By Donna Feldman, MS, RD

It’s hard enough for a woman to deal with breast cancer. Unfortunately, the treatment may add insult to injury for some women: certain regimens for certain women can lead to weight gain. As if the physical and emotional toll of surgery, radiation, chemotherapy and losing one’s hair wasn’t enough, many patients have to deal with unwelcome extra pounds. Fortunately, recent research indicates this weight gain may not be inevitable. Certainly the possibility of weight gain shouldn’t deter anyone from getting appropriate treatment.

Not all patients are affected
Not all breast cancer patients gain weight. Studies indicate that, in general, the patients who are most affected are premenopausal women who receive chemotherapy as part of their treatment. Postmenopausal women, and those who receive only radiation treatment are less likely to gain. Of course, some women lose weight, or have no weight change. The big question is: does chemotherapy treatment somehow set women up for weight gain, or is some other factor causing it? Research hints at some answers.

Is chemo to blame?
Does chemotherapy somehow alter metabolism, causing weight gain? Many studies have looked at this possibility. In one from Duke University, premenopausal breast cancer patients on chemotherapy were compared to a similar group not on chemo. Over a year, the chemo patients gained twice as much weight. And, unlike typical weight gain, this was mostly just fat. Another study followed breast cancer patients for 10 years after diagnosis, and found that women under age 55 tended to gain weight compared to older women, and gained at a faster rate than non-cancer patients.

Lifestyle factors
All these studies looked not just at chemotherapy, but also at lifestyle factors that impact weight, including diet and exercise. One universal finding is that breast cancer patients who gain weight report much less physical activity than those who do not gain. In other words, exercise has a profound impact on this type of weight gain. It’s easy to imagine how this would happen. The exhaustion and anxiety of treatment regimens is so disruptive that regular exercise routines are thrown off. You may just be too tired to think about jogging or biking or even walking. Even if you didn’t have a regular exercise routine before diagnosis, you might spend more time resting during cancer treatment. The result: fewer calories burned. If you don’t reduce your food intake accordingly, you are likely to gain weight.

An unfortunate cause for some patients might be overeating due to depression. Some anti-depressants can themselves lead to overeating, and breast cancer patients may be given these medications to help them deal with their situation. Or untreated depression could lead some breast cancer patients to overeat, and gain weight.

Why premenopausal women?
There is no good answer to why premenopausal breast cancer patients are more likely to gain weight, but there is speculation. One theory is that the treatment actually creates premature menopause. And as any woman of a certain age knows, menopause slows metabolism. Many women gain weight gradually throughout normal menopause, which may take several years. Breast cancer treatment speeds up the effect, and you might end up with the metabolism of a person 10 or more years older. If you continue eating as usual, you set yourself up for weight gain.

Conclusion--Have a plan
If you are facing breast cancer treatment that includes chemotherapy, discuss your weight concerns with your health care team. This discussion is especially important if you are taking anti-depressants, or suspect your diagnosis is leading to serious depression.

To combat weight gain, you will need to keep up physical activity as much as reasonably possible. You might find that certain rigorous activities, like running, are more difficult. If that’s the case, don’t simply give up. Walking or other activities that are easier to do, or fit your schedule better, should be considered at least temporarily. Make your diet as healthy as possible, emphasizing low fat/high fiber foods. But leave room for foods you enjoy. Cancer treatment is bad enough without missing foods you enjoy.