Objective: To establish a predicting model of survival rates and to evaluate the weighted contributions of each key prognostic factor of the patients with salivary adenoid cystic carcinoma (SACC).
Methods: One hundred and eighteen follow-up cases with SACC were analyzed for the survival study with retrospective cohort method. Ten possible clinical and pathologic factors were selected. A multivariate analysis was performed by Cox proportional hazard model and prognostic index (PI) was calculated. According to the PI, all cases were divided into three risk subgroups respectively: lower, intermediate and higher risk subgroups. Ten-year survival rate and median survival time were calculated and the predicting models of survival rates were established.
Results: The significant prognostic factors influencing the survival rate were age at diagnosis, clinical presentation, TNM clinical stage, treatment, surgical margins (P < 0.05). The predicting formula was PI = 0.031X(2) + 0.665X(5) + 0.420X(6)-0.576X(7) + 0.999X(10). According to the value of PI, the prognosis of the patients was significantly different among the three subgroups (P < 0.05). In the three risk subgroups, 10-year survival rates were 83.56%, 31.45% and 11.20% respectively, the median survival time was 18 years, 7 years and 4 years respectively.
Conclusions: The established predicting model of survival rates can predict the prognosis of the patients with SACC.