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Background: 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. Methods: 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.Results: 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].Conclusions: 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.

Colorectal cancer survivorship has risen in recent years because of earlier detection and advances in treatment. Primary care providers (PCPs) may see more of these patients in their daily practices. This article discusses some of the most common issues patients face after completing treatment for colorectal cancer and describes how PCPs can help.

245 Background: Skeletal metastasis (SM) in advanced PDAC is an infrequent occurrence and has been previously reported to be < 2.5%. However; pathological fractures in these patients can result in intractable pain, immobilization and a significant deterioration in quality of life. Methods: A retrospective analysis was conducted of patients (pts) with advanced PDAC receiving palliative chemotherapy. Data collection included age, gender, ECOG, sites of disease, and overall survival (OS). Statistical analysis included Kaplan Meier survival analysis. Results: The 135 pts included had a median age of 65.8 years (range: 53.7–91.3); 5 (31.2%) were women and 11 (68.7%) had an ECOG performance status of 0 or 1. A majority of patients received combination therapy that was either gemcitabine or 5-flurouracil based. Sixteen pts (11.8%) had skeletal metastasis with the primary tumor located in the pancreatic body/tail (11 pts - 68.7%).The sites of SM included thoracic vertebrae (8), lumbar vertebrae (5), pelvis (5), ribs (4), sacrum (4), scapula (3), acetabulum (2), cervical vertebrae (2), femoral head (2), sternum (1) and humerus head (1). A majority of the lesions were osteolytic (62.5%) with a median time of diagnosis of SM from initial diagnosis being 1.25 months (range 0-33). Bone pain was observed as the initial symptom in 5 pts (32%), 1 pt (6.2%) had a pathological fracture. The mOS for patients with SM was 6.5 months (range 0-38) when compared to 8 months (range 0-147) without SM.The mOS for pts treated with gemcitabine based regimen was 5.75 months (range 2.5-14), and patients who received multiple lines of therapy including gemcitabine and 5-FU based regimens was 15 months (range 5-38). Survival from onset of skeletal metastases ranged from 0-14 months (mOS: 4 months). Conclusions: More effective systemic therapies which improve mOS are likely to result in increased incidence of SM. The most common sites observed were the thoracic and lumbar vertebrae and pathological fractures in these sites can be catastrophic. Therefore careful evaluation of skeletal signs and symptoms, early detection and intervention will be important to prevent morbidity and mortality from pathological fractures.

261 Background: Cell-free tumor DNA (cfDNA) has potential to provide minimally invasive patient specific biomarkers to monitor tumor burden. Tumor-specific copy number instability (CNI) are used to quantify tumor-derived cfDNA in the plasma. We prospectively computed CNI Scores of cfDNA to compare with radiological and Ca 19-9 responses. Methods: In a laboratory blinded, prospective single-institution study, 119 plasma samples from 33 patients (pts) with PDAC were analyzed. Time-points were at baseline (C1), 2nd (C2) and 3rd (C3) cycle of systemic therapy. Tumor cfDNA was measured with a CNI scoring assay that quantifies cfDNA with somatic macro-alterations. CNI Score (CNIs) of 31 was defined as ref. range (97.5 % - control group; N = 135), pts below this threshold were censored. Progression of disease (PD) defined as C3 CNIs > 93 (3-fold threshold) and difference to the baseline > 31 (dispersion of reference population). Mutant KRAS in plasma was measured using ddPCR in a subset 22 pts. Pts with an increase of > 0.06% (critical difference) were classified PD. Radiologic imaging results were compared with CNIs and CA19-9 changes from baseline to C3, respectively. Results: By standard radiological imaging 33 pts were classified as: 14 PR/CR, 10 SD, 9 PD. 27/33 pts (81%) were evaluable by CNIs which ranged from decrease of 2017 - increase of 645. The C3 CNI classifier yielded a sensitivity of 86% for predicting PD and 95% for SD/PR/CR. KRAS classification yielded an accuracy of 72%, and only 3/9 PD were accurately predicted (33%). 26/33 pts were secretors evaluable by CA19-9. Only 2/8 PD pts showed increasing values in CA19-9 and 6/8 of evaluable by CNI; 5/6 showed increasing CNI scores. 3/20 deemed as SD on imaging with increasing values of CA19-9 were noted to have decreasing CNIs. CNI Score classification was significantly better than CA19-9 (P = 0.001 and 0.63, respectively). Conclusions: Our evaluation of a comparative study on cfDNA and CA19-9 versus imaging suggest that CNI quantification is potentially a more reliable blood-based marker for early assessment of efficacy to systemic therapy in PDAC. Furthermore, for patients not expressing CA19-9 it could serve as an alternative monitoring aid.