Predictive factors for node involvement in papillary thyroid carcinoma. Univariate and multivariate analyses

For patients with papillary thyroid carcinoma, lymph node involvement is a common complication, resulting in node dissection and its resulting morbidi ty. To determine means of limiting lymph node dissections, we attempted to define intra-operative criteria predictive of node metastasis and so identi fy the patients likely to benefit from this procedure. This retrospective s tudy concerned 158 patients (118 female) treated between 1974 and 1996 for papillary thyroid carcinoma by total thyroidectomy associated with bilatera l (central and lateral) (n = 119) or unilateral (n = 39) dissection. The fo llowing criteria were used to study the predictive value of node involvemen t: age, sex, tumour size, tumour site, uni- or multifocality, existence or not of a tumour capsule, existence or nor of perithyroid involvement and pr esence or not of vascular invasion. 99 patients (63%) had node involvement. Four factors showed predictive value for node involvement in univariate an alysis: vascular invasion (P = 0.02), male sex (P = 0.008), absence of a tu mour capsule (P < 0.0001) and perithyroid involvement (P < 0.0001). Two fac tors were predictive in multivariate analysis: absence of a tumour capsule and perithyroid involvement. Our results enabled us to calculate the risk o f node involvement for each patient as a function of the existence of a per itumoral capsule and/or perithyroid involvement and to determine the indica tion for dissection. When neither of these factors was present, the risk of node involvement was 38.3% and dissection was not considered essential. If both risk factors were found, the risk was 87.1% and dissection was consid ered necessary. (C) 1999 Elsevier Science Ltd. All rights reserved.