EAU 2018: U-SMART: (UCSD small mass ALT RENAL score tumor diameter) A novel scoring system of preoperative predictors to stratify oncologic risk of small renal masses
Better predictors of bad actors can help fine tune appropriate patients for AS. The group at UCSD, with a historical interest in the management of small renal masses and RCC, have developed a scoring system incorporating patient factors, serum markers, and morphometric characteristics to help discriminate benign disease from high grade pathology and thereby help guide clinical decision making.
This was a single-institution retrospective study, with its inherent limitations and flaws. They looked at surgically treated SRMs from 2003−2017. Demographic and clinical factors, blood work, and RENAL nephrometry scores were analyzed. Patients were categorized into 3 groups based on their surgical pathology: benign (BNGN), low grade (LG), or high grade (HG) disease.
Under this new scoring system (U-SMART), each significant variable was analyzed by risk group and broken into quartiles. The 75th percentile of the HG group was assigned a value of 3. Below the 75th percentile of the BNGN group was assigned a value of 1; values that fell between these cutoffs were assigned 2 points. Variables were summed to develop a comprehensive index score.
They identified 312 patients with SRMs, of which 65 were benign, 204 LG, and 43 HG. The benign and malignant cohorts were similar in terms of age, comorbidities (HTN, diabetes) and BMI. Patients with benign tumors were primarily female (55%) – which is usual as they are more common in female patients. The malignant tumors were also larger in size (2.53 vs. 1.89 cm).
Factors associated with increased risk of HG malignancy were male sex (OR 1.868, p=0.045), higher ALT (OR 1.036, p=0.022), higher RENAL score (OR 1.318, p=0.002), and larger tumor diameter (OR 2.415, p<0.001), so the scoring system was created based on these variables. Due to the binary outcome of sex, a score of 1−2 was applied. Due to an OR >2 on logistic regression, tumor diameter score emphasis was increased by doubling the points associated with it (2−6). All other variables retained a score of 1−3; final scores ranged 5−14.
Patients with low (5−8), intermediate (9−11) and high (12−14) scores had 32.8%, 5.2% and 0% frequency of BNGN pathology. Patients with low, intermediate and high scores had 7.7%, 18.6% and 34.9% frequency of HG pathology. ROC analysis revealed an area under the curve of 0.767 for the index score.
The authors report this as an initial scoring system to potentially help risk stratify patients. However, it is a surgically treated series and needs to be validated in an AS cohort and in external cohorts.
Speaker: Yim K
Co-Author(s): Bindayi A., Ryan S., Reddy M., Nasseri R., Hamilton Z., Derweesh I.
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark