Thyroid cancer: Is hyperthyroidism protective?

Introduction: In the past, hyperthyroidism was thought to be protective against thyroid cancer. However, the relationship be-tween thyroid stimulating hormone (TSH) and cancer has become more prominent within the last 15 years. In addition, surgical techniques related to thyroid cancer have also seen many changes over the past several years. In the current study, we review these changes in surgical techniques, and examine the relationship between thyroid functions and cancer development. Materials and methods: We retrospectively evaluated the records of 239 patients who underwent thyroidectomy in the General Surgery Department of Istanbul Medeniyet University Faculty of Medicine between January 1999 and January 2014. Patients who underwent thyroidectomy between 1999 and 2006 were categorized in subgroup I, and those who underwent the surgery between 2006 and 2014 were categorized in subgroup II. Data from 2006 were included in both groups. There were 157 patients who had preoperative serum TSH levels that were either normal (0.27-4.20 μIU/mL) or high (>4.20 μIU/mL); these patients were categorized in "subgroup I for TSH". There were 82 patients who had low preoperative serum TSH levels; these were categorized in "subgroup II for TSH". Results: Of the cases with thyroid cancer, 84.9% were women, 15.1% were men, and their mean age was 46.62±13.65 (16-80) years. Of the cases with thyroid cancer, 54.4% had papillary carcinoma, 37.2% had micropapillary carcinoma, 4.6% had follicular carcinoma, 3% had medullary carcinoma, and 0.8% had anaplastic carcinoma. When operation types were evaluated according to the years in which they were performed (1999-2014), the total thyroidectomy rate was significantly higher in Group II (2006-2014) than in Group I (1999-2006, p<0.05). The bilateral subtotal thyroidectomy rate was significantly higher in Group I (1999-2-6, p<0.05). When we examined pathology results with respect to TSH levels, there was no significant association between TSH levels and papillary carcinoma or other carcinoma types (p>0.05). On the other hand, micropapillary carcinoma was signifi-cantly more frequent among patients with low TSH levels (p=0.003). Conclusion: The gold standard for the treatment of thyroid cancer is surgical resection, and currently, the most preferred opera-tion type is total or near-total thyroidectomy; this is due to its advantages related to recurrence and survival, as well as low complication rates. © 2017 Surgical Society of Northern Greece. All rights reserved.