Is the Patient Cured ?
Menée à partir d'échantillons plasmatiques prélevés avant chirurgie et après chimiothérapie sur 96 patients atteints d'un cancer du côlon de stade III récemment diagnostiqué (âge médian : 64 ans ; durée médiane de suivi : 28,9 mois), cette étude multicentrique évalue l'association entre la détection de l'ADN tumoral circulant et l'intervalle de récidive à 3 ans
After administering a therapy with curative intent, patients and physicians have 1 key question in mind: is the cancer cured? Unfortunately, because of the limitations of our current standard of surveillance, we can never be sure that all the tumor cells have been eradicated and therefore never be sure of a cure. An implication of this view is that even patients who have responded to treatment still need posttherapy prognostic factors to predict the patient’s outcome after treatment.In this issue of JAMA Oncology, Tie et al hypothesized that circulating tumor DNA (ctDNA) level, measured after surgery and again after chemotherapy, can accurately predict which patients with colon cancer are at high risk for recurrence during a 3-year interval. Their prospective study recruited 100 consecutive patients with newly diagnosed stage III colon cancer who were planned to receive 6 months of adjuvant chemotherapy. The investigators sequenced 15 genes that are commonly mutated in colorectal cancer and identified at least 1 somatic mutation in the tumor tissue of each of the 96 eligible patients. Circulating tumor DNA was identified in 20 of 96 postsurgical patients and 15 of 89 postsurgical and postchemotherapy patients. The presence of ctDNA was an independent factor associated with a poor prognosis in both situations. Their hypothesis that ctDNA could accurately predict which patients were, post therapy, at high risk for a recurrence was not well supported by a receiver operating characteristic (ROC) for postsurgical ctDNA of 0.64 (95% CI, 0.60-0.66). However, the ROC increased with the addition of the pT and pN factors to 0.69 (95% CI, 0.65-0.72). Importantly, the postchemotherapy ctDNA ROC was 0.70 (95% CI, 0.66-0.72), which increased with the addition of pT and pN to 0.78 (95% CI, 0.73-0.81). The addition of ctDNA after surgery to this model did not improve its accuracy, suggesting that the ctDNA status after adjuvant therapy is the more relevant prognostic factor.
JAMA Oncology , éditorial, 2018