(67) Systemic and Local Therapy in the Management of Metastatic Pancreatic Adenocarcinoma to the Oral Cavity: A Systematic Review and Case Report

Abstract: Metastatic pancreatic adenocarcinoma to the oral cavity is exceedingly rare, representing less than 0.5% of reported primary tumors that metastasize to the oral cavity.¹ Distant spread of pancreatic adenocarcinoma indicates a poor prognosis, often necessitating a transition to a more palliative treatment approach depending on the patient’s functional status.2 Oral metastatic lesions may cause pain, numbness, swelling, and trismus which can significantly impact quality of life. Through examining reported cases, this paper aims to systematically review both systemic and local therapies utilized in managing metastatic pancreatic lesions of the oral cavity. Additionally, this study introduces the case of a 43‐year‐old man with a primary pancreatic adenocarcinoma with metastasis to the mandible to the literature.

A systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines utilizing PubMed, Embase and Google Scholar databases. Among the 211 publications screened, 15 were included describing patients with primary pancreatic adenocarcinoma with metastases to the oral cavity. Reports were excluded if the metastatic lesion was outside of the oral cavity, the primary tumor was not histologically defined as pancreatic adenocarcinoma or if the report was not written in English.
Statistical analyses were performed to evaluate epidemiological data, orofacial symptoms, systemic and local treatment modalities utilized, the effect of local therapy and survival from the time of detection of the oral metastatic lesion.

The average age at diagnosis of oral metastases was 59.9 years. The majority of cases were in males (68.7%) with 31.2% of cases in females. The most common site of metastasis was the mandible in 75% of cases, followed by the tongue in 18.75% and the maxilla in 6.25%. In 31.2% of cases, the oral lesion was the first manifestation of the patient’s oncologic disease. The majority (87.5%) of patients experienced orofacial symptoms. The most common symptom was pain in 75% of patients, followed by swelling in 37.5%, and paresthesia in 25%. One patient (6.25%) experienced bleeding from the lesion. Regarding treatment, 56.2% of patients underwent systemic chemotherapy. Additionally, 43.75% of patients underwent local radiotherapy (RT) to the oral lesion. In 71% of cases (7 patients) where local radiotherapy was used, the authors noted improvement in the patient’s symptoms. In 4 of the 7 (57.1%) cases where RT was used, there was reduction in pain, 1 out of 7 (14.2%) experienced improved oral intake, and 1 out of 7 (14.2%) reported macroscopic disappearance of the mass. The only adverse effect of local radiotherapy noted was bleeding in 1 (14.2%) case. The average survival time after the detection of oral metastasis was 8.1 months.

Oral cavity pancreatic metastatic lesions may cause significant symptoms including pain, swelling, trismus, paresthesia, and reduced oral intake. Treatment modalities are currently based on the National Comprehensive Cancer Network Guidelines for pancreatic metastatic disease. Therapy is often adjusted based on tolerability and goals of care. Radiation therapy (RT) can be used as an adjunct to standard-of-care chemotherapy for metastatic pancreatic adenocarcinoma.2 Specifically, in cases of oral metastasis of pancreatic adenocarcinoma, the use of radiation therapy to the oral and maxillofacial region appears to alleviate pain, reduce the size of lesions, and secondarily improve oral intake. Given the good clinical response of oral metastasis to RT in these reported cases, clinicians should consider its use in patients with metastatic pancreatic adenocarcinoma to the oral cavity.

References:

1. Lopes AM, Freitas F. Metastasis of malignant tumors to the oral cavity: Systematic review of case reports and case series. J Stomatol Oral Maxillofac Surg. 2023 Feb;124

2. NCCN Clinical Practice Guidelines in Oncology for Pancreatic Adenocarcinoma. February, 2025
NAFigure 1: PRISMA Flowchart Figure 2: Cases of pancreatic adenocarcinoma with metastasis to the oral cavity Figure 3. Case histology of metastatic pancreatic adenocarcinoma