Objective: To investigate the incidence of renal cell carcinoma, classified by sex, age group and region in Japan, following a 5-year interval after a previous survey performed in 1997.
Methods:The survey was conducted between the beginning of January 2002 and the end of December 2002. A total of 1288 institutions in all 47 prefectures throughout Japan were requested to register cases. Results: There were 7405 persons with renal cell carcinoma, consisting of 5063 males and 2342 females. Crude incidence rates were 8.2 and 3.6 per 100 000 population for men and women, respectively. Incidence rates in the Hokkaido region were highest followed by the Shikoku region. Conclusions: Despite incidence of renal cell carcinoma increasing to 7405 from the 6358 persons in 1997, statistical data reported by the Ministry of Health, Labor and Welfare indicate that rising age-adjusted death rate for this tumor reached a ceiling in the past decade. Early detection may have contributed to this current trend; however, further epidemiological research is required to fully elucidate this. Key words: epidemiology, incidence, Japan, renal cell carcinoma.
IntroductionRenal cell carcinoma (RCC) is a relatively common tumor, accounting for approximately 3% of adult malignancies.1 Currently, increased use of imaging procedures during routine medical check-ups or by chance during follow-up examination for other diseases provides increased discovery of this carcinoma in its early stages.2 This disease is best treated by surgical removal with an excellent survival rate if found early. However, once the disease has become metastatic or recurrent, it has a poor prognosis with median survival time of 10 months, 3 even after cytokine therapy using interferon or interleukin-2 with a global response rate of 15%. 4 A previous nationwide study to investigate prevalence of RCC in 1997 showed 6358 persons with a diagnosis of RCC (4372 men and 1986 women).5 After an interval of 5 years since the previous study, the present study was conducted with the approval of the Scientific Committee of the Japanese Urological Association, to investigate the change in incidence of RCC and obtain some insight into developing strategies for treatment of RCC.
Methods
Description of registered patientsThe survey was conducted on RCC diagnosed between the beginning of January 2002 and the end of December 2002. Patients with clinically diagnosed RCC, for whom pathological diagnosis had not been made, were included; however, patients pathologically diagnosed to not be RCC (i.e. transitional cell carcinoma, nephroblastoma, nonepithelial tumors or others) were excluded from the study. All contributing institutions were asked to exclude patients treated elsewhere prior to visiting the institutions included in this study, to avoid possible duplicate registrations.
Data collectionRegistration was requested from 1306 general hospitals and clinics in 47 prefectures in Japan, with at least one full-time urologist on their staff. These institutions included 102 medical university h...