Impact of cisplatin dose intensity on human papillomavirus-related and -unrelated locally advanced head and neck squamous cell carcinoma.

AIM: The aim is to evaluate the impact of cisplatin dose modification on outcomes of human papillomavirus (HPV)-related (HPV+) and HPV-unrelated (HPV-) locally advanced head and neck cancer (LAHNC) treated with chemoradiotherapy (CRT). PATIENTS AND METHODS: A pooled analysis was conducted of stage III/IV oropharyngeal cancer (OPC), carcinoma of unknown primary (CUP) and laryngo-hypopharyngeal cancer (LHC) patients treated with single-agent cisplatin CRT in 2000-2012 from two tertiary academic cancer centres. HPV status was determined by p16 staining and/or in situ hybridisation. LHC was assumed to be HPV-. Unknown HPV status OPC/CUPs were excluded. Overall survival (OS) was calculated. Multivariable analysis (MVA) evaluated the impact of cisplatin dose intensity on survival for HPV+ and HPV- cohorts separately. RESULTS: A total of 404 HPV+ and 255 HPV- LAHNC (481 OPC, 18 CUP, 160 LHC) patients were included. Median follow-up was 4.3 (0.5-11.9) years. Three-year OS for cisplatin <200, =200, and >200 mg/m(2) subgroups were 52%, 60%, and 72% (P = 0.001) for the HPV- and 91%, 90%, and 91% (P = 0.30) for the HPV+ patients. MVA confirmed a survival benefit with cisplatin >200 mg/m(2) for the HPV- (hazard ratio [HR] 0.5, 95% confidence interval [CI]: 0.3-0.7, P < 0.001) but not for HPV+ (HR 0.6, 95% CI: 0.4-1.1, P = 0.104). There was a superior OS trend in the HPV+ T4 or N3 high-risk subset (N = 107) with cisplatin >200 mg/m(2) (HR 0.5, 95% CI: 0.2-1.1, P = 0.07). CONCLUSIONS: A survival benefit of cisplatin dose >200 mg/m(2) is evident for HPV- LAHNC patients, but not for HPV+ cohort overall, although the T4 or N3 subset may benefit from a higher cumulative cisplatin dose.