Women 60 years and older who received no systemic adjuvant therapy for early-stage breast tumors were at no greater mortality risk than similarly aged women in the general population, a recent study demonstrated.

With indications for adjuvant endocrine treatment of breast cancer gradually increasing over the past several years, Peer Christiansen, MD, of Aarhus University Hospital in Aarhus, Denmark, and colleagues sought to define subgroups of patients who may or may not benefit from this therapy. They undertook a population-based cohort study of 3,197 women who had not been given adjuvant hormone therapy or chemotherapy. The patients were node-negative and had estrogen receptor-positive and/or progesterone receptor-positive tumors (except medullary tumors). All women were aged 35 to 74 years at the time of surgery, and had tumors no larger than 20 mm. They were categorized as having grade 1 ductal carcinoma, grade 1 or 2 invasive lobular carcinoma, or other or unknown histopathology.

During a median follow-up of 14.8 years postoperatively, mortality rates were 2,356 per 100,000 person-years in the study group, compared with 1,790 per 100,000 person-years in the general population of women. As the researchers reported in Journal of the National Cancer Institute, the excess mortality rate was highest for patients aged 35 to 39 years and lowest for those aged 60 to 64 years. Mortality was also higher for the women with tumors larger than 10 mm.

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But the study also identified a group of low-risk patients 60 years or older with mortality rates comparable to that of the general population. Women in this subset had hormone-responsive tumors of 10 mm or less and low-grade disease (grade 1 ductal carcinoma, or grade 1 or 2 invasive lobular carcinoma). These findings indicate that such patients might not benefit from adjuvant endocrine therapy.