Top Line: At ASTRO 2018 we learned circulating tumor (ct)HPV-DNA may be a powerful tool in the detection of recurrences following definitive radiation for p16(+) oropharyngeal cancer.
The Study: Now we bring you the full manuscript with more patients and more deets. As a reminder, this was a multi-institutional prospective biomarker study of now 103 patients. Definitive treatment here meant 70 Gy with concurrent chemo—unless simultaneously enrolled in a de-intensification trial where they received 60 Gy with weekly cisplatin (n=87) or unless they had cT1-2N0-1 disease and received no chemo (n=16). So, if you do the math, actually no one received the standard 70 Gy with concurrent chemo… In any case, at baseline, 84/103 (82%) had ctDNA for the HPV strain 16, another 8/103 (8%) had ctDNA for an alternative high-risk strain 31/33/35, and interestingly the remaining 11/103 (11%) without any detectable ctHPV-DNA were more likely to have long smoking histories and cT4 tumors suggesting a different biology altogether. Now, the analysis gets tricky with clearly lots of post-hoc explorations, but to be fair the authors were learning about ctHPV-DNA kinetics as they went. They eventually honed in on “rapid clearance” ( >95% clearance by treatment week 4) of ctHPV16-DNA as an excellent predictor of disease control. Finally, with only 3/52 healthy controls and 0/60 p16(-) tumors harboring detectable ctHPV-DNA, does anyone else see serum HPV screening with reflex man-throat paps in our future..? Just sayin.
TBL: Notwithstanding its exploratory nature, this brings us some fascinating possibilities of ctHPV-DNA monitoring (and screening?) that can easily be performed in conjunction with any number of ongoing trials. | Chera, Clin Cancer Res 2019


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