Stereotactic body radiation therapy plus induction or adjuvant chemotherapy for early stage but medically inoperable pancreatic cancer: A propensity score-matched analysis of a prospectively collected database.

Background: To evaluate and compare the efficacy and safety of stereotactic body radiation therapy (SBRT) plus induction chemotherapy and SBRT plus adjuvant therapy.

Methods: Patients with radiographically resectable, biopsy-proven pancreatic cancer were enrolled. Data were prospectively collected from 2012 to 2016. Cox proportional hazards regression was used to identify factors predictive of survival. Propensity score matching analysis was performed to assess the efficacy of SBRT combined with different timing of chemotherapy.

Results: One hundred patients were enrolled with 48 receiving induction chemotherapy and 52 undergoing adjuvant chemotherapy. The median overall survival (OS) and progression-free survival (PFS) were 17.5 months (95% CI: 15.8-19.2 months) and 13.7 months (95% CI: 12.3-15.1 months), respectively. Patients with adjuvant chemotherapy ( <0.001), CA19-9 response ( <0.001) and BED (biological effective dose, α/β = 10) ≥ 60 Gy ( = 0.024) had a longer OS, while the former two correlated with PFS. Patients with more positive factors had a superior OS and PFS. After propensity score matching analysis, there were 23 patients from each group included in the analysis. Longer OS (23.1 months versus 15.6, <0.001) and PFS (18.0 months versus 11.6 months, <0.001) were found in patients with adjuvant chemotherapy compared with those with induction chemotherapy.

Conclusion: SBRT was safe and effective in early stage pancreatic cancer. Combined with adjuvant chemotherapy, SBRT could be an alternative for patients with resectable pancreatic cancer but not eligible for surgical resection.