Background: Second primary tumors (SPT) constitute a major threat to the survival of patients with laryngeal carcinoma. However, to the authors' knowledge little is known regarding the risk factors for developing SPTs or about the strategy to be followed to avoid them.
Methods: Eight hundred seventy-six male patients with laryngeal/hypopharyngeal carcinoma enrolled in a population-based, case-control study in 5 centers from South Europe during 1979-1982 were followed up to ascertain the occurrence of SPTs. Standardized incidence ratios were calculated to estimate the risk of SPT occurring in the cohort. Cox proportional hazard models were fitted to estimate the hazard ratio for development of SPTs in relation to use of tobacco smoking, alcohol consumption, and dietary habits before the first primary tumor.
Results: One hundred forty-five patients developed an SPT with an annual average rate of 2.1%. An excess risk of developing an SPT of the tongue, mouth, esophagus, and lung was observed. No elevated risks of SPTs were observed in other organs. Alcohol consumption strongly increased the risk of developing an SPT of the upper aerodigestive tract (UADT). Heavy cumulative cigarette smoking increased the risk of developing a lung SPT. A protective effect of high intake of citrus fruit was noticed for SPT in the lung, whereas high butter intake was associated with an increased risk for SPT of the UADT.
Conclusions: Continuous medical surveillance was essential in the UADT and lung to reduce the risk from an SPT after initial laryngeal/hypopahryngeal carcinoma. Alcohol consumption before the first primary tumor was a risk factor for SPT of the UADT. The study suggested a protective role of citrus fruits in the development of a lung SPT.