Clinical Outcomes of Moderately Hypofractionated Concurrent Chemoradiotherapy for Newly Diagnosed Glioblastoma

• Published in: Yonsei medical journal Vol. 64; no. 2; pp. 94 - 103
• Main Authors: Kim, Nalee, Lim, Do Hoon, Choi, Jung Won, Lee, Jung-Il, Kong, Doo-Sik, Seol, Ho Jun, Nam, Do-Hyun
• Format: Journal Article
• Language: English
• Published: Korea (South) Yonsei University College of Medicine 01.02.2023; 연세대학교의과대학
• Subjects: Brain - pathology; Brain Neoplasms - drug therapy; Brain Neoplasms - pathology; Brain Neoplasms - radiotherapy; Chemoradiotherapy - adverse effects; Glioblastoma - drug therapy; Glioblastoma - radiotherapy; Humans; Original; Radiation Dose Hypofractionation; Temozolomide - therapeutic use; 의학일반; temozolomide; hypofractionation; lymphopenia; Glioblastoma; radiation therapy
• ISSN: 0513-5796; 1976-2437; 1976-2437
• DOI: 10.3349/ymj.2022.0352

Hypofractionated radiotherapy (HypoRT) has recently been implemented in patients with glioblastoma (GBM) receiving concurrent temozolomide. Lymphopenia during treatment (LDT) is considered an important prognostic factor of clinical outcomes for GBM. We aimed to investigate the outcomes of HypoRT. Among 223 patients with GBM, 145 and 78 were treated with conventionally fractionated RT (ConvRT, 60 Gy in 30 fractions) and HypoRT (58.5 Gy in 25 fractions), respectively. To balance characteristics between the two groups, propensity score matching (PSM) was performed. Patients in the HypoRT group were older and had smaller tumors than those in the ConvRT group ( <0.05). Furthermore, dose distributions to the brain were significantly lower in HypoRT than in ConvRT ( <0.001). Changes in absolute lymphocyte counts (ALC) during treatment were significantly lower after HypoRT than after ConvRT ( =0.018). With a median follow-up of 16.9 months, HypoRT showed comparable progression-free survival (9.9 months vs. 10.5 months) and overall survival (27.2 months vs. 26.6 months) to ConvRT (all >0.05). Multivariable analysis before PSM revealed that ≥grade 2 LDT at 6 months was associated with inferior outcomes. Subsequent analysis demonstrated that HypoRT significantly reduced the rate of ≥grade 2 LDT at 6 months post-RT before and after PSM. HypoRT with 58.5 Gy in 25 fractions could provide comparable oncologic outcomes and significantly reduce the ALC changes. In addition, HypoRT decreased the LDT. Further investigation should be warranted to suggest the significance of reduced LDT through HypoRT affecting survival outcomes.