Heterogeneous prognosis and adjuvant chemotherapy in pathological stage I non-small cell lung cancer patients

BACKGROUND Even after curative resection, the prognosis of pathological stage I non-small cell lung cancer (NSCLC) can be heterogeneous, and the use of adjuvant chemotherapy in these patients is controversial. We aimed to identify the prognostic factors and role of adjuvant chemotherapy in pathological stage I NSCLC. METHODS We retrospectively analyzed the correlations between clinicopathological factors and survival in 179 patients with resected pathological stage I NSCLC. RESULTS After a median follow-up of 93 months, overall and disease-free survival were not significantly different between pathological stage IA (n = 138) and IB (n = 41) patients. The prognosis of pathological stage I patients with poorly differentiated tumors was significantly worse than that of those with non-poorly differentiated tumors (P = 0.003). Multivariate analysis revealed that poor tumor differentiation was an independent factor for poor survival (hazard ratio = 6.889). A marginally significant survival benefit was observed in poorly differentiated pathological stage I patients who received adjuvant chemotherapy (P = 0.053). Pathological stage IA patients who received adjuvant chemotherapy had a worse prognosis than those who did not receive adjuvant chemotherapy (P < 0.001), whereas pathological stage IA patients with poorly differentiated tumors who received adjuvant chemotherapy had better survival than who did not receive adjuvant chemotherapy (P < 0.001). CONCLUSIONS Poor differentiation is an independent prognostic factor in pathological stage I NSCLC after surgical resection. Adjuvant chemotherapy may be beneficial in poorly differentiated pathological stage IA NSCLC patients.