Weight Gain After Breast Cancer Deadly

Weight gain after a diagnosis of invasive breast cancer can be deadly.
For every 11 pounds gained, the risk of dying from breast cancer increases by 14%,
according to a new study.

"If women gained more than 22 pounds, they were 83% more likely to die
of breast cancer than those who gained or lost less than 5 pounds," says
Hazel B. Nichols, a doctoral student in epidemiology at Johns Hopkins Bloomberg
School of Public Health in Baltimore.

She led the study, presented at the American Association for Cancer
Research's Sixth Annual International Conference on Frontiers in Cancer
Prevention Research in Philadelphia.

At the same meeting, other researchers reported that women with breast
cancer who had high insulin levels, which tend to occur in heavier women, are
also at an increased risk of death.

Weight Gain-Death Risk Study

In the first study, Nichols and her colleagues evaluated nearly 4,000 women
who had been diagnosed with invasive breast cancer in the years 1988 to
2001.

They asked the women to report their weight, weight gain, physical activity,
diet, medication history, and quality of life, following them
up for more than six years.

During the follow-up, 121 women died of breast cancer and 421 died from all
causes, including breast cancer.

When the researchers looked at weight status and death, the risk of breast
cancer death was more than twice as high among those women who were obese after
the diagnosis (who may or may not have been obese before) compared with those
who were normal weight during the follow-up, Nichols found.

Obesity is defined as having a
body mass index or BMI of 30
or above. A 5-foot-4 woman who weighs 175 has a BMI of 30.

"We do see a trend, in general, that there is increased risk of breast
cancer mortality with increasing body mass index," Nichols tells
WebMD. 

Being overweight but not obese was not as risky, Nichols says. Overweight
women with a BMI of 25 to 29.9, she found, were 1.3 times more likely to die
from their breast cancer, an increased risk that could have been due to chance
in the study.

The study did have an important limitation, Nichols tells WebMD. "We did
not have extensive information on other medical conditions in later age,"
she says. "The extremes in risk may be related to other medical conditions
that affect your risk of dying."

Insulin-Breast Cancer Death Link

In a second study, women with invasive breast cancer and high blood levels
of C-peptide, a marker of insulin secretion, were more likely to die than women
with lower C-peptide levels, according to Melinda Irwin, PhD, MPH, an assistant
professor at the Yale University School of Public Health in New Haven,
Conn.

"Women who are heavier tend to have higher C-peptide or higher insulin
levels," she tells WebMD.

Her team followed 689 women enrolled in a National Cancer Institute
initiative study known as the HEAL (Health, Eating, Activity and Lifestyle)
study. All had breast cancer, but not type 2 diabetes . They were all
postmenopausal, either naturally or due to chemotherapy.

Irwin's team monitored health status periodically, from six months after the
diagnosis until 2004 or until the patient's death, taking blood samples to
measure their C-peptide levels.

The younger the women were, the more dramatic the risk of death linked with
high C-peptide, she says. Women with high C-peptide levels who were ages 40 to
55 when they provided the blood samples had a nearly five times increased risk
of breast cancer death compared with the same ages of women who had lower
C-peptide levels.

Perspective on Weight Gain and Breast Cancer

The new findings echo previous research that has found a link not only
between excess weight and death in breast cancer patients but also excess
weight and breast cancer recurrence.

Excess weight can also inrease risk of getting breast cancer, other
research has found, at least for postmenopausal women. "In the
postmenopausal period, adipose tissue is the primary source of estrogen,"
Nichols says. "So the greater BMI in postmenopausal women may increase
exposure to circulating estrogen [thus "feeding" the cancer]."

The message is clear, Irwin says. Paying attention to diet and exercise and
trying to maintain a healthy weight is crucial.

By Kathleen Doheny
Reviewed by Louise Chang
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