Screen: 5
Joseph Kwon, MD
Dallas, TX
Title: Predictive Factors for Oliogometastatic Renal Cell Carcinoma Patients Treated with Stereotactic Ablative Radiation (SAbR)
Purpose/Objective(s): SAbR has shown promise in controlling oligometastatic renal cell carcinoma (omRCC). While careful selection of patients is critical, the selection criteria for patients who will benefit from sequential SAbR afforded delay in systemic therapy (ST) remains unknown. To identify optimal patient selection criteria, we analyzed long-term follow-up of omRCC patients treated with sequential SAbR to derive predictors for patients who benefit the most from this strategy.
Materials/
Methods: We retrospectively reviewed omRCC patients with up to five sites of metastasis treated with curative intent and sequential SAbR from November 2007 to July 2022. Overall survival (OS), progression-free survival (PFS), local control (LC), and freedom from systemic therapy (FST) were analyzed using Kaplan-Meier analysis. Predictors for FST were analyzed using univariate and multivariate analysis. Local control assessments were made with RECIST 1.1 and toxicity assessments with CTCAE 5.0.
Results: We analyzed 153 patients who underwent SAbR to 337 metastases with a median follow-up of 27.0 months. Survival details are summarized in Table I. One-year and 3-year local control rates were 99.3% (97.2, 99.8) and 97.6% (93.2, 99.2) respectively. Patients with bone (one-year FST 47.9 months, p = 0.024) and brain (one-year FST 55.6 months, p = 0.015) metastases had lower FST on univariate analysis. Compared to the historically reported PFS of systemic therapy, the PFS of systemic therapies in our cohort were not significantly different (Ipi/Nivo 11.6 months vs 5.7 months; Pazopanib 8.4 months vs 10.5 months; Cabozantinib 7.4 months vs 19.2 months).
Conclusion: SAbR is safe and effective in controlling omRCC and is able to delay ST without compromising its efficacy. Bone and brain metastasis patients appear to do worse with sequential disease control with SAbR. Prospective studies are required to verify these findings.
| Abstract 3315 - Table 1: Survival estimates | |||
|
| Median (months) (95% CI) | 1-year (%) (95% CI) | 3-year (%) (95% CI) |
| Overall survival | 61.3 (50.7, 84.1) | 92.3% (86.5, 95.7) | 73.6% (64.3, 80.8) |
| Progression-free survival (n = 149) | 10.8 (8.8, 14.6) | 48.0% (39.4, 56.1) | 22.0% (14.6, 30.4) |
| Freedom from systemic treatment | 32.0 (21.1, 50.8) | 69.0% (60.7, 75.9) | 47.3% (37.4, 56.5) |
| Time on 1st systemic treatment (n = 75) | 10.0 (6.1, 15.9) | 45.3% (33.2, 56.7) | 11.4% (4.8, 21.2) |
| IO or IO/IO treatment (n = 18) | 5.7 (3.5, 31.8) | 29.6% (10.3, 52.1) | 14.8% (1.3, 43.4) |
| VEGF-I treatment (n = 45) | 15.4 (6.4, 19.2) | 54.6% (38.2, 68.3) | 13.0% (4.8, 25.4) |
|
|
|
|
|
| Nivolumab+Ipilimumab (n = 13) | 5.7 (3.4, 9.3) | 20.5% (3.8, 46.3) | - |
| Pazopanib (n = 29) | 10.5 (4.0, 20.9) | 48.3% (29.5, 64.8) | 17.2% (6.3, 32.7) |
| Cabozantinib (n = 5) | 19.2 (3.7, NR) | 75.0% (12.8, 96.1) | - |
| Local control (n = 300 lesions) | Not reached | 99.3% (97.2, 99.8) | 97.6% (93.2, 99.2) |