Chemoradiotherapy versus chemotherapy for locally advanced unresectable pancreatic cancer: A systematic review and meta-analysis.

PURPOSE: To determine the benefit of adding radiotherapy (RT) to chemotherapy for patients with locally advanced unresectable pancreatic cancer (LAUPC).

METHODS: We searched MEDLINE for comparative studies comparing chemoradiotherapy with chemotherapy for patients with LAUPC. We performed the meta-analysis with random effects model. The primary outcome was overall survival (OS); secondary outcomes include progression-free survival (PFS) and adverse events (AE).

RESULTS: We found five randomized (RCT) and three observational studies (OBS) including 830 patients. For RCTs, the addition of radiotherapy did not improve PFS (hazard ratio [HR] 0.90; 95% confidence interval [CI], 0.74-1.10; P = 0.30; I2   =  11%,) or OS (HR 0.87; 95% CI, 0.63-1.21; P = 0.41; I2 = 67%,) and was associated with increased grade 3 or 4 gastrointestinal AE. In contrast, OBS reported an improvement in PFS (HR 0.58; 95% CI, 0.37-0.92; P = 0.02; I2 = 32%) and OS (HR 0.48; 95% CI, 0.35-0.60; P < 0.0001; I2 = 6%).

CONCLUSION: The addition of radiotherapy did not improve the OS and PFS in RCTs. The divergence in results seen in OBS may be due to imbalance in baseline characteristics. Further research incorporating biomarkers may help to better select patients who will benefit from RT.