Radiation vs. trans-oral surgery for treatment de-escalation in HPV-related oropharyngeal cancers: Primary analysis of the ORATOR2 randomized trial.

BACKGROUND

The optimal treatment de-escalation approach for HPV-related oropharyngeal squamous cell carcinomas (OPSCC) is unknown. The objective was to assess two de-escalation approaches: primary radiotherapy (RT) vs. transoral surgical (TOS).

PATIENTS AND

METHODS

Patients with T1-T2 N0-2 HPV-related OPSCC were randomly assigned to primary RT (60 Gy with concurrent weekly cisplatin in node-positive) vs. TOS + neck dissection (ND) (and adjuvant reduced-dose RT depending on pathology). The primary endpoint was 2-year OS (hypothesized to be 94 % in each arm, compared to 84 %). Secondary endpoints included comparisons of survival and quality of life between arms. The trial was stopped early due to two treatment related deaths in the surgical arm.

RESULTS

Sixty-one patients were randomized (n = 30 in RT arm and n = 31 in TOS+ND arm), with a median age of 62 years (IQR: 57-68). The majority were male (n = 51) and never-smokers (n = 31). Median follow-up was 3.7 years (IQR: 3.1-4.5 years). In the RT arm, the primary endpoint for acceptability was met (p = 0.008), and two-year OS was 100 % (95 % confidence interval [CI]: 100-100 %). In the TOS+ND arm, the primary endpoint was not met (p = 0.296) and two-year OS was 90 % (95 % CI: 71-97 %), significantly worse than the RT arm (p = 0.041). Two-year progression-free survival (PFS) were 100 % (95 % CI: 100-100 %) vs. 86 % (95 % CI: 67-95 %) respectively (p = 0.012). Mean (± SD) 2-year MDADI total scores were 89 ± 13 vs. 83 ± 11, respectively (p = 0.11), and grade 2-5 toxicity rates were similar (n = 21 vs. n = 24 respectively, p = 0.51), with no additional grade 5 events.

CONCLUSION

For treatment de-escalation, a primary RT approach achieved excellent oncologic and functional outcomes and should be tested in phase III de-escalation trials.

TRIAL REGISTRATION: Clinicaltrials.gov NCT03210103.