Peak rcc incidence occurs in patients more than 65 years of age 4 . Patients in that age group often have significant medical comorbidities that might affect the choice of therapeutic options.Management of srms must be individualized, because several patient-and tumour-related factors affect management strategy. The identification of these parameters necessitates revisiting the natural history of srms and the safety and efficacy of the various available treatment modalities.
NATURAL HISTORY OF SRMsUnderstanding the biologic behaviour and natural history of srms is crucial in predicting tumour growth and metastatic potential, so as to properly select the methods and optimal timing of intervention.
Pathologic FeaturesA significant number of srms will prove to be benign. Vasudevan et al. reported a 33% benign histology in 70 renal masses smaller than 5 cm 5 . Similarly, a report of 100 laparoscopic partial nephrectomies for a mean tumour size of 2.9 cm showed that 32% of the surgeries were performed for benign disease, as indicated by the final pathology specimen 6 .The common perception that srms are always indolent tumours is not completely true. Of renal masses smaller than 4 cm, 20%-30% are reported to be aggressive tumours with highly metastatic potential, even if dimensionally small 7,8 . Other reported series identified aggressive pathology features in 25%-38% of srms 7,9 . In addition, Hsu et al. also demonstrated extracapsular extension in 38% of 50 resected rccs smaller than 3 cm 7 .Lesions between 3 cm and 4 cm in diameter are most likely to have aggressive pathologic features. Perinephric fat invasion is found in 4.2% of tumours smaller than 2 cm, 14.9% of tumours 2.1-3 cm, and 35.7% of tumours 3.1-4 cm 9 . The Fuhrman grade of small rcc tumours is low in most cases; only 5%-6.5% of tumours 2-3 cm and 18.7%-25.5% of tumours 3-4 cm have a high Fuhrman grade (3 or 4) 9,10 .
ABSTRACTThe recent stage migration observed for renal tumours is contributing to a significant increase in the diagnosis of small renal masses. This evolution has led to a significant change in the approach to renal masses. New options such as observation or energy ablation are gaining popularity in a subset of this patient population. In addition, the observed changes directly contribute to the increased use of nephron-sparing surgery. A better understanding of the various characteristics of these masses will allow for a better understanding of the natural history of these masses and for selection of the optimal therapeutic approach.