Menopausal hormone therapy treatment options and ovarian cancer risk: A Swedish prospective population-based matched-cohort study

Menée en Suède auprès de 288 950 femmes de plus de 40 ans ayant reçu un traitement hormonal substitutif entre 2005 et 2012, cette étude analyse l'association entre les divers types de THS (type de molécules, mode d'administration, etc.) et le risque de cancer de l'ovaire (572 cas)

International Journal of Cancer, sous presse, 2019, résumé

Résumé en anglais

Although menopausal hormone therapy (MHT) seemingly increases the risk of ovarian cancer, evidence is insufficient whether the risk varies between various MHT formulations, regimens and administration modes. With the aim of filling these knowledge gaps, we investigated the effect of different MHT treatment options on the risk of ovarian cancer. This prospective Swedish population-based matched-cohort study included all women ≥40 years having used systemic MHT between 2005 and 2012 (288,950 ever-users), group-level matched (1:3) to 866,546 nonusers. MHT use was ascertained from the Swedish Prescribed Drug Registry and data was linked to several national health data registries. Multivariable conditional logistic regression provided odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for parity, and comorbidities. Current EP-MHT use was associated with a modestly increased risk of ovarian cancer (OR = 1.38, 95% CI 1.18–1.62), while no consistent risk was found among past users (OR = 1.00, 95% CI 0.84–1.18). Current continuous testosterone derived (OR = 1.50, 95% CI 1.15–1.96) regimens increased the risk whereas progesterone derived (OR = 1.48, 95% CI 1.00–2.21) regimens increased the risk marginally. Nonsignificant positive associations were observed for sequential regimens (OR = 1.87, 95% CI 0.70–5.08; OR = 1.54, 95% CI 0.96–2.47, respectively). An inverse relationship was observed for all E-MHT use (OR = 0.25, 95% CI 0.22–0.29), but this association might partly be explained by underreporting of oophorectomies or tubal ligations. Current cutaneous EP-MHT (OR = 1.28, 95% CI 0.81–2.02) suggested a possibly lower risk than oral MHT (OR = 1.48, 95% CI 1.25–1.75). In conclusion EP-MHT, notably continuous regimens, were associated with a modestly increased risk of ovarian cancer. The role of E-MHT requires further clarification.