Universal initial active surveillance (AS) for patients with small renal masses (SRMs) using predefined progression criteria can safely delay or avoid treatment for most patients with initial maximum tumor diameters less than 3 cm, according to study findings presented at the 20th annual meeting of the Society of Urologic Oncology in Washington, DC.

In a poster presentation, investigators led by Eric Kauffman, MD, of the Roswell Park Comprehensive Cancer Center in Buffalo, New York, reported their initial experience with a novel SRM management approach that includes a universal AS recommendation for all patients with SRMs who did not have progression at presentation and AS management using specific prospectively applied progression criteria for converting to treatment.

The study included 123 patients with SRMs who had more than 3 months of follow-up initially managed with AS. The initial median maximum tumor diameter was 2.2 cm (range 0.9-3.9 cm). The primary study outcome was progression-free survival (PFS).

Progression criteria for recommending treatment at presentation or during AS were absence of benign tumor biopsy histology plus any of the following: presence of a maximum tumor diameter greater than 4 cm; a tumor growth rate greater than 5 mm per year; maximum tumor diameter greater than 3 cm plus a tumor growth rate of 3 mm or greater per year; high-risk biopsy histology; tumor stage greater than cT3a stage; or symptoms.

During a median follow-up of 30 months, 35 patients (29%) met at least 1 progression criterion.

Patients with a maximum tumor diameter less than 2 cm, 2.1-3 cm, and greater than 3 cm had 3-year PFS rates of 83%, 75%, and 45%, respectively, Dr Kauffman and his colleagues reported. Metastasis-free survival rates for patients who progressed and did not progress was 100%.

Of the 35 patients who progressed while on AS, 28 (80%) converted to treatment (27 with surgery and 1 with ablation). Only 1 (1%) of 88 patients who did not progress converted to treatment because of anxiety or other causes. In addition, 61% of resected tumors had adverse renal cell carcinoma (RCC) pathology (high-grade tumors and/or stage pT3a disease).

The AS protocol can differentiate aggressive and indolent tumors for treatment selection by avoiding removal of benign tumors “and enriching resection for adverse RCC pathology,” the investigators concluded in their study abstract.

Dr Kauffman’s group noted that the risk of metastasis for patients with SRMs on AS is low and frequently outweighed by treatment-related morbidity or mortality. The current literature on AS for SRMs, they pointed out, is confounded by highly selected patients with SRMs who were unfit for treatment. Consequently, treatment rates and standardized progression criteria for triggering treatment for healthier patients with SRMs are not well defined.

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Reference

Menon A, White T, James G, et al. Initial outcomes for universal active surveillance of small renal masses using pre-defined progression criteria for treatment conversation. Presented at the 20th annual meeting of the Society of Urologic Oncology held December 4 to 6 in Washington, DC. Poster 172.