A prospective observational study of the clinical and pathological impact of stereotactic body radiotherapy (SBRT) as a neoadjuvant strategy of chemoradiation in pancreatic cancer.

Purpose/objective(s): To improve the curative resection rates and prognoses, a variety of neoadjuvant (NA) strategies have been explored in PDAC. In our institution, non-metastatic PDACs have been treated with a NA intent with induction multiagent chemotherapy and SBRT. The primary endpoint was to increase R0 resection rate. The secondary endpoints were the analysis of the clinical tolerance, the pathological response, the local control (LC) and the OS.

Materials/methods: All consecutive patients with non-metastatic PDAC underwent SBRT as part of the NA strategy were included. A total dose of 40-62 Gy were delivered in 5-10 fractions. Surgery was performed after SBRT and restaging.

Results: Since February 2014 to December 2018, 45 patients were enrolled. Thirty-two patients underwent surgery (71.1%), 10 out of 15 were initially unresectable disease patients (66.75%). R0 resection rate was 93% (30 patients) and pN0 status was achieved in 20 patients (60.6%). Tumour regression grade (TRG): 12 patients with complete response or marked response (TRG 0-1: 37.5%), 16 patients with moderate response (TRG 2: 50%) and four patients with poor response (TRG 3: 12.5%). The median follow-up was 16.2 m (range 6.6-59.6 m) since diagnosis. The LC rate achieved was very high (95.5%). Actuarial 12 and 24 m OS was 67.4% and 35.9% respectively. No grade 3 or higher toxicity related to SBRT was observed.

Conclusion: The results are encouraging, suggesting that SBRT has a significant role in the management of these patients and further studies will be necessary to prove these findings.