Variation in Practice Patterns Among Radiation Oncologists Treating Oropharyngeal Cancers

Given the favorable prognosis of HPV-mediated (HPV+) oropharyngeal (OPX) cancers, studies have attempted to de-escalate therapy. We surveyed expert head and neck (H&N) radiation oncologists to better understand practice patterns to inform future clinical trial design.

Participants were identified using publicly available radiation committees. Treatment of ≥12 cases of noncutaneous H&N cancer within the last year was required. A 25-question survey was sent through email using an anonymous RedCap link. Results were compared using RedCap statistics and χ2 tests.

Fifty-five H&N radiation oncologists participated in the survey (36%), representing 41 institutions. Three participants were excluded. Most physicians treat definitively to 69.96 or 70 Gy in 33 to 35 fractions (96% HPV+, 98% HPV-). The average CTV expansion is 3.6 mm. Yet, CTV expansions for HPV+ OPX vary considerably, with 48% of responders expanding 0 to 3 mm. In addition, 13 physicians use a smaller CTV expansion for HPV+ OPX lymph nodes, while 39 use the same expansion. In the HPV- postoperative setting, 96% of responders treat to 60 Gy, whereas in HPV+ disease, 52% treat to 60 Gy, and 35% prescribe only 50 Gy (P<0.05). In HPV+ OPX, the most common indications for postoperative radiation include positive surgical margins (SM) and extranodal extension (ENE) (100%), pT3-4 (98%), and ≥2 involved nodes (92%), with chemotherapy indicated for positive SM and ENE (98% HPV+, 100% HPV-).

There is significant variation and a lack of consensus in radiation planning for OPX cancers among institutions, which may impact resident training and patient outcomes.