Risk of second cancers among lung cancer patients.

The risk of a second cancer among lung cancer patients was investigated using Finnish Cancer Registry data from 1953 to 1989. Among the 36,528 patients with a primary cancer of the lung, 504 new cancers were diagnosed six months or more after the diagnosis of lung cancer, yielding a standardized incidence ratio significantly lower than expected (SIR = 0.81). A significant excess of cancers of the larynx (SIR = 2.10) and urinary bladder (SIR = 1.35) was observed Among lung cancer patients below 60 years of age, the risks of oesophageal cancer (SIR = 2.47) and kidney cancer (SIR = 2.48) were also significantly elevated. The risk of a second cancer among lung cancer patients increased with the length of follow-up, and there was some indication of an excess risk of oesophageal cancer and leukaemia among lung cancer patients subject to radiotherapy.