Hormonal Outcomes Following Hemithyroidectomy

Objective To assess hormonal outcomes and thyroid hormone (TH) replacement after hemithyroidectomy (HT). Study Design Retrospective chart review. Setting Quaternary care hospital system. Methods A retrospective analysis was performed on patients who had an HT at Cleveland Clinic between 2000 and 2010 with outcomes assessed up to 5 years post-HT. Patients with overt hypothyroidism (OH; thyroid-stimulating hormone [TSH] >10 mIU/L, TSH >4.2 mIU/L on thyroid hormone [TH]), subclinical hypothyroidism (SH; TSH >4.2-10 mIU/L, no TH), or euthyroidism (EU; TSH 0.4-4.2 mIU/L, no TH) were compared. Patients with SH who returned to EU were compared to those who continued to have SH. For immediate start on TH, a receiver operating characteristic analysis was performed to determine dosage of TH above which suppression of TSH Results We identified 335 patients (average age 51 years, 78% female, median follow-up of 50 months). Of the 210 not immediately started on TH, 32.4% were OH, 13.3% were SH, and 54.3% were EU. EU patients were younger (48 years), had more remaining gland, were less likely to have lymphocytic infiltrate, and had a lower preoperative TSH (1.2 mIU/L). In the SH group, 58.3% of patients normalized their TSH. With immediate TH start, 45% developed suppressed TSH. Those on LT4 >1.05 mcg/kg/d were more likely to suppress (sensitivity 89%). Conclusion Most patients post-HT will remain EU, and immediate start of TH may lead to TSH suppression. Those with SH may ultimately normalize TSH. These findings together suggest that observation may be a better option than TH replacement after HT.