AUA 2017: The nuclear grade and prognosis are unrelated to the TNM stage in multilocular cystic renal cell neoplasm of low malignant potential

Boston, MA ( There are numerous subtypes of renal cell carcinoma (RCC), and the aggressiveness of the subtypes can vary substantially. As the literature grows, we have come to realize that there are many relatively indolent, incidentally found subtypes of RCC. Multilocular cystic clear cell renal cell neoplasm of low malignant potential, also known as multilocular cystic renal cell carcinoma (MCRCC) is one of those subtypes.

In this study, the authors provide their single-institution retrospective review of 76 cases identified over an 8 year period. In their institution, this represented 1.7% of the 4345 cases of RCC. The authors subsequently go on to note that most of the patients were asymptomatic and young (mean age 46.7 years). Their main findings, however, are that the nuclear grade was unrelated to the TNM stage (P=0.451). Of the 76 patients, 66 (86.8%) were followed up for a median of 52 months (<5 years), and no tumor recurrence or metastasis was found, no differences were found in the prognosis of different TNM groups.

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With no recurrence or progression, I feel it is hard for them to make any conclusion on the effect of TNM stage and nuclear grade on outcomes. Additionally, as the majority of the patients had <4 cm, Fuhrman grade 1, pT1a, we wouldn’t expect poor prognosis anyway. The authors should be careful about making such statements with limited follow-up and no events.

Additionally, the authors did not comment on the role of renal tumor biopsy in their practice and whether that may affect management.

However, prior work by our colleagues at the University of Toronto demonstrated similarly good outcomes with MCRCC (Bhatt et al. 2016) using a provincial cancer registry in Canada. Both of these studies establish that MCRCC is likely an indolent disease that is being over-treated.

The authors do suggest that follow-up can be extended to help reduce unnecessary imaging.

Bhatt JR, Jewett MA, Richard PO, Kawaguchi S, Timilshina N, Evans A, Alibhai S, Finelli A. Multilocular Cystic Renal Cell Carcinoma: Pathological T Staging Makes No Difference to Favorable Outcomes and Should be Reclassified. J Urol. 2016 Nov;196(5):1350-1355. doi: 10.1016/j.juro.2016.05.118. Epub 2016 Jun 21.

Presented by: Teng Li, PhD

Co-Authors: Kan Gong, Xianghui Ning, Shuanghe Peng, Jiangyi Wang, Qun He, Xinyu Yang

Written By: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto
Twitter: @tchandra_uromd

at the 2017 AUA Annual Meeting - May 12 - 16, 2017 – Boston, Massachusetts, USA