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 post-trial 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.