[Replacement therapy in menopause and risk for breast tumors]

The relationship between hormone replacement therapy (HRT) and breast cancer risk was analysed in a case-control study, conducted in the period 1991-1994 in six Italian areas, on 2569 patients with breast cancer and 2588 controls. Ever HRT use was reported by 7.5% of cases and controls (OR = 1.2; 95% CI: 0.9-1.5). The risk increased with increasing duration of use. There was no clear pattern of risk with reference to time since starting use, but the OR was significantly elevated for women who had stopped HRT within the last 10 years; the result was consistent across strata of identified covariates, and was significantly related to duration of use. This study confirms the absence of a strong association between HRT and breast cancer risk, although the risk estimate was above unity for women who had used HRT for 5 years or longer. However, the risk was significantly elevated in the short to medium term after use, particularly for long-term use.