Total tumor diameter: the neglected value in papillary thyroid microcarcinoma

摘要

Background Tumor multifocality is not uncommon in papillary thyroid carcinoma (PTC), especially in micro-PTC. However, assessing the size of the largest tumor may underestimate effect of additional foci. We aimed to investigate the effect of total tumor diameter (TTD) on clinicopathological features of micro-PTC. Methods Data from 442 patients who underwent thyroidectomy with cervical lymph node dissection for PTC were retrospectively analyzed. Patients were classified into subgroups according to multifocality and TTD. The relationships of clinicopathological features among these groups were analyzed. Results Multifocality was observed in 119 patients (26.9%). TTD >1 cm and presence of extrathyroidal extension (ETE) were significantly higher in multifocal tumors compared to unifocal tumor (P 1 cm to those with unifocal micro-PTC or multifocal micro-PTC with TTD 1 cm and macro-PTC or multifocal macro-PTC. The risk of CLNM was 2.056 (P = 0.044) times higher in multifocal micro-PTC with TTD >1 cm than in unifocal micro-PTC. Conclusion For multifocal micro-PTC, TTD can better assess the aggressiveness of the tumor. Multifocal micro-PTC with TTD >1 cm was more aggressive than unifocal micro-PTC or multifocal micro-PTC with TTD < 1 cm.