REFCOR guidelines for sinonasal adenoid cystic carcinoma

Sinonasal adenoid cystic carcinoma (ACC) is a rare seromucosal gland tumor, accounting for 7.5% of sinonasal cavity cancers. It is a distinct entity, with slow progression, strong perineural tropism and high risk of late recurrence. Since the time of the 2009 French guidelines, large multicenter studies have been reported, enabling more precise clinical, pathologic and therapeutic analysis. To update the previous guidelines, a systematic review was performed, using PRISMA guidelines and the PubMed, Scopus and Web of Science databases for the period 2009-2020. English and French language articles were selected on strict inclusion criteria, resulting in 23 studies analyzed out of 283. Data were classified according to the French Health Authority levels of evidence, as a scientific basis for the new REFCOR guidelines published in 2022. We here present a short version of the scientific rationale. Results confirmed frequently late clinical presentation, with most tumors staged T3 or T4 at diagnosis. Histologically, solid tumors and perineural or bone infiltration were of poorer prognosis. Overall 5-year survival ranges from 61% to 87%, but risk of recurrence beyond 20 years requires prolonged monitoring. Treatment is based on complete surgical resection. Adjuvant radiotherapy, preferably with intensity modulation, is indicated in case of risk factors. In unresectable or recurrent forms, exclusive hadron therapy is a good option. Systemic treatments show limited efficacy, with no neoadjuvant forms or current recommendations for concomitant chemoradiotherapy. Targeted therapies, on the other hand, are promising.