The Prevalence of Malignant Tumours among Women with a History of Hyperthyroidism: St. Petersburg Case-Control Study

Abstract

Objective: Thyroid diseases are the most common endocrine disorders. The association between thyroid disease and cancer risk remains unclear. Some epidemiological studies have demonstrated an increased risk of cancer in women with history of the hyperthyroidism.

Aim: To assess cancer incidence and to calculate the relative risk (RR) of malignant tumors in patients with history of hyperthyroidism.

Materials and Methods: A randomized, retrospective, case-control study was conducted among women with history of Graves’ disease and nodular toxic goiter in 1999–2009. inclusive. the study consisted of 1362 patients with history of hyperthyroidism, a comparison group is used consisting of 1144 patients with eu- and hyperthyroidism. Cancer incidence is estimated for March 31, 2018.

Results: The relative risk of cancer in women with history of hyperthyroidism was 2.36 (95% CI 1.63-3.42, χ2 = 22.16, p <0.01), the relative risk of hormone-dependent tumors amounted to 2.65 (95% CI 1.7–4.13, χ2 = 20.59, p <0.01). The relative risk of colorectal cancer and ovarian cancer was increased: RR = 3.53 (95% CI 1.34–9.32, χ2 = 7.4, p <0.01) and RR = 3.27 (95% CI 1.388–6.76, χ2 = 11.49, p <0.01) respectively.

Conclusions: We found an increased risk of colorectal and ovarian cancers in women with hyperthyroidism. Women with history of hyperthyroidism should be attributed to the group of increased cancer risk, that requires a set of measures for primary and secondary prevention of cancer.