Results of surgical treatment for non-small cell lung cancer of 20 mm or less in diameter

Background: Surgical efficacy is still unsatisfactory for small lung cancer; accordingly, minimal resection has recently been the focus of increased study. The objective of the current study was to evaluate the factors associated with small lung cancer, and to determine whether such factors are reliable predictors of long-term survival. Methods: We retrospectively investigated 130 patients with histologically confirmed non-small cell carcinoma, whose treatments were primarily surgical, with no chemotherapy or radiotherapy prior to surgery. All tumors were located peripherally and were less than 20 mm in diameter. Follow-up was performed for five-year and eight-year survivors and multivariate analysis with Cox's proportional hazards regression model was performed. Results: Of all 130 patients, the 5-year survival rate among patients with tumors less than 15 mm was 82.5%, vs. 57.4% of patients with tumors with a diameter of 16 - 20 mm. The 5-year survival rate of patients who were node negative was 73.9% while it was 28.5% for node-positive patients. Status of nodal invasion was also significantly associated with survival in small-size tumors (p < 0.0001). Furthermore, the 5-year survival rate among patients with pleural involvement was 55% vs. 83.8% for patients without pleural involvement. Using multivariate Cox analysis, lymph node involvement (p=0.0004), size (p=0.0475), and pleural invasion (p=0.0482) were found to be independent prognostic factors in cases of tumors 20 mm or less in diameter. Conclusions: The results of this study at least demonstrate that the optimal therapy for patients with nodal involvement or patients with tumors of 16 - 20 mm must be carefully determined even in cases of small lung cancer.