Stoeckli, Sandro Johannes

ABSTRACT Objectives To characterize practice patterns and outcomes in the management of low‐ and intermediate‐grade salivary gland carcinoma prior to the existence of treatment guidelines. Methods Analysis of a registry of patients who underwent parotid and submandibular gland resections for low‐and intermediate‐grade carcinomas between 2010 and 2019. Results Of all 786 patients included in the study, 726 (92%) had preoperative imaging and 653 (83%) had preoperative biopsy. Of the 729 patients with parotid gland cancer, the majority underwent superficial ( n = 384, 53%) or total ( n = 254, 35%) parotidectomy. In patients with facial nerve preservation, total parotidectomy was associated with a significant increase in transient facial weakness (72/177 (41%) vs. 82/311 (26%), RR 0.65, 95% CI 0.50–0.84, p < 0.05) and permanent facial nerve weakness (23/176 (13%) vs. 16/301 (5%), RR 0.41, 95% CI 0.22–0.75, p < 0.05) compared to superficial parotidectomy. Adjuvant radiation therapy ( RT ) was delivered to 285 (36%) patients. The proportion of patients receiving adjuvant RT declined significantly over the time period from 2015 to 2019 compared to 2010 to 2014 at 162/504 (32%) and 123/282 (44%), respectively ( RR 0.74, 95% CI 0.61–0.89, p < 0.05). When comparing the time periods from 2015 to 2019 and 2010 to 2014, there was no significant difference in local control rates ( RR 0.52, 95% CI 0.26–1.04, p = 0.06) or regional control rates ( RR 0.75, 95% CI 0.26–2.13, p = 0.58). Conclusions Management of low‐ and intermediate‐grade salivary cancer from 2010 to 2019 was variable, which is expected given the rarity and heterogeneity of the disease and the lack of treatment guidelines prior to 2021. Most patients with parotid malignancies underwent superficial or total parotidectomy. The extent of parotidectomy had an impact on facial nerve function outcomes. Delivery of adjuvant radiation trended down with time. The data presented here will support dissemination of the guidelines and provide data that could inform future trials. Level of Evidence 2b.

ImportancePostoperative radiation therapy for close surgical margins in low- to intermediate-grade salivary carcinomas lacks multi-institutional supportive evidence.ObjectiveTo evaluate the oncologic outcomes for low- and intermediate-grade salivary carcinomas with close and positive margins.Design, Setting, and ParticipantsThe 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 MeasuresMain outcomes were risk factors for local recurrence.ResultsA 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 RelevanceIn 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.