Nonanatomic prognostic factors in resected nonsmall cell lung carcinoma: the importance of perineural invasion as a new prognostic marker

Background A number of prognostic factors have been reported for resected nonsmall cell lung carcinoma. Although none of them reported to have greater prognostic impact than the TNM staging system, which is based on anatomical descriptions of tumors, the prognoses of a significant number of patients are not in agreement with real survival of the patients. Moreover, certain histopathologic properties of the tumor (such as lymphatic and vascular invasion) could help to predict the survival of the patients. Methods A retrospective study was conducted on 82 surgically resected nonsmall cell lung carcinomas, and the following prognostic factors were evaluated in univariate analysis: age, gender, clinical and surgical-pathologic T and N status, histologic type of tumor, grade of differentiation, lymphatic invasion, vascular invasion, and perineural invasion. Results Lymphatic invasion and perineural invasion of the tumor were found to be significant prognostic factors (p = 0.02 and p = 0004). Blood vessel invasion (venous or arterial involvement) had no prognostic impact (p> 0.05). According to multivariate analyses, three factors were selected as prognostic indicators: (1) clinical N status (p = 0.027), (2) lymphatic invasion (p = 0.027) and (3) perineural invasion (p = 0.0148). By combining these factors we identified a poor prognostic subgroup of patients with stage I disease. Conclusions Our study showed that lymphatic vessel and perineural invasion of the tumor could be prognostic factors, along with anatomical determinants such as cN and surgical-pathologic stage of the pulmonary carcinoma.