Three-Dimensional Conformal focal radiotherapy (30 Gy in 5 fractions) – An useful substitute for Stereotactic radiosurgery In Brain oligometastases: A Single-institutional Case Series

Abstract

Stereotactic Radiosurgery/Radiotherapy (SRS/SRT) or neurosurgery is the standard of care for brain oligometastases (≤4 in number). SRS/SRT is only applicable for highly selected patients due to stringent size criteria (≤4 cm) and unavailability of this advanced technology in majority radiation centers in India. Hypofractionated focal 3-dimensional conformal radiotherapy (30 Gy in 5 fractions in 5 consecutive days) represents an attractive clinical alternative to SRS/SRT. In our series, we report dosimetric and clinical outcomes of nine patients (single brain metastatic foci, median size 3.4 cm). Radiotherapy was planned using coplanar and noncoplanar beams, conventional 1 cm multileaf collimators, and 3-mm planning target volume margins on a 6 MV linear accelerator. We were able to achieve sharp-dose falloff and excellent clinical outcome in our short follow-up. This protocol seems to be a feasible and well-tolerated alternative to SRS/SRT. We have designed a long-term Phase III prospective study to validate this regimen in larger population (ineligible for SRS/SRT).