Case Study on Colorectal Cancer Surveillance Using ctDNA

This case study examines the use of the Oncodetect MRD test for monitoring a 64-year-old male patient diagnosed with colorectal cancer (CRC). The patient underwent surgical resection of the primary tumor, after which positive circulating tumor DNA (ctDNA) was detected. The study details the patient's treatment strategy, which included a six-month course of adjuvant chemotherapy with FOLFOX. Following treatment, ctDNA levels were reassessed, leading to molecular clearance. However, five months post-chemotherapy, rising ctDNA levels indicated a potential recurrence, prompting increased surveillance. Imaging studies revealed a solitary liver lesion, which was surgically removed. Post-operative ctDNA analysis indicated a return to negative status. The case emphasizes the role of ctDNA monitoring in post-operative management of CRC, allowing for early detection of recurrence and timely intervention. The patient continues to be monitored closely with quarterly ctDNA testing and routine imaging assessments.