Stereotactic Body Radiation Therapy for the Definitive Treatment of Early Stage Kidney Cancer: A Survival Comparison With Surgery, Tumor Ablation, and Observation

Abstract

Purpose: Partial nephrectomy is the preferred definitive treatment for early stage kidney cancer, with tumor ablative techniques or active surveillance reserved for patients not undergoing surgery. Stereotactic body radiation therapy (SBRT) has emerged as a potential noninvasive alternative for patients with early stage kidney cancer not amenable to surgery, with early reports suggesting excellent rates of local control and limited toxicity. Methods and Materials: The national cancer database from 2004 to 2014 was queried for patients who received a diagnosis of T1N0M0 kidney cancer. Treatments were categorized as surgery (partial or total nephrectomy), tumor ablation (cryoablation or thermal ablation), SBRT (radiation therapy in 5 fractions or less to a total biological effective dose [BED 10 ] of 72 or more), or observation. A propensity score was generated by multinomial logistic regression. A Cox proportional hazards model was fit to determine association between overall survival and treatment group with propensity score adjustments for patient, demographic, and treatment characteristics. Results: A total of 165,298 received surgery, 17,196 underwent tumor ablation, 104 underwent SBRT, and 18,241 were observed. Median follow-up was 51 months. On multivariable analysis, surgery, tumor ablation, and SBRT were associated with a decreased risk of death compared with observation, with hazard ratios of 0.25 (95% confidence interval, 0.24-0.26, P < .001), 0.36 (0.35-0.38, P < .001), and 0.56 (0.39-0.79, P < .001), respectively. When stratifying by BED 10 and compared with observation, hazard ratio for risk of death for patients treated with SBRT to a BED 10 100 (n Z 62) and a BED 10 <100 (n Z 42) was 0.34 (0.19-0.60, P < .001) and 0.90 (0.58-1.4, P Z .64), respectively. Conclusions: In this population-based cohort, patients undergoing high-dose SBRT (BED 10 100) for early stage kidney cancer demonstrated longer survival compared with patients undergoing observation. This may be a promising noninvasive treatment option for nonsurgical candidates with prospective efficacy and safety assessments meriting study in future clinical trials.

Stereotactic body radiation therapy for kidney cancer. Where do we stand?

“…In terms of dose, there is a general consensus on administering a biologically equivalent 2 Gy dose (EQD2) higher than 100 Gy, although some studies suggest that surpassing 70 Gy would be enough 12,16,17 . The treatment is administered in 1–10 fx, being 3 fx the most employed and with no dose‐limiting toxicity reported in the dose escalation studies, such as the phase I study by Ponsky et al 4,16 .…”

“…Five‐year relapse‐free survival was 99.4% for partial nephrectomy versus 89.3% for ablative therapies. Moreover, Grant et al 17 . stratified SBRT treatments according to a biologically effective dose (BED) higher or lower than 100 Gy and observed that the subgroup with BED >100 Gy achieved better OS than the active surveillance group.…”

The Role of Daily Adaptive Stereotactic MR-Guided Radiotherapy for Renal Cell Cancer

“…This is a favorable result since online MRgRT plan adaptation is a time-consuming procedure. In this group of patients, MRgRT delivery will be faster, and these patients could be candidates for further hypofractionation [ 30 ].…”

Cryoablation for the Treatment of Kidney Cancer: Comparison With Other Treatment Modalities and Review of Current Treatment

“…RT provides an advantage when surgery is not indicated. One article conducted a population-based cohort study and found that SBRT led to longer survival compared to observation alone [ 37 ]. In patients with primary RCC, SBRT was observed to have a local control rate of above 90% with only a 0-9% chance of grades 3-4 toxicity [ 36 ].…”