Liquid biopsy is likely to play an increasingly important role in the identification of patients with colorectal cancer (CRC) with a chance of relapse after surgery, and has the potential to optimize treatment for individual patients, according to new research presented in Congress of the European Society of Medical Oncology (ESMO), held in Barcelona
Of 805 patients in the phase III IDEA-FRANCE trial who underwent a liquid biopsy before adjuvant chemotherapy for stage III CRC, 109 (13.5 percent) had circulating tumor DNA (cDNA) in the blood. In this group, two-year disease-free survival (DFS) was 64%, compared with 82 percent in those with negative cDNA.
“In this large prospective trial, we confirm that cDNA is an independent prognostic factor in colorectal cancer and that approximately six in 10 patients with positive cDNA will remain disease free two years after standard adjuvant chemotherapy, compared with eight in each 10 of those who have negative cDNA, ”explains study author Professor Julien Taieb, from European Hospital Georges Pompidou, in Paris France).
IDEA-FRANCE also showed that six months of adjuvant treatment was greater than three months in patients with positive and negative cDNA, and that patients with positive cDNA treated for six months had a prognosis similar to that of patients with negative cDNA treated for three months. . Adjuvant therapy was FOLFOX (folinic acid, fluorouracil and oxaliplatin) in 90 percent of cases.
“The cDNA test did not predict which patients should receive three or six months of adjuvant chemotherapy and there is ongoing debate about the optimal type and duration of treatment for patients who are positive for cDNA, but now we know that cDNA is a prognostic factor. important that it will be very useful to stratify patients and conduct future colorectal cancer trials, ”says Taieb.
“In all subgroups, patients with positive cDNA who only received three months of adjuvant therapy had the worst prognosis,” he adds.
Between 30 percent and 50 percent of patients have localized relapse of CRC despite optimal primary therapy, so a second study reported at the 2019 ESMO Congress investigated whether the cDNA can be used to detect a minimal residual disease and identify those at risk of recurrence.
The results showed that the post-surgical plasma cDNA predicted a metastatic relapse a median of 10 months before the recurrence was visible on radiological examinations. The researchers concluded that plasma cDNA tests open an opportunity for the precision treatment of patients with localized CRC.
Commenting on the results of the CCR presentations, Professor Alberto Bardelli, from the University of Turin (Italy), points out that, “when patients undergo surgery for early-stage colorectal cancer, doubts remain as to whether The disease has been completely eradicated and, as a result, patients often receive adjuvant chemotherapy. But, the results of IDEA-FRANCE have shown that we can now use a blood test to determine if the patient is clean or not. ”
He adds: “The study is also one of the first to show that, in the future, it may be possible to use a liquid biopsy to direct the therapy and identify which patients can avoid chemotherapy after surgery and which should receive it. If other studies confirm the results of IDEA-FRANCE, I think they will change clinical practice, so the new data is very interesting. ”