Radiation therapy after lumpectomy and five years of treatment with the drug tamoxifen can dramatically reduce the risk of both cancer recurrence and new tumors in older women with early breast cancer, according to researchers from Wake Forest University School of Medicine and colleagues.
"While these treatments are standard care for younger patients, it is has been shown that older women are less likely to receive them," said lead author Ann M. Geiger, M.P.H., Ph.D., an associate professor of public health sciences at Wake Forest and formerly of Kaiser Permanente Southern California. "Our results provide strong evidence of the importance of providing high quality care to all patients, regardless of age."
The results, reported on-line today in Cancer, a journal of the American Cancer Society, will be published in the March 1 print issue of the journal.
Geiger said there is a pressing need for information about the effectiveness of breast cancer treatments in women over 65 because this is an expanding segment of the U.S. population. Women in this age group are at the highest risk for breast cancer and make up half of those diagnosed, but only recently have been included in treatment trials.
"Based on our findings, we recommend that mastectomy, or lumpectomy with radiation therapy, along with adequate duration of hormone therapy for women with hormone-responsive tumors, be considered standard therapy in women of all ages and health conditions, except for those with very limited life expectancies," said Geiger.
The study also included women undergoing chemotherapy, but the number of participants wasn't large enough to evaluate the treatment's effectiveness.
The study involved 1,837 women age 65 or older with early stage breast cancer that was confined to the breast or lymph nodes. The women underwent either mastectomy or lumpectomy, also known as breast-conserving surgery, from 1990 to 1994. Treatment was at one of six health systems (in Washington, Massachusetts, Minnesota, California, and New Mexico) that were part of the Cancer Research Network funded by the National Cancer Institute.
Participants were identified from medical records and were followed for 10 years. Researchers recorded all cancer recurrences: "local" recurrences in the same breast, "regional" recurrences in the lymph nodes, skin or chest muscle on the same side as the original diagnosis, and "distant" recurrences in the brain or other areas of the body. They also recorded cases of new breast tumors, not related to the original tumor, in the opposite breast -- known as a second primary breast cancer.
Twenty percent of women treated with mastectomy or lumpectomy experienced a recurrence or second primary breast cancer during the follow-up. Women treated with lumpectomy but no radiation therapy had a risk of local or regional recurrence that was 3.5 times higher than women radiation therapy after their surgery. The increased risk of any recurrence or second primary breast cancer was 60 percent higher.
The study also revealed that for women who took tamoxifen, but not chemotherapy, those who took the drug for less than a year had a 90 percent higher risk of a recurrence than women who took the drug for five years. Tamoxifen, a drug that blocks the effects of estrogen on the body, is often used to treat women whose tumors are sensitive to estrogen.
One-third of the study participants were 65-69 years old, half were 70-79 and 20 percent were 80 and older. About 80 percent of the women were white, 10 percent were black and 10 percent were Hispanic, Asian or Pacific Islanders.
Co-researchers were Soe Soe Thwin, M.S., Timothy L. Lash, D.Sc., and Marianne Prout, M.D., all with Boston University School of Public Health; Diana S.M. Buist, Group Health Center for Health Studies in Seattle, Wash.; Feifei Wei, Ph.D., HealthPartners Research Foundation in Minneapolis, Minn.; Terry S. Field, D.Sc., Meyers Primary Care Institute/Fallon Community Health Plan; Marianne Ulcickas Yood, Henry Ford Health System; Floyd J. Frost, Ph.D., Lovelace Health Systems, Albuquerque, N.M.; and Shelley M. Enger, Ph.D., Kaiser Permanente Southern California. Rebecca A. Silliman, M.D., Ph.D., of Boston University Medical Center was the lead investigator for the larger study of which this was one piece.
Materials provided by Wake Forest University Baptist Medical Center. Note: Content may be edited for style and length.
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