Volume 129, Issue 20 p. 3263-3274
ORIGINAL ARTICLE

The protective role of postoperative radiation therapy in low and intermediate grade major salivary gland malignancies: A study of the Canadian Head and Neck Collaborative Research Initiative

Grégoire B. Morand MD, MSc

Corresponding Author

Grégoire B. Morand MD, MSc

Department of Otolaryngology Head and Neck Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada

Correspondence

Grégoire B. Morand, Department of Otorhinolaryngology-Head and Neck Surgery, Jewish General Hospital, McGill University, 3755 Cote Ste Catherine Road, Montreal, QC Canada.

Email: [email protected]

Contribution: Conceptualization, Data curation, ​Investigation, Methodology, Project administration, Writing - original draft

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Antoine Eskander MD, ScM

Antoine Eskander MD, ScM

Department of Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada

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Rui Fu PhD

Rui Fu PhD

Department of Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada

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John de Almeida MD, MSc

John de Almeida MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada

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David Goldstein MD, MSc

David Goldstein MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada

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Hesameddin Noroozi MD, MPH

Hesameddin Noroozi MD, MPH

Department of Otolaryngology-Head and Neck Surgery, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada

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Ali Hosni MD

Ali Hosni MD

Department of Radiation Oncology, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada

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Hadi Seikaly MD

Hadi Seikaly MD

Division of Otolaryngology-Head and Neck Surgery, University of Alberta, Edmonton, Alberta, Canada

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Paul Tabet MD, MSc

Paul Tabet MD, MSc

Division of Otolaryngology-Head and Neck Surgery, University of Alberta, Edmonton, Alberta, Canada

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Justin M. Pyne MD

Justin M. Pyne MD

Division of Otolaryngology-Head and Neck Surgery, University of Alberta, Edmonton, Alberta, Canada

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T. Wayne Matthews MD

T. Wayne Matthews MD

Department Otolaryngology-Head and Neck Surgery, University of Calgary, Calgary, Alberta, Canada

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Joseph Dort MD

Joseph Dort MD

Department Otolaryngology-Head and Neck Surgery, University of Calgary, Calgary, Alberta, Canada

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Steve Nakoneshny BSc

Steve Nakoneshny BSc

Department Otolaryngology-Head and Neck Surgery, University of Calgary, Calgary, Alberta, Canada

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Apostolos Christopoulos MD, MSc

Apostolos Christopoulos MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Centre Hospitalier de l’Université de Montreal (CHUM), Université de Montreal, Montreal, Quebec, Canada

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Houda Bahig MD, PhD

Houda Bahig MD, PhD

Department of Radiation Oncology, CHUM, Université de Montreal, Montreal, Quebec, Canada

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Stephanie Johnson-Obaseki MD, MPH

Stephanie Johnson-Obaseki MD, MPH

Department of Otolaryngology-Head and Neck Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada

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Nadia Hua MD

Nadia Hua MD

Department of Otolaryngology-Head and Neck Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada

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Marc Gaudet MD

Marc Gaudet MD

Department of Radiation Oncology, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada

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Alborz Jooya MDCM

Alborz Jooya MDCM

Department of Radiation Oncology, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada

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Anthony Nichols MD

Anthony Nichols MD

Department of Otolaryngology-Head and Neck Surgery and Oncology, London Health Sciences Center, London, Ontario, Canada

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Francisco Laxague MD

Francisco Laxague MD

Department of Otolaryngology-Head and Neck Surgery and Oncology, London Health Sciences Center, London, Ontario, Canada

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Matthew Cecchini MD, PhD

Matthew Cecchini MD, PhD

Department of Otolaryngology-Head and Neck Surgery and Oncology, London Health Sciences Center, London, Ontario, Canada

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Jenny Du MD

Jenny Du MD

Department of Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada

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Justin Shapiro MD, MSc

Justin Shapiro MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada

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Irene Karam MD

Irene Karam MD

Department of Radiation Oncology, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada

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Peter T. Dziegielewski MD

Peter T. Dziegielewski MD

Department of Otolaryngology-Head and Neck Surgery, University of Florida Health Shands Hospital, University of Florida, Gainesville, Florida, USA

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Krishna Hanubal MD

Krishna Hanubal MD

Department of Otolaryngology-Head and Neck Surgery, University of Florida Health Shands Hospital, University of Florida, Gainesville, Florida, USA

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Boban Erovic MD, MBA

Boban Erovic MD, MBA

Institute of Head and Neck Diseases, Evangelical Hospital, Vienna, Austria

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Stefan Grasl MD

Stefan Grasl MD

Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria

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Joel Davies MD, MSc

Joel Davies MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada

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Eric Monteiro MD, MSc

Eric Monteiro MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada

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Maru Gete MD

Maru Gete MD

Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada

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Ian Witterick MD, MSc

Ian Witterick MD, MSc

Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada

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Nader Sadeghi MD

Nader Sadeghi MD

Department of Otolaryngology-Head and Neck Surgery, McGill University Health Center, McGill University, Montreal, Quebec, Canada

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Keith Richardson MD, MSc

Keith Richardson MD, MSc

Department of Otolaryngology-Head and Neck Surgery, McGill University Health Center, McGill University, Montreal, Quebec, Canada

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George Shenouda MD

George Shenouda MD

Department of Radiation Oncology, McGill University Heath Center, Montreal, Quebec, Canada

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Anastasios Maniakas MD, PhD

Anastasios Maniakas MD, PhD

Department Otolaryngology-Head and Neck Surgery, Hôpital Maisonneuve-Rosemont, Université de Montreal, Montreal, Quebec, Canada

Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA

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Vivianne Landry MD

Vivianne Landry MD

Department Otolaryngology-Head and Neck Surgery, Hôpital Maisonneuve-Rosemont, Université de Montreal, Montreal, Quebec, Canada

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Michael Gupta MD

Michael Gupta MD

Department of Otolaryngology-Head and Neck Surgery, McMaster University, Hamilton, Ontario, Canada

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Kelvin Zhou MD

Kelvin Zhou MD

Department of Otolaryngology-Head and Neck Surgery, McMaster University, Hamilton, Ontario, Canada

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Alex M. Mlynarek MD, MSc

Alex M. Mlynarek MD, MSc

Department of Otolaryngology Head and Neck Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada

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Marc Pusztaszeri MD

Marc Pusztaszeri MD

Department of Pathology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada

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Khalil Sultanem MD

Khalil Sultanem MD

Department of Radiation Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada

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Michael P. Hier MD

Michael P. Hier MD

Department of Otolaryngology Head and Neck Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada

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First published: 04 July 2023

Abstract

Background

The objective of this study was to examine the utility of postoperative radiation for low and intermediate grade cancers of the parotid and submandibular glands.

Methods

The authors conducted a retrospective, Canadian-led, international, multi-institutional analysis of a patient cohort with low or intermediate grade salivary gland cancer of the parotid or submandibular gland who were treated from 2010 until 2020 with or without postoperative radiation therapy. A multivariable, marginal Cox proportional hazards regression analysis was performed to quantify the association between locoregional recurrence (LRR) and receipt of postoperative radiation therapy while accounting for patient-level factors and the clustering of patients by institution.

Results

In total, 621 patients across 14 tertiary care centers were included in the study; of these, 309 patients (49.8%) received postoperative radiation therapy. Tumor histologies included 182 (29.3%) acinic cell carcinomas, 312 (50.2%) mucoepidermoid carcinomas, and 137 (20.5%) other low or intermediate grade primary salivary gland carcinomas. Kaplan–Meier LRR-free survival at 10 years was 89.0% (95% confidence interval [CI], 84.9%–93.3%). In multivariable Cox regression analysis, postoperative radiation therapy was independently associated with a lower hazard of LRR (adjusted hazard ratio, 0.53; 95% CI, 0.29–0.97). The multivariable model estimated that the marginal probability of LRR within 10 years was 15.4% without radiation and 8.8% with radiation. The number needed to treat was 16 patients (95% CI, 14–18 patients). Radiation therapy had no benefit in patients who had early stage, low-grade salivary gland cancer without evidence of nodal disease and negative margins.

Conclusions

Postoperative radiation therapy may reduce LLR in some low and intermediate grade salivary gland cancers with adverse features, but it had no benefit in patients who had early stage, low-grade salivary gland cancer with negative margins.

CONFLICT OF INTEREST STATEMENT

Bahig Houda reports personal fees from AstraZeneca outside the submitted work. Anthony Nichols reports grants/contracts from Novartis Pharmaceuticals Canada and Lab Corporation outside the submitted work. Ian Witterick reports personal fees from GlaxoSmithKline and Proteocyte Diagnostics Inc. outside the submitted work. The remaining authors declared no conflicts of interest.

DATA AVAILABILITY STATEMENT

The data sets generated for this study can be obtained upon reasonable request by email to the corresponding author.