Analysis of stage and clinical/prognostic factors for lung cancer from SEER registries: AJCC staging and collaborative stage data collection system.

BACKGROUND: The American Joint Committee on Cancer (AJCC) 7th edition introduced major changes in the staging of lung cancer, including the tumor (T), node (N), metastasis (M)-TNM-system and new stage/prognostic site-specific factors (SSFs), collected under the Collaborative Stage Version 2 (CSv2) Data Collection System. The intent was to improve the stage precision that could guide treatment options and ultimately lead to better survival. This report examines stage trends, the change in stage distributions from the AJCC 6th to the 7th edition, and findings of the prognostic SSFs for 2010 lung cancer cases.
METHODS: Data were from the November 2012 submission of 18 Surveillance, Epidemiology, and End Results (SEER) Program population-based registries. A total of 344,797 cases of lung cancer, diagnosed in 2004-2010, were analyzed.
RESULTS: The percentages of small tumors and early-stage lung cancer cases increased from 2004 to 2010. The AJCC 7th edition, implemented for 2010 diagnosis year, subclassified tumor size and reclassified multiple tumor nodules, pleural effusions, and involvement of tumors in the contralateral lung, resulting in a slight decrease in stage IB and stage IIIB and a small increase in stage IIA and stage IV. Overall about 80% of cases remained the same stage group in the AJCC 6th and 7th editions. About 21% of lung cancer patients had separate tumor nodules in the ipsilateral (same) lung, and 23% of the surgically resected patients had visceral pleural invasion, both adverse prognostic factors.
CONCLUSIONS: It is feasible for high-quality population-based registries such as the SEER Program to collect more refined staging and prognostic SSFs that allows better categorization of lung cancer patients with different clinical outcomes and to assess their survival.