Thyroid cancer risk increases with hysterectomy

Among postmenopausal women, the risk for thyroid cancer is increased with hysterectomy regardless of oophorectomy status, according to recently published data.

Use of exogenous estrogen was associated with lower risk for thyroid cancer in women who had undergone hysterectomy without oophorectomy, particularly for those with long duration use of hormone therapy, researchers wrote.

Juhua Luo, PhD, associate professor in the department of epidemiology and biostatistics at the School of Public Health, Indiana University Bloomington, and colleagues evaluated data from the Women’s Health Initiative on 127,566 women aged 50 to 79 years who were enrolled between 1993 and 1998 to determine the relationships between hysterectomy, bilateral salpingo-oophorectomy and thyroid cancer incidence. Follow-up was a mean 14.4 years.

At baseline, 36.7% of women had undergone hysterectomy, and 55% of them had bilateral salpingo-oophorectomy. Through follow-up, 344 participants developed thyroid cancer.

An increased risk for thyroid cancer was related to hysterectomy, regardless of ovarian status (HR = 1.46; 95% CI, 1.16-1.85). A similar increased risk for thyroid cancer was found in participants with hysterectomy alone and participants with hysterectomy plus bilateral salpingo-oophorectomy compared with participants without hysterectomy.

The risk for thyroid cancer was not associated with HT use in participants without hysterectomy and participants with hysterectomy plus bilateral salpingo-oophorectomy, but HT use in participants with hysterectomy alone was associated with a significantly lower risk for thyroid cancer (HR = 0.47; 95% CI, 0.28-0.78). This was especially pronounced in participants using HT for 10 or more years (HR = 0.24; 95% CI, 0.11-0.52).

Compared with participants without hysterectomy, participants with hysterectomy had an increased risk for thyroid cancer (HR = 1.78; 95% CI, 1.33-2.37).

“Our large prospective study observed that hysterectomy regardless of oophorectomy status was associated with increased risk of thyroid cancer among postmenopausal women,” the researchers wrote. “[HT] use was associated with lower or no risk of thyroid cancer. These findings did not support that exogenous estrogen is a risk factor and estrogen deprivation is a protective factor for thyroid cancer. Our study suggests that when deciding to remove the uterus for benign conditions, possible increased risk of thyroid cancer should be considered.” – by Amber Cox

Disclosure: The researchers report no relevant financial disclosures.