Pancreatic Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) Radiomic Metrics Correlate With Pathologic Molecular Markers: An Exploratory Analysis International Journal of Radiation Oncology, Biology, Physics POSTER VIEWING ABSTRACT| VOLUME 96, ISSUE 2, SUPPLEMENT , E178-E179, OCTOBER 01, 2016
Date
10/01/2016Abstract
Purpose/Objective(s)
Radiation therapy (RT) for pancreatic ductal adenocarcinoma (PDAC) is optimally suited for patients harboring a molecular predisposition for local tumor progression. Molecular classification in PDAC is challenging due to limited malignant tissue from FNA specimens. Radiomic metrics from diagnostic imaging that correlate with PDAC molecular profiles could help to identify those patients most likely to benefit from RT.
Materials/Methods
Patients with PDAC enrolled on a prospective phase II molecular profiling study with pretreatment MRI and CT scans suitable for radiomics were analyzed. Patients were considered eligible with resectable or borderline resectable PDAC, at least 18 years of age, ECOG performance status of 2 or less, with acceptable laboratory values per study. Tumor radiomic metrics measured included: percentage of T1 enhancement, peak height, time to peak contrast enhancement, uptake rate, apparent diffusion coefficient (ADC), and CT number. Tumor molecular markers measured by immunohistochemistry (IHC) included: Ribonucleotide reductase M1 (RRM1), Equilibrative nucleoside transporter (ENT1), thymidylate synthase (TYMS), topoisomerase1 (TOPO1), excision repair cross complementation group 1 (ERCC1), secreted protein acidic and rich in cysteine (SPARC), and deleted in pancreatic cancer locus 4 (DPC4/SMAD4). Percentage staining was measured on FNA pre-operatively and on surgical specimens in those who went on to resection after neoadjuvant therapy. Radiomic and molecular profiling metrics from both FNA and surgical specimens were correlated using a Spearman’s correlation (Rs).
Results
Thirty patients met inclusion criteria. Percentage of T1 enhancement was found to correlate with % TOPO1 staining on FNA (Rs = 0.399, P = 0.029). Peak height was negatively associated with the % ERCC1 staining in the surgical specimen (Rs = -0.441, P = 0.04). Time to peak contrast enhancement was negatively associated with the % TYMS staining on the surgical specimen (Rs = -0.431, P = 0.04). Uptake rate was negatively associated with the % ENT1 from specimen FNA (Rs -0.369, P = 0.045). The uptake rate also correlated with % TOPO1 staining from specimen FNA (Rs = 0.417, P = 0.022). The ADC value was found to correlate with the % RRM1 from the surgical specimen (Rs = 0.440, P = 0.036). The % SPARC staining on FNA was found to correlate with CT number (Rs = 0.656, P = 0.002). A statistical trend was observed between % DPC4/SMAD4 staining on FNA and percent of T1 enhancement (Rs = 0.371, P = 0.089).
Conclusion
MRI and CT radiomic metrics correlate with the presence of certain PDAC molecular characteristics. If validated, these radiomic metrics could provide a minimally invasive and readily available technique to aid in selecting an optimal treatment strategy for patients with PDAC.
Author List
W.A. Hall E.S. Paulson A. Vistocky S. Tsai E.J. Koay P.M. Knechtges D. Evans K. Christians P. Ritch B. George K. Oshima A. Li B.A. EricksonAuthor
Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of WisconsinView Online
