Comparison of chemotherapeutic efficacy between LCNEC diagnosed using large specimens and possible LCNEC diagnosed using small biopsy specimens.

BACKGROUND: It is often difficult to diagnose large cell neuroendocrine carcinomas (LCNEC) of the lung using small biopsy specimens. Some recent studies attempted to diagnose LCNEC using biopsy specimens; in 2011, the International Association for the Study of Lung Cancer pathological panels suggested possible LCNEC as a diagnosis for LCNEC by using biopsy specimens. Here, we compared the chemotherapeutic efficacy in possible LCNEC and LCNEC diagnosed using surgically resected specimens.
METHODS: We retrospectively reviewed patients who received platinum-based chemotherapy as first-line chemotherapy at our institution during September 2002-September 2011. Further, we compared the clinical characteristics, chemotherapeutic responses, and survival outcomes of patients diagnosed as having "LCNEC definite" with those diagnosed as having "possible LCNEC."
RESULTS: We selected 34 patients of whom 10 were diagnosed with LCNEC using surgically resected specimens and 24 patients with possible LCNEC were diagnosed using small biopsy specimens. In both groups, almost all patients were men and were smokers. Small-cell carcinoma-based chemotherapy, such as platinum plus irinotecan or platinum plus etoposide, was used for treating 60 % LCNEC patients (6/10) and 67 % possible LCNEC patients. In the LCNEC and possible LCNEC groups, respectively, the response rate was 70 and 54 % (p = 0.39), median progression-free survival was 2.9 and 4.4 months (p = 0.20), and median survival time was 12.8 and 9.1 months (p = 0.50).
CONCLUSION: No statistically significant differences were found in chemotherapeutic responses and survival outcomes between the 2 groups, which suggests that chemotherapeutic efficacy is similar in both possible LCNEC and LCNEC.