Efficacy of Neoadjuvant Radiotherapy After Chemotherapy and the Optimal Interval from Radiotherapy to Surgery for Borderline Resectable and Resectable Pancreatic Cancer.

Abstract

Background: Benefits of neoadjuvant treatment for pancreatic cancer with major vessel invasion has been demonstrated through randomized controlled trials; however, the optimal neoadjuvant treatment strategy remains controversial, especially for radiotherapy. Therefore, we aimed to evaluate the efficacy and safety of neoadjuvant radiotherapy followed by chemotherapy and the optimal time interval to undergo surgery after radiotherapy in (borderline) resectable pancreatic cancer.

Methods: Between 2013 and 2022, patients with (borderline) resectable pancreatic cancer with vessel contact who received 5-fluorouracil with leucovorin, oxaliplatin, and irinotecan or gemcitabine and nanoparticle albumin-bound paclitaxel as initial treatment following surgery were included. Patients who received radiotherapy after chemotherapy and those who did not were matched using 1:1 nearest-neighbor propensity scores. Propensity scores were measured using the tumor size at initial image, duration of neoadjuvant chemotherapy, and responsiveness to neoadjuvant chemotherapy.

Results: Of 212 patients, 166 patients were retrieved for the matched cohort. Patients who received radiotherapy had significantly better postoperative survival, local control, and R0 resection rates than those who did not. Furthermore, patients who underwent surgery within 4 weeks after completing radiotherapy had lower intraoperative blood loss and a clinically relevant postoperative pancreatic fistula rate than those who underwent surgery after more than 4 weeks.

Conclusions: In patients with (borderline) resectable pancreatic cancer with vessel contact who were scheduled for curative-intent surgery after neoadjuvant chemotherapy, additional radiotherapy was associated with better postoperative survival and local control. Furthermore, our findings suggested that scheduling surgery within 4 weeks following radiation therapy might enhance the perioperative outcomes.