Overall Survival of Biopsy-confirmed T1B and T2A Kidney Cancers Managed With Observation: Prognostic Value of Tumor Histology

Jamie Michael; Nermarie Velazquez; Audrey Renson; Hung-Jui Tan; Tracy L Rose; Chelsea Osterman; Matthew Milowsky; Matt Raynor; Stella K Kang; William C Huang; Marc A Bjurlin

doi:10.1016/j.clgc.2020.12.006

Overall Survival of Biopsy-confirmed T1B and T2A Kidney Cancers Managed With Observation: Prognostic Value of Tumor Histology

Clin Genitourin Cancer. 2021 Aug;19(4):280-287. doi: 10.1016/j.clgc.2020.12.006. Epub 2021 Jan 6.

Authors

Affiliations

¹ School of Medicine, University of North Carolina, Chapel Hill, NC.
² Division of Urologic Oncology, Department of Urology, NYU Langone Health, New York, NY.
³ Department of Clinical Research, NYU Langone Hospital - Brooklyn, Brooklyn, NY.
⁴ Department of Urology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC.
⁵ Division of Oncology, Department of Medicine, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC.
⁶ Department of Radiology, NYU Langone Health, New York, NY; Department of Population Health, NYU School of Medicine, New York, NY.
⁷ Department of Urology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC. Electronic address: marc_bjurlin@med.unc.edu.

PMID: 33582101
DOI: 10.1016/j.clgc.2020.12.006

Abstract

Introduction: The natural history of T1b (4-7 cm) or T2a (> 7-10 cm) kidney cancers managed with observation is not well-understood. The aim of our study was to determine if the addition of histologic subtype to a predictive model of overall survival (OS) that includes covariates for competing risks in observed, biopsy-proven, T1b and T2a renal cell carcinomas (RCCs) improves the model's performance.

Materials and methods: We queried the National Cancer Database for patients with biopsy-proven stage T1b or T2a RCC and managed nonoperatively between 2004 and 2015. OS was estimated by Kaplan-Meier curves based on histologic subtype. The concordance index (c-index) from a Cox proportional hazards model was used to estimate the extent to which histologic subtypes predict survival for each stage when included in a model along with competing risks of age, gender, race/ethnicity, insurance status, area-level socioeconomic indicators, Charlson-Deyo index, and tumor grade.

Results: A total of 937 patients (754 with T1b and 185 with T2a) with biopsy-proven RCC were identified. Kaplan-Meier analysis suggested differences in OS by histologic subtype where sarcomatoid, followed by clear cell, papillary, and chromophobe, had the highest mortality risk at 1, 3, and 5 years. However, there was marginal improvement in the multivariable model of OS using competing risks and histology (c-index, 0.64 and 0.697) compared with competing risks alone (c-index, 0.631 and 0.671) for T1b and T2a RCCs, respectively.

Conclusions: In patients with T1b or T2a RCC managed with observation, incorporation of histologic subtype into a risk-stratification model to determine prognostic OS did not improve modeling of OS compared with variables representing competing risks. Histologic subtype of observed T1b and T2a RCC appears to have prognostic OS value when not considering competing risks. These findings may impact the usefulness of renal biopsy to inform decision-making when managing patients with T1b and T2a renal tumors with observation.

Keywords: Active surveillance; Histologic subtype; Overall survival; Renal cell carcinoma; Stage T1B and T2A.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Biopsy
Carcinoma, Renal Cell* / pathology
Carcinoma, Renal Cell* / therapy
Humans
Kidney Neoplasms* / pathology
Kidney Neoplasms* / therapy
Neoplasm Staging
Prognosis