Concurrent immunoradiation is associated with inferior survival as compared to chemoradiation for HPV-Associated Oropharyngeal Squamous Cell Carcinomas

Purpose: Current trials for HPV-associated oropharyngeal SCCs (OP-SCCs) are evaluating treatment de-escalation including use of concurrent immunotherapy with radiation therapy. Given a lack of prospective data following concurrent immunoradiation (I-RT), we aimed to examine this question utilizing the National Cancer Data Base (NCDB).

Methodology: The NCDB was queried for patients with HPV-associated OP-SCCs that would have been eligible for NRG HN-002 (AJCC 7th edition T1-T2/N1-N2b and T3/N0-N2b) or HN-005 (AJCC 7th edition T1-T2/N1-N2a and T3/N0-N2a). Patients were stratified into (I-RT), concurrent chemoradiation (C-RT), and radiation therapy alone (RT) arms. Kaplan-Meier analysis and log-rank tests were utilized for comparison of overall survival (OS) between treatment arms followed by a Cox multivariate (MVA) proportional-hazards model controlling for tumor and patient characteristics and propensity-score weighted (PSW) analyses.

Results: We identified 2,735 patients eligible for NRG HN-005; 133 received I-RT, 1,951 patients received C-RT, and 594 received RT. Median age was 62 years (range: 27-90) with a median Charlson-Deyo co-morbidity score of 0 (range: 0-3). The vast majority were cN1-N2a (88.8%) and 26.5% were cT3. Inferior 3-year and 8-year OS was noted following I-RT (84.5% and 74.1%; p=0.016) vs. C-RT (91.3% and 79.0%) with no significant difference vs. RT (87.0% and 75.6%; p=0.33). This was maintained on both MVA (HR = 1.61(95% CI: 1.04-2.49); p=0.032) and PSW-analysis (HR = 1.69 (95% CI: 1.09-2.61); p=0.019).

Conclusions: I-RT was associated with significantly poorer OS vs. C-RT with no benefit compared to RT for HPV-associated OP-SCCs. Concurrent immunoradiation is not recommended outside of currently accruing clinical trials.

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