Renal lesions with low R.E.N.A.L nephrometry score are associated with more indolent renal cell carcinomas (RCCs) or benign histology: findings in an Australian cohort

Abstract

OBJECTIVE• To validate the relationship of the R.E.N.A.L nephrometry score to histological features of renal lesions treated by surgical excision by radical nephrectomy (RN) or nephron-sparing surgery (NSS) at an Australian tertiary referral centre. PATIENTS AND METHODS• Patients undergoing surgery between 2005 and 2009 with imaging studies available were included.• The R.E.N.A.L. nephrometry score is an objective measure of factors important in determining suitability for NSS, e.g. size, exophytic nature, proximity to collecting system and polar location, and R.E.N.A.L scoring was done using the online template at www.nephrometry.com .• Pathological details were collected by retrospective chart review.• Comparisons were made using chisquared or Fisher ' s exact tests and trends analysed by linear regression. RESULTS• The rate of benign pathology decreased from 12/58 (20.7%) low-complexity lesions to 1/16 (6.2%) high-complexity lesions ( P = 0.09), renal cell carcinomas (RCCs) were stable between 45/58 (77.6%) and 13/16 (81.2%), but other malignancies increased ( P = 0.058) from 1/58 (1.7%) to 2/16 (12.5%).• Among the RCCs, high vs low R.E.N.A.L score was associated with an increasing risk of clear cell histology (84.6% vs 64.4%, P < 0.05), stage ≥ pT3 (76.9% vs 8.9%, P < 0.001) and grade 4 tumours (15.4% vs 2.2%, P < 0.05), and conversely with a lower risk of papillary histology (0% vs 24.4%, P < 0.02) and stage T1a (0% vs 84.4%, P < 0.001). CONCLUSIONS• Increasing R.E.N.A.L score is associated with histological features of tumour aggressiveness, thus reinforcing the need for RN for lesions with a high score, and conversely the safety of NSS or observation for lesions with a low score.

Editorial Comment from Dr Mitsui to Association of RENAL nephrometry score with outcomes of minimally invasive partial nephrectomy

“…Second, RNS was significantly correlated with histological findings of renal masses, as previously shown in other studies . Recent advances in imaging technology have led to earlier detection of asymptomatic and organ‐confined renal masses of smaller size.…”

Clinical analysis of the PADUA and the RENAL scoring systems for renal neoplasms: A retrospective study of 245 patients undergoing laparoscopic partial nephrectomy

“…A study by Satasivam et al . showed that an increasing RENAL score is associated with histological features of tumor aggressiveness . Ficarra et al .…”

A Literature Review of Renal Surgical Anatomy and Surgical Strategies for Partial Nephrectomy

“…External validation revealed an area under the curve of 73% for prediction of high-grade disease [40]. Likewise, recent studies showed that higher tumor complexity according to the RENAL score is associated with high-grade disease and clear-cell subtype [41,42]. …”