De-Escalation Treatment Strategies in HPV-Positive Oropharyngeal Squamous Cell Carcinoma: An Umbrella Review of Systematic Reviews and Meta-Analyses.

Abstract

De-escalation strategies for human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) aim to reduce late morbidity while preserving cure rates, but evidence syntheses provide inconsistent conclusions and may be affected by overlap of primary studies. We performed an umbrella review of systematic reviews (SRs) and meta-analyses (MAs) evaluating de-escalation approaches versus standard-of-care therapy in HPV-positive (or p16-positive) OPSCC. MEDLINE (PubMed), Embase, and the Cochrane Database of SRs were searched from inception to December 1, 2025. Two reviewers independently screened records and extracted data. Overlap among included SR/MAs was quantified using the corrected covered area (CCA); when overlap was substantial, an index review was prioritized based on methodological quality, recency, and completeness of outcomes. Review-level quality and risk of bias were assessed using AMSTAR-2 and ROBIS. Strength of evidence was graded with a restricted Ioannidis-style framework (p-value + sample-size thresholds). Outcomes included overall survival (OS), progression-free survival (PFS), locoregional control (LRC), distant control, and acute/late toxicity. Evidence clustered into four domains. (1) Definitive systemic substitution: an RCT-only index MA (five trials; n = 1560) showed that replacing cisplatin with cetuximab during definitive radiotherapy was associated with inferior OS (HR: 2.83; 95% CI: 1.22-6.57) and inferior LRC (HR: 2.78; 95% CI: 1.77-4.39), without a statistically significant reduction in late grade ≥ 3 toxicity (RR: 0.63; 95% CI: 0.36-1.10). The two RCT-only syntheses were fully overlapping (CCA, 100%). (2) Broad de-intensification: across 55 studies (n = 38 929), de-intensified strategies were associated with worse OS (HR: 1.33; 95% CI: 1.17-1.52), PFS (HR: 2.11; 95% CI: 1.65-2.69), LRC (HR: 2.51; 95% CI: 1.75-3.59), and distant control (HR: 1.90; 95% CI: 1.25-2.90). (3) Post-transoral surgery adjuvant de-intensification: at the time of the Cochrane review (2018), no completed eligible RCTs were identified; updated trial-level data are now available (ADEPT closed early; ECOG-E3311 long-term follow-up published in 2025; PATHOS phase III enrollment completing in 2025). (4) Reduced-dose radiotherapy: evidence remains limited to a registered protocol. In cisplatin-eligible HPV-positive OPSCC, cetuximab substitution compromises oncologic outcomes without reliable severe late-toxicity reduction; other de-escalation approaches should remain trial-based until robust patient-reported and functional data demonstrate a meaningful net benefit.