Background
Retrospective secondary analysis of phase III RTOG 0129 (accelerated vs standard fractionation CRT). 323 of 721 patients had oropharyngeal SCC with tissue for p16/HPV testing (p16 IHC + HPV ISH). Goal: define prognostic significance of HPV and build a risk-stratification model.
Interventions and follow up
Design: retrospective subset of RTOG 0129 (cisplatin-based CRT for stage III–IV OPSCC) stratifying outcomes by HPV/p16 status
Primary endpoint: OS and PFS by HPV status
mFollow up: 4.8 yr
Primary endpoint: OS and PFS by HPV status
mFollow up: 4.8 yr
Results
3-yr OS (HPV+ vs HPV−): 82.4% vs 57.1%, P<.001; HR 0.42
3-yr OS (HPV+ low risk): 93.0%
3-yr PFS (HPV+ vs HPV−): 73.7% vs 43.4%, P<.001
Risk groups (HPV, pack-years, T/N): low, intermediate, high — markedly different outcomes
3-yr OS (HPV+ low risk): 93.0%
3-yr PFS (HPV+ vs HPV−): 73.7% vs 43.4%, P<.001
Risk groups (HPV, pack-years, T/N): low, intermediate, high — markedly different outcomes
Adverse events
Grade ≥3 toxicity: similar across HPV status (identical CRT in RTOG 0129)
HPV+ population: younger, lower smoking burden, better performance status—may contribute to outcome independent of RT response
Note: toxicity not the primary focus of this report
HPV+ population: younger, lower smoking burden, better performance status—may contribute to outcome independent of RT response
Note: toxicity not the primary focus of this report
Conclusions
HPV-positive OPSCC has significantly better OS and PFS than HPV-negative disease after concurrent CRT (3-yr OS 82.4% vs 57.1%). Combined with T/N stage and smoking, HPV defines three distinct risk groups, providing rationale for de-escalation trials.
Key Limitations
Retrospective, hypothesis-generating subset (tissue available in only 323/721); p16 surrogate for HPV; risk model derived and not independently validated here.
Clinical Context
Defining analysis establishing HPV/p16 as the dominant prognostic factor in OPSCC; underpins the separate AJCC 8th-edition staging for p16+ disease and motivated subsequent de-intensification trials.