The Role of Postoperative Radiotherapy for Large Nerve Perineural Spread of Cancer of the Head and Neck

Immunotherapy for the treatment of perineural spread in cutaneous head and neck squamous cell carcinoma: Time to rethink treatment paradigms

BACKGROUND

Immune checkpoint inhibitors have shown promising antitumour activity. Application in head and neck cutaneous squamous cell carcinoma (cSCC) large nerve perineural spread (PNS) is limited.

METHODS

Retrospective review of 13 patients with PNS receiving anti-PD-1 therapy from September 2017 to May 2021 is presented. Primary endpoints were objective response (complete or partial response) and median time to progression, determined by Head and Neck Multi-Disciplinary Team (MDT) and independent radiology review of magnetic resonance imaging (MRI) and/or computed tomography/positron emission tomography (CT/PET).

RESULTS

Objective response was observed in 9/13 patients (69%), with complete response in 6 (46%) and partial response in 3 patients (23%). Median time to response was 2.1 months (IQR 1.8-2.7 months). There were 3 (23%) patients with progressive disease, with median time to progression of 3.5 months. There were no grade 3-4 treatment related adverse events.

CONCLUSIONS

This case series supports developing evidence for anti-PD-1 checkpoint inhibitor therapy for perineural spread, supporting future prospective clinical trials in this patient population.

Radiation Therapy for Adenoid Cystic Carcinoma of the Head and Neck

Simple Summary

Adenoid cystic carcinoma is a rare histology arising in the head and neck region that has a high propensity for perineural invasion. While surgical resection is the preferred primary treatment modality, adjuvant radiotherapy is often indicated to improve local control. For unresectable disease, definitive radiotherapy can be utilized. Given the predilection for perineural tumor spread, target volumes often must encompass relevant nerve pathways back to the base of skull. Treatment strategies for ACC must therefore balance the disease burden and risk of failure against the morbidity of treatment.

Abstract

Adenoid cystic carcinoma of the head and neck is an uncommon malignancy that can arise in the major or minor salivary glands. Perineural invasion (PNI) is an extremely frequent finding in cases of adenoid cystic carcinoma (ACC) that can be associated with significant patient morbidity and poor prognosis. By contrast, ACC rarely demonstrates lymphovascular space invasion thereby making PNI the major avenue for metastasis and a driver of treatment rationale and design. Radiotherapy is often utilized post-operatively to improve locoregional control or as a primary therapy in unresectable disease. Here we aim to review the role of radiotherapy in the management of this malignancy with a focus on target delineation and treatment regimens in the definitive, recurrent, and metastatic settings.

Significance of perineural invasion in locally advanced bucco alveolar complex carcinomas treated with surgery and postoperative radiation ± concurrent chemotherapy

BACKGROUND

The purpose of this study was to evaluate prognostic factors, locoregional control, and survival in locally advanced bucco-alveolar complex cancers.

METHODS

A retrospective review of 83 patients treated between January 2009 and December 2012 with bucco-alveolar complex cancers was conducted. All patients had surgery and adjuvant radiotherapy with intensity-modulated radiotherapy (IMRT) with/without concurrent chemotherapy. Survival analysis was performed using Kaplan-Meier and multivariable Cox regression model.

RESULTS

On univariate and multivariate analysis, perineural invasion (PNI) was found to be an independent adverse risk factor. Patients with PNI-positive disease had significantly worse 2-year disease-free survival (DFS), locoregional failure free survival, and overall survival (OS) as compared to patients with PNI-negative disease (P < 0. 001, 0.001 and < 0. 001) respectively.

CONCLUSION

Compared with patients with PNI-negative disease, patients with PNI-positive disease had much worse outcome despite aggressive adjuvant treatment. It warrants escalation of therapy and modification in radiation portals to cover neural pathways in patients with PNI-positive disease.