Main Session

Sep 28

PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology

2685 - Palliative Radiotherapy for Metastases to the Calvarium and Skull Base: A Systematic Review and Pooled Analysis

03:00pm - 04:00pm ET

Poster Hall - Exhibit Hall A

Screen: 23

POSTER

Presenter(s)

Aquila Akingbade, MD - Western University, London, ON

A. Akingbade^1,2, S. Shahhat^1,2, E. Akingbade³, and T. Nguyen^1,2; ¹Western University, London, ON, Canada, ²Department of Radiation Oncology, London Health Sciences Centre, London, ON, Canada, ³Faculty of Health, School of Kinesiology and Health Science, York University, Toronto, ON, Canada

Purpose/Objective(s):

Skull metastases (SM) frequently cause pain, cranial neuropathies, and other neurologic deficits that impair quality of life. Palliative radiotherapy (RT) is a non-invasive treatment option, but techniques and outcomes vary. We systematically reviewed and pooled available evidence.

Materials/Methods:

PubMed, EMBASE, and Cochrane (Jan 1990–Sep 2023) were searched for studies evaluating primary RT for SM. Studies of primary skull malignancies, brain parenchymal metastases, non-English reports, without quantitative endpoints, post-operative cohorts, or series with <5 patients were excluded. Technique, local control (LC), overall survival (OS), symptom response, and toxicity were extracted. Kaplan–Meier LC (6/12 months) and OS (6/12/24 months) proportions were pooled using random-effects meta-analysis of logit-transformed proportions. As standard errors and 95% CIs were unavailable, event counts were approximated from each study’s proportion and sample size; heterogeneity was summarized with I² and t².

Results:

Of 5027 records, 12 studies, all retrospective, met criteria, comprising 290 patients treated between 1980–2020; 10 (83%) were full-text. Eleven studies focused exclusively on skull base lesions; one included both skull base and calvarium lesions. Reported median follow-up ranged 1–45 months (overall range 0–102). Reported median age ranged 53.5–73 years (range 29–88). Median time from primary diagnosis to SM (n=6) ranged 16–52.7 months (range 0–339.4 months). Techniques included fractionated stereotactic RT (n=4), conventional external beam RT (n=4), stereotactic radiosurgery (n=2), and mixed approaches (n=2). Median dose ranged 15–39 Gy (overall range 8Gy/1–60Gy/4 fractions). Median planning target volume (n=6) ranged 2.9–61.6 cm³ (overall range 0.28–112 cm³). Pooled LC was 87.2% at 6 months (95% CI 20.1–99.5; I² 76.4; t² 1.22; n=3) and 78.5% at 12 months (95% CI 49.4–93.2; I² 64.5; t² 0.39; n=4). Pooled OS was 58.2% at 6 months (95% CI 14.2–92.2; I² 87.7; t² 1.54; n=4), 50.9% at 12 months (95% CI 20.2–80.9; I² 82.6; t² 1.05; n=5), and 27.7% at 24 months (95% CI 7.7–63.9; I² 75.2; t² 0.67; n=4). Significant heterogeneity was observed across endpoints. Among studies reporting baseline symptoms (n=10), 75–100% of patients were symptomatic; pooled symptom response (complete/partial) was 77.8% (95% CI 65.5–88.1; I² 71.0; n=11) and pooled non-response (stable/progressive) was 20.1% (95% CI 9.3-33.8%). Acute toxicity (n=8 studies) was predominantly grade 1–2 (alopecia, fatigue, headache, nausea, erythema) with no grade 4–5 events; late toxicity was rare.

Conclusion:

Survival after SM is limited, but RT achieves excellent LC and clinically meaningful symptom relief with predominantly low-grade toxicity. Substantial variation in technique, dose and fractionation likely contributed to heterogeneity, supporting the need for standardized reporting and prospective studies to define optimal palliative regimens.