Impact of revised stage classification of lung cancer on survival - A military experience

Study objectives: This report reviews results of surgical management of lung cancer at a miliary medical center using the revised 1997 stage classification and determines the impact of the revised system on survival rates. It also compares our results with the recent reports from Japan and from a large, multinational study involving several institutions. Design: Retrospective review. Setting: Department of Cardiothoracic Surgery, Walter Reed Army Medical Center (WRAMC), Washington, DC. Patients or participants: Active military members, their dependents, and eligible retired military members who were admitted to WRAMC for surgical treatment of lung cancer between January 1984 and December 1996. Methods: Records of all patients who had surgical resection wit intent to cure were reviewed. Data extracted included clinical and pathologic stages according to the 1997 revised stage classification. Survival probabilities for the stages were calculated by the Kaplan-Meier actuarial method. The long rank test was used to compare survival rates between stages and stage subsets. A p value < 0.05 was considered statistically significant. Measurements and results: Five hundred fifty-two of the 1,398 patients with primary lung cancers underwent curative surgical resection (39.5%). The operative mortality was 2%. Using the revised 1997 stage classification, the survival rate for stage IA was 77%; IB, 62%; IIA, 57%; IIB, 47%; IIIA, 28%; IIIB, 20%; and IV, 0%. The overall actuarial 5-year and 10-year survival rates were 58% and 45%, respectively (median survival, 3.3 years; mean survival 3.9 +/- 0.1 years). Conclusions: Our results confirm the justification for the recent revisions in the staging system of lung cancer; however, there are still discrepancies that cannot be explained.