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. 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.

Automated summary

Adenoid cystic carcinoma (ACC) is a rare malignancy in the head and neck region with a high propensity for perineural invasion, often necessitating a balance between disease burden and treatment morbidity. Radiotherapy plays a crucial role in improving local control and managing unresectable disease, particularly in cases of perineural invasion. Target delineation and treatment regimens in different settings, including definitive, recurrent, and metastatic disease, are important considerations in the management of ACC.