Positive relationship between subsequent chemotherapy and overall survival in pancreatic cancer: Meta-analysis of postprogression survival for first-line chemotherapy

Purpose To gain a better understanding of the impact of postprogression survival (PPS) and post-trial anticancer therapy on overall survival (OS) in first-line pancreatic cancer patients. Methods A literature search identified 54 randomized trials, focusing on gemcitabine monotherapy to eliminate effects of heterogeneity of first-line regimens. We evaluated the relation between OS and either progression-free survival (PFS) or PPS. We also examined whether any association might be affected by the year of completion of trial enrollment. Results For all 54 trials, PPS was strongly associated with OS (r = 0.844), whereas PFS was moderately associated with OS (r = 0.623). Average OS and PPS were significantly longer in recent trials than in older trials, (7.29 versus 6.15 months, p < 0.001) and (3.64 versus 2.86 months, p < 0.001), respectively. The correlation between OS and PPS in recent trials was much stronger than that in older trials (r = 0.846 versus 0.729). The relation between OS and PFS in recent and older trials did not differ (r = 0.595 versus 0.563). The percentage of patients with post-trial treatment was significantly higher in recent trials than in older trials (52.7 versus 39.7%, p < 0.001). The rate of posttrial anticancer therapy was significantly associated with OS (r = 0.910). Conclusions We found an increase in median PPS in accordance with an increase in median OS in recent trials compared with older trials and that rate of post-trial anticancer therapy was strongly associated with median OS. It is important that researchers be aware of these findings in designing clinical trials of first-line chemotherapy for pancreatic cancer patients.