Questions under study: Lung cancer belongs to the most common cancers in Switzerland. We examined trends in lung cancer incidence, with focus on sex, histology and laterality, in the Canton of Zurich since 1980.
Material and methods: Registry data consisting of 16 798 lung cancer cases from 1980 to 2010 were analysed. Cases were classified into adenocarcinoma (ADC), squamous cell carcinoma (SCC), small-cell carcinoma (SCLC), large cell tumour and carcinoid tumour. Age-standardised (European standard) incidence rates (IR) per 100 000 person-years, male-to-female incidence-rate ratio (M/F-IRR), and left-to-right lung incidence-rate ratio (L/R-IRR) were calculated.
Results: Over the study period, ADC occurred most frequently (31.9%), followed by SCC (29.1%), SCLC (15.4%), large cell carcinoma (6.3%), and carcinoid tumour (1.5%). Other/unspecified subtypes accounted for 15.7%. In men, the IR of SCC decreased from 34.2/100 000 (95% confidence interval [CI] 32.5-35.9) in 1980 to 12.8/100 000 (12.0-13.6) in 2010, but increased in women from 3.4/100 000 (2.7-4.0) to 4.0/100 000 (3.4-4.5). The IR of ADC increased in women from 5.1/100 000 (4.1-5.8) to 12.6/100 000 (11.8-13.4) and in men from 15.1/100 000 (14.0-16.3) to 19.4/100 000 (18.4-20.4). Overall M/F-IRR was 2.61; the highest ratio (5.8) was seen for SCC and the lowest (0.77) for carcinoid tumour. All histological subtypes showed a higher susceptibility of the right lung.
Conclusion: Our data reflect the global increase of lung cancer in women. ADC increased over time in women and men, whereas SCC decreased markedly among men. These trends may have occurred owing to changes in smoking behaviour and cigarette composition.