BOSTON – Obesity increases the odds of a woman with breast cancer dying from her disease, according to a retrospective data analysis.
Further, this link between obesity and breast cancer death is strongest among those obese women who have estrogen receptor (ER)–positive cancer, according to the analysis of data on nearly 4,000 participants in the California Teachers Study.
“This is another reason why the public should be aware of the importance of maintaining a healthy body weight, particularly how it pertains to cancer and especially breast cancer,” according to Christina M. Dieli-Conwright, Ph.D., an assistant research professor at City of Hope National Medical Center, Duarte, Calif., who presented the findings at the meeting.
The study looked at a cohort of women who had taken a self-administered baseline questionnaire in 1995-1996 and who were diagnosed with their first primary invasive breast cancer during 1995-2006. Of the 3,995 women studied through 2007, 262 died of breast cancer and 321 died of nonbreast cancer causes.
There was a significant link between breast cancer mortality and body mass index. Women who were obese (BMI of at least 30 kg/m
When the data were stratified according to ER status, weight and breast cancer mortality were significantly related in women who were ER positive, but not in ER-negative women. Obese women who were ER positive had a 64% increased risk of death due to breast cancer compared with those who had a BMI of less than 25. No significant associations were seen between weight and death due to all causes according to ER receptor status. Interestingly, there was more than a threefold increase in death from breast cancer in women who were ER negative if they were overweight at age 18 years.
Dr. Dieli-Conwright reported having no conflicts of interest.