Second primary cancers in patients with lung carcinoma.

BACKGROUND: There are only limited population-based data available regarding the risk of developing a second cancer after a diagnosis of lung carcinoma.

METHODS: Data collected from the Cancer Registry of the Swiss Canton of Vaud (comprised of approximately 600,000 inhabitants) were used to estimate the incidence of a second metachronous primary cancer following a diagnosis of lung carcinoma. Between 1974 and 1996, 5794 cases of lung carcinoma (occurring in 4728 males and 1066 females) were followed actively until the end of 1996.

RESULTS: One hundred seventy-five second primary neoplasms were registered (occurring in 146 males and 29 females). Significant excess rates were observed for all cancer sites (standardized incidence ratio [SIR] = 1.2), cancers of the oral cavity and pharynx (SIR = 2.7), and lung (SIR = 1.7). SIRs also were above unity for cancers of the esophagus (SIR = 1.8), pancreas (SIR = 1.5), bladder (SIR = 1.8), kidney (SIR = 2.3), and the female breast (SIR = 2.0). Excess rates for all cancer sites together and tobacco-related neoplasms were systematically higher at a younger age (< 60 years). The overall cumulative risk of lung cancer was 1.8% at 5 years and 4.7% at 10 years and was 5% and 11%, respectively, for any tobacco-related tumor. The estimates were consistent for squamous cell carcinoma and adenocarcinoma of the lung.

CONCLUSIONS: There were substantial excesses of second lung carcinomas as well as other major tobacco-related neoplasms, but not of colorectal carcinoma, prostate carcinoma, or lymphoid neoplasms after the diagnosis of a primary lung carcinoma. This study emphasizes the importance of smoking cessation even after a diagnosis of lung carcinoma.