Outcomes following IMRT alone in head and neck squamous cell carcinoma ordinarily managed with concurrent...

We report outcomes following IMRT-alone in patients with head-and-neck squamous cell carcinoma (HNSCC) ordinarily managed with concurrent chemo-radiotherapy.

HNSCC (excluding T1-2 N0) patients treated with IMRT-alone from 2005 to 2019 were included and restaged according to TNM-8. Overall survival (OS) was stratified by TNM-8 stage subgroups within HPV-positive (HPV + ) and separately within HPV-negative (HPV-) HNSCC. Multivariable analysis (MVA) identified prognostic factors for OS.

A total of 460 patients with HPV + and 623 HPV- HNSCC were identified. Reasons for chemotherapy omission were: age > 70 years and/or frailty (n = 551, 51 %), cisplatin contraindication (n = 241, 22 %), patient' preference (n = 106, 10 %), and clinician's decision (n = 185, 17 %). IMRT was delivered mostly using altered-fractionation: moderately-accelerated (70 Gy/35 fractions [f]/6 weeks [w], 55 %), hypofractionated (60 Gy/25f/5w, 14 %), and hyperfractionated-accelerated (64 Gy/40f/4w, 25 %). Median follow-up was 5.0 years. Five-year OS for HPV + stage-I-single node, stage-I-multiple nodes, stage-II-T1-2 N2, stage-II-T3 N0-N2, and stage-III were 90 %, 79 %%, 80 %, 64 %, and 33 %, and for HPV- stage III, IVA, and IVB were 47 %, 27 %, and 13 %, respectively. MVA confirmed lower OS in HPV + stage-I-multiple nodes (p = 0.03), II-T3 N0-N2 and III (vs stage-I-single node) and HPV- stage IVA/IVB (vs III) (p < 0.01), and marginally lower OS in HPV + stage-II-T3 N0-2 (vs I-single node) (p = 0.07).

Altered fractionated IMRT-alone is a valid option for patients with HPV + stage I-single node HNSCC, and an acceptable alternative for elderly/frail or cisplatin ineligible patients with HPV + stage I-multiple nodes and T1-2 N2 HNSCC. Patients with HPV + T3-T4 or N3 and HPV- stage III/IV HNSCC had unsatisfactory OS, requiring further research into alternative options.