Comparison of Two Palliative Hypofractionated Radiotherapy Regimens in Poor-Prognosis High-Grade Glioma: A Propensity-Matched Analysis.

Purpose/Objective(s) The prognosis of high-grade glioma (HGG) in elderly patients (> 65 years) and/or those with low Karnofsky performance status (KPS ≤60) is generally poor with an expected median survival of 6-10 months despite aggressive multi-modality treatment. The most optimal therapeutic regimen including radiotherapy (RT) dose-fractionation for this group remains an area of active research. In the last two decades, hypofractionated RT using high-dose per fraction (> 2.5-5 Gy/fraction) has been tested as a resource-sparing alternative to conventionally fractionated RT with significant reduction in the number of fractions to limit patient visits and/or shorten overall duration of treatment while achieving similar disease-related outcomes. The present study aimed to assess compliance to planned RT and overall survival (OS) in patients treated with two hypofractionation regimens. Materials/Methods Patients with poor-prognosis HGG (elderly and/or poor performance status) receiving post-operative palliative-intent hypofractionated RT following maximal safe resection were included. Hypofractionation comprised of long-course (LC) RT delivering 35 Gy/7 fractions, 5 Gy/fraction, once-weekly over 6-weeks (N = 100) or short-course (SC) RT delivering 35 Gy/10 fractions, 3.5 Gy/fraction, 5 fractions per week over 2-weeks (N = 55). None of the patients were treated with concurrent temozolomide (TMZ) but received adjuvant TMZ 1-month after completion of RT on physician discretion. Age, KPS, and histological grade were used as covariates for propensity-matched analysis to compare LCRT versus SCRT cohorts using OS as the primary endpoint. Results Baseline patient characteristics were reasonably balanced in the two cohorts. Patients treated with LCRT were somewhat older compared to SCRT (median age 60 vs 56 years) while baseline performance status of LCRT cohort was slightly better than SCRT (median KPS 60 vs 50). The distribution of histologic grade III and IV gliomas was also similar in both cohorts. Compliance to planned RT was significantly better in SCRT compared to LCRT cohort (89% vs 53%, P = 0.03). Propensity-matched analysis included 70 and 53 patients from LCRT and SCRT cohorts respectively. Patients treated with SCRT had significantly better outcomes with median OS of 9.2 months (95% CI: 7.5-10.9 months) compared 3.4 months (95% CI: 2.4-4.6 months) in the LCRT cohort (P = 0.004). Conclusion SCRT appears to be an optimal resource-sparing palliative hypofractionated RT regimen in patients with poor-prognosis HGG with better compliance to planned therapy and improved survival outcomes. Author Disclosure T. Gupta: None. S. Pant: None. B. Likonda: None. A. Dasgupta: None. A. Chatterjee: None. S. Kannan: None. G. Sastri: None. S.R. Trivedi: None. D. Dutta: None. R. Jalali: None.