1MO - A multicenter, randomized, open-label, controlled trial to compare recurrence pattern of reduced margins vs RTOG protocol in adjuvant chemoradiation of high-grade glioma

Background

The current standard treatment for high-grade glioma (HGG) involves maximal surgical resection and adjuvant radiotherapy, with or without concurrent chemotherapy, followed by adjuvant chemotherapy. Target volume delineation of HGG is still a subject of investigation. This study aimed to assess the feasibility, safety, and efficacy of using a smaller margin than what is recommended in the latest ESTRO/ACROP guideline in HGG radiotherapy.

Methods

In this multicenter, randomized, open-label, controlled trial, patients aged 18 to 75 years with grade 3 and 4 gliomas were included after surgery and were randomly assigned to either the standard group based on RTOG guideline or the intervention group with a smaller margin of 1 cm. After chemoradiation, patients were followed up every three months with brain MRI. The recurrence pattern was determined by the 95% isodose line on the treatment planning CT scan at the time of imaging progression.

Results

A total of 258 patients were randomly assigned to two groups. Both groups were similar in terms of age, gender, radiotherapy technique, IDH mutation status, type of surgery, surgery-radiotherapy interval, duration of adjuvant chemotherapy, GTV60 volume, and GTV46 volume. Grade 3 tumors were more frequent in the control group (31.3% vs. 18.8%, p=0.02). There was no significant difference in the in-field recurrence rates between the two groups (intervention: 84% vs control: 83.8%, p=0.829). Table: 1MO

Survival analysis between two groups

^a: standard error

Conclusions

Adjuvant radiotherapy of HGG with smaller margins does not compromise the recurrence pattern of the tumor. Therefore, it is safe to recommend a smaller margin in order to spare more normal brain tissue.

Clinical trial identification

Iranian Registry for Clinical Trials (IRCT): IRCT20210215050367N1, protocol date 2021-03-6.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

This research was funded by Mashhad University of Medical Sciences (grant number 990018).

Disclosure

All authors have declared no conflicts of interest.