Contralateral papillary thyroid cancer is frequent at completion thyroidectomy with no difference in low- and high-risk patients

Total (or near-total) thyroidectomy (TT) is considered by many as the most\r\nadequate treatment for papillary thyroid carcinoma (PTC). In patients who have\r\nundergone lobectomy, the necessity of performing a completion thyroidectomy (CT) \r\nis still discussed. The aim of this retrospective study was to evaluate tumor\r\nbilaterality in patients initially treated with partial thyroidectomy for PTC and\r\nwho then underwent CT. We studied 182 patients treated with CT after lobectomy\r\nand/or isthmectomy for PTC diagnosed from 1969-1998. Mean age at diagnosis was\r\n40+/-14.5 years and mean interval between partial thyroidectomy and CT was\r\n19.8+/-56.8 months. At CT, 80 of 182 patients (44%) had one or more foci of tumor\r\nin the remaining thyroid lobe, always of the same papillary histotype, associated\r\nwith ipsilateral lymph node metastases in 22 cases. In addition, 10 patients with\r\nno tumoral foci in the thyroid specimen had evidence of lymph node metastases.\r\nThe rate of bilateral tumor was not different when patients were analyzed\r\naccording to the classification of "low-" or "high-risk." Among several clinical \r\nfeatures, the presence of lymph node metastases at the first surgical treatment\r\nand time interval between first treatment and CT were correlated with higher\r\nfrequency of bilaterality (p = 0.033 and p = 0.044, respectively). The\r\npostsurgical 131I whole-body scan revealed the presence of persistent lymph node \r\nmetastases or diffuse micronodular lung metastases in 7 and 6 patients,\r\nrespectively. In conclusion, PTC was frequently bilateral in our series and this \r\nbilaterality was independent from the "low-" or "high-risk" classification. On\r\nthese bases, we believe that PTC should be treated with TT when diagnosed before \r\nsurgery and submitted to CT, if partial surgery was the initial intervention.