Adenoid Cystic Carcinoma and Carbon Ion Only Irradiation (ACCO)

Adenoid cystic tumors are rare tumors of the head and neck region. Despite their slow growth, re-irradiation is often necessary due to the high metastatic risk. Patients are usually irradiated with photons or, as here at the Heidelberg University Hospital, with a combination of carbon ions and photons. So far, there is no data from Europe available for the sole irradiation with carbon ions. The present ACCO (Adenoid Cystic Carcinoma and Carbon ion Only irradiation) study, a prospective, open-label, phase II, single-arm, investigator-initiated study, will therefore investigate the sole radiotherapy of carbon ions in this tumor entity. Irradiation is applied - significantly shorter than the combination therapy - in about 4 weeks (22 fractions); patients are followed up for further 5 years after the start of therapy. Carbon ions alone are expected to increase local tumor control rates from 60% to 70% after 5 years (primary objective criterion of this study). In order to reject the null hypothesis with a power of 80% and a significance level of 5%, 175 patients are included (including a drop-out rate of 15%). Secondary objective criteria are progression-free survival, overall survival, acute and late toxicity, and quality of life.

Inclusion Criteria: Histologically confirmed adenoid cystic carcinoma in the head and neck area Indication for irradiation: non-operable or R1/R2 resected or perineural sheat invasion (Pn+) or pT3/pT4 Informed consent KI > 60% or ECOG 0/1 (minimum: self-sufficiency, normal activity or work not possible) Age 18-80 years Exclusion Criteria: rejection of the study by the patient Patient is not able to consent Stage IV (distant metastases), except lung metastases < 1cm lymph node involvement (clinical or pathological) Previous radiotherapy in the head and neck area Active medical implants for which there is no ion radiation authorization at the time of treatment (e.g., cardiac pacemaker, defibrillator, ...) Contraindication to MR imaging Simultaneous participation in another clinical study that could influence the outcome of this study or the other study Pregnancy

Lang K, Adeberg S, Harrabi S, Held T, Kieser M, Debus J, Herfarth K. Adenoid cystic Carcinoma and Carbon ion Only irradiation (ACCO): Study protocol for a prospective, open, randomized, two-armed, phase II study. BMC Cancer. 2021 Jul 15;21(1):812. doi: 10.1186/s12885-021-08473-5.