Cross-country comparisons of colon and rectal cancer mortality suggest the existence of differences in risk factors in eastern and western Europe

Cross-country comparisons suggest shared risk factors for carcinomas, including male lung adenocarcinoma and colon cancer development

Smoking is clearly the major risk factor for both squamous cell carcinomas (SCCs) and adenocarcinomas (ACs) of the lung, although less so for the latter, where other influences appear to be important. In order to determine whether cross-country comparisons might provide evidence of shared risk factors with cancers in other organs of males, an examination of IARC/WHO data for cancer incidence was made for countries/registries in Europe, North America, Australia and Asia. Significant simple correlations, which persisted on partial analysis, were observed between lung SCCs and tumors of the larynx (P < 0.001), but not the buccal cavity or oesophagus, along with a link to rectal ACs (P < 0.001). Incidences of lung ACs also correlated with those for colon ACs (P < 0.001) but not lung SCCs. Oesophageal ACs were only related to colon cancers at the simple correlation level, this not persisting on partial analysis or separation into Asian and Western groups. The results suggest that blood borne factors, like hormones, may be important as determinants for the increasingly prevalent lung AC.