Neoadjuvant therapy with intensity-modulated radiotherapy combined with S-1 for borderline-resectable pancreatic cancer.

Aim: We evaluated the efficacy of neoadjuvant chemotherapy with intensity-modulated radiotherapy (NAC-IMRT) in patients with borderline-resectable pancreatic cancer (BRPC).

Methods: BRPC patients were treated with IMRT (45 Gy/15fr) combined with two courses of S-1 (40 mg/m bid) before surgery. Outcomes after NAC-IMRT, surgery, and survival were then evaluated. This single-center retrospective study assessed 26 consecutive patients.

Results: Twenty-six patients (BR-PV: 7, BR-A: 19) with a median age of 73 years were enrolled from 2016 to 2021. Ten (38%) patients were 75-years-old and above. Twenty-three patients completed NAC-IMRT treatment. The median reductions in tumor size and cancer antigen 19-9 level were 13.6% and 69%, respectively. All 26 patients underwent resection within a median time of 71 days after NAC-IMRT initiation. R0 resection was achieved in 24 patients (92%). The median overall survival (OS) was 28.0 months, and the 1- and 3-year OS rates were 100% and 34%, respectively. The median progression-free survival (PFS) was 12.5 months, and the 1- and 3-year PFS rates were 50% and 32%, respectively. No significant differences were observed in OS between the patients under and over the age of 75 (29 vs. 20 months, p = 0.86). The 12 patients who completed NAC-IMRT, resection, and subsequent adjuvant chemotherapy (AC) exhibited a 3-year survival rate of 73%, which was significantly better than that of the patients who did not receive or complete AC (median OS, not reached vs. 19 months, p < 0.001).

Conclusion: NAC-IMRT showed outstanding clinical efficacy with acceptable tolerability in patients with BRPC, including geriatric patients.