Impact of smoking on the age at diagnosis of upper tract urothelial carcinoma: Subanalysis of the Japanese Urological Association multi-institutional national database

Objectives: To examine the influence of smoking history on the diagnosis and other tumor characteristics of upper tract urothelial carcinoma in Japan. Methods: A total of 1509 patients with upper tract urothelial carcinoma who were diagnosed in 2005 from 348 Japanese institutions were registered using the multi-institutional national database of the Japanese Urological Association and included in this analysis. Clinical data of the patients were collected in 2011. The associations between the patients' self-reported smoking history and their age at the diagnosis of upper tract urothelial carcinoma, sex, pathological T stage and tumor grade were analyzed. Results: The mean age at the diagnosis of upper tract urothelial carcinoma was approximately 5 years earlier for the 238 current smokers than for the 618 current non-smokers (P < 0.0001). Similar associations between smoking and the early diagnosis of upper tract urothelial carcinoma were shown in the sex subgroups and in subgroups stratified by pathological T stages. Among the current smokers, the age at diagnosis for the smoking ≥20 cigarettes per day group was 6.5 years lower than that of the <20 cigarettes per day group, which was significantly different (P < 0.0001). Conclusion: Current smoking is a significant risk factor for the earlier diagnosis of upper tract urothelial carcinoma. The finding is important from the perspective of both healthcare and medical economies.