Role of ctDNA to predict risk of recurrence following potentially curative resection of biliary tract and pancreatic malignancies
AffiliationThe Christie NHS Foundation Trust, Manchester, United Kingdom
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AbstractBackground: The potential role of ctDNA to identify residual disease after potentially curative resection has been suggested in some malignancies; its role in resected pancreatico(P)-biliary(B) malignancies is unknown. Methods: Patients diagnosed with PB malignancies underwent molecular profiling (ctDNA) using FoundationMedicine Liquid (72 cancer-related genes) following potentially curative resection. Baseline patient characteristics and molecular profiling outcomes, including mutant allele frequency (MAF) for pathological alterations were extracted. Primary objective: prevalence of ctDNA identification and its correlation with recurrence (relapse-free survival (RFS) and relapse rate). Results: Total of 11 individuals had ctDNA analysed following potentially curative resection for PB malignancies: 8 B (4 extra-hepatic cholangiocarcinoma (eCCA), 2 ampulla, 1 intrahepatic cholangiocarcinoma (iCCA), 1 gallbladder cancer (GBC)) and 3 P. Baseline characteristics: 6 female (54.55%), median age 71.59 years (range 39.98-81.19). Most were pT2 (45.45%), pN0 (54.55%) and R0 (63.64%). Following surgery, 6 patients were started on adjuvant chemotherapy; at the end of follow-up (data cut-off 25/6/2020; median follow-up 11.15 months (range 5.45-13.52); 5 relapsed (45.45%) and 2 died (18.18%). Estimated median RFS was 11.43 months (95% CI 2.28-not reached); median overall survival was not reached. No sample failed ctDNA analysis; presence of ctDNA was identified in 3/11 (27.27%) of the samples; 2 and 1 samples had 2 and 1 pathological alterations identified, respectively: ALK fusion (1 sample; GBC), TP53 mutation (2 samples; eCCA and GBC), CHEK2 mutation (1 sample; pancreas), IDH2 mutation (1 sample; eCCA). Mean maximum MAF was 1.47 (2 in biliary; 0.43 in pancreas). Variants of unknown significance were identified in 72.73% of the samples (87.5% in B; 33.33% in P; p-value 0.152). None of the baseline characteristics explored correlated with presence of ctDNA. There was a trend towards increased relapse risk in the patients with ctDNA present following potentially curative surgery; Cox regression for RFS [HR 2.64 (95% CI 0.36-19.31); median RFS 11.44 months (95% CI 2.28-not reached) vs 10.87 (95% CI 2.21-not reached)]; relapse rate 37.5% (ctDNA absent) vs 66.67% (ctDNA present); statistical significance was not reached (p-value 0.340 and p-value 0.545, respectively). Conclusions: This pilot study demonstrates the feasibility of testing for ctDNA following potentially curative resection in PB malignancies. Presence of ctDNA may be associated with increased relapse risk; further studies are required to increase sample size and assess clinical implications.
CitationLamarca A, McNamara MG, Hubner R, Valle JW. Role of ctDNA to predict risk of recurrence following potentially curative resection of biliary tract and pancreatic malignancies. JCO. 2021 Jan 20;39(3_suppl):336–336.
JournalJournal of Clinical Oncology
TypeMeetings and Proceedings