Background: While surgical resection is the treatment of choice for adenoid cystic carcinoma (ACC), patients with metastasis and those who cannot undergo surgery receive palliative chemotherapy. However, the role of palliative chemotherapy is not clear yet. This study aimed to evaluate the efficacy of chemotherapy with cyclophosphamide, doxorubicin, and cisplatin (CAP) for patients with ACC; and to analyze the relationship between the pre-chemotherapy tumor growth rate (P-TGR) and treatment outcomes in patients with the recurred metastatic unresectable ACC.
Methods: We retrospectively analyzed the clinical data and treatment outcomes of patients who diagnosed ACC and treated with CAP chemotherapy. Response evaluation was performed using computed tomography (CT) images obtained before and after chemotherapy according to the RECIST 1.1. P-TGR was defined as the difference of the sum of the largest diameter of the target lesion per unit of time between the pre-baseline and baseline CT images.
Results: Fourteen patients with ACC who were treated with CAP were enrolled. Median patient age was 49 years, and the patients received a median of 5 CAP treatment cycles. Two patients achieved partial response (PR) and 10 patients showed stable disease. Response rate was 14.3%, and the disease control rate was 85.7%. Median progression-free survival was 5.7 months (95% CI: 4.3 to not reached) and the median overall survival was 23.4 months (95% CI: 12.9 to not reached). A low P-TGR was associated with a good response to CAP (correlation coefficient, 0.56).
Conclusions: Palliative CAP chemotherapy demonstrated a modest anti-cancer effect for ACC. A low P-TGR was associated with a good response to CAP chemotherapy.
Keywords: Cyclophosphamide; adenoid cystic carcinoma (ACC); cisplatin; doxorubicin; tumor growth rate.