Quad shot revival.
Top Line: The “quad shot” (3.7 Gy x 4 twice daily for two days) was born in the split-course era as a palliative radiation regimen for painful or bleeding pelvic tumors.
The Study: In the ensuing half-century, it largely fell out of vogue along with other split-course regimens. But just like mom jeans and Doc Martens, anything with a solid design will eventually become trendy once again. After all, the myriad theoretical benefits of quad shot remain, especially for low alpha-beta tumors like sarcomas. For one, 14.7Gy/4 yields a higher BED than the traditional 30Gy/10. Second, the ability to repeat quad shot for 3-4 cycles every 2-4 weeks solves the classic push and pull between maximizing tumor control for those who do well and minimizing side effects for those who don’t. Speaking of, it only asks for two days of patient commitment per cycle. With that in mind, here is a retrospective look at 28 patients receiving quad shot radiation to 40 unresectable recurrent (n=31) or metastatic (n=9) sarcomas. There’s a twist, though: it was done with protons recognizing the possibility for previously irradiated tumors (n=5 here). Nearly two-thirds of tumors received at least 3 cycles of quad shot. Median survival free from local progression was 11 months, and subjective symptom response rate was 70%.
TBL: Quad shot radiation for up to 4 cycles is a safe and effective palliative treatment for unresectable sarcoma. | Lee, Cancer Med 2021