Patterns of mortality after prolonged follow-up of a randomized trial using granulocyte colony-stimulating factor (G-CSF) to maintain chemotherapy dose intensity in non-Hodgkin lymphoma (NHL)

Abstract

7590 Background: Recombinant G-CSF is commonly used to maintain chemotherapy dose intensity and reduce the incidence of infective complications in the management of NHL. The possible impact of this effect on mortality patterns after prolonged follow-up is worthy of investigation. We investigated the long-term survival and incidence of second malignancies in the first randomized trial utilising recombinant G-CSF in NHL (Pettengell R et al Blood 1992, 80: 1430–1436). Methods: Data on overall survival (OS), progression-free survival (PFS), freedom from progression (FFP) and the incidence of second malignancies were extracted from medical records and cancer registry databases for 80 patients with aggressive subtypes of NHL, who had previously been randomised to receive either VAPEC-B chemotherapy alone (39 patients) or VAPEC-B with G-CSF (41 patients). 10 year survival figures were extracted and Kaplan-Meier survival curves were drawn for the above parameters and compared between treatment groups using the log-rank test. Results: Median follow-up was 11.8 years for surviving patients (range 7.8–13.1 yrs). Patients receiving G-CSF achieved a 12% higher median dose intensity of chemotherapy. No significant differences were found in PFS or OS but 10 year FFP appeared to be better in the G-CSF arm (60.8%) compared with the control arm (45.6%) (log-rank test p=0.12). Eleven deaths from non-NHL causes occurred in the G-CSF arm compared with three in the control arm (log- rank test p=0.06). Five second malignancies were detected on long-term follow-up in the G-CSF arm compared with two in the control arm. Conclusions: The demonstration of different mortality patterns in the two arms may be related to the greater dose intensity of chemotherapy received in the G-CSF arm. Although, our study has insufficient statistical power to draw definite conclusions, this finding warrants further investigation. No significant financial relationships to disclose.