Intraoperative or postoperative stereotactic radiotherapy for brain metastases: time to systemic treatment onset and other patient-relevant outcomes

Cerebellar glioblastoma in adults: a comparative single-center matched pair analysis and systematic review of the literature

PURPOSE

The rarity of cerebellar glioblastoma presents a significant challenge in clinical practice due to the lack of extensive prognostic data on long-term survival rates, rendering it an underrepresented entity compared to its supratentorial counterpart. This study aims to analyze potential differences in survival outcome between patients with cerebellar and supratentorial glioblastomas.

METHODS

From 2009 to 2020, 8 patients underwent surgical treatment for cerebellar glioblastoma at the authors' institution. These patients were individually matched with a cohort of 205 consecutive patients from our institutional database with supratentorial glioblastoma, taking into account key prognostic parameters. Progression-free survival (PFS) and overall survival (OS) rates were compared. Additionally, we performed a systematic literature review to compile further survival data on cerebellar glioblastoma patients.

RESULTS

The median OS for cerebellar glioblastoma patients was 18 months (95% CI 11-25). The balanced matched-pair analysis showed no significant difference in survival when compared to patients with supratentorial glioblastoma, exhibiting a median OS of 23 months (95% CI 0-62) (p = 0.63). Respective values for PFS were 8 months (95% CI 4-12) for cerebellar and 7 months (95% CI 0-16) for supratentorial glioblastoma (p = 0.2). The systematic review revealed that median OS for cerebellar glioblastoma in current literature ranges from 7 to 21 months.

CONCLUSIONS

The present findings indicate that patients with supra- and infratentorial glioblastoma do not significantly differ in regard to survival outcome parameters. This similarity in prognosis might encourage clinicians to consider surgical interventions for both supra- and infratentorial glioblastoma in a similar manner.

Intraoperative radiotherapy after neurosurgical resection of brain metastases as institutional standard treatment- update of the oncological outcome form a single center cohort after 117 procedures

PURPOSE

Stereotactic radiotherapy (SRT) is the predominant method for the irradiation of resection cavities after resection of brain metastases (BM). Intraoperative radiotherapy (IORT) with 50 kV x-rays is an alternative way to irradiate the resection cavity focally. We have already reported the outcome of our first 40 IORT patients treated until 2020. Since then, IORT has become the predominant cavity treatment in our center due to patients´ choice.

METHODS

We retrospectively analyzed the outcomes of all patients who underwent resection of BM and IORT between 2013 and August 2023 at Augsburg University Medical Center (UKA).

RESULTS

We identified 105 patients with 117 resected BM treated with 50 kV x-ray IORT. Median diameter of the resected metastases was 3.1 cm (range 1.3 - 7.0 cm). Median applied dose was 20 Gy. All patients received standardized follow-up (FU) including three-monthly MRI of the brain. Mean FU was 14 months, with a median MRI FU for patients alive of nine months. Median overall survival (OS) of all treated patients was 18.2 months (estimated 1-year OS 57.7%). The observed local control (LC) rate of the resection cavity was 90.5% (estimated 1-year LC 84.2%). Distant brain control (DC) was 61.9% (estimated 1-year DC 47.9%). Only 16.2% of all patients needed WBI in the further course of disease. The observed radio necrosis rate was 2.6%.

CONCLUSION

After 117 procedures IORT still appears to be a safe and appealing way to perform cavity RT after neurosurgical resection of BM with low toxicity and excellent LC.

Multicentric Assessment of Safety and Efficacy of Combinatorial Adjuvant Brain Metastasis Treatment by Intraoperative Radiation Therapy and Immunotherapy

PURPOSE

After surgical resection of brain metastases (BMs), intraoperative radiation therapy (IORT) provides a promising alternative to adjuvant external beam radiation therapy by enabling superior organ-at-risk preservation, reduction of in-hospital times, and timely admission to subsequent systemic treatments, which increasingly comprise novel targeted immunotherapeutic approaches. We sought to assess the safety and efficacy of IORT in combination with immune checkpoint inhibitors (ICIs) and other targeted therapies (TTs).

METHODS AND MATERIALS

In a multicentric approach incorporating individual patient data from 6 international IORT centers, all patients with BMs undergoing IORT were retrospectively assessed for combinatorial treatment with ICIs/TTs and evaluated for toxicity and cumulative rates, including wound dehiscence, radiation necrosis, leptomeningeal spread, local control, distant brain progression (DBP), and estimated overall survival.

RESULTS

In total, 103 lesions with a median diameter of 34 mm receiving IORT combined with immunomodulatory systemic treatment or other TTs were included. The median follow-up was 13.2 (range, 1.2-102.4) months, and the median IORT dose was 25 (range, 18-30) Gy prescribed to the applicator surface. There was 1 grade 3 adverse event related to IORT recorded (2.2%). A 4.9% cumulative radiation necrosis rate was observed. The 1-year local control rate was 98.0%, and the 1-year DBP-free survival rate was 60.0%. Median time to DBP was 5.5 (range, 1.0-18.5) months in the subgroup of patients experiencing DBP, and the cumulative leptomeningeal spread rate was 4.9%. The median estimated overall survival was 26 (range, 1.2 to not reached) months with a 1-year survival rate of 74.0%. Early initiation of immunotherapy/TTs was associated with a nonsignificant trend toward improved DBP rate and overall survival.

CONCLUSIONS

The combination of ICIs/TTs with IORT for resected BMs does not seem to increase toxicity and yields encouraging local control outcomes in the difficult-to-treat subgroup of larger BMs. Time gaps between surgery and systemic treatment could be shortened or avoided. The definitive role of IORT in local control after BM resection will be defined in a prospective trial.