Unadjusted overall survival in patients taking rituximab plus chemotherapy, chemotherapy alone, and rituximab monotherapy. (A) chemotherapy alone (CT alone) has the solid line (lower curve), and rituximab plus chemotherapy (R + CT) has the dashed line. (B) Rituximab monotherapy. Curves represent the survival estimate and the 95% confidence interval. Numbers at the bottom of the figures indicate the number of patients under observation at each time point.