In the neck of the beholder.
Top Line: There’s a lot of ways to theoretically de-escalate radiation therapy for HPV+ oropharyngeal cancer, and unilateral neck treatment is one of them.
The Study: For years, ASTRO has recommended unilateral treatment as an option for well-lateralized tonsil cancers with up to one involved lymph node. That's because pooled experiences estimate risk of contralateral neck failure at 2.4%, and isolated neck failure are typically amenable to surgical salvage. This substudy of TROG 12.01, one of the many randomized trials confirming that concurrent cisplatin is not where we want to be de-escalating, asked whether the primary endpoint of patient-reported radiation symptom severity scores differed based on unilateral or bilateral neck irradiation volumes. This is a pretty brilliant way to ask this question given the rigorous prospective collection of patient toxicity. Of 74 patients with lateralized T1-2N1-2b SCC of the tonsil, 26 had unilateral treatment and 48 had bilateral. Surprisingly, there was no detectable difference in any of the myriad patient-reported outcomes at virtually any time point with the exception of slightly worse dry mouth at 2 years after bilateral treatment. This was largely because patient-reported outcomes after bilateral treatment were excellent. The authors posit two hypotheses that may explain these head-scratching results. First—and this one we find fascinating—is that, when patients fill out these forms, they’re not comparing themselves to other patients in the waiting room but to their own pre-treatment experience, meaning a sore throat is a sore throat when compared to a perfectly normal throat at baseline. Second, toxicity just might not be that bad regardless among low-risk, fit, trial-eligible patients.
TBL: “While many clinicians may agonize over the decision to treat with bilateral radiation in borderline cases based on the perceived additional morbidity in patients who are likely to be cured of their disease, it is hoped that this data will bring some peace of mind when considering treatment options and in shared-decision making discussion." | McDowell, Int J Radiat Oncol Biol Phys 2022