Prognosis and distribution of lymph nodes metastases in resectable primary pulmonary lymphoepithelioma-like carcinoma: A large cohort from a single center.

BACKGROUND: Primary pulmonary lymphoepithelioma-like carcinoma is a rare subtype of lung cancer. Until now, the characteristics of lymph nodes metastases in resectable cases have not yet been reported.

METHODS: In this study, a total of 87 consecutive patients with primary pulmonary lymphoepithelioma-like carcinoma that received surgical treatment were investigated from October 1999 to August 2016. The clinical and radiological data and follow-up information were extracted from hospital records in detail.

RESULTS: In a univariate analysis, those patients with an early pathological stage (I-II), low rate of lymph node metastases (<30%) and a low number of positive lymph nodes (<5) showed longer recurrence-free survival and overall survival (all P < 0.05). However, the early pathological stage was identified as the only factor independently associated with recurrence-free survival by multivariate analysis (P = 0.038). In a preoperative lymph nodes evaluation, the accuracy and specificity of computed tomography alone were 52.9% (46/87) and 88% (302/343), respectively, and 73.2% of these cases with incorrect nodal staging (30/41) were upstaged. Skipping metastases were more frequent in operated stage N2 cases (71.4%), whereas whether or not those patients showed skipping metastasis did not affect their recurrence-free survival or overall survival (P > 0.05). The highest metastasis frequencies for specific lobes with primary lymphoepithelioma-like carcinoma are as follows: #5 left upper lobe (21.4%); #7 left lower lobe (40.7%); #2R (28.6%) and/or #4R (14.3%) right upper lobe; #7 (42.9%) right lower lobe; #7 (28%) and/or superior mediastinal nodes (36%) right middle lobe.

CONCLUSION: Based on accurate staging and uncertain survival benefit, complete mediastinal lymph nodes dissection is still required for curative resection.