Prognostic factors for long term results of the treatment of patients with malignant submandibular gland tumors.

Background: Concerning malignant submandibular gland tumors, a rare disease entity, there are few recent reports of long term treatment results and of prognostic factors modifying these results.

Methods: The clinical data of 43 patients with malignant submandibular gland tumors who were treated at the Netherlands Cancer Institute between 1973 and 1994 were reviewed to evaluate treatment results and to control described prognostic factors. The median follow-up for patients alive at the end of follow-up was 143 months. Only univariate analyses were performed.

Results: The crude 5- and 10-year survival rates were 50% and 36%, respectively; the 5- and 10-year disease specific survival (DSS) rates were 61% and 51%, respectively; and the 5- and 10-year recurrence free percentages were 57% and 52%, respectively. Factors predicting crude survival were age at diagnosis (P = 0.0006), International Union Against Cancer/American Joint Committee on Cancer (UICC/ AJCC) TNM classification and its regrouping into tumor stage (P = 0.001), and clinical skin invasion (P = 0.005). In surgically treated patients, soft tissue invasion (P = 0.005), metastatic lymph nodes (P = 0.006), and perineural growth (P = 0.01) were prognostic for survival. Factors predicting DSS were the UICC/AJCC TNM classification and regrouping into tumor stage (P = 0.002). In surgical patients, perineural growth (P = 0.0008) conferred a lower DSS. Factors predicting tumor recurrence were the UICC/AJCC TNM classification and its regrouping into tumor stage (P = 0.009). In surgical patients, perineural growth (P = 0.003) predicts tumor recurrence.

Conclusions: Of patients with submandibular gland carcinoma treated according to a stable treatment protocol in a European tertiary referral center, 52% were tumor free 10 years later. Patients exhibiting the described adverse prognostic factors are likely to benefit from added radiotherapy.