Cohort study of standardized treatment pathways by multidisciplinary tumor board decision making in patients with salivary gland malignancies

Salivary gland malignancies (SGM) are heterogeneous regarding origin, biology and prognosis. We investigated patterns of clinical and pathological features and outcome differences attributable to standardized decision making for treatment pathways before and after establishing our multidisciplinary tumor board (MDTB) in 2007. We retrospectively analyzed data of electronic health records, the Saxon cancer registry and the clinic's tumor database (1990-2024). Statistical analysis included contingency tables, Pearson's chi-squared tests for categorical, Student's t test for numerical data, Kaplan-Meier cumulative survival plots and log-rank tests for time-dependent outcome measures. Among 200 patients, 83 were diagnosed before and 117 since 2007. Treatment modalities included surgery in 93% of cases, with 33.5% receiving adjuvant radiotherapy and 12.5% receiving adjuvant chemo-radiotherapy. We observed disease progression in 50% of patients. Locoregional free survival was superior since 2007 (p = .035). Distant metastasis-free survival (DMFS) decreased related to earlier detection of distant metastasis (M1) linked to prevention of deaths from the index cancer in patients with M1 at diagnosis or relapse (rM1) since 2007 (p = .120). Moreover, conditional OS was not affected for patients with M1/rM1 diagnosis by numerically increased detection of distant metastasis since 2007 (p = .574). MDTB decision making at a certified cancer center is accompanied by increasing numbers of diagnosis of SGM and better locoregional control but not DMFS due to higher metastasis detection rate and treatment. Despite excellent and numerically improved disease-specific survival, 10-years OS remained similar.