Abstract
The oncologic benefit of adjuvant radiotherapy (aRT) and the impact of facial nerve sacrifice have not been examined for early-stage low- and intermediate-grade salivary gland carcinomas (LIG-SGCs) with isolated perineural invasion (PNI) and no other adverse features.
Using a multi-institutional, international cohort established by the American Head and Neck Society (AHNS) Salivary Gland Section, we examined T1-2N0 LIG-SGCs, excluding tumor spillage, positive margins, positive lymphovascular invasion, and unreported PNI. We compared local recurrence rates between the isolated PNI and control arms. Multivariate hazard regression was used to evaluate the risk of local recurrence across PNI, adjuvant radiation therapy (aRT), and facial nerve sacrifice.
Among 336 patients across 35 centers, 24 (7 %) patients had isolated PNI as the only high-risk feature. aRT was significantly more common among patients with isolated PNI (n = 10/24 or 42 %, RR: 2.32, 95 % CI: 1.37–3.94) than controls (n = 56/312 or 18 %). aRT was not significantly associated with local control, even after controlling for PNI and facial nerve sacrifice (HR: 0.34, 95 % CI: 0.04–3.06). Within the isolated PNI cohort, one recurrence occurred in the aRT group (n = 1/10, 10 %) and one in the group without aRT (n = 1/14 or 7 %). Thirty (91 %) patients who underwent facial nerve sacrifice had no PNI on final histopathology, with all 30 having full preoperative facial nerve function.
aRT may not necessarily reduce local recurrence for early-stage LIG-SGCs with isolated PNI. In patients with preoperative normal facial nerve function, facial nerve sacrifice may not be necessary.
•Adjuvant radiotherapy (aRT) is often offeredfor salivary gland carcinomas in the setting of high-risk features, including perineural invasion (PNI).•In the case of low- and intermediate-grade tumors with isolated PNI, aRT may not significantly improve local control.•In patients with preoperative normal facial nerve function, facial nerve sacrifice in low- to intermediate-grade salivary carcinomas may not be necessary.