PURPOSE

To assess the associations between ovarian cancer and depot medroxyprogesterone acetate (DMPA), intrauterine contraceptive devices (IUDs), and partner vasectomy.

METHODS

We undertook a New Zealand-wide population-based case-control study. During 2013-2015, 205 eligible cases were identified from the cancer registry (152 [74%] participated) and 1,735 eligible controls were randomly selected from the electoral roll (837 [48%] participated). A postal questionnaire was used to gather information.

RESULTS

Ever-use of vasectomy was inversely associated with ovarian cancer in age-adjusted analysis, but not in multivariable analysis (OR = 0.67, 95% CI = 0.46-0.96, and OR = 0.82; 95% CI = 0.54-1.23, respectively). A suggestive trend towards lower risk with longer duration of reliance on partner vasectomy was observed (P-trend = 0.08). Ever-use and duration of use of DMPA were not associated with ovarian cancer. Although ever-use of IUDs was not associated with ovarian cancer, duration of use of IUDs was associated with higher risk (P-trend = 0.04). There were also statistically significant inverse associations between ovarian cancer and use of oral contraceptives, parity, and breastfeeding.

CONCLUSIONS

Prolonged use of IUDs may increase the risk of ovarian cancer. It is also possible that an inverse association exists between ovarian cancer and partner vasectomy.