Abstract
Metabolic intratumoral heterogeneity (ITH) is known to be related with cancer treatment outcome. However, information on the temporal changes in metabolic ITH during chemotherapy and the correlations between metabolic changes and treatment outcomes in patients with pancreatic cancer is sparse. We aimed to analyze the temporal changes in metabolic ITH and the predictive role of its changes in advanced pancreatic cancer patients who underwent palliative chemotherapy. Methods: We prospectively enrolled unresectable locally advanced or metastatic pancreatic cancer patients before first-line palliative chemotherapy. [18F]fluorodeoxyglucose positron emission tomography was performed at baseline (T1) and at the first response follow-up (T2). Standardized uptake values (SUVs), volumetric parameters, and textural features of the primary pancreatic tumor were analyzed. Relationships between the parameters at T1, T2, and changes in the parameters with treatment response, progression-free survival (PFS), and overall survival (OS) were assessed. Results: Among 63 enrolled patients, the best objective response rate was 25.8% (95% confidence interval [CI], 14.6% to 37.0%). The median PFS and OS were 7.1 months (95% CI, 5.1 to 9.7 months) and 10.1 months (95% CI, 8.6 to 12.7 months), respectively. Most of the parameters changed significantly during the first-line chemotherapy, in a way of reducing ITH. Metabolic ITH was more profoundly reduced in responders than in nonresponders. Multiple Cox regression analysis identified high baseline compacity (P = 0.023) and smaller decreases in SUVpeak (P = 0.007) and entropygray-level co-occurrence matrix (GLCM) (P = 0.033) to be independently associated with poor PFS. Patients with a high CA 19-9 (P = 0.042), high pretreatment SUVpeak (P = 0.008), and high coefficient of variance at T2 (P = 0.04) showed worse OS. Conclusion: Reduction in metabolic ITH during palliative chemotherapy in advanced pancreatic cancer patients is associated with treatment response and might be predictive of PFS and OS.
- Oncology: Pancreas
- PET/CT
- [18F]FDG PET
- intratumoral heterogeneity
- pancreatic cancer
- texture analysis
- tumor metabolism
- Copyright © 2019 by the Society of Nuclear Medicine and Molecular Imaging, Inc.