Weight Change During Chemotherapy Worsens Breast Cancer Prognosis
Posted Dec 01 2010 10:11am
Numerous studies have made it clear that being overweight or obese is a major risk factor for breast cancer . It has also been reported that weight gain after developing breast cancer is linked to an increase in breast cancer recurrence and a decrease in breast cancer survival, though these results have been inconsistent to date. Unfortunately, many women gain weight during breast cancer therapy.
A new breast cancer research study ( free to download ) examined the effect of weight change (loss or gain) during anthracycline-based chemotherapy on disease-free and overall survival in 111 women diagnosed with early stage breast cancer or locally advanced breast cancer. For this study, change in body weight was assessed by calculating the difference between body weight before chemotherapy was started and after chemotherapy was completed. The breast cancer patients were categorized as (1) experiencing weight change (greater than 5% weight loss or weight gain) or (2) having a stable weight and were then followed for about 20 years on average. The breast cancer researchers reported that
69% breast cancer patients maintained a stable body weight, while 17% lost weight and 14% gained weight for a total of 31% that showed a weight change of more than 5%.
Breast cancer patients with a an initial healthy body weight (BMI less than 24) had substantially higher odds of overall survival and disease-free survival.
Breast cancer patients who experienced a more than 5% weight change had more than a 2-fold increased risk for breast cancer recurrence and death.
This is an interesting and important new breast cancer study. Not only does this study confirm that being overweight increases one's risk for breast cancer, but this study suggests that maintaining a stable body weight during anthracycline-based chemotherapy is an important goal for which breast cancer patients should strive. While previous studies have been inconsistent when looked at overall in regards to how weight change during chemotherapy effects breast cancer outcomes, many of these studies have been done in overweight women treated with different chemotherapy drugs. In this study, over half of the breast cancer patients were at a healthy body weight suggesting that weight change during chemotherapy, regardless of starting body weight, might worsen breast cancer outcomes.
It is unfortunate that weight change was looked at only as a whole rather than also looking at the women who gained weight and the women who lost weight as separate groups. Previous research has suggested that weight loss can reduce markers of breast cancer risk, while being overweight increases breast cancer recurrence and decreases survival. The breast cancer researchers indicated that there were not enough breast cancer patients in this new study to analyze these groups separately. The specific effect of weight loss or weight gain during chemotherapy on breast cancer outcomes is uncertain at this time, but, hopefully, future studies will provide a clearer answer.