963P Clinical and histological prognostic factors of recurrent and/or metastatic salivary gland adenoid cystic carcinoma

Abstract

About 40% of radically treated adenoid cystic carcinoma (AdCC) patients (pts) will recur locoregionally and up to 60% will develop distant metastasis. Factors influencing the risk of recurrence have been studied, but very few data exist about prognostic factors in recurrent/metastatic (RM) disease that could guide clinicians in the selection and tailoring of further treatments. Main aim of the study is to evaluate patient, treatment and disease characteristics impacting on survival for RM pts. We retrospectively evaluated a series of 135 head and neck AdCC treated with curative surgery at the Otolaryngology Head and Neck Surgery Department of the University of Brescia, Italy, from 1997 to 2016 and we retrieved data from 41 pts who relapsed. The following clinical and histological characteristics, both at first treatment and at diagnosis of relapse, were analysed and linked to overall survival (OS): gender, age, pain, cranial nerve deficit, stage, grading (according to Perzin), subsite of origin, biochemical analysis (neutrophil/lymphocytes, albumin), disease free interval (DFI), site of relapse and site of metastasis. Relapsing patients were mainly female (59%), with median age 55 years (21-83) and with primary disease in major (27%) or minor (73%) salivary gland. Grading was scored as low, intermediate, high in 27%, 39%, and 34% of cases, respectively. 71% of patients had undergone adjuvant radiotherapy after primary surgery. Site of recurrence was local in 73%, regional in 12% and distant in 39%; lung represented the most frequent site of distant failure. Median disease free-interval (DFI) was 25 months (4-142). Only high grade (HR 5,1; 1,2-20,7; p= 0,021) was associated with worse 2-year OS since the diagnosis of RM disease; on the contrary, patients with DFI longer than 25 months had higher 2-year OS (HR 0,351; 0,157-0,786; p= 0,01). Grading of disease at the time of first diagnosis and DFI are the main factors guiding prognosis after relapse of AdCC. Given the paucity of clinical prognostic data, we support extensive molecular analysis as next step of research.