A High Frequency of Lobectomy Instead of Total Thyroidectomy to Treat Medullary Thyroid Cancer in Korea: Data from the Korean National Health Insurance Service.

Although total thyroidectomy with or without central neck dissection is the standard treatment of choice for medullary thyroid cancer (MTC) [1], Ahn et al. [2] demonstrated several interesting characteristics regarding the treatment of MTCs in Korea. Based on data from the Korean National Health Insurance Service (KNHIS), the authors showed that 35% of patients underwent lobectomy instead of total thyroidectomy for the initial treatment of MTCs during 2004 to 2016. This proportion did not change during the study period, and is relatively high compared to previously reported findings from other countries, which ranged from 9% to 26%. The authors deduced that the higher frequency of small MTCs (less than 1 cm) may have been one of the reasons for this finding regarding surgical techniques; however, the data on tumor size were obtained by referring to other sources [3], since the big data from KNHIS did not provide the pathologic characteristics of cancers in detail. Additionally, the authors also suggested that the difficulty of the preoperative diagnosis of MTC [4] could lead to minimal diagnostic surgery such as lobectomy. Interestingly, the rate of completion surgery was only 3.3% in their study, suggesting that minimal surgery has consistently been preferred in Korea, without any changes throughout the study period. These are interesting findings regarding real-world practice in Korea. Indeed, several other clinical characteristics, including the predominance of female sex [2] and sporadic MTCs, were different from those reported in other countries [3,5], suggesting that the long-term disease-specific prognosis and survival should be studied, especially in patients who undergo minimal surgery. Another interesting finding is that radioactive iodine therapy was performed in a subset of patients, although its frequency decreased overall [2]. The authors suggested that MTC may cooccur with papillary thyroid cancer (PTC) or follicular thyroid cancer (FTC). It would be worthwhile to conduct a comparative study of clinical characteristics and clinical prognosis of MTC alone versus MTC with concomitant PTC or FTC.