Clinicopathological features and the impact of the new TNM classification of malignant tumors in patients with pulmonary large cell neuroendocrine carcinoma.

The prognosis of patients with large-cell neuroendocrine carcinoma (LCNEC) of the lung is extremely poor and the optimal treatment for these patients has yet to be determined. In this study, we described the clinicopathological characteristics of LCNECs and compared the prognoses of corresponding stages determined by the guidelines of the 6th and 7th editions of the TNM classification of malignant tumors. Clinical data from 42 patients diagnosed with primary LCNEC who underwent treatment at Kitasato University Hospital between 1991 and 2009 were retrospectively analyzed. On follow-up of 42 patients, 22 (52.4%) had confirmed recurrent tumors, including 8 patients with mediastinal lymph node recurrences and 19 with distant metastases. The sites of distant metastases included the brain in 8, bone in 8, liver in 7, lungs in 5 and adrenal glands in 4 patients. For all the patients, the 5-year overall survival rate was 34.7% and the 5-year disease-free survival rate was 32.9%. The 5-year overall survival rates of patients with stage I cancers according to the 6th and 7th staging editions was 51.3% (6th n=18, 7th n=16). Thirteen of 42 patients (31.0%) also had metachronous or synchronous primary cancers. Patients with LCNEC had poor outcomes, even those with stage I tumors classified according to the 7th edition of the TNM classification. Therefore, frequent recurrences in addition to metachronous or synchronous primary cancers in patients with LCNEC should be treated.