2148 - Stereotactic Central/Core Ablative Radiation Therapy (SCART) for Recurrent Glioblastoma: A Multi-Center Case Series

03:00pm - 04:00pm ET

Poster Hall - Exhibit Hall A

Screen: 10

POSTER

Presenter(s)

Qiuxia Lu, MD - Foshan Fosun ChanCheng Hospital, Foshan, Guangdong

Q. Lu¹, W. Yan², Y. Li¹, E. M. Wang³, S. Li¹, J. Song⁴, X. Shi¹, and J. Yang⁴; ¹Foshan Fosun Chancheng Hospital, Foshan, Guangdong, China, ²College of Medicine, University of Kentucky, Lexington, KY, ³Huashan Hospital, Fudan University, Shanghai, Shanghai, China, ⁴Junxin Oncology Institute, Foshan, Guangdong, China

Purpose/Objective(s):

Glioblastoma (GBM) recurrence is nearly universal despite aggressive upfront therapy, and salvage options remain limited. Stereotactic central/core ablative radiation therapy (SCART) delivers an ablative dose to an intratumoral stereotactic target volume (STV) while maintaining a low dose (~5 Gy/fraction) at the gross tumor volume (GTV) boundary, potentially enabling treatment of larger tumors while mitigating normal tissue toxicity. We report real-world outcomes of SCART for recurrent GBM after standard-of-care therapy.

Materials/Methods: We retrospectively reviewed consecutive adults with recurrent GBM treated with SCART at two institutions. SCART plans prescribed an ablative dose to a central STV within the enhancing tumor core. Overall survival (OS) was measured from first SCART to death or last follow-up using the Kaplan–Meier method. Volumetric response was assessed using tumor volumes at follow-up imaging when available.

Results:

Nine patients underwent 11 SCART courses. Median age was 58 years (range, 43–83); 77.8% were male. IDH status was wild-type in 4 and unknown in 5. Core prescription schedules included 15 Gy × 1 (n=2), 15 Gy × 2 (n=2), 15 Gy × 3 (n=6), and 18 Gy × 3 (n=1), with core BED₁₀ ranging from 37.5–151.2 Gy. Median baseline GTV was 98.4 cm³ (range, 8.9–700.9) and median STV was 11.31 cm³ (range, 1.59–53.97). The median STV/GTV ratio was 13.4%. With median follow-up of 10.1 months, median OS from first SCART was 10.1 months; 6-, 12-, and 24-month OS rates were 66.7%, 44.4%, and 33.3%, respectively. Volumetric follow-up was available for 7 courses: all 7 demonstrated tumor volume reduction at first post-SCART assessment, with median best volumetric reduction of 60.4% (range, 10.8–95.7%).

Conclusion: This experience suggests that SCART can be effectively applied to recurrent GBM regardless of tumor size. By utilizing a partial-volume strategy, we observed consistent early tumor shrinkage and survival outcomes that align with other re-irradiation standards—even in cases where bulky disease precluded whole-volume dose escalation. These results support the need for prospective evaluation using standardized toxicity and response metrics. Prospective studies are now needed to standardize response and toxicity assessments for this technique.