Thyroid cancer risk in women after hysterectomy: A nationwide cohort study.

ABSTRACT

OBJECTIVES: Hysterectomy is commonly performed for benign uterine pathologies but there is some controversy over whether it is associated with an increased risk of thyroid cancer. This study examines the associations of hysterectomy with ovarian conservation or with bilateral salpingo-oophorectomy and thyroid cancer incidence in Taiwan. METHODS: We analyzed data from a nationwide health insurance claims database and identified 29,577 women aged ≥30 years who underwent hysterectomy with ovarian conservation or hysterectomy with bilateral salpingo-oophorectomy between 2000 and 2016. Propensity score-matching analyses were performed at ratios of 11 for the hysterectomy and no-hysterectomy groups, to reduce selection bias. We monitored thyroid cancer occurrence in both groups until 2017. Cox regression was used to calculate hazard ratios with 95 % confidence intervals and determine thyroid cancer risk in women who underwent hysterectomy. RESULTS: The study comprised 29,577 patients who underwent any hysterectomy and 29,577 participants who did not. The mean follow-up period was 10.03 ± 4.92 years. Patients who underwent hysterectomy had higher thyroid cancer incidence (4.72 per 10,000 person-years) than those who did not (3.06 per 10,000 person-years) and a greater risk of any thyroid cancer (adjusted hazard ratio = 1.40; 95 % confidence interval = 1.08-1.82). However, there was no association between hysterectomy with bilateral salpingo-oophorectomy and thyroid cancer incidence (p > 0.05). CONCLUSIONS: Our findings suggest that women who undergo hysterectomy are at a higher risk of developing thyroid cancer than those who do not.