Incidence of second primary malignancies in patients with thyroid cancer in the Turkish population

Abstract

Background/aim: Thyroid cancer is the most common endocrine malignancy. Recently the incidence has been increasing fastercompared to other malignancies. Different studies have shown that the incidence of breast cancer in patients followed due to thyroidcancer has increased, and vice versa. The aim of this study was to evaluate the frequency of second primary cancers in the follow-up ofpatients with thyroid cancer.Materials and methods: In this study, 1196 patients with thyroid cancer were evaluated in the Necmettin Erbakan University MeramMedical School’s Department of Endocrinology between 2004 and 2018. Demographic characteristics and radiological and pathologicalresults of the patients were recorded. The presence of accompanying second malignancies in patients with thyroid cancer was investigated.Results: In our study, 985 (82.4%) women (mean age: 46.1 ± 13.3 years) and 211 (17.6%) men (mean age: 49.9 ± 14.2 years) wereevaluated. The median follow-up was 63 months (2–164 months). Of the 1196 patients, 1126 (94.1%) had no additional cancer and 70(5.9%) patients had a second malignancy. The accompanying second malignancies were breast cancer in 24 (2%) patients, skin cancerin 8 (0.7%) patients, renal cell cancer in 5 (0.4%) patients, lung cancer in 5 (0.4%) patients, colon cancer in 5 (0.4%) patients, lymphomain 5 (0.4%) patients, endometrial cancer in 4 (0.3%) patients, and 14 cases of other rare types of cancer.Conclusion: In our study, it was found that the most common second primary malignancy in patients with thyroid cancer was breastcancer. However, other cancers (skin cancer, renal cell cancer, lymphoma, and colon, lung, or endometrial cancer) may occur in patientswith thyroid cancer.