Surveillance After Treatment of Adenoid Cystic Carcinoma of the Head and Neck: Review of Institutional Outcomes and Proposed Surveillance Imaging Protocol

Introduction

Long term survival for adenoid cystic carcinoma (ACC) arising from the head and neck declines for many decades after initial treatment due to late disease relapse. Follow up and surveillance imaging practices vary due to limited evidence as well as a lack of international guidelines (until 2021).

Methods

A retrospective cohort study was conducted for patients treated curatively for ACC between 2007 and 2024 at a single institution. Clinicopathologic information, treatment details, patterns of follow-up (including radiologic investigations) and oncological outcomes are reported.

Results

51 patients comprised the study cohort. Median age was 50 years; 96% of patients underwent surgery and adjuvant radiation therapy. Median follow-up was 7.65 years. 5-year overall survival (OS) and disease-free survival (DFS) were 88% and 73% respectively. 18% and 61% of patients underwent surveillance imaging within 3- and 12-months of treatment completion respectively. 80% of first recurrences were detected on surveillance imaging. Half the episodes of first disease recurrence occurred within 5 years of initial treatment, a further 25% within 10 years and the remaining 25% occurred > 10 years post treatment.

Conclusion

This cohort of patients curatively treated for ACC at a single institution highlights the propensity for late distant relapse as well as heterogeneity of surveillance imaging. A local institutional protocol is proposed based upon the 2021 ASCO guidelines to standardise clinical and radiologic follow-up for this group.