LAUSR

BACKGROUND Whether multifocal papillary thyroid carcinoma (PTC) is more associated with recurrence than unifocal PTC is controversial. This study investigates the appropriateness of lobectomy for patients with preoperatively detected unilateral multifocal PTC. METHODS This study retrospectively analyzed 198 patients with unilateral multifocal PTC at the Asan Medical Center between 2000 and 2005. Clinicopathological features and locoregional recurrence rates were compared according to operation type (lobectomy, n = 62; total thyroidectomy (TT), n = 136). RESULTS The lateral neck lymph node area was the most frequent recurrence site. Univariate analyses showed that gross extrathyroidal extension (ETE), bilateral multifocal malignancy diagnosed after operation (bilaterality), lymph node (LN) metastasis, lymphovascular invasion, tumor size (≥2 vs < 2 cm), and extranodal extension (ENE) were associated with locoregional recurrence (P < 0.05). Multivariate analyses showed that ENE (hazard ratio (HR), 5.7; p = 0.007; 95% confidence interval (CI) = 1.1-9.8), LN metastasis (HR, 8.6; p = 0.046; 95% CI = 1.1-70.7), and lymphovascular invasion (HR, 11.1; p = 0.001; 95% CI = 2.7-46.1) were significantly associated with locoregional recurrence. The occult contralateral malignancy (rate, 15.4% of TT patients) and gross ETE were not risk factors for locoregional recurrence in the multivariate analysis of this study. CONCLUSION Lobectomy may be considered as an alternative treatment to TT for patients with preoperatively detected unilateral multifocal PTC with diameters less than 2 cm, even in the pres-ence of risk fac-tors, such as gross ETE, and the pos-si-bil-ity of oc-cult ma-lig-nancy of the con-tralat-eral lobe. Although recurrence in the contralateral lobe after lobectomy could be diagnosed in unilateral multifocal PTC, it would not increase the rates of locoregional recurrence and death.