Kaplan-Meier analysis of salivary gland tumors: prognosis and long-term survival.

Abstract

We evaluated the impact of various tumor related parameters on survival probability in a cohort of patients with malignant salivary tumors, using the Kaplan-Meier analysis. We measured patients up to 15years following therapy, looking at T N M stage, grade perineural invasion and extra-parenchymal spread. Of 101 patients diagnosed with various salivary malignant tumors in our medical center, 79 patients survived while 22 died with disease (DWD). The impact of distant metastasis (M+) was devastating (survival probability at 60months and at 180months dropped from 0.93 (M-) to 0.40 (M+) and from 0.67 to 0.40, respectively, p = 0.0001), the impact of perineural invasion was severe (at 180months the probability of survival dropped from 0.75 to 0.21, p = 0.002). Higher stage tumor also decreased survival (from 0.82 to 0.53 at 180months, p = 0.002) as did poor histological grade (from 0.85 to 0.48 at 180months, p = 0.019). Neck metastasis (N+) impact was quite moderate (at 180months the probability of survival dropped from 0.69 to 0.58, p = 0.044) while neither tumor size (T) nor extra-parenchymal spread significantly affected survival. Salivary tumor location and its potential to infiltrate nerves and blood vessels and to metastasize is the most telling parameter. Systemic therapy aimed at halting distant metastatic spread is the most effective therapeutic goal. Dissection of N0 neck metastasis is not necessarily a valuable treatment.