Strength in numbers.
And we’re not talking fractions. Some read the ASTRO / ASCO / AUA 2018 guidelines on hypofractionated radiation for prostate cancer and were left unsatisfied with the very “meh” enthusiasm behind ultra-hypofractionation (aka SBRT). So they designed this meta-analysis that includes data on over 6K(!) patients receiving prostate SBRT on prospective studies, over three-quarters of which included patients with intermediate-risk disease and over one-third high-risk disease. Three clinically-meaningful primary endpoints were analyzed: biochemical control, physician-graded toxicity, and patient-reported quality of life. Rate of survival with biochemical control at 7 years was an impressive 94%, and a tiny minority experienced grade 3+ GU (2%) or GI (1%) late toxicities with EPIC scores returning to baseline within 2 years. TBL: The authors dare you to deem this “low-quality” evidence. | Jackson, Int J Radiat Oncol Biol Phys 2019
Notably, Only 8% of patients were high risk in this analysis. Mostly half and half low and intermediate risk patients.
ReplyDeleteLow quality evidence for high risk, for sure!
Looks like Katz paper from Frontier 2016 has a good breakdown of high risk treated with ultra hypofrac, as well as unfavorable intermediate risk vs. favorable intermediate risk. Unfavorable intermediate risk and high risk patients have a 7y pcPFS of less than 70%, compare to 9y bcPFS of 78% in ASCENDE-RT for high risk patients
Delete(cross comparison, so be wary, but hypofrac still looks worse). The same is likely true for omission of pelvic RT for unfavorable intermediate risk and higher risk patients, regardless if moderate hypofrac or ultra hypofrac. The real question is how much of the seminal vesicles to cover (less or no SV coverage needed, no ECE = better candidate for ultra hypofrac?).... and more importantly how to treat the nodes with these hypofrac regimens. Anybody besides Fox Chase asking this? What about 25/5 to nodes for unfavorable IR and higher risk? Seems like a reasonable place to start based on normal tissue toxicities, given what we know from TG-101 and the updated UK SBRT data from 2017 [Hanna Clinical Oncology 2017].
Link to Katz paper here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4937020/