May 18 (HealthDay News) -- In another sign of the challenges facing the health-care industry as it tries to serve the poor, researchers from North Carolina are reporting that nearly four in 10 poor women recovering from breast cancer do not take the drugs recommended to keep their cancer from returning.
Those who do not follow instructions to take these drugs, medications that block hormones, face a higher risk of dying, said study author Dr. Gretchen Kimmick.
The findings don't examine whether wealthier women are more likely to take the drugs, nor do they reveal trends over time.
Even so, they raise questions about poor women's lack of adherence to the drug regimens, including whether it's due to factors other than money because government-funded insurance would cover almost all the cost.
"The key right now is that we've got to figure out why they didn't get the standard treatment," said Kimmick, an associate professor in medical oncology at Duke University.
The study included 1,491 low-income women, who averaged 67 years old and were recovering from breast cancer, which had been diagnosed between 1998 and 2002.
The researchers found that 36 percent of the women failed to fill prescriptions for the recommended drugs to prevent the return of a type of breast cancer known as hormone receptor-positive. Women in the study had that type or an unknown type of breast cancer; two-thirds had undergone mastectomies.
Of those who did fill initial prescriptions, 40 percent stopped the drugs before the end of the year-long period.
The study, funded by the U.S. National Cancer Institute and the drug company AstraZeneca, appears in the May 18 online issue of the Journal of Clinical Oncology.
Drugs such as the well-known medication tamoxifen, which AstraZeneca markets, are thought to help prevent the recurrence of breast cancer. Kimmick said that they seem to kill cancer cells by blocking estrogen from getting to them.
Treatments such as radiation and chemotherapy don't always kill cells that "snuck out," and the drugs appear to target them, she said.
But some women might have trouble getting into the routine of taking the drugs, she said. Side effects are also possible.
Cost could be a factor in some cases, but the women in the study paid only a "minimal" co-payment for the drugs, Kimmick said.
There are other possible explanations. Dr. Leonidas G. Koniaris, a surgical oncologist who's familiar with the study's findings, said that some women might not realize the value of the drugs.
It's also possible that people from certain cultures could have more mistrust of doctors and medical treatments, said Koniaris, chairman of surgical oncology and an associate professor of surgery at the University of Miami.
Ultimately, he said, women's survival is at risk if they don't follow instructions. Though the drugs won't make a difference to women whose breast cancer was cured by initial treatment, he said, "for one in 10 or one in 20, their chance for cure and long-term survival is shortened by not taking the medications."
SOURCES: Gretchen Kimmick, M.D., associate professor, medical oncology, Duke University, Durham, N.C.; Leonidas G. Koniaris, M.D., associate professor and Alan Livingstone chair in surgical oncology, University of Miami; May 18, 2009, Journal of Clinical Oncology, online