What dose and fractionation is safe to use for palliation of a large pelvic mass several years after definitive prostate brachytherapy?

The prescription, technique and modality would depend on histology, size and involvement/distance from organs at risk.

At our institution we have often utilized high-dose spatially fractionated radiation therapy (GRID) for large tumors followed by a traditional hypofractionated palliative RT regimen. This involves delivering a single high dose fraction of GRID therapy (approximately 12-16Gy) using 1cm MLC derived GRIDs. It is thought to incite reoxygenation with high tumor cell kill, allowing for higher efficiency of the following traditional EBRT.

Reference for more info below:

https://www.ncbi.nlm.nih.gov/pubmed/21531514

In your particular case I would weigh gauge the likely longevity of the patient against the risks of reirradiation. I als...