Hysterectomy, oophorectomy and risk of non-Hodgkin's lymphoma.

Hysterectomy is associated with an increased risk for adverse health outcomes. However, its connection to the risk of non-Hodgkin's lymphoma (NHL) remains unclear. The aims of our study were to investigate the associations between hysterectomy, oophorectomy and risk of NHL and its major subtypes (eg, diffuse large B-cell lymphoma [DLBCL]), and whether these associations were modified by exogenous hormone use. Postmenopausal women (n = 141,621) aged 50-79 years at enrollment (1993-1998) from the Women's Health Initiative were followed for an average of 17.2 years. Hysterectomy and oophorectomy were self-reported at baseline. Incident NHL cases were confirmed by central review of medical records and pathology reports. During the follow-up period, a total of 1719 women were diagnosed with NHL. Hysterectomy, regardless of oophorectomy status, was associated with an increased risk of NHL (hazard ratio [HR] = 1.23, 95% confidence interval [CI]: 1.05-1.44). Oophorectomy was not independently associated with NHL risk after adjusting for hysterectomy. When stratified by hormone use, the association between hysterectomy and NHL risk was confined to women who had never used hormone therapy (HR = 1.35, 95% CI: 1.06-1.71), especially for DLBCL subtype (P for interaction = .01), and to those who had undergone hysterectomy before the age of 55. Our large prospective study showed that hysterectomy was a risk factor of NHL. Findings varied by hormone use. Future studies incorporating detailed information on the types and indications of hysterectomy may deepen our understanding of the mechanisms underlying DLBCL development and its potential interactions with hormone use.