How do you dose or sequence therapy to overcome radioresistance from oligometastatic disease from RCC?

RAPPORT (NCT02855203) [Siva et al., PMID 34953600] was a phase I/II trial which used a combination of RT and pembrolizumab. RT was given with SBRT (20 Gy/1# prescribed to the 80% isodose line) or conventional radiotherapy (30 Gy/10#) when the treatment volume was in close proximity to a dose-limiting organ (i.e., the RT dose was not randomized). Eight cycles of pembrolizumab were given beginning on day 5 after RT. The radiographic response rates after SBRT and conventional RT were roughly the same for measures of ≥ 50% radiographic reduction and complete response (100% reduction). These were ≈55-60% and ≈ 30-35%, respectively. This may be due simply to the efficacy of pembrolizumab alone or some unique issue with the efficacy of a 20 Gy in ...