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 adequate treatment for papillary thyroid carcinoma (PTC). In patients who h ave undergone lobectomy, the necessity of performing a completion thyroidec tomy (CT) is still discussed. The aim of this retrospective study was to ev aluate tumor bilaterality in patients initially treated with partial thyroi dectomy for PTC and who then underwent CT. We studied 182 patients treated with CT after lobectomy and/or isthmectomy for PTC diagnosed from 1969-1998 . Mean age at diagnosis was 40 +/- 14.5 years and mean interval between par tial thyroidectomy and CT was 19.8 +/- 56.8 months. At CT, 80 of 182 patien ts (44%) had one or more foci of tumor in the remaining thyroid lobe, alway s of the same papillary histotype, associated with ipsilateral lymph node m etastases in 22 cases. In addition, 10 patients with no tumoral foci in the thyroid specimen had evidence of lymph node metastases. The rate of bilate ral tumor was not different when patients were analyzed according to the cl assification of " low-" or "highrisk." Among several clinical features, the presence of lymph node metastases at the first surgical treatment and time interval between first treatment and CT were correlated with higher freque ncy of bilaterality (p = 0.033 and p = 0.044, respectively). The postsurgic al I-131 whole-body scan revealed the presence of persistent lymph node met astases. or diffuse micronodular lung metastases in 7 and 6 patients, respe ctively. In conclusion, PTC was frequently bilateral in our series and this bilaterality was independent from the "low-" or "highrisk" classification. On these bases, we believe that PTC should be treated with TT when diagnos ed before surgery and submitted to CT, if partial surgery was the initial i ntervention.