The extent of the initial surgical treatment for patients with papillary thyroid carcinoma (PTC) is controversial. Many surgeons think thattotal thyroidectomy is the most optimal treatment for PTC because of its potential bilaterality. Therefore, bilaterality is an important factor for determining the extent of surgical resection. The aim of this retrospective study is to analyze the relationship between tumor bilaterality and the other clinicopathological factors.

We conducted a retrospective analysis of 140 patients with PTC and who underwent total thyroidectomy with central lymph node dissection from January to December 2007 at our institution.

Among 140 patients, 50 patients (35.7%) had PTC in the bilateral lobes. Of these 50 patients, only 17 patients (34.0%) were operated on under the preoperative diagnosis of bilateral PTC. Two factors, 1) presence of the capsular invasion (P=0.007) and 2) an increase of the tumor size (P=0.023), were statistically correlated with bilaterality. There were no significant associations between bilaterality and the other clinicopathological factors,including age, extrathyroidal invasion and lymph node metastasis.

For the surgical care of PTC, bilaterality must always be considered even though the tumor is diagnosed preoperatively as unilateral PTC. Furthermore, thorough preoperative evaluation is mandatory if unilateral lobectomy is regarded as a therapeutic option for PTC patients.