Oncologic Safety of Close Margins in Patients With Low- to Intermediate-Grade Major Salivary Gland Carcinoma
Authors: Sajisevi Mirabelle , Nguyen Kenny , Callas Peter , Holcomb Andrew J. , Vural Emre , Davis Kyle P. , Thomas Carissa M. , Plonowska-Hirschfeld Karolina A. , Stein John S. , Eskander Antoine , Kakarala Kiran , Enepekides Danny J. , Hier Michael P. , Ryan William R. ,   American Head and Neck Society Salivary Gland Section, Asarkar Ameya A. , Aulet Ricardo , Bell Rebecca K. , Blasco Michael A. , Bowmaster Vanessa B. , Burruss Clayton P. , Chung Jeffson , Chan Kimberly , Chang Brent A. , Coffey Charles S. , Cognetti David M. , Cooper Dylan J. , Cordero Joehassin , Donovan John , Du Yue (Jennifer) , Dundar Yusuf , Dedivitis Rogerio A. , Edwards Heather A. , Erovic Boban M. , Feinberg Philip A. , Garvey Emily A. , Goldstein David P. , Goodman Joseph F. , Goulart Rafael N. , Goyal Neerav , Grasl Stefan , Giurintano Jonathan P. , Gupta Nikita , Habib Andy M. , Hackman Trevor G. , Hara Jared H. , Henson Christina , Hinni Michael L. , Hua Nadia , Johnson-Obaseki Stephanie , Juloori Aditya , Kalman Noah S. , Kejner Alexandra E. , Khaja Sobia F. , Ku Jamie A. , Lambert Arnaud , Luu Bao K. , Magliocca Kelly R. , dos Santos Luiz R. Medina , Michael Cara , Miles Brett A. , de Melo Giulianno Molina , Moore Michael G. , Morand Gregoire B. , Moura Kauê , Mukdad Laith , Noroozi Hesameddin , Patel Rusha , Paydarfar Joseph A. , Sadeghi Nader , Savaria Fabrice N. , Schmitt Nicole C. , Shapiro Justin , Shaver Timothy B. , Stoeckli Sandro J. , St. John Maie , Stokes William Alvo , Sulibhavi Anita , Tasoulas Jason , Vendra Varun , Vinh Daniel B. , Virgen Celina G. , Wooten Christian , Woody Neil M. , Young Geoffrey D. 
Published: December 2023

Importance

Postoperative radiation therapy for close surgical margins in low- to intermediate-grade salivary carcinomas lacks multi-institutional supportive evidence.

Objective

To evaluate the oncologic outcomes for low- and intermediate-grade salivary carcinomas with close and positive margins.

Design, Setting, and Participants

The American Head and Neck Society Salivary Gland Section conducted a retrospective cohort study from 2010 to 2019 at 41 centers. Margins were classified as R0 (negative), R1 (microscopically positive), or R2 (macroscopically positive). R0 margins were subclassified into clear (&amp;gt;1 mm) or close (≤1 mm). Data analysis was performed from June to October 2023.

Main Outcomes and Measures

Main outcomes were risk factors for local recurrence.

Results

A total of 865 patients (median [IQR] age at surgery, 56 [43-66] years; 553 female individuals [64%] and 312 male individuals [36%]) were included. Of these, 801 (93%) had parotid carcinoma and 64 (7%) had submandibular gland carcinoma, and 748 (86%) had low-grade tumors and 117 (14%) had intermediate-grade tumors, with the following surgical margins: R0 in 673 (78%), R1 in 168 (19%), and R2 in 24 (3%). Close margins were found in 395 of 499 patients with R0 margins (79%), for whom margin distances were measured. A total of 305 patients (35%) underwent postoperative radiation therapy. Of all 865 patients, 35 (4%) had local recurrence with a median (IQR) follow-up of 35.3 (13.9-59.1) months. In patients with close margins as the sole risk factor for recurrence, the local recurrence rates were similar between those who underwent postoperative radiation therapy (0 of 46) or observation (4 of 165 [2%]). Patients with clear margins (n = 104) had no recurrences. The local recurrence rate in patients with R1 or R2 margins was better in those irradiated (2 of 128 [2%]) compared to observed (13 of 64 [20%]) (hazard ratio [HR], 0.05; 95% CI, 0.01-0.24). Multivariable analysis for local recurrence found the following independent factors: age at diagnosis (HR for a 10-year increase in age, 1.33; 95% CI, 1.06-1.67), R1 vs R0 (HR, 5.21; 95% CI, 2.58-10.54), lymphovascular invasion (HR, 4.47; 95% CI, 1.43-13.99), and postoperative radiation therapy (HR, 0.10; 95% CI, 0.04-0.29). The 3-year local recurrence-free survivals for the study population were 96% vs 97% in the close margin group.

Conclusions and Relevance

In this cohort study of patients with low- and intermediate-grade major salivary gland carcinoma, postoperative radiation therapy for positive margins was associated with decreased risk of local recurrence. In isolation from other risk factors for local recurrence, select patients with close surgical margins (≤1 mm) may safely be considered for observation.