BOSTON -- Among women receiving treatment for early-stage breast cancer, patients with disabilities had higher breast cancer mortality rates and were less likely than other women to receive standard treatment following breast-conserving surgery, according to a study in the Nov. 7 issue of the Annals of Internal Medicine.
Led by researchers at Beth Israel Deaconess Medical Center (BIDMC), the findings represent the first and largest population-based study to look at cancer treatment for patients with disabilities.
"Because clinical trials typically exclude this population, there is little scientific evidence available to guide doctors in their treatment decisions,"explains the study's lead author Ellen McCarthy, PhD, MPH, of the Division of General Medicine and Primary Care at BIDMC and Assistant Professor of Medicine at Harvard Medical School (HMS). "Consequently, very little is known about cancer treatments for individuals with disabilities."
There are two accepted therapeutic options for early stage breast cancer: mastectomy (removal of the entire breast) and breast-conserving surgery (removal of only the cancer) combined with axillary lymph node dissection and radiation therapy. (Axillary node dissection consists of removal of the lymph nodes to see whether they contain cancer. Radiation therapy consists of daily treatments for approximately six weeks following surgery.) In 1990, the National Institutes of Health (NIH) deemed both treatments equally effective with regard to survival and recurrence of cancer.
However, as the authors describe in their article, "Despite this, studies have repeatedly found that many women with traits that can suggest a social disadvantage – including older age, race or ethnicity, low socioeconomic status [income or education], rural residence and lack of health insurance – do not receive breast-conserving surgery."
Noting that women with disabilities who develop early-stage breast cancer are another "potentially vulnerable group," McCarthy and her coauthors set out to compare the likelihood of receiving initial treatment for early-stage breast cancer between women with and without disabilities, and their survival following diagnosis. They also examined the association between initial treatment and survival in the two groups of women.
Using data from the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Result) tumor registry combined with information from Medicare records, the researchers analyzed a study group consisting of 100,311 women aged 21 to 64 diagnosed with early stage breast cancer during the period between January 1988 and December 1999. Of this group, they determined that 2,800 women were disabled at the time of diagnosis. (Disability was determined based on records documenting the receipt of Social Security Disability Insurance [SSDI] benefits along with Medicare qualifications. Because the Social Security Administration does not release specific information to non-government investigators, the authors were unable to determine the underlying cause of disability.)
After adjusting for demographic and tumor characteristics, the researchers' final analysis found that the women with disabilities were 20 percent less likely to receive breast-conserving surgery compared with women without disabilities. Furthermore, the women with disabilities who did receive breast-conserving surgery were 19 percent less likely to receive lymph node dissection and 17 percent less likely to receive radiation therapy following their surgery – both considered part of the standard treatment protocol – than were the other women. The findings also showed that women with disabilities had a 29 percent higher risk of dying from their breast cancer but, says McCarthy, the differences in initial treatment did not explain the survival disadvantage among women with disabilities.
"The explanation for our findings is multi-factorial," explains senior author Lisa Iezzoni, MD, MSc, Professor of Medicine at HMS, who has studied health care issues as they apply to disabled individuals for more than 10 years and at the time of the study served as Co-Director of Research in BIDMC's Division of Primary Care and General Medicine.
"Among some women with disabilities, there may be a greater possibility for complications [arising from the treatment] due to their physical conditions [which could account for the higher mortality rate.] Their physicians may be less likely to offer them the less invasive option of breast-conserving surgery, assuming that physical appearance is not important to them [accounting for higher rates of mastectomy rather than breast-conserving surgery].
"And logistical issues could also be playing a role," she adds. "The women with disabilities may, for example, be unable to arrange for daily transportation to and from radiation therapy treatments, or, in the case of disabled patients with movement disorders, their conditions might make it physically difficult for them to undergo required radiation treatments."
Among these various findings, notes McCarthy, the lack of radiation therapy for the women with disabilities who underwent breast-conserving surgery is of particular concern.
"Our research shows that these women were not receiving standard post-surgical therapy including adjuvant radiation therapy," she says. "This means that they are at higher risk that their cancer will come back and they could potentially experience greater rates of cancer-related morbidity."
The authors recommend that future research focus on the potential reasons for these lower radiotherapy rates, including the extent to which the disparities reflect patients' preferences for treatment, patient-physician communication, inadequate access, and other barriers to care,such as transportation.
"Because this is such a large study, we hope it will serve as a starting point for understanding what is happening [among disabled populations] when it comes to cancer treatment," explains McCarthy. "These findings tell us that there are indeed differences in treatment decisions, but do not tell us the reasons for these differences."
Concludes Iezzoni, "We need to be vigilant when a woman with a disability has breast cancer. We need to better understand how she views her treatment choices given her physical, social and life context and we need to make sure that she has the best information available to make treatment decisions for herself."
In addition to McCarthy and Iezzoni, study coauthors include BIDMC researchers Reed Drews, MD, Long Ngo, PhD and Donglin Li, MD, MPH; and Richard Roetzheim, MD, MSPH, and Thomas Chirikos, PhD, of the H. Lee Moffitt Cancer Center, University of South Florida.
This study was supported by a grant from the National Cancer Institute.
Beth Israel Deaconess Medical Center is a patient care, research and teaching affiliate of Harvard Medical School and ranks third in National Institutes of Health funding among independent hospitals nationwide. BIDMC is clinically affiliated with the Joslin Diabetes Center and is a research partner of the Dana-Farber/Harvard Cancer Center. BIDMC is the official hospital of the Boston Red Sox. For more information, visit www.bidmc.harvard.edu.
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