Therapeutic response assessment in pancreatic ductal adenocarcinoma: society of abdominal radiology review paper on the role of morphological and functional imaging techniques.

Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States and is projected to be the second by 2030. Systemic combination chemotherapy is considered an essential first-line treatment for the majority of patients with PDA, in both the neoadjuvant and palliative settings. In addition, a number of novel therapies are being tested in clinical trials for patients with advanced PDA. In all cases, accurate and timely assessment of treatment response is critical to guide therapy, reduce drug toxicities and cost from a failing therapy, and aid adaptive clinical trials. Conventional morphological imaging has significant limitations, especially in the context of determining primary tumor response and resectability following neoadjuvant therapies. In this article, we provide an overview of current therapy options for PDA, highlight several morphological imaging findings that may be helpful to reduce over-staging following neoadjuvant therapy, and discuss a number of emerging imaging, and non-imaging, tools that have shown promise in providing a more precise quantification of disease burden and treatment response in PDA.

18F-FDG PET/CT and lung cancer: value of fourth and subsequent posttherapy follow-up scans for patient management.

UNLABELLED: The Centers for Medicare and Medicaid Services recently ruled that only 3 posttherapy follow-up (18)F-FDG PET/CT scans are funded for a tumor type per patient and any additional follow-up PET/CT scans will be funded at the discretion of the local Medicare administrator. The purpose of this study was to evaluate the added value of 4 or more follow-up PET/CT scans to clinical assessment and impact on patient management. METHODS: This was an institutional review board-approved, retrospective study. A total of 1,171 patients with biopsy-proven lung cancer who had undergone (18)F-FDG PET/CT at a single tertiary center from 2001 to 2013 were identified. Among these, 85 patients (7.3%) had undergone 4 or more follow-up PET/CT scans, for a total of 285 fourth and subsequent follow-up PET/CT scans. Median follow-up from the fourth follow-up PET/CT scan was 31.4 mo (range, 0-155.2 mo). The follow-up PET/CT scan results were correlated with clinical assessment and treatment changes. RESULTS: Of the 285 fourth and subsequent follow-up PET/CT scans, 149 (52.28%) were interpreted as positive and 136 (47.7%) as negative for recurrence or metastasis. A total of 47 patients (55.3%) died during the study period. PET/CT identified recurrence or metastasis in 44.3% of scans performed without prior clinical suspicion and ruled out recurrence or metastasis in 24.2% of scans performed with prior clinical suspicion. The PET/CT scan resulted in a treatment change in 28.1% (80/285) of the patients. New treatment was initiated for 20.4% (58/285) of the scans, treatment was changed in 5.6% (16/285), and ongoing treatment was stopped in 2.1% (6/285). CONCLUSION: The fourth and subsequent (18)F-FDG PET/CT scans performed during follow-up after completion of primary treatment added value to clinical assessment and changed management 28.1% of the time.

CT and MRI assessment of symptomatic organized pancreatic fluid collections and pancreatic duct disruption: an interreader variability study using the revised Atlanta classification 2012.

PURPOSE: Compare CT and MRI for fluid/debris component estimate and pancreatic duct (PD) communication with organized pancreatic fluid collections in acute pancreatitis. Evaluate fat density globules on CT as marker for debris. METHODS: 29 Patients with 46 collections with CECT and MRI performed ≥4 weeks of symptom onset assessed for necrotizing pancreatitis, estimated percentage of fluid volume and PD involvement by two radiologists on separate occasions. T2WI used as standard for estimated percentage of fluid volume. Presence of fat globules and fluid attenuation on CT was recorded. Spearman rank correlation and kappa statistics were used to assess the correlation between imaging techniques and interreader agreement, respectively. RESULTS: Necrotizing pancreatitis seen on CT in 27 (93%, κ 0.119) vs. 20 (69%, κ 0.748) patients on MRI. CT identified 42 WON and 4 pseudocysts vs. 34 WON, and 12 pseudocysts on MRI. Higher interreader agreement for percentage fluid volume on MRI (κ = 0.55) vs. CT (κ = 0.196). Accuracy of CT in evaluation of percentage fluid volume was 65% using T2WI MRI used as standard. Fat globules identified on CT in 13(65%) out of 20 collections containing <75% fluid vs. 4(15%) out of 26 collections containing >75% fluid (p = 0.0001). PD involvement confidently excluded on CT in 68% collections vs. 93% on MRI. CONCLUSION: MRI demonstrates higher reproducibility for fluid to debris component estimation. Fat globules on CT were frequently seen in organized pancreatic fluid collections with large amount of debris. PD disruption more confidently excluded on MRI. This information may be helpful for pre-procedure planning.