Skeletal metastases in advanced pancreatic ductal adenocarcinoma: a retrospective analysis

Skeletal metastases (SM) in advanced pancreatic ductal adenocarcinoma (PDAC) is an infrequent occurrence that has been previously reported in literature to occur in less than 2.5% of the cases. Complications such as pathological fractures can result in intractable pain, immobilization and a significant deterioration in quality of life. The purpose of this study is to improve the understanding of the increasing incidence of SM and the importance of surveillance and adequate management of SM in these patients.

A retrospective analysis was conducted using a clinical database at a single tertiary care institution for cancer patients; this included 207 patients with advanced PDAC diagnosed between December 2004 and March 2017 receiving palliative chemotherapy. SM were identified by computerized tomography (CT)/fluorodeoxyglucose positron emission tomography (FDG-PET)/magnetic resonance imaging (MRI). Information regarding demographics, clinical course and date of last follow-up/death were collected. After a median follow-up of 11 months, an analysis was conducted, including a Kaplan-Meier survival analysis.

The study included 207 patients; 19 out of 207 patients (9.2%) developed SM; the primary tumor was located in the pancreatic body/tail in 12 out of 19 patients (63.2%). The thoracic and lumbar vertebrae were the most common sites of SM. Other common synchronous sites of metastases included the liver and lung. A majority of the lesions were osteolytic (63.2%). The median time of diagnosis from the initial diagnosis was 2 months (range, 0-60 months). Bone pain was observed as the initial symptom in 7 out of 19 patients (36.8%), 2 out of 19 patients (10.5%) had a pathological fracture and 1 out of 19 patients (5.3%) developed a para-spinal mass causing inferior vena cava compression. The median survival period for patients with SM was 11 months (range, 0-62 months) and for those without SM was 12 months (range, 0-147 months) [hazard ratio (HR) 1.24, 95% confidence interval (CI): 0.66-2.30, P=0.51].

There has been a challenge with regards to management of the increasing number of patients with SM. Thoracic and lumbar vertebrae are the most common sites and pathological fractures in these sites can be catastrophic. Careful evaluation of skeletal signs and symptoms, early detection and intervention are essential to prevent morbidity and mortality from complications in patients with PDAC and SM.