Bias in Treating Older Breast Cancer Patients
According to a report just released by the U.S. Agency for Healthcare Research Quality, and simultaneously published in the journal Cancer, elderly women with early-stage breast cancer are not being offered the same range of treatment options as their younger counterparts.
Dr. Jeanne Mandelblatt of the Georgetown University School of Medicine and colleagues studied 718 women aged 67 or older who were being treated at 29 hospitals across the country for newly diagnosed, localized breast cancer.
They found that the oldest women, those aged 80 and older, were significantly less likely than women 67 to 79 years old to be referred to a radiation oncologist. They noted that women sent to a radiation oncologist were 20 times more likely to have breast-conservation therapy rather than other treatments.
Of those who did receive breast-conservation therapy, very elderly women were 70 percent less likely to receive chemotherapy than younger patients, and they were 3.4 times less likely to receive radiation therapy. The researchers suggested that part of the reason for this discrepancy in treatment is that "there remains substantial scientific uncertainty as to the most appropriate treatment for older women."
This is unfortunate, however, because a recent report published in the Journal of the National Cancer Institute found that elderly women with early breast cancer have survival rates similar to women in the general population, partly because tumor growth in older patients is slower than in younger patients.
Dr. Sami Diab of Rocky Mountain Cancer Centers in Aurora, Colorado and colleagues reviewed the records of more than 300,000 breast cancer patients in the Surveillance, Epidemiology and End Results (SEER) registry and the San Antonio Breast Cancer database. They wrote that tumors appear to become less aggressive as a woman gets older. It therefore makes a difference, they said, whether the patient is 50 or 60 or 80 years old.
The researchers found that when breast cancer in elderly patients is detected early, when tumor size is less than 2 cm, and the lymph nodes are not involved, their survival rate is similar to that of women in the general population. This should encourage physicians to treat their older patients as consistently and with as many treatment options as they do their younger ones, Diab said. He further suggested that treatments could also be better tailored to older patients because their tumors are less aggressive.
According to another report published in the journal Cancer, women between the ages of 60 and 69 who are diagnosed with breast cancer have a higher rate of disease-free survival and a lower rate of local recurrence than younger women. Dr. Jonathan Golledge from Charing Cross Hospital in London evaluated 784 breast cancer patients and also found that the treatments being offered to them differed significantly depending on their age.
Golledge wrote that younger women were nearly twice as likely as older women to experience local relapse. Among women aged 60 and older, the recurrence rate at 3 years was 2.4 percent, versus 8.5 percent in younger women. He also noted that women 70 years or older experienced better 3-year disease-free survival when treated with standard therapy (72 percent) than when treated with tamoxifen alone (58 percent).
And yet, women over age 60 whose cancer had not spread to their lymph nodes were less likely to receive standard chemotherapy (1 percent) or radiation therapy (45 percent) than were younger women (18 percent and 68 percent, respectively). On the other hand, older women were more likely to receive tamoxifen (94 percent, versus 73 percent for younger women).
Late last year a highly controversial article was published in the Journal of the American Medical Association which suggested that mammography screening offered little life-extending benefit for women older than 69 years of age.
Dr. Karla Kerlikowske of the University of California at San Francisco and colleagues analyzed the value of continuing mammography for elderly women by looking at breast cancer deaths averted, life expectancy, and incremental cost-effectiveness.
The researchers compared three screening strategies:
Bone mineral density can be a predictor of breast cancer in older women. It serves as a marker of lifetime exposure to estrogen, which has been strongly linked to breast cancer risk.
Compared to the first strategy, the second strategy of continued mammography screening to age 79 based on high bone mineral density would only prevent 9.4 more deaths per 10,000 women screened, they calculated. The third strategy-continuing biennial mammography through age 79-would spare only an additional 1.4 deaths per 10,000 women screened.
The authors wrote that "routine screening mammography is cost-effective for women aged 50 to 69 years since breast cancer is the leading cause of death in these women, even among a screened population." However, they suggested that "in contrast, among elderly women, cardiovascular disease is the leading cause of death, with more women dying of other causes after detection of breast cancer whether or not they undergo screening mammography."
They recommended that physicians decide on a case-by-case basis whether screening mammography would be beneficial for an older patient, paying particular attention to factor's such as a woman's bone mineral density, her comfort level with the procedure, and her personal views on preventive care.
The authors noted that many women older than 65 years of age already undergo bone mineral density measurements to assess their risk for fractures, and these measurements could be used to help make decisions about whether to continue mammography screening. Women with high bone mineral density levels are at increased risk for breast cancer and therefore would be better candidates for regular mammography screening, they said.
Given such conflicting results, it is no wonder that older women diagnosed with breast cancer are confused about the best course of treatment for their disease. And unfortunately, older patients are still not sufficiently enrolled in clinical trials for cancer drugs, thus providing little hope for definitive answers in the coming years.
A study published in the New England Journal of Medicine looked at how many patients 65 years of age and older were involved in 164 Southwest Oncology Group (SWOG) cancer treatment trials between 1993 and 1996. Dr. Laura Hutchins of the University of Arkansas for Medical Sciences in Little Rock and colleagues analyzed treatment trials for 15 types of cancer and found that older patients are "substantially underrepresented."
"Patients who were 65 years of age or older accounted for 25 percent of patients in SWOG trials, as compared with 63 percent in the U.S. population of patients with cancer," they wrote.
They added that the underenrollment of older patients was "particularly striking" for breast cancer studies. In those trials, only 9 percent of participants were 65 years of age or older, versus 49 percent of patients in the general population with breast cancer.
Hutchins echoed what many other researchers have also concluded: Far too many doctors-and even patients themselves-assume that older patients would not be able to tolerate or benefit from many of the most promising treatments under study.
However, given that the number of people over the age of 65 is expected to double in the coming decades, such assumptions could be disastrous.
SOURCES:
Cancer, August 1, 2000; 89: 561-573
Journal of the National Cancer Institute, April 5, 2000; 92: 550-556
Journal of the American Medical Association, Dec. 8, 1999; 282: 2156-2163
"Health, United States: 2000," National Center for Health Statistics, U.S. Centers for Disease Control and Prevention
Cancer, January 15, 2000; 88: 369-374
Cancer, May 1, 2000; 88: 2054-2060
New England Journal of Medicine, December 30, 1999; 341: 2061-2067
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