!”

I ask, what emotion does that thought trigger?

…Is it anger?

And if you feel hopeless, what action will you most likely take? You guessed it…you probably won’t take action.

So now I ask, How can you challenge this belief? How can you trigger a new emotion?

Maybe it’s thinking like this:

Losing this weight is a challenge, but I will succeed DESPITE this diagnosis. Not only for my family, but for myself and for others. I will be an inspiration for other women in my situation.

These thoughts trigger feelings of hope and determination, right?

And when you are determined, like I know you are and like Kathy is, you will take action. And actions lead to results.

2.) Describe Your Why

The reason “why” you want to lose weight is the fire that fuels your motivation.

Weight loss after a diagnosis can be a long road with many bumps and discouragements along the way. And that’s why it is absolutely critical to describe why you want to lose weight, so you can turn to it when times get tough.

What is your why?

  • Are you doing this to regain control?
  • To improve your self-image?
  • To prove to yourself that you can?

Loving the way you feel and look contributes so much to your overall well-being.


It’s about the confidence you gain. It’s about the new outlook on life you get. It’s about realizing your beliefs and assumptions were just that…beliefs and assumptions.

It’s about a new attitude of, “What’s next?” because when you conquer yourself, you truly feel like you can overcome anything, and that is life changing!

Here’s how gaining control changed Kathy’s life.

“In one week my husband and I are having the holiday of our dreams. We are going to Canada (very long plane ride for us from Sydney!) and doing 2 weeks of walking in the Rockies. I am the most fit and able I have been since cancer 5 years ago.”

This is the power of why!

3.) Conquer Emotional Eating

Emotional eating is when we eat outside of being physically hungry. It’s when we turn to food to fill a void or to numb our emotions.

This is an important concept, especially now. Earlier, we spoke about anxiety, worry, and despair. So often, eating is a way to comfort ourselves and how to cope with these negative emotions.

So not only do we have to question our beliefs, we must question our hunger.

If you suspect your hunger might be emotional, ask yourself what you are really hungry for?

  • Perhaps, it’s been a stressful day.
  • Maybe we’re seeking the pleasure of food.

Sometimes, it can be very helpful to explore what it feels like to have the need go unmet by simply writing about it. Many clients have reported that this eases the discomfort tremendously, and of course, like all discomfort (and pleasure) it will subside.

Helping clients overcome emotional eating is a big part of what we do.

4.) Get Support

Deciding to lose weight is a big step in putting your health first. And you may genuinely believe you cannot beat this extra weight.

That’s why it is important to have someone on your side. Someone in your corner that will give you daily support and motivation.

Kathy points out, “The daily feedback was key to getting me over the line! I genuinely was not sure I could lose weight.”

And this exactly what we do at MyBodyTutor, we are there with you every step of the way.

  • We have countless examples of people who were told they could expect to gain weight and to just accept this fact, but didn’t, like Amy.
  • Countless examples of people who just believed their body was stuck like Laurie.
  • Countless examples of people who thought it was “genetically impossible” to have the body they wanted like Matt.

If you need help losing weight and building a plan that will work for you, this is what we live for!

When you join MyBodyTutor, you’ll get practical, real-life support from coaches that understand the struggles of life.

And if you have questions about the program, email me. I read and respond to every email I get.

More Stories For You

  • Gratitude: The Secret of Happiness (And Weight Loss Success)

  • How To Change Eating Habits (Permanently)

  • I don’t have time to go to the gym. What can I do?

Is Weight Gain a Side Effect of Tamoxifen?

Keeping your weight in check can be tough during and after cancer treatment. This is true whether you’re taking medications that affect your appetite or weight, or if other physical or emotional factors are causing weight gain.

Here are six ways you can help manage your weight after cancer:

1. Eat the right foods

Reducing the amount of insulin-triggering foods you eat can help.

When you eat brown rice instead of white rice, for example, the carbohydrates cause less of a blood sugar spike, therefore less of an insulin surge. Higher insulin levels can mean more fat storage.

2. Don’t rely on counting calories only

When it comes to weight loss, as well as overall health, eating whole foods should be emphasized over counting calories.

A diet low in calories but high in refined carbs and processed foods will leave you hungry and tired. Opt for unprocessed protein-filled foods and fresh produce.

3. Track what you eat

You can track what you’re eating without counting calories. Chances are, you might be eating more than you realize, or more processed foods than you thought.

Keeping a log can help you monitor your eating habits and uncover opportunities for improvement.

4. Gradually start moving again

After treatment, you may not be able to hit the gym for a high-intensity workout. Instead of giving up on exercise altogether, gradually increase your activity level.

Gardening, walking, dancing, and tai chi are all good options. These types of activities can boost your mood, too.

5. Explore meditation

Deep breathing exercises can help manage stress hormones that contribute to weight gain. It can also help with focus, sleep, depression, and more.

Even a few minutes a day can make a difference on your outlook. Try a meditation app or take a class at your local yoga center.

6. Be patient

Finally, remember that weight loss can take time. It’s especially more challenging as you get older.

If you still have difficulty managing your weight despite making lifestyle changes, talk to your doctor about possible medical interventions.

Does tamoxifen affect the patient’s weight?

Expert answer

Tamoxifen is an oral anti-estrogen used to treat women with estrogen receptor positive breast cancer. It is taken once daily and blocks the estrogen receptor on cancer and normal cells. It prevents estrogen synthesized from the ovary, adrenal or fat tissue form stimulating the cancer to grow. It is given to women who have no evidence of disease after surgery but may have residual disease that is too small to see. It is also given to select women with active disease spread throughout the body (metastatic disease). Tamoxifen and similar compounds, the aromatase inhibitors, are used to prevent relapse or keep metastatic disease from growing.

When given as adjuvant therapy, meaning to prevent cancer from returning, these drugs are given for five and occasionally up to seven years. About 10 percent of women taking these drugs report unexpected weight gain. Most women report that it is easier to lose weight after stopping tamoxifen, but it is still a challenge. For those taking these drugs and those who just stopped I recommend a diet high in protein and with five to nine servings of fruit or vegetables per day. If you are able, do 30 minutes of aerobic exercise five times per week. Aerobic exercise includes activity in which you are winded but not short of breath such that you cannot keep up a conversation.

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