(UroToday.com) Dr. Steven Monda gave a presentation sharing his team’s work on the association between tumor size and metastases. A greater proportion of incidental renal masses are being diagnosed at smaller sizes and among patients of older age. The current data that exists regarding the correlation between size and metastases is primarily based on single center nephrectomy registries. With more patients undergoing biopsy and active surveillance, it is crucial to update the current data. Thus, Dr. Monda and colleagues sought to create an updated assessment of renal masses’ metastatic potential for specific histologies and at varying tumor sizes. The goal was to determine what percentage of patients are metastatic at a given tumor size.
Within SEER data, 181,096 renal cell carcinoma (RCC) patients between 2004 and 2019 were evaluated for metastatic status upon presentation. All renal masses were of known size ranging between 0.5 to 20 cm. The histology was defined by ICD-O-3 diagnosis codes and non-localized disease was identified through assessment of nodal and metastatic staging. Assessments were specifically performed on clear cell (ccRCC), papillary (pRCC), and chromophobe (chrRCC), as well as RCC with sarcomatoid features (sarcRCC). The proportions of patients that were non-localized at various tumor sizes were reported in order to perform logistic regression, which was then used to establish statistical significance.
Dr. Monda explained how although metastatic potential is small at the thresholds established, it is still certainly present. Of note, 2-3 centimeters size tumors had a 1.5% risk of ccRCC and 1.3% in chrRCC; with every centimeter increase in size above this, the metastatic risk in turn increases. Across even larger tumor sizes, metastatic risk remains exceptionally low. Despite the small metastatic potential, Dr. Monda expressed how a “2.5% risk at 3-4 centimeters is still a significant risk in something that younger patients should be counseled around.” In conclusion, their study reported a much higher likelihood of metastatic disease across all tumor histology and sizes than the previous data from nephrectomy cohorts. The likelihood that a renal mass is metastatic upon presentation varies widely on its histology and size. As such, both are critical factors for physicians to consider when treating patients with renal masses.
Table 1. The proportion of patients with metastatic disease for a given size of primary
Figure 1. The incidence and proportion of metastatic disease for any RCC.
Figure 2. The metastatic proportion by size for each histology.
Presented by: Steven Monda, MD, Department of Urologic Surgery, University of California Davis, Sacramento, CA
Written by: Thao Vu, Department of Urology, University of California Irvine, @thaonvu_ on Twitter during the 2023 American Urological Association (AUA) Annual Meeting, Chicago, IL, April 27 – May 1, 2023