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; Antoine Eskander; Rui Fu; John de Almeida; David Goldstein; Hesameddin Noroozi; Ali Hosni; Hadi Seikaly; Paul Tabet; Justin M Pyne; T Wayne Matthews; Joseph Dort; Steve Nakoneshny; Apostolos Christopoulos; Houda Bahig; Stephanie Johnson-Obaseki; Nadia Hua; Marc Gaudet; Alborz Jooya; Anthony Nichols; Francisco Laxague; Matthew Cecchini; Jenny Du; Justin Shapiro; Irene Karam; Peter T Dziegielewski; Krishna Hanubal; Boban Erovic; Stefan Grasl; Joel Davies; Eric Monteiro; Maru Gete; Ian Witterick; Nader Sadeghi; Keith Richardson; George Shenouda; Anastasios Maniakas; Vivianne Landry; Michael Gupta; Kelvin Zhou; Alex M Mlynarek; Marc Pusztaszeri; Khalil Sultanem; Michael P Hier

doi:10.1002/cncr.34932

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

Cancer. 2023 Oct 15;129(20):3263-3274. doi: 10.1002/cncr.34932. Epub 2023 Jul 4.

Authors

Grégoire B Morand¹, Antoine Eskander², Rui Fu², John de Almeida³, David Goldstein³, Hesameddin Noroozi³, Ali Hosni⁴, Hadi Seikaly⁵, Paul Tabet⁵, Justin M Pyne⁵, T Wayne Matthews⁶, Joseph Dort⁶, Steve Nakoneshny⁶, Apostolos Christopoulos⁷, Houda Bahig⁸, Stephanie Johnson-Obaseki⁹, Nadia Hua⁹, Marc Gaudet¹⁰, Alborz Jooya¹⁰, Anthony Nichols¹¹, Francisco Laxague¹¹, Matthew Cecchini¹¹, Jenny Du², Justin Shapiro², Irene Karam¹², Peter T Dziegielewski¹³, Krishna Hanubal¹³, Boban Erovic¹⁴, Stefan Grasl¹⁵, Joel Davies¹⁶, Eric Monteiro¹⁶, Maru Gete¹⁶, Ian Witterick¹⁶, Nader Sadeghi¹⁷, Keith Richardson¹⁷, George Shenouda¹⁸, Anastasios Maniakas^{19

20}, Vivianne Landry¹⁹, Michael Gupta²¹, Kelvin Zhou²¹, Alex M Mlynarek¹, Marc Pusztaszeri²², Khalil Sultanem²³, Michael P Hier¹

Affiliations

¹ Department of Otolaryngology Head and Neck Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
² Department of Otolaryngology-Head and Neck Surgery, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada.
³ Department of Otolaryngology-Head and Neck Surgery, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada.
⁴ Department of Radiation Oncology, Princess Margaret Cancer Center-University Health Network, University of Toronto, Toronto, Ontario, Canada.
⁵ Division of Otolaryngology-Head and Neck Surgery, University of Alberta, Edmonton, Alberta, Canada.
⁶ Department Otolaryngology-Head and Neck Surgery, University of Calgary, Calgary, Alberta, Canada.
⁷ Department of Otolaryngology-Head and Neck Surgery, Centre Hospitalier de l'Université de Montreal (CHUM), Université de Montreal, Montreal, Quebec, Canada.
⁸ Department of Radiation Oncology, CHUM, Université de Montreal, Montreal, Quebec, Canada.
⁹ Department of Otolaryngology-Head and Neck Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
¹⁰ Department of Radiation Oncology, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada.
¹¹ Department of Otolaryngology-Head and Neck Surgery and Oncology, London Health Sciences Center, London, Ontario, Canada.
¹² Department of Radiation Oncology, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada.
¹³ Department of Otolaryngology-Head and Neck Surgery, University of Florida Health Shands Hospital, University of Florida, Gainesville, Florida, USA.
¹⁴ Institute of Head and Neck Diseases, Evangelical Hospital, Vienna, Austria.
¹⁵ Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna, Austria.
¹⁶ Department of Otolaryngology-Head and Neck Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
¹⁷ Department of Otolaryngology-Head and Neck Surgery, McGill University Health Center, McGill University, Montreal, Quebec, Canada.
¹⁸ Department of Radiation Oncology, McGill University Heath Center, Montreal, Quebec, Canada.
¹⁹ Department Otolaryngology-Head and Neck Surgery, Hôpital Maisonneuve-Rosemont, Université de Montreal, Montreal, Quebec, Canada.
²⁰ Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
²¹ Department of Otolaryngology-Head and Neck Surgery, McMaster University, Hamilton, Ontario, Canada.
²² Department of Pathology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
²³ Department of Radiation Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.

PMID: 37401841
DOI: 10.1002/cncr.34932

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.

Keywords: acinar cell; adjuvant; carcinoma; mucoepidermoid; parotid neoplasms; radiation therapy; salivary gland neoplasms.

MeSH terms

Canada / epidemiology
Humans
Neoplasm Recurrence, Local* / pathology
Neoplasm Recurrence, Local* / prevention & control
Neoplasm Staging
Radiotherapy, Adjuvant
Retrospective Studies
Salivary Gland Neoplasms* / radiotherapy
Salivary Gland Neoplasms* / surgery
Salivary Glands / pathology