# Outcomes and Predictors of Recurrence and Survival in Surgically Resected Localized Chromophobe Renal Cell Carcinoma: Results from the Canadian Kidney Cancer Information System (CKCis)

## TL;DR

This study finds that most patients with surgically removed chromophobe kidney cancer have good outcomes, but some with advanced disease face higher risks of recurrence and death.

## Contribution

The study identifies specific predictors of recurrence and survival in chromophobe renal cell carcinoma using a large Canadian cohort.

## Key findings

- Patients with localized chromophobe RCC had 93.6% recurrence-free survival at 5 years and 90.2% at 10 years.
- Predictors of recurrence included higher pT stage, sarcomatoid features, positive margins, and tumor necrosis.
- Overall survival was 94.5% at 5 years and 83.7% at 10 years, with predictors including high pT stage and older age.

## Abstract

Chromophobe renal cell cancer (chRCC) is an uncommon subtype of kidney cancer. This research focuses on patients who present with chRCC in their kidney and have it surgically removed. Baseline factors like sex, age, and size of tumour will be presented as well as pathological features of the cancer after surgical resection. This study shows that the majority of patients have very good outcomes, and cancer does not recur. There is, however, a subset of patients with more advanced disease in the kidney (higher stage and larger tumours) and other pathological features who have worse outcomes. Identifying these patients may help improve cancer outcomes in the future.

Chromophobe RCC (chRCC) represents 5–10% of all RCC; however, data regarding outcomes and predictors of recurrence and survival in localized disease are limited. The Canadian Kidney Cancer Information System (CKCis) is a multi-institutional prospective cohort. Patients who had surgical resection for clinically localized chRCC between January 2011 and July 2024 were included. Descriptive statistics were used, and cancer recurrence and time to death were estimated using Kaplan–Meier curves. Associations between baseline and tumour characteristics and recurrence and survival were assessed using Cox proportional hazards models. The study cohort included 790 patients. Median follow-up was 4.9 years, mean age was 57.8 years and 57.5% were male. Partial nephrectomy occurred in 52.7% and radical in 47.3%. Recurrence-free survival was 93.6% at 5 years and 90.2% at 10 years. In the 45 patients who recurred, 40 had metastatic disease, 3 had local recurrences, and 2 had new contralateral disease. Predictors of recurrence included a higher pT stage, sarcomatoid features, positive margins, and tumour necrosis. Overall survival was 94.5% at 5 years and 83.7% at 10 years. Predictors of death included high pT stage, increase in pathological size, and increasing age at diagnosis. In this large Canadian cohort, patients with surgically resected, localized chRCC had favourable 5- and 10-year oncologic outcomes. These favourable outcomes are a reminder that not all RCC patients with non-clear cell histologies should be pooled together as a single entity. There is, however, a subgroup of patients with less favourable outcomes who should be the focus of future research that aims to prevent recurrence and RCC death.