CONTEXT

Nonsmall cell lung cancers with neuroendocrine differentiation (NSCLC-ND) may demonstrate biologic behavior intermediate between NSCLC and small cell lung cancer (SCLC) with impact on prognosis.

METHODS

We analyzed 116 consecutive patients with Stage III and IV NSCLC who were diagnosed and treated between 2001 and 2006. Using immuno-histochemical staining for neuron-specific enolase (NSE), chromogranin A (ChrA), and synaptophysin (Syn), 29 (25%) NSCLC-ND were identified.

RESULTS

Expression of NSE was present in 22.4%, ChrA in 15.5% and Syn in 14.8% of patients with NSCLC. Therapeutic response was significantly better in the NSCLC-ND group and specimens with > 30% neuroendocrine (NE)-differentiated tumor cells showed favourable therapeutic response (P < 0.05). Multivariate binary logistic regression showed that percentage of NE positive tumor cells was a significant independent prognostic factor associated with a favourable outcome. Receiver operating characteristic (ROC) curves and areas under ROC curves confirmed that percentage of NE-differentiated tumor cells could be useful prediction factor of therapeutic response. Moreover, according to percentage of NE-differentiated tumor cells, optimal cutoffs and related sensitivities and specificities were determined for each markers.

CONCLUSION

Advanced-stage NSCLC with NE tumor cells are clinically less aggressive tumors. Percentage of NE-differentiated tumor cells identifies patients with favourable therapy response to paclitaxel-cisplatin.