Is 60 the new 70?

Top Line: Right now, we’re in the midst of a scramble of sorts to find ways of de-intensifying treatment for HPV-mediated oropharyngeal cancer while still maintaining excellent outcomes.

The Study: Quick recap. RTOG 1016 and De-ESCALaTE HPV showed that overall survival and locoregional control were significantly worse with cetuxmiab compared to cisplatin and 70 Gy radiation. Not to mention, cetuximab wasn’t really even less intensive. These trials provide the background skepticism for all the mounting phase II data out there. That data includes: omitting RT to pN0 neck in the postop setting, only giving 30-36 Gy in a BID fashion in the postop setting, and giving 30 Gy in 15 fractions to the low-risk volume in the definitive setting. The ASCO bottom line is that de-intensification should only be done on a clinical trial. Here we have report from a single-arm phase II trial of de-intensified radiation dose in the definitive setting. Patients had AJCC 7th Ed. T0-3, N0-2c, p16-positive oropharyngeal cancer and a minimal smoking history. They received a maximum of 60 Gy with concurrent weekly cisplatin (30 mg/m2). The high risk volume included gross tumor plus a 5-10mm margin, which received 60 Gy in 30 factions. Everything else (pretty standard elective nodal coverage) received 54 Gy at 1.8 Gy per fraction. Toxicity seemed favorable with no late grade 3+ events and a 34% feeding tube rate at the end of treatment. At two years, the rate of both locoregional control and overall survival was 95%. 

TBL: Lower dose radiation (60 Gy) and less intensive cisplatin (weekly) appears to have favorable outcomes and toxicity in patients with p16-positive oropharyngeal cancer in this single-arm phase II trial. | Chera, J Clin Oncol 2019