Because hormones increase the density of breast tissue, researchers have suspected that HRT use would make it more difficult to detect tumors on mammograms. As a result, it was suspected that tumors in patients who have received HRT might not be detected until they were larger and more advanced. However, of 144 study patients using HRT, 84 had their tumors detected by mammogram, while 60 were detected by other methods. Comparatively, of 148 non-HRT users, 63 had their tumors detected by mammogram, while 85 were detected by palpation (feeling for lumps).
Even more surprising, among the women whose tumors were detected by mammogram, HRT users had a 100 percent survival rate, while nonusers had only an 87 percent survival rate after six years. The study found significantly fewer cases of invasive tumors among HRT users, and higher incidences of T1 lesions, stage 1 tumors and node-negative tumors--all signs of a less aggressive disease.
"From this data it appears that HRT use had only beneficial effects on breast cancer detection and outcomes, with no visible negative effects," said Rodney F. Pommier, M.D., associate professor of surgery in the OHSU School of Medicine and principal investigator of the study.
Hormone replacement therapy has come under fire in recent months after several studies indicated that long-term use of combination hormone therapies can lead to slight increases in heart disease, stroke and breast cancer among patients.