[Epidemiology of tumors of the renal parenchyma]

Renal cell carcinoma is responsible for about 2% of all cancer deaths in developed countries and represents 80-85% of all tumors of the kidney. Its etiology is still largely undefined. Its incidence varies among countries, with the highest rates in North Americans and Scandinavians. Its incidence is steadily rising in the last ten years. The location of the tumor suppressor gene on chromosome 3p has contributed to the understanding of tumor pathogenesis. Renal cell carcinoma occurs nearly twice as often in men as in women. Patients are generally more than 40 years old at diagnosis, usually in the fifth to seventh decade of life. This tumor is more common among urban than rural residents, but it was not a consistent association with education or socio-economic status. Recently large epidemiologic studies showed an increased risk of renal-cell cancer in relation to tobacco smoking, with a relative risk of about 2 for current smokers. Other established risk factors are elevated body mass index (mainly in women) and a family history of the disease. Occupational exposure to chemicals appears to have little significance, although associations with specific products, such as asbestos fibres, have been reported. Some relationship has been observed between renal-cell cancer and hypertension, use of anti-hypertensives and kidney diseases, although this issue remains open to discussion. Data are inconsistent on the role of nutrition, mainly for fats and proteins, while vegetable and fruit consumption seems to convey some protection on renal-cell cancer risk. The risk of renal-cell cancer was not materially elevated in relation to coffee, tea and alcohol intake and, in women, oral contraceptive use, hormone replacement therapy, and menstrual factors.