**2. Epidemiology of RCC in hemodialysis patients**

Patients with ESRD on dialysis have more than 100 times greater risk of RCC than age-matched healthy controls [20-22]. In a series of 831, 804 dialysis patients followed up for an average of 2. 5 years, 2, 053 (0. 25%) patients were diagnosed as having RCC, representing a 3. 6-fold increased risk over the general population [23]. Kojima et al. reported that in a cohort of 2, 624 patients 81. 8% developed ACDK during a median dialysis time of 11 years and that 1. 68% developed RCC [24]. The risk is considered to be progressively higher in patients with a longer duration of dialysis. According to some recent publications, a long duration of dialysis (> 10y) has a stronger association with ACD-associated RCC than other subtypes of RCC [25-27]. In a multicenter retrospective study by Neuzillet et al. , RCC developing in patients with ESRD has many favorable clinical, pathologic, and outcome features compared with RCC in patients without ESRD.

According to a multicenter retrospective study, more patients diagnosed as having RCC are young and asymptomatic in the ESRD group than the non-ESRD counterpart [28]. Denton et al. reported that of 260 patients who underwent ipsilateral native nephrectomy at the time of transplantation, 11 (4. 2%) diagnosed as RCC with short duration of hemodialysis, and age was significant risk factor of RCC [11]. In ESRD patients, modality of dialysis does not appear to associate with the incidence of RCC; the incidence of RCC is almost same in patients on hemodialysis and those on peritoneal dialysis. Savaji et al. reported the annual incidence of RCC was estimated to be 130 per 100, 000 patients on peritoneal dialysis [29].
