OBJECTIVEWell differentiated thyroid carcinoma (WDTC) may be located in the isthmus. The guidelines now have not mentioned an appropriate procedure for WDTC in the isthmus. The aim of this study was to retrospectively analyze the outcomes in patients with WDTC in the isthmus treated at our institution.

METHODSTwenty-seven patients with WDTC in the isthmus were managed by surgery in the Cancer Hospital of Chinese Academy of Medical Sciences from 1985-2006. Their demographic data, surgical procedures, pathological features, stages and outcomes were analyzed.

RESULTSFive patients were men and 22 were women. The median age was 41 (range, 20-69) years. Nine patients received isthmusectomy, fourteen patients received extended isthmusectomy and four received isthmusectomy with unilateral lobectomy. There were no complications of recurrent laryngeal nerve palsy or hypocalcaemia. The median size of lesion was 1.0 cm(range, 0.5-4.0 cm). Sixteen patients had a pathologically T1a lesion (pT1a), seven patients were pT1b, two patients were pT2 and two pT3. Three patients had papillary carcinoma detected in perithyroid lymph nodes (pN1a). Among the 27 cases, 25 patients had a solitary malignant nodule confined to the isthmus, one had two malignant nodules confined to the isthmus and one had two malignant nodules located separately in the isthmus and right lobe. The patients were followed up with a median follow-up time of 85 months(range, 37-274 months). The 5-year recurrence-free survival was 95.2% and overall survival rate was 100%.

CONCLUSIONSOur results suggest that isthmusectomy or extended isthmusectomy are feasible and efficient for the patients with WDTC located in the isthmus, and concurrent pretracheal lymph node dissection should be considered.