Retrospective analysis of low-risk differentiated thyroid tumours: is lobectomy the adequate approach?

Introduction: According to the recommendation of the American Thyroid Association 2015 guideline, the treatment of 1-4 cm (T1b-2) low-risk differentiated thyroid cancer (DTC) is lobectomy without radioiodine therapy. Objective: Retrospective analysis of multifocality in surgical and histological data of T1-2 patients living on moderate iodine intake. Methods: Analysis of the pathological characterisation of 81 low-risk (T1-2) DTC patients who underwent total thy-roidectomy. Patients were treated at Flor Ferenc Hospital, Kistarcsa, Hungary, between 2013 and 2019. Results: 64 patients had T1, while 17 patients had T2 status. 65/81 (80.2%) patients had papillary, and 16/81 (19.8%) had follicular subtype. Lymph node metastasis was detected up to 18.4% in papillary and 18% in follicular patients. Multifocal tumours were detected in 25% (16/64) of T1 patients, of these 10.9% (7/64) was unilateral and 14.1% (9/64) was bilateral. Multifocal tumours were detected in 11.7% (2/17) of T2 patients; both were bilateral. Distribution of T1-2 bilateral multifocal patients (11/81; 13.5%) was n = 3 T1a-, n = 6 T1b and n = 2 T2 stadium, from these 10 patients received radioiodine treatment. The sizes of contralateral tumours were <5 mm in 9 patients, and >5 mm in 2 patients. Conclusions: Due to the frequent (13.5%) bilateral multifocality in T1-2 DTC patients, we suggest total thyroidec-tomy instead of lobectomy. After lobectomy, the follow-up of the contralateral tumours is almost impossible by ul-trasonography due to the small tumour size (on average 2.8 mm) and frequently detected benign nodules; therefore the multifocality might remain undetected, which can distort the plan for adjuvant treatment.