Prognostic Factors in Salivary Gland Malignancies: A Multicenter Study of 229 Patients from the Polish Salivary Network Database.

Background/

Objectives

The multitude of histological and genetic features of salivary gland malignancies (SGMs) hampers the ability of the doctors' board to make a clear and quick decision on how aggressively treatment should be initiated. Despite treatment guidelines, it is difficult to determine the appropriate extent and invasiveness of surgery based on preliminary patient data. The aim of this study is to define the factors that have a significant impact on the oncological outcome of SGM treatment and to create an algorithm for finding the combinations of predictors with a particularly unfavorable impact on survival.

Methods

A multicenter retrospective analysis was conducted on 2653 patients with salivary gland tumors (SGTs), including 229 with SGMs (parotid 204/229 = 89.1%; submandibular 25/229 = 10.9%), treated at seven Polish university departments from 2015 to 2022. All patients, except those with malignant lymphoma, underwent surgery followed by radiotherapy. Seventeen potential survival-impacting variables were analyzed: thirteen preoperative and four surgical specimens. The preoperative group aids in deciding surgical aggressiveness, while the postoperative group supports decisions on adjuvant treatment escalation. The main outcome measures were disease-free survival (DFS) and overall survival (OS).

Results

SGMs constituted 8.63% of all SGTs, with 204 (89%) in the parotid and 25 (11%) in the submandibular glands. The average age was 63.38 years, with a male predominance (54%). Clinical and radiological signs of malignancy were reported in 45.4% and 54.6% of patients, respectively, with facial nerve palsy reported in 13%. Postoperative specimens revealed 23 histological types, and R0 resections were achieved in 168/229 cases (73%). Fifty-six patients (24.5%) died of cancer within five years. Significant survival factors included gender, urban residence, previous chemical and radiation exposure, clinical malignancy symptoms, pT-stage, pN-stage, clinical stage, and resection margins.

Conclusions

The prognosis for SGM remains unsatisfactory, which would suggest more aggressive treatment; thus, carefully collected clinical data could support the decision-making process. Significantly worse survival has been demonstrated in the presence of unfavorable clinical factors, so defining new elements of medical history may be a step towards improving treatment outcomes.