Hormone replacement therapy and risk of lymphomas and myelomas.

The relation between post-menopausal hormone replacement therapy (HRT) and lymphoid neoplasms was analysed using data from a case-control study conducted in northern Italy between 1983 and 1992. Cases included 26 incident, histologically confirmed, post-menopausal female patients of Hodgkin's Disease (HD), 145 non-Hodgkin's lymphomas (NHL) and 65 multiple myelomas (MM), between 45 and 79 years of age. The control group comprised 361 women (age range 45-79 years) admitted to the same network of hospitals for acute, non-neoplastic conditions. The multivariate odds ratio (OR) for ever HRT users was 0.7 [95% confidence interval (CI) 0.2-2.8] for HD, 0.7 (95% CI 0.3-1.4) for NHL, and 0.2 (95% CI 0.1-1.0) for MM. No clear pattern of association was found for duration or recently of use. Despite the relatively small number of cases, due to the rarity of the disease, and the low frequency of HRT use in this population, these findings provide additional information for any global risk-benefit assessment of HRT use.