December 3, 2007 — A new study of mostly low-income women is linking poverty to excess body fat and a striking increased risk for breast cancer recurrence. The findings were reported in Atlanta, Georgia at the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved meeting by the American Association for Cancer Research.
"Poverty is an important marker for limited access to healthcare, late-stage disease, and worse outcomes, and the fact is that poor adults are more likely to be obese," lead author Dolly Quispe, MD, a hematology-oncology fellow at the Feist-Weiller Cancer Center in Shreveport, Louisiana, said in a news release. "The goal here is to determine whether there is a correlation of obesity and poverty with breast cancer recurrence and to quantify it."
The research team examined the medical records of 349 women diagnosed with breast cancer. The Feist-Weiller Cancer Center provides medical care to a significant portion of poor patients in Louisiana, a state with a 20% poverty rate.
In the sample, 45% of patients were black and the rest were white, making the study 1 of the largest with a high proportion of black breast cancer patients. A total of 25% of patients lived in counties with high poverty rates. In all, 20% received free healthcare and 25% were enrolled in Medicaid. "This is a snapshot of breast cancer incidence in people without insurance," Dr. Quispe said.
The researchers found that black patients were 62% more likely to have limited economic means, 88% more likely to be overweight and obese, and 46% more likely to be premenopausal.
Breast cancer recurred in 69 patients and, after adjustment for body weight, race, menopausal status, age at diagnosis, and cancer stage, body mass index (BMI) at diagnosis remained a statistically significant predictor of cancer recurrence.
A Patient With a BMI of 30 Had a 20% Greater Risk for Relapse
Dr. Quispe and her team found that a breast cancer patient with a BMI of 30 kg/m2 had a 20% greater risk for relapse than a patient with a BMI below 25 kg/m2. Not only was this risk evident in postmenopausal women, the group reports, the risk was present in premenopausal women too.
Asked by Medscape Oncology to comment on the work, Kala Visvanathan, MD, a medical oncology and cancer epidemiologist at the Johns Hopkins Breast Cancer Center, in Baltimore, Maryland, called this a very interesting and important study. "This is a vital group to look at and tends to be a difficult population to study," she noted.
Dr. Visvanathan said that these results are not surprising, but they are encouraging, considering obesity is a modifiable risk factor. "I suspect the low socioeconomic status accounted for the increased risk more than the fact that the patients were African American," she added.
"This is a good first step, and I encourage the authors to keep going," Dr. Visvanathan said. She would like to see additional prospective work to further this retrospective study.
Speaking to Medscape Oncology, Ruth O'Regan, MD, from Emory University's Winship Cancer Institute, in Atlanta, Georgia, said she agrees. "This study is consistent with the hypotheses of many and had a very long follow-up, but I would still consider this an initial study, and there is definitely more work to be done on the subject," she said.
Dr. O'Regan said she agrees that low socioeconomic status is linked to obesity and poorer outcomes for patients, but she suspects that biologic factors are also at play. "I consider it a weakness of the study that the authors did not account for the type of breast cancer patients developed," she said.
"African Americans, especially young black women, tend to develop more aggressive breast cancers, and often cancers with no available targeted therapies," Dr. O'Regan said. Previous studies examining the disparity between black and white patients have evaluated the role of deadly so-called triple-negative cancers.
"It's hard to say whether this is playing a role or not, but I would think the investigators would have access to tissues and could explore this question," Dr. O'Regan added.
The research team also noted a high rate of cancer relapse in younger patients. "Many studies have found that obesity in postmenopausal women is a risk factor for breast cancer development, but those few that correlate excess body weight and cancer in premenopausal women have been mixed," Amanda Sun, MD, PhD, the study's senior investigator and an oncologist at the Feist-Weiller Cancer Center, said in a news release.
"Given the high prevalence of obesity and overweight in our population of African Americans with low socioeconomic status," the researchers conclude, "prospective studies on intervention targeting diet and weight control could potentially improve outcomes in breast cancer."
Dr. O'Regan told Medscape Oncology that "the obesity epidemic is a critical problem, and it's something that we want to fix, regardless of its role in breast cancer. It's clear that diet plays an important role in overall health."
The study was funded by the Feist-Weiller Cancer Center at Louisian State University Health Sciences Center, in Shreveport, Louisiana.
The Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved: Abstract A-34. Presented November 28, 2007.
Medscape Medical News © 2007 Medscape
Cite this: Allison Gandey. Obesity Contributes to Increased Risk for Breast Cancer Relapse - Medscape - Dec 03, 2007.