Metastatic tumours to the oral cavity: a survival study with a special focus on gingival metastases.

AIMS: To describe survival from oral metastases, particularly gingival metastases, and to identify clinical prognostic variables.

MATERIALS AND METHODS: A series of 39 patients were studied, analysing age, gender, primary tumour site, oral metastases site and histological type.

RESULTS: Mean age: 62.3+/-9.2 years, with similar prevalence by gender. The most frequent sites for primary tumours were the kidney (20.5%), lung (20.5%) and breast (20.5%). Gingival metastases represented 63.6% of all oral soft tissue metastases (7/11). The average time between primary tumour diagnosis and appearance of the gingival metastases was 9.7+/-13.4 months. The median survival time since gingival metastases appearance was 5.2 months [95% confidence interval (CI)=0-13.6]; no statistically significant difference with other oral locations was found by the Kaplan-Meier curves (log rank: 0.29; p>0.05). Oral metastases involving the gingiva were more frequently found in the maxilla (85.7%versus 14.3%), whereas intra-osseous metastatic tumours were more frequent in the mandible (77.8%versus 22.2%; p<0.05; odds ratio=21; 95% CI=2.0-210.1). None of the variables considered had a prognostic value as indicated by the Kaplan-Meier test.

PRACTICAL IMPLICATIONS: The data in this paper show that 25% (and in other studies up to 37%) of oral metastases came from unknown primary tumours; thus a biopsy with histopathologic analysis is mandatory for every patient with a gingival mass.

CONCLUSIONS: This study reinforces the significance of gingival metastases as a poor prognosis indicator. Dental practitioners should suspect that gingival masses mimicking benign or inflammatory lesions may represent a sign of underlying malignant tumours.