By Anthony J. Brown, MD
NEW YORK (Reuters Health) – The risk of developing breast cancer, particularly the lobular subtype, is elevated with "recent long-term" use of hormone replacement therapy (HRT), according to a report published in the February 13th issue of the Journal of the American Medical Association.
Dr. Emily White, from the Fred Hutchinson Cancer Research Center in Seattle, and colleagues compared the HRT histories of 705 postmenopausal women with breast cancer to those of 692 age-matched controls. The investigators evaluated the use of two types of HRT, estrogen alone and estrogen plus progestin, and focused on recent long-term use, defined as use for 5 years in the 6 years prior to diagnosis.
"We found that recent long-term use of HRT increased breast cancer risk by 70% for all types of breast cancer," Dr. White told Reuters Health. "The evidence is now quite strong that both types of HRT increase the risk of breast cancer," she added.
"The risk of nonlobular cancers was increased by 50% with HRT use," Dr. White noted. In contrast, "recent long-term [HRT] use was tied a threefold increased risk of lobular tumors, while current use was linked to a fourfold increased risk."
Dr. White noted that "this study had several strengths in terms of fewer biases than previous" studies. "We didn't rely on recall of HRT use by the women, instead we used computerized pharmacy records," she noted. "In addition, because all of the women originally selected for the study participated, there was no non-response bias."
"At this point, we really need to reevaluate the risks and benefits of HRT," Dr. White said. "The alleged benefits of HRT are becoming weaker, while the risks are becoming stronger," she added. Results from the Women's Health Initiative, a major randomized trial of HRT, should be available in a few years, she said