Oncocytic Renal Neoplasms Developed Distant Metastases: Long-term Follow-up in Two Health Systems

Document Type

Conference Proceeding

Publication Date

5-2025

Publication Title

Journal of Urology

Abstract

INTRODUCTION AND OBJECTIVE: The 2022 WHO guidelines advise against diagnosing oncocytoma on needle biopsy alone due to limited sampling and similarities with malignant tumors. This shift to classifying localized renal masses as “oncocytic renal neoplasm (ORN), not further classified” impacts clinical practice, as patients eligible for active surveillance (AS) no longer receive reports indicating benign pathology. Limited long-term data on ORN and new entities within this group have raised concerns. This study provides extended follow-up on patients with ORN diagnoses from two institutions to assess metastasis risk.

METHODS: Patients diagnosed with ORN at Corewell Health and Fox Chase Cancer Center (1998-2023) were reviewed. The ORN category includes oncocytoma, chromophobe renal cell carcinoma (RCC), and other rare oncocytic tumors. Chart reviews assessed recurrence, classifying cases as no recurrence, local recurrence (same/contralateral kidney), or distant recurrence.

RESULTS: Among 896 ORN patients, 94 (10%) were managed without intervention and surgery was performed in 802 (90%) patients at a median of 34 days after diagnosis. Median follow-up was 5.4 years (IQR: 2.7-9.7) for the entire cohort, with deaths observed in 160 patients (median: 7.0 years after dx). Biopsy and surgery pathology are in Table 1. 865 patients (97%) had no recurrence, 12 (1.3%) had local recurrence, and 19 (2.1%) had distant recurrence, and only occurred in chromophobe RCC, with no recurrences in oncocytoma or other ORN types. For 454 patients with localized (T1N0M0) ≤5 cm N0 M0, no distant recurrences occurred at a median follow-up of 5.1 years (IQR: 1.9-9.1) (Table 1).

CONCLUSIONS: This study provides long-term data on patients with ORN of all types, ranging from chrom RCC to oncocytoma. While a subset of chromophobe RCC patients with larger tumors developed distant metastases, no recurrence occurred in oncocytoma or hybrid neoplasms. Approximately 1% of ≤5 cm T1N0M0 ORN cases had local recurrence, reflecting the multifocal nature of these tumors, but none progressed to metastasis. These findings support AS for small, localized ORN, bolstering evidence for AS in this group.

Volume

213

Issue

5 Suppl

First Page

e11

Last Page

e11

Comments

American Urology Association Annual Meeting, April 26-29, 2025, Las Vegas, NV

DOI

10.1097/01.JU.0001109704.44053.60.02

ISSN

1527-3792

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