Link Between CTC Status and Radiotherapy Benefit in Early-Stage Breast Cancer
Posted: Thursday, July 19, 2018
“Circulating tumor cell status may be an important predictive clinical marker for the benefit of radiotherapy in patients with early-stage breast cancer,” wrote the authors of a large analysis published in JAMA Oncology. Led by Chelain R. Goodman, MD, PhD, of Northwestern University Feinberg School of Medicine in Chicago, the researchers consider their findings “hypothesis generating,” warranting further evaluation of circulating tumor cell (CTC)-based management in this patient population in a prospective trial.
“Patients with at least 1 circulating tumor cell and who received radiotherapy after breast-conserving surgery had significantly longer local recurrence-free survival, disease-free survival, and overall survival compared with those who did not receive radiotherapy,” noted Dr. Goodman and colleagues. “Patients without circulating tumor cells did not experience longer survival outcomes after radiotherapy.”
The patient study data were from two sources: The National Cancer Database (NCDB) included 1,697 patients (399 of whom were CTC-positive), and the phase III SUCCESS trial included 1,516 patients (294 of whom were CTC-positive). All but 16 patients were women. Of all patients in the NCDB cohort, 57% received adjuvant radiotherapy, as did 82% of CTC-negative and 84% of CTC-positive patients in the SUCCESS cohort.
The team’s extensive data analysis found, for instance, that within the NCDB cohort, the association of radiotherapy with 4-year overall survival was dependent on CTC status (P < .001); the same was true of 5-year disease-free survival within the SUCCESS cohort (P = .04). Also, in the SUCCESS cohort, CTC-positive patients treated with radiotherapy exhibited longer local-recurrence free survival (P < .001), disease-free survival (P < .001), and overall survival (P = .003).