Predictors of outcome in patients receiving stereotactic body radiation therapy for borderline resectable and locally advanced pancreatic cancers

Aims: To evaluate the outcomes in borderline resectable (BRPC) and locally advanced pancreatic cancer (LAPC) receiving neoadjuvant chemotherapy (NACT) and stereotactic body radiotherapy (SBRT) followed by surgery when feasible. Methods: Consecutive patients of BRPC and LAPC treated from May 2015 to December 2019 were included. All underwent NACT with FOLFIRINOX/Gem Nabpacli 4-6 cycles, followed by SBRT with differential planning target volume (PTV) dose of 36-46 Gy over 5-6 fractions. Local progression-free survival (LPFS), distant metastasis free survival (DMFS), overall survival (OS) were estimated. Results: Eighty-nine (50 BRPC and 39 LAPC) patients with a median follow-up of 26.0 months were identified. Of the 33 (37%) patients surgically explored and 19 (47.5%) BRPC and 4 (10.2%) LAPC patients underwentsurgery, 21 (91.6%) had R0 resection. The median OS and disease free survival (DFS) of patients who underwent surgery was 28.4 +/- 3.4 and 23 +/- 5 months, respectively. The patients who did not undergo surgery the median OS and LPFS were 19 +/- 1.4 and 12 +/- 1 months, respectively. Patients who underwent surgery in BRPC cohort had significantly better DFS (23 vs 12 months, p=0.001) and OS (28 vs 19 months, p=0.035). On multivariate analysis, Eastern Cooperative Oncology Group (ECOG) < 2 [hazard ratio (HR): 2.77 (1.2-6.2; 0.014)], head location [3.7 (1.44-9.6; 0.007)], and radiological response post-NACT-SBRT [4.38 (1.08- 17.7; 0.039)] were significant predictors of outcome in both the cohorts. No grade >= 3 late radiotherapy (RT)related toxicities were seen. Conclusion: Stereotactic body radiotherapy is safe and effective for local control and aids in improving the outcomes in pancreatic cancers.