World Health Organization Classification of Tumours Pathology and ...

Renal cell carcinomaJ.N. EbleK. TogashiP. PisaniDefinitionRenal cell carcinoma is a group of malignanciesarising from the epithelium of therenal tubules.Epidemiology of renal cell cancerRenal cell cancer (RCC) represents onaverage over 90% of all malignancies ofthe kidney that occur in adults in bothsexes. Overall it is the 12th most commonsite in men and 17th in women. Inmales living in industrialized areasincluding Japan, it is as common as non-Hodgkin lymphoma ranking 6th, while inless developed areas it ranks 16th, in thesame order of magnitude as carcinomaof the nasopharynx. In women it ranks12th and 17th in developed and developingcountries respectively {749}. Theincidence is low in the African and Asiancontinents but not in Latin America wherearound 1995 Uruguay recorded one ofthe highest rates in the world. The highestrates in both men and women wereobserved in the Czech Republic with 20and 10 annual new cases per 100,000population respectively, age standardized{2016}. The lowest rates recordedwere less that 1 new case per 100,000showing a 10-fold variation in the risk ofthe disease. The latest systematic analysesof time trends of the incidence of kidneycancer indicate a general increase inboth sexes in all monitored regions, upuntil the mid-80s {481}. These trendswere paralleled by mortality, which thereafterbegan to slow down or even fall insome high risk countries {2843}. After thelow peak in children due to nephroblastoma,the incidence of renal cell cancerincreases steadily after age 40 years asmost epithelial tumours but the risk levelsoff or even declines from age 75 in bothsexes. It is two to three times more commonin men than in women in both highand low risk countries {2016}.EtiologyTobacco smoking is a major cause of kidneycancer and accounts for at least39% of all cases in males {2015}.Exposure to carcinogenic arsenic compoundsin industrial processes orthrough drinking water increases the riskof renal cancer by 30% {1150}. Severalother environmental chemicals havebeen addressed as possible carcinogensfor the kidney but definitive evidencehas not been established. Theseinclude asbestos, cadmium, someorganic solvents, pesticides and fungaltoxins. Some steroidal estrogens and thenonsteroidal diethylstilboestrol inducetumours in hamster {1150,1154}, but todate an excess has not been reported inexposed humans. Estrogens could beMalesinvolved in the mechanism that inducesRCC in overweight and obese individuals.Several epidemiological studies bothprospective and retrospective, conductedin many different populations haveestablished that the risk of kidney cancerincreases steadily with increasing bodymass index (BMI), the most commonmeasure of overweight {1156}. The incidenceof RCC in obese people (BMI>29kg/m 2 ) is double that of normal individualsand about 50% increased if overweight(BMI 25-30 kg/m 2 ) {221}. Thesame authors estimated that in EuropeFemalesFig. 1.01 Estimates of the age-standardized incidence rates of kidney cancer, adjusted to the world standardage distribution (ASR). From Globocan 2000 {749}.12 Tumours of the kidney