Small renal masses (SRMs) usually have a favorable prognosis. Many studies have shown that cancer-specific survival (CSS) is comparable among various treatment options, such as partial nephrectomy, percutaneous thermal ablation, stereotactic body radiotherapy, and active surveillance (AS). Therefore, the choice of treatment should be based on patient background and tumor characteristics rather than on oncologic concerns alone. Important patient factors include age, comorbidities, renal function, and life expectancy. Tumor size, growth rate, and anatomical location also influence this decision. In older or frail patients, immediate intervention may represent overtreatment, as the risk of periprocedural complications and renal function loss may outweigh the limited oncological benefit. Recent AS studies have demonstrated excellent CSS and very low metastatic rates; however, many of these prospective cohorts included patients with limited life expectancies and relatively short follow-up periods, which limit their generalizability. This review summarizes the current evidence regarding local treatment options and surveillance strategies for SRMs, focusing on oncologic outcomes, renal function, and patient selection. Finally, we highlight the rationale and design of the ongoing JCOG2409 prospective comparative study in medically operable adults aged ≥75 years with a solitary renal mass that evaluates standardized AS versus upfront interventions.
Japanese journal of clinical oncology. 2026 May 02 [Epub ahead of print]
Goshi Kitano, Takahiro Kojima, Takahiro Osawa, Haruka Miyata, Kazuyuki Numakura, Hiroshi Kitamura
Department of Urology, Aichi Cancer Center, 1-1 Kanokoden, Chikusa-ku, Nagoya, Aichi JP 464-861, Japan., Department of Urology and Molecular Oncology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata JP 951-8510, Japan., Department of Urology, Hokkaido University Hospital, Kita 14, Nishi 5, Kita-ku, Sapporo, Hokkaido JP 060-8648, Japan., Department of Renal and Urologic Surgery Asahikawa, Medical University, 2-1-1-1 Midorigaoka-higashi, Asahikawa, Hokkaido JP 078-8510, Â Japan., Department of Urology, Faculty of Medicine, University of Toyama, 2630 Sugitani, Toyama, Toyama JP 930-0194, Japan.