Two-Session Radiosurgery for Large Primary Tumors Affecting the Brain.

Area of Science:

• Neurosurgery
• Radiation Oncology
• Oncology

Background:

• Surgery may not be suitable for large or strategically located primary brain tumors.
• Single-session stereotactic radiosurgery (SRS) may be limited in dose delivery for large tumors or those near critical structures.
• Two-session radiosurgery has emerged as a strategy for dose escalation in secondary brain tumors.

Purpose of the Study:

• To evaluate the safety and efficacy of upfront two-session radiosurgery for primary brain tumors.
• To assess tumor response and toxicity in patients with large or centrally located primary brain tumors treated with a two-stage SRS approach.

Main Methods:

• Eight patients with primary brain tumors were treated with two-session radiosurgery between May 2017 and January 2020.
• Treatment involved two SRS sessions separated by approximately 30 days, with dose adjustments based on tumor volume and location.
• Tumor response was assessed using imaging (RECIST criteria) and clinical evaluations (Karnofsky Performance Status).

Main Results:

• Nine tumors across eight patients were treated, with a mean initial volume of 15 mL.
• Tumor volume decreased significantly between sessions, with a mean reduction to 73.6% of the original size.
• At a mean follow-up of 336.5 days, seven patients were alive with five partial responses and three stable disease cases; no adverse radiation effects were reported.

Conclusions:

• Two-stage SRS is a safe and effective method for dose escalation in large primary brain tumors, particularly those requiring treatment in radiation-sensitive areas.
• The technique shows potential for achieving significant tumor shrinkage and disease control.
• Longer follow-up studies are necessary to confirm long-term efficacy across different primary brain tumor subtypes.