Use of radiation therapy in neoadjuvany treatment for pancreatic adenocarcinoma decreases risk of postoperative pancreatic fistula: A nsqip analysis

Abstract

Presenter: Christopher Mangieri MD | Wake Forest University Background: Neoadjuvant therapy for pancreatic cancer decreases the risk of post-operative pancreatic fistula (POPF). However, there is a paucity of published data specifying which neoadjuvant regimen is most protective against POPF development. We evaluated the differences between neoadjuvant chemotherapy (CT), radiation therapy (RT), and chemotherapy/radiation therapy (CRT) in regard to effect on POPF rates. We hypothesize combined therapy decreases POPF. Methods: The main and targeted pancreatectomy National Surgical Quality Improvement (NSQIP) registries for 2014-2016 were retrospectively reviewed. Cases that did not contain information on the use of neoadjuvant therapy or POPF development were excluded. Additionally, cases that did not identify a malignant etiology were excluded. Linear regression analysis of NSQIP factors that have previously been shown to be associated with or suspected to be associated with POPF was performed. Factors included neoadjuvant therapy, sex, age, BMI, diabetes, smoking, steroid therapy, preoperative weight loss, preoperative albumin level, perioperative blood transfusions, wound classification, ASA classification, duct size (6mm), gland texture (soft, intermediate, hard), and anastomotic technique. Factors identified to be statistically significant with the development of POPF were then compared between cases that received neoadjuvant CT, RT, and CRT. Results: 10,117 cases were analyzed. Development of POPF was significantly associated with lack of neoadjuvant therapy, male sex, higher BMI, non-diabetic status, post-operative blood transfusion, decreased duct size, and soft gland texture. Neoadjuvant therapy, BMI, duct size, and gland texture had the strongest associations with development of POPF (all p values < 0.0001). Overall 1,765 cases (17.45%) underwent neoadjuvant therapy. 1,031 cases underwent CT, 62 cases underwent RT, and 672 cases underwent CRT. The POPF rates were 20.1%, 11.15%, 4.84%, and 8.18% for cases that received no neoadjuvant therapy, CT, RT, and CRT respectively (p value < 0.0001). Comparison of POPF rates between groups receiving only neoadjuvant therapy demonstrated persistent significant differences with the inclusion of radiation therapy (p value 0.039). Decreasing POPF rates correlated significantly with firmer gland texture with the hard gland rates being 54.84%, 54.17%, 42.48%, and 29.01% in the RT, CRT, CT, and no therapy groups respectively (p value < 0.001). Comparison of the neoadjuvant treatment groups revealed no statistically significant differences between duct size, diabetic status, post-operative transfusions, and BMI. Conclusion: To our knowledge this is the largest analysis of specific neoadjuvant regimens in regard to the development of POPF following pancreaticoduodenectomy. The addition of radiation therapy to neoadjuvant regimens provides the strongest protective effect. This is potentially due to increased fibrosis in the pancreatic parenchyma from the radiation therapy resulting in a firmer gland. These findings provide additional support to alleviate concerns the use of neoadjuvant therapy with radiation will increase adverse outcomes after pancreaticoduodenectomy.