Prognostic significance of tumor size in patients with stage III non-small cell lung cancer: A SEER database survey
7529 Background: Although tumor size is a known predictor of stage I and II non-small cell lung cancer (NSCLC) treated with surgery or radiotherapy, there is limited information regarding its prognostic significance in patients with mediastinal lymph node involvement. Methods: The Surveillance Epidemiology and End Results (SEER) registry was queried for patients with unresected NSCLC stage III, without malignant pleural effusion, aged 21 or older, and diagnosed between 1998 and 2003. Tumor size was defined as S1 (0.1–3 cm), S2 (3.1–5 cm), S3 (5.1–7 cm) and S4 (7.1–20 cm). Demographic variables included age, gender, race and histology. The Kaplan-Meier method was used to estimate the overall survival (OS) and disease-specific survival (DSS), and the Cox proportional hazard model to evaluate whether tumor size remained an independent risk factor after adjusting for stage and other demographic variables. Results: A total of 12,205 patients met the eligibility criteria. Median age at diagnosis was 70 years and most patients were male (58.8%) and white (81.3%). Tumor size was a statistically significant predictor for both overall survival (p<0.0001) and disease-specific survival (p<0.0001) on multivariate analysis. Selected groups of patients with smaller stage IIIB disease had better OS compared to patients with stage IIIA, including; IIIBS1 vs. IIIAS3 (p=0.0005) or IIIA S4 (p<0.0001) and IIIBS2 vs. IIIAS4 (p=0.0001). Conclusions: Tumor size is an independent predictor for OS and DSS in patients with unresected stage III NSCLC and should be considered in the stratification of patients treated in this setting. [Table: see text] No significant financial relationships to disclose.