Second primary cancers in laryngeal cancer patients in Slovenia, 1961-1996

We analysed the incidence of second primary cancers (SPC) in male laryngeal cancer patients in Slovenia and their survival for the period of 1961-1996. Data were taken from the population-based Cancer Registry of Slovenia. The person-years approach was used and the risk for SPC was expressed as a standardised incidence ratio (SIR). Survival analysis was carried out using the Kaplan-Meier method. Of 2275 male patients, 369 developed SPC (16.2%, total SIR 2.83), most commonly in the head and neck region (SIR 6.07-15.97), lung (SIR 4.15), oesophagus (SIR 4.66), and bladder (SIR 3.0), which points to an important role of common risk factors of smoking and alcohol. SPC were diagnosed in significant excess up to 20 years after the diagnosis of laryngeal cancer. The median survival time from the diagnosis of laryngeal cancer was 3.25 years for patients without a SPC and 6.47 years for patients who developed a SPC. However, the median survival time from the diagnosis of a SPC was only 0.84 years. Patients with laryngeal cancer in Slovenia have a higher risk of developing a SPC than was reported in similar studies in Europe and the USA. This high risk is partly responsible for their relatively poor survival.