Successful Treatment of Adenoid Cystic Carcinoma with the Application of a High-Dose Stereotactic Body Radiotherapy Boost.

Background Adenoid cystic carcinoma (ACC) should be treated with a surgical procedure. Unfortunately, in some cases, such procedures are impossible to perform. In that event, radiotherapy can be used as a form of radical treatment, although ACC is established as a radio- and chemoresistant tumour. Therefore, unconventional fractionated radiotherapy needs to be considered. Case presentation Here, we present a case study of a patient with an unresectable tumour of the choanae and nasopharynx treated with a stereotactic radiotherapy boost in combination with conventional radiotherapy. We achieved complete clinical regression after application of a 1 × 18 Gy boost followed by conventional radiotherapy at 50 Gy in 25 fractions. The early and late tolerance of this treatment were positive. During the 2-year follow-up, local and distant recurrence were not detected. Conclusions This case represents an individualized, modern and safe approach to unresectable ACC. This is one of the first cases to show the use of a combination of stereotactic and conventional radiotherapy in radical, conservative cancer treatment.