Rodney Pommier, M.D., and colleagues looked at the records of 292 postmenopausal patients with breast cancer to determine whether taking hormone replacement therapy was associated with the detection of breast cancer with use of palpation or mammography or with clinical outcome.

According to background information in the article, previous studies have indicated that therapy can increase the risk for development of breast cancer. Because replacement therapy increases the density of mammary tissue, some researchers believe that breast cancers may be harder to detect in patients taking hormone therapy; thus, the disease may be in more advanced stages when detected. The team hypothesized that is this relation were valid, the tumors of patients taking hormone replacement therapy would be more likely to be detected though palpation.

The researchers performed a retrospective study of the records of 292 postmenopausal patients diagnosed with breast cancer between March 1994 and January 2002. Of the total, 144 women were receiving replacement therapy at time of diagnosis and 148 women had not received such therapy. The average patient age was 66 years, and there was no significant difference in age at diagnosis between the two groups.

The researchers found that 84 cases of cancer among the women who used replacement therapy were detected by mammography, with 60 detected by palpation. Among non-users of hormone replacement therapy, 63 cases were detected by mammography with 85 detected by palpation.

Among replacement therapy users, 23 patients were diagnosed with ductal carcinoma in situ; among the nonusers, 14 women were diagnosed with ductal carcinoma in situ.

There was no significant difference between groups in tumor size, number of positive nodes, or incidence of stage IV tumors. The six-year survival rate for patients with mammographically detected tumors was 94 percent compared with 78 percent for patients whose tumors were detected by palpation.

"In this study, hormone replacement therapy had only beneficial and no discernable harmful effects on breast cancer detection or outcome. Fears of decreased mammographic detection of breast cancer in patients who received [hormone replacement therapy] prior to diagnosis were not substantiated in this study. In addition, concern that hormone replacement therapy induces aggressive tumor progression was refuted by improved survival rates. It is plausible that the beneficial effects of hormone replacement therapy on breast cancer could outweigh its reported risk of a slight increase in the incidence of the disease," write the authors.