FFS survival from 18 months after the onset of treatment according to the pattern of molecular response. Seventy-five patients with at least three PCR determinations in this period were included. Three patterns could be distinguished: (A) 35 patients achieved molecular response and sustained it at least for 18 months, (B) 25 patients achieved molecular response but reverted back to PCR-positive status, and (C) 15 patients did not achieve molecular response. Patients who relapsed before 18 months were omitted from the analysis. Landmark: 18 months; P < .05.