Multiple tumors in the same kidney: incidence and therapeutic implications.

Conservative surgery is proposed by many authors for small kidney tumors. We reviewed retrospectively the pathology reports of 727 operated patients. In 257, tumor diameter was less than or equal to 5 cm, in 158 it was less than or equal to 4 cm, and in 78 it was less than or equal to 3 cm. The number of multiple tumors were 26 (10.1%), 17 (10.75%), and 10 (12.8%) respectively, which means that there is a 10% potential risk of leaving a tumor in situ in case of conservative surgery. There is no security size limit. These parameters have to be considered before proposing conservative surgery for small kidney tumors as a standard treatment.