In what situations would you routinely offer 25 Gy/5 fx for glioblastoma?

We use this regimen in two situations, based on clinical need.

1. Ultra short course in very poor performers unwilling for more elaborate treatment and needing very short term palliation.
2. Recurrent GBM's, not resectable but reasonable targets for SRS, but too large for single session 15-17Gy in one session.

With due respect, this disease does not leave us room for being slaves to trials, I see 2 GBM's a week and until trials or therapies catch up and show a significant benefit, I regard the management of GBM's a clinical problem. Sorry for being frank!

We do not routinely use this fractionation scheme given the limited data generated with this schedule to date. In general, we reserve this only for the elderly, frail patients, who cannot commute for a 15 fraction or longer schedule. In practice, if more than 2/3 of the brain volume is going to be exposed, I personally do not use this option, although, that is not data-driven. It is important to remember that the data do strongly support standard fractionation; for example, in the ANOCEF trial, 50 Gy in standard fractionation, compared to best supportive care was superior in terms of OS in the elderly (70 or older) with decent KPS (70 or greater), and importantly, this schedule did not result in significant QOL deterioration or loss of cogn...

25 Gy/5 has been used in elderly patients with glioblastoma or patients with poor performance status. Several other hypofractionation schedules from 34 Gy/10 to 40 Gy/15 have also been used. Many years ago (before temozolomide), we performed a small trial using 50 Gy/10 and found that patients with necrosis after treatment lived longer (Floyd et al., PMID 14967426). Currently, we have an in-house protocol for elderly patients using 34 Gy/10 with temozolomide and the early result has been published (Yusuf et al., PMID 29694955). I have never used 25 Gy/5 but suspect that elderly patients or patients with poor performance status diagnosed with multifocal glioblastoma could be considered (since there has been a long experience of 20 Gy/5 whole...

Outside of a study, I have never used a 5 fraction regimen for treating glioblastoma. But I have often used relatively short regiments, eg, 3000-4500 cGy in 10-15 fractions. I have used 3000/10fx for patients with very large volume disease since we know it is generally safe for whole brain. And I have had some patients appear to have some stabilization of disease for a few months. I have more often used 3500-4500 in 10-15 fx in those with smaller volume disease. Again, only anecdotal impressions that this has provided some temporary palliative benefit.

But I am not sure that 2000/5 wouldn’t give the same temporary benefit as 3000/10 since both have been used with similar efficacy for whole brain metastases.

So… I think 2500 in 5fx might b...