incidence of thyroid papillary cancer in contralateral lobe

background & objectives: prognosis of thyroid papillary cancer is quite well long lasting, so a 10- year survival is observed in more than 90% cases. in this study, rate of incidence of thyroid papillary cancer in contralateral lobe was assessed among patients who had a surgical thyroidectomy re-operation. materials & methods: in this retrospective study, we examined 82 patients diagnosed with thyroid papillary cancer that had thyroid lobectomy surgery first and thyroidectomy re-operation next from 1997 to 2007. results: of 82 patients studied, 33 (40%) were diagnosed with papillary cancer in contralateral lobe. no significant relationship was observed between age, sex, size of the original tumor, intervals between two surgical operations and incidence rate of papillary cancer in contralateral lobe; however, due to tumor's multifocusing and presence of metastasis spread to lymphatic glands, an increase in tumor risk was caused in remaining of the thyroid. following thyroidectomy re-operation, no complications were common highly, but a few of them included: rln transient paralysis in six patients (7.3%); rln permanent paralysis in two patients (2.5%) fleeting hypokalemia in nine patients (11%); and persistent hypoparathyoidism in one patient (1.2%). following surgical operation, five patients (6%) suffered hematoma two cases of which needed re-operation. conclusions: surprisingly, the incidence rate of thyroid papillary cancer was relatively high in the remaining tissue of contralateral lobe. we believe that such patients must undergo treatment of thyroidectomy re-operation which can be performed with acceptable complication rate, maintaining patient’s health.