Weight gain helps predict breast-cancer recurrence

Two new studies of breast-cancer patients highlight the role that a woman's physical condition—including body weight—have on her chance of survival. Both were presented this week at the American Association for Cancer Research annual meeting in Orlando.

In the first, researchers at Kaiser Permanente in Northern California analyzed data from 18,336 women diagnosed with invasive breast cancer. Those who gained an "extreme" amount of weight—more than 22 pounds—within the four years following their diagnosis were 14 percent more likely to experience a cancer recurrence compared with women whose weight stayed within 5 pounds of their pre-diagnosis weight.

The risk was especially pronounced among women who'd been at a healthy weight (body-mass index of less than 25) prior to their diagnosis. They had not only an increased risk of recurrence but a 25 percent higher risk of dying from their cancer. Moderate weight gain—up to 22 pounds—didn't impact survival. Previous research has linked overweight or obesity at the time of diagnosis with poorer breast-cancer survival, but few studies have looked at the risks of weight gain after diagnosis, as this one did.

In the second study, researchers from the University of California San Diego pooled data on nearly 9,400 women with early-stage breast cancer. They found that those with the lowest physical-health scores—a combination of the patients' perceptions of physical functioning, pain, and limitations—at the time of diagnosis were 27 percent more likely to experience either a recurrence of their cancer or a new breast cancer over the next seven years, on average. And they had a 65 percent higher risk of dying from any cause compared with women who had better physical-health scores.

Women with low physical-health scores also tended to be less physically active and were more likely to be overweight and to have high blood pressure, diabetes, and sleep problems, though it's not clear whether those factors were a cause of poor physical health or a consequence. Either way, the researchers concluded that just a 5 percent improvement in a women's physical-health score could substantially reduce her risk of cancer recurrence and death.

Bottom line: While the studies aren't conclusive, they provide more reason for breast-cancer patients to stay active, maintain a healthy weight, adopt good sleep habits, and make other lifestyle changes.

Sources
Weight gain after a breast cancer diagnosis and breast cancer outcomes [American Association for Cancer Research]

Physical health scores predict breast cancer outcomes [American Association for Cancer Research]

—Jamie Hirsh