Obese women more likely to have breast cancer at later stage: Study

American Society of Breast SurgeonsMay 3 2010

Obese women are more likely to have breast cancer detected at a later stage and to have lymph node metastases when diagnosed than women who are not obese, according to a study presented this week at the Annual Meeting of the American Society of Breast Surgeons.

“Obese women in our study had larger tumors than the non-obese women, but were less likely to find these cancers through a self breast exam. The majority were diagnosed through mammography, suggesting breast cancers may be more difficult to palpate in obese women. These results were significant”

"Obese women in our study had larger tumors than the non-obese women, but were less likely to find these cancers through a self breast exam. The majority were diagnosed through mammography, suggesting breast cancers may be more difficult to palpate in obese women. These results were significant," said lead researcher Danielle Haakinson, MD, Surgical Resident at the Mayo Clinic in Arizona.

The research also found obese women had a lower overall cancer survival rate, probably due to later stage disease at diagnosis. However, other illnesses associated with obesity may also affect survival.

This study underscores the importance of regular mammograms for obese women. "Without mammogram screening, breast cancer diagnosis may be delayed," Dr. Haakinson comments. "This information must be shared with both women and their primary care providers. Other studies have found that obese women are less likely to comply with regular breast cancer screening practices. This, combined with possible increased difficulties in finding a lump in large breasts, may contribute to the poorer breast cancer survival rate among obese women."

In the study, researchers compared 327 women classified as obese by accepted body mass index standards (BMI>30) with 1025 patients not considered obese who were treated for invasive breast cancer from 2000 to 2008 at the Mayo Clinic in Arizona. They found that 10 % fewer obese women were seen by doctors for evaluation of a mass found on a self breast exam than were non-obese patients.

"While a number of factors may come into play, another possibility is that obese women simply are less likely to examine their breasts thoroughly, possibly because they are uncomfortable with their body image," comments Dr. Haakinson.

Noting that other research has uncovered links between breast cancer and obesity, Dr. Haakinson says that her findings may result from a combination of factors. "Obese women already have increased breast cancer risk," she comments. "Now, this study shows they present with more advanced stages of breast cancer."

"Interestingly, we did not find an increase in tumor characteristics associated with poor survival in obese women. Therefore finding their cancers when smaller might boost their survival rate."

Experts agree that obesity is a significant, growing health risk and has been linked to numerous cancers. Dr. Haakinson says, "The message is clear—obese women must be particularly vigilant in pursuing breast cancer screening through annual mammograms and check ups. The good news is that these are relatively easy steps to take once a woman understands the positive impact on her health."