The impact of the granulocyte colony-stimulating factor on chemotherapy dose intensity and cancer survival: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The granulocyte colony-stimulating factor (G-CSF) is utilized to reduce neutropenic complications in patients receiving cancer chemotherapy. This study represents a systematic review and evidence summary of the impact of G-CSF support on chemotherapy dose intensity and overall mortality. MATERIALS AND METHODS: All randomized controlled trials (RCTs) comparing chemotherapy with or without G-CSF support and reporting all-cause mortality with at least 2 years of follow-up were sought. Dual-blind data abstraction of disease, treatment, patient and outcome study results with conflict resolution by third party was carried out. RESULTS: The search revealed 61 randomized comparisons of chemotherapy with or without initial G-CSF support. Death was reported in 4251 patients randomized to G-CSFs and in 5188 controls. Relative risk (RR) with G-CSF support for all-cause mortality was 0.93 (95% confidence interval: 0.90-0.96; P < 0.001). RR for mortality varied by intended chemotherapy dose and schedule: same dose and schedule (RR = 0.96; P = 0.060), dose dense (RR = 0.89; P < 0.001), dose escalation (RR = 0.92; P = 0.019) and drug substitution or addition (RR = 0.94; P = 0.003). Greater RR reduction was observed among studies with longer follow-up (P = 0.02), where treatment was for curative intent (RR = 0.91; P < 0.001), and where survival was the primary outcome (RR = 0.91; P < 0.001). CONCLUSIONS: All-cause mortality is reduced in patients receiving chemotherapy with primary G-CSF support. The greatest impact was observed in RCTs in patients receiving dose-dense schedules.