Second primary cancers in patients with lung carcinoma

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

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.

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.

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.