Highlights from

ESMO 2019

European Society for Medical Oncology Congress 2019

Barcelona 27 September - 01 October 2019

Liquid biopsy identifies relapse in patients with colorectal cancer after surgery

Prof. Julien Taieb (Hopital European Georges Pompidou, Paris, France) presented the phase 3 IDEA-FRANCE trial, in which 805 stage 3 colorectal cancer (CRC) patients were prospectively enrolled to have a liquid biopsy prior to adjuvant chemotherapy. Of these patients, 109 (13.5%) had circulating tumour DNA (ctDNA) in their blood. In this group, 2-year disease-free survival (DFS) was 64%, compared to 82% in those who were ctDNA-negative [1].

A substantial number (30-50%) of patients with localised CRC relapse, despite primary optimal therapy. This study aimed to identify those at risk of recurrence. "In this large prospective trial, we confirmed that ctDNA is an independent prognostic factor in colorectal cancer and that approximately 6 out of 10 patients who are ctDNA-positive will remain disease-free 2 years after standard adjuvant chemotherapy, compared to 8 out of 10 of those who are ctDNA-negative," said Prof. Taieb.

IDEA-FRANCE also showed that 6 months of adjuvant treatment was superior to 3 months in both ctDNA-positive and -negative patients. Furthermore, ctDNA-positive patients treated for 6 months had a similar prognosis to ctDNA-negative patients treated for 3 months. Adjuvant therapy was FOLFOX (folinic acid, fluorouracil, and oxaliplatin) in 90% of cases.

"ctDNA testing did not predict which patients should have 3 or 6 months of adjuvant chemotherapy and there is continuing debate over the optimal type and duration of treatment for patients who are ctDNA-positive, but we do now know that ctDNA is a major prognostic factor which will be very useful in stratifying patients and driving future trials of CRC," said Prof. Taieb. "In all subgroups, ctDNA-positive patients who only had 3 months of adjuvant therapy had the worst prognosis," he added.

  1. Taieb J et al. Analysis of Circulating tumour DNA (ctDNA) from patients enrolled in the IDEA-FRANCE Phase III trial: prognostic and predictive value for adjuvant treatment duration. ESMO Congress 2019, 27 Sept-1 October 2019, Barcelona, Catalonia, Spain, Abstract LBA30_PR

Top image: STEVE GSCHMEISSNER / SCIENCE PHOTO LIBRARY

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