It takes two.

Top Line: Is reduced-dose radiation a safe way to de-escalate treatment intensity for HPV-mediated oropharyngeal squamous cell carcinoma?

The Study: We first heard the results of HN002 back at ASTRO 2019. HN002 was a randomized phase II trial compared reduced-dose radiation alone (60 Gy in 30 fractions, 6 fractions per week) to reduced dose radiation (60 Gy in 30 fractions, 5 fractions per week) with weekly cisplatin. It’s important to understand that this trial was designed to find the best experimental arm for a phase III showdown with standard chemoradiation. It wasn’t designed to establish either regimen for use in routine practice. Progression-free survival (efficacy) and MD Anderson dysphagia inventory (MDADI, toxicity) were used to evaluate each arm against benchmarks from prior trials. Also, patients had to be in the most favorable risk category having < 10 years smoking history, no T4 disease, and no N2c disease (AJCC 7th). 60 Gy went to primary and nodal disease with 54 Gy to intermediate risk CTV and 48 Gy to elective neck levels. Over 300 patients were randomized, and at 2 years, PFS was 90.5% with CRT and 87.6% with RT, which was not significantly different. However, the rate of locoregional failure was significantly higher in the RT arm (9.5% vs 3.3%). Notably, distant failure was the most frequent site of failure in the CRT arm (35% of failures) whereas local failure was most frequent with RT (42% of failures). There was no difference in the decline in swallowing function at 1 year between arms. The CRT arm, though, had significantly higher acute grade 3-4 toxicity (79.6% vs. 52.4%).

TBL: HN005 is comparing 70 Gy with cisplatin to 60 Gy reduced dose RT and either cisplatin or nivolumab. | Yom, J Clin Oncol 2021


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