Relationship between tumor size and disease stage in non-small cell lung cancer

Background: Whether tumor size and stage distribution are correlated remains controversial. The objective is to assess the relationship between tumor size and disease stage distribution in non-small cell lung cancer (NSCLC). Methods: We conducted a retrospective analysis of 917 cases of NSCLC that were resected in the Cancer Hospital of Fudan University and Shanghai Sixth Hospital between January 2000 and February 2009. Tumor sizes were grouped into five categories: <= 20 mm, 21 to 30 mm, 31 to 50 mm, 51 to 70 mm and <= 71 mm. Results: Age and tumor size affected stage distribution: patients 60 years or older had a higher percentage of N0M0 disease than patients younger than 60 years (61.67% vs. 44.85%, p < 0.01). The smaller the tumor, the more likely the disease was N0M0 status (p < 0.05). For tumors <= 20 mm in diameter, the proportion of cases with N0M0 status was 70.79%, compared to 58.88% for 21 to 30 mm, 48.03% for 31 to 50 mm, 47.55% for 51 to 70 mm, 33.33% for <= 71 mm. The mean (+/- SD) tumor size of cases with N0M0 status was 37.17 +/- 21.34 mm, compared to 45.75 +/- 23.19 mm for cases with other status. Conclusions: There is a statistically significant relationship between tumor size and distribution of disease stage of primary NSCLC tumors: the smaller the tumor, the more likely the disease is N0M0 status.