Growth kinetics of small renal masses: A prospective analysis from the Renal Cell Carcinoma Consortium of Canada

Abstract

Introduction: Most small renal masses (SRMs) are diagnosed incidentally and have a low malignant potential. As more elderly patients and infirm patients are diagnosed with SRMs, there is an increased interest in active surveillance (AS) with delayed intervention. Patient and tumour characteristics relating to aggressive disease have not been well-studied. The objective was to determine predictors of growth of SRMs treated with AS. Methods: A multicentre prospective phase 2 clinical trial was conducted on 207 SRMs in 169 patients in 8 institutions in Canada from 2004 to 2009; in these patients treatment was delayed until disease progression. Patient and tumour characteristics were evaluated to determine predictors of growth of SRMs by measuring rates of change in growth (on imaging) over time. All patients underwent AS for presumed renal cell carcinoma (RCC) based on diagnostic imaging. We used the following factors to develop a predictive model of tumour growth with binary recursive partitioning analysis: patient characteristics (age, symptoms at diagnosis) and tumour characteristics (consistency [solid vs. cystic] and maximum diameter at diagnosis. Results: With a median follow-up of 603 days, 169 patients (with 207 SRMs) were followed prospectively. Age, symptoms at diagnosis, tumour consistency and maximum diameter of the renal mass were not predictors of growth. This cohort was limited by lack of availability of patient and tumour characteristics, such as sex, degree of endophytic component and tumour location. Conclusion: Slow growth rates and the low malignant potential of SRMs have led to AS as a treatment option in the elderly and infirm population. In a large prospective cohort, we have shown that age, symptoms, tumour consistency and maximum diameter of the mass at diagnosis are not predictors of growth of T1a lesions. More knowledge on predictors of growth of SRMs is needed.

The role of active surveillance of small renal masses

“…(18) A further analysis on this cohort of patients revealed that patient age, symptoms at diagnosis, tumour pattern and maximum diameter were not predictors of the growth of SRMs. (25) Finally, Pierorazio during AS (cancer-specific survival 100%), while the overall survival in this group of patients was respectively 96% and 75% at 2 and 5 years compared to 98% and 96% in the active intervention group. (23) Further analysis based on the DISSRM registry has recently shown that patients on active surveillance have a better preservation of renal function assessed by eGFR compared to patients who undergo radical nephrectomy, but not to those who underwent partial nephrectomy.…”

Small renal masses in the era of personalized medicine: Tumor heterogeneity, growth kinetics, and risk of metastasis

“…They showed that none of the evaluated factors (age, symptoms at diagnosis, tumor consistency, and maximum diameter of the mass) significantly predicted tumor growth. After a median follow-up of more than 18 months, the median growth rate was 0.12 cm/y [45].…”

Active surveillance for clinically localized renal tumors: An updated review of current indications and clinical outcomes

“…Notably, no significant clinical or radiological predictors of growth kinetics were found. 60 The predictive role of tumor dimension at the time of presentation has been a matter of debate in literature. In the study by Schiavina et al, the size was not a significant predictor of growth kinetics.…”