Stereotactic Body Radiation Therapy for Locally Advanced Pancreatic Cancer: A Systematic Review and Pooled Analysis of 19 Trials.

Purpose: Although surgery is the standard of care for resectable pancreatic cancer (PC), standard-dose chemoradiation therapy and chemotherapy alone are suitable for patients with unresectable disease. Stereotactic body radiation therapy (SBRT) is an alternative, focused local therapy that delivers high radiation doses within a few fractions to the cancer, sparing the surrounding critical tissue. We performed a systematic review and pooled analysis of published trials to evaluate the efficacy and safety of this emerging treatment modality.

Methods And Materials: We searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, SCOPUS, the Web of Science, and CINAHL for publications regarding SBRT for locally advanced PC. The 1-year overall survival (OS) rate was the primary endpoint, and the median OS, 2-year OS rate, 1-year locoregional control (LRC) rate, and grade 3 to 4 toxicities were the secondary endpoints. A multivariate random-effects meta-analysis was performed to calculate the aggregated OS rates at 1 and 2 years and the 1-year LRC rate.

Results: A total of 19 studies, encompassing 1009 patients, were included in the present analysis. The pooled 1-year OS was 51.6% in 13 trials with data available. The median OS ranged from 5.7 to 47 months (median 17). The LRC rate at 1 year was 72.3%. Overall, the occurrence of severe adverse events did not exceed 10%. LRC appeared to correlate with the total SBRT dose and the number of fractions.

Conclusions: The advantages of SBRT in terms of treatment time, satisfactory OS, and LRC indicate that it is an effective option for inoperable PC. However, a definitive validation of this treatment modality in large randomized studies is required, owing to the nonrandomized nature of the included studies and the limitations of small single-center series that include mixed populations.