Clinical features of unresectable high-grade lung neuroendocrine carcinoma diagnosed using biopsy specimens

The overall clinicopathological features or the optimal therapy for large cell neuroendocrine carcinoma (LCNEC) have yet to be defined, because LCNEC has not been studied in the same depth as had small cell lung carcinoma (SCLC) in both clinical and biological standpoints. The aim of this study was to elucidate the clinical features of high-grade neuroendocrine carcinoma (HGNEC)-probable LCNEC diagnosed by biopsy, and compare therapeutic efficacy with patients with SCLC.

We retrospectively examined the chart of total of 25 patients who underwent chemotherapy or chemoradiotherapy as initial therapy for a histologic diagnosis of HGNEC-probable LCNEC, using biopsy samples and compared their data with those of 180 patients with SCLC. We analyzed their responses to chemotherapy and/or radiation therapy and survival outcomes.

In 25 patients with HGNEC-probable LCNEC, 18 patients initially received chemotherapy (17 (94%) of whom received platinum-based chemotherapy) with an overall response rate (ORR) of 61%. The remaining 7 patients received chemoradiotherapy with an ORR of 86%, and 12 of the 25 patients who received second-line chemotherapy had an ORR of 17%. A total of 101 patients with SCLC who initially received chemotherapy had an ORR of 63%, and 79 patients who initially received chemoradiotherapy had an ORR of 98%, and 102 of the 180 patients who received second-line chemotherapy had an ORR of 45%. The 1-year overall survival rate for patients with stage IV HGNEC-probable LCNEC (n=13) and those with ED-SCLC (n=80) was 34% and 49%, respectively (p=0.84).

The overall response rate to initial treatment and the survival outcomes of HGNEC-probable LCNEC were comparable to those of SCLC, but the effectiveness of second-line chemotherapy appeared to differ between the 2 groups.