Latest Hormone Studies

Hormone Replacement Therapy in Relation to Breast Cancer

Increased by 60% to 85% in recent long-term users of HRT
(Source: JAMA, Feb 13th, 2002)

Studies of long-term hormone replacement therapy (HRT) suggest an associated increased risk of breast cancer, but whether this association differs according to histologic type of cancer has not been extensively studied.

Results: The incidence of breast cancer, all histologic types combined, was increased by 60% to 85% in recent long-term users of HRT, whether estrogen alone or estrogen plus progestin. Longer use of HRT (odds ratio [OR], 3.07 for 57 months or more; 95% confidence interval [CI], 1.55-6.06) and current use of combination therapy (OR, 3.91; 95% CI, 2.05-7.44) were associated with increased risk of lobular breast cancer. Long-term HRT use was associated with a 50% increase in nonlobular cancer (OR, 1.52 for 57 months or more; 95% CI, 1.01-2.29).

Conclusion: Our data adds to the growing body of evidence that recent long-term use of HRT is associated with an increased risk of breast cancer and that such use may be related particularly to lobular tumors.

Sources: Chi-Ling Chen, PhD; Noel S. Weiss, MD, DrPH; Polly Newcomb, PhD; William Barlow, PhD; Emily White, PhD

Funding/Support of this Study: This work was supported in part by Breast Cancer Surveillance Cooperative Agreement UO1CA63731 from the National Cancer Institute.

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