Prognostic effect of professional oral care in estrogen receptor-positive metastatic breast cancer patients treated with everolimus and exemestane enrolled in Oral Care-BC: a randomized controlled trial

Background: The Oral Care BC-trial reported that professional oral care (POC) reduces the incidence and severity of oral mucositis in patients receiving everolimus (EVE) and exemestane (EXE). However, the effect of POC on clinical response among patients receiving EVE and EXE was not established. We compared outcomes for estrogen receptor-positive metastatic breast cancer patients that received POC to those that had not and evaluated clinical prognostic factors. All patients simultaneously received EVE and EXE. Methods: Between May 2015 and Dec 2017, 174 eligible patients were enrolled in the Oral Care-BC trial. The primary endpoint was the comparative incidence of grade 1 or worse oral mucositis, as evaluated by an oncologist over 8 weeks between groups. The secondary endpoints were progression-free survival (PFS) and overall survival (OS). Data were collected after a follow-up period of 13.9 months. Results: There were no significant differences in PFS between the POC and Control Groups ( P = 0.801). A BMI < 25 mg/m 2 and non-visceral metastasis were associated with longer PFS ( P = 0.018 and P = 0.003, respectively) and the use of bone modifying agents (BMA) was associated with shorter PFS ( P = 0.028). The PFS and OS between the POC and control groups were not significantly different in the Oral-Care BC trial. Conclusions: POC did not influence the prognosis of estrogen receptor-positive metastatic breast cancer patients. Patients with non-visceral metastasis, a BMI < 25 mg/m 2 , and who did not receive BMA while receiving EVE and EXE may have better prognoses. Trial registration: The study protocol was registered online at the University Hospital Medical Information Network (UMIN), Japan (protocol ID 000016109), on January 5, 2015 and at ClinicalTrials.gov (NCT02376985).