Proton beam therapy in the treatment of adenoid cystic carcinoma of the head and neck: a single enterprise retrospective cohort study
Abstract
Background and aimsAdenoid cystic carcinoma (ACC) is a rare salivary gland malignancy with high propensity for perineural invasion (PNI) and relative radioresistance. Proton beam therapy (PBT) may improve tumor control through improved target coverage, as well as higher physical and biologic dose while limiting dose to surrounding critical structures. This single-enterprise two-site study reports outcomes and toxicity in patients with ACC of the head and neck (HN) region treated with curative-intent PBT.MethodsFrom 2015–2025, 89 patients with HN ACC were treated with curative-intent PBT. Patients with distant metastases or prior radiotherapy (RT) were excluded. Clinical outcomes were assessed retrospectively. Toxicities were recorded prospectively using CTCAE v5.0. The Kaplan–Meier method was used to estimate local tumor control (LC), distant metastasis-free survival (DMFS) and overall survival (OS). Hazard ratios, 95% confidence intervals (CIs), and test of association between tumor and treatment variables and outcomes were estimated using Cox proportional hazards regression analysis.ResultsMedian follow-up was 3.1 years. Sixty-nine patients underwent surgery followed by postoperative PBT, while 20 received definitive PBT for unresectable disease. The 3-year LC rate was 98.3% following postoperative PBT and 82.6% following definitive PBT. Treatment approach was not significantly associated with LC. Three-year DMFS was 86.2% and 64.9%, respectively, while 3-year OS was 94.4% in both cohorts. Twenty-one patients developed distant metastases, most commonly involving the lungs. Six patients experienced acute grade 3 toxicities, including dysphagia, mucositis, and dermatitis; seven experienced late grade 3 toxicities, most commonly osteoradionecrosis (n=4). One patient had both acute and late toxicity. No grade 4 or 5 toxicities occurred.ConclusionsCurative-intent PBT was associated with favorable LC and acceptable toxicity. Outcomes according to definitive versus postoperative treatment should be interpreted descriptively due to substantial baseline differences between groups and confounding by indication. Longer follow-up and larger studies are needed.
Related
- Modeling the Microenvironmental Dynamics of Adenoid Cystic Carcinoma in Lacrimal Gland with Treatment Intervention
- Revisiting proton therapy for adenoid cystic carcinoma: a case worth making
- Palatal Island Flap With Adjuvant Radiotherapy for Hard Palate Adenoid Cystic Carcinoma: 2-year Outcomes
- Challenges in managing tracheal adenoid cystic carcinoma of the proximal trachea complicated by COVID-19 and bilateral vocal cord palsy
- Postoperative radiotherapy after tracheal reconstruction with cryopreserved aortic allograft for adenoid cystic carcinoma
BibTeX
@article{rohit2026proton,
title = {{Proton beam therapy in the treatment of adenoid cystic carcinoma of the head and neck: a single enterprise retrospective cohort study}},
author = {Astha Rohit and Molly Voss and Heather Gunn and Daniel Ma and Samir Patel and Scott Lester and Jean-Claude Rwigema and Michelle Neben-Wittich and Robert Foote and David Mason Routman and Yolanda Garces and Jessica Wison and Daniel Price and Jeffrey Janus and Michae Hinni and Ashish V Chintakuntlawar and Katharine Price and Patrick McGarrah and Adam Holtzman and Homan Mohammadi and Lisa McGee},
journal = {Frontiers in Oncology},
year = {2026},
month = nov,
doi = {10.3389/fonc.2026.1968350},
url = {https://www.frontiersin.org/articles/10.3389/fonc.2026.1968350},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Proton beam therapy in the treatment of adenoid cystic carcinoma of the head and neck: a single enterprise retrospective cohort study
AU - Astha Rohit
AU - Molly Voss
AU - Heather Gunn
AU - Daniel Ma
AU - Samir Patel
AU - Scott Lester
AU - Jean-Claude Rwigema
AU - Michelle Neben-Wittich
AU - Robert Foote
AU - David Mason Routman
AU - Yolanda Garces
AU - Jessica Wison
AU - Daniel Price
AU - Jeffrey Janus
AU - Michae Hinni
AU - Ashish V Chintakuntlawar
AU - Katharine Price
AU - Patrick McGarrah
AU - Adam Holtzman
AU - Homan Mohammadi
AU - Lisa McGee
PY - 2026
DA - 2026/11/04
JO - Frontiers in Oncology
DO - 10.3389/fonc.2026.1968350
UR - https://www.frontiersin.org/articles/10.3389/fonc.2026.1968350
AB - Background and aimsAdenoid cystic carcinoma (ACC) is a rare salivary gland malignancy with high propensity for perineural invasion (PNI) and relative radioresistance. Proton beam therapy (PBT) may improve tumor control through improved target coverage, as well as higher physical and biologic dose while limiting dose to surrounding critical structures. This single-enterprise two-site study reports outcomes and toxicity in patients with ACC of the head and neck (HN) region treated with curative-intent PBT.MethodsFrom 2015–2025, 89 patients with HN ACC were treated with curative-intent PBT. Patients with distant metastases or prior radiotherapy (RT) were excluded. Clinical outcomes were assessed retrospectively. Toxicities were recorded prospectively using CTCAE v5.0. The Kaplan–Meier method was used to estimate local tumor control (LC), distant metastasis-free survival (DMFS) and overall survival (OS). Hazard ratios, 95% confidence intervals (CIs), and test of association between tumor and treatment variables and outcomes were estimated using Cox proportional hazards regression analysis.ResultsMedian follow-up was 3.1 years. Sixty-nine patients underwent surgery followed by postoperative PBT, while 20 received definitive PBT for unresectable disease. The 3-year LC rate was 98.3% following postoperative PBT and 82.6% following definitive PBT. Treatment approach was not significantly associated with LC. Three-year DMFS was 86.2% and 64.9%, respectively, while 3-year OS was 94.4% in both cohorts. Twenty-one patients developed distant metastases, most commonly involving the lungs. Six patients experienced acute grade 3 toxicities, including dysphagia, mucositis, and dermatitis; seven experienced late grade 3 toxicities, most commonly osteoradionecrosis (n=4). One patient had both acute and late toxicity. No grade 4 or 5 toxicities occurred.ConclusionsCurative-intent PBT was associated with favorable LC and acceptable toxicity. Outcomes according to definitive versus postoperative treatment should be interpreted descriptively due to substantial baseline differences between groups and confounding by indication. Longer follow-up and larger studies are needed.
SN - 2234-943X
ER -