Stereotactic Body Radiation Therapy (SBRT) in a Standardized Neoadjuvant Therapy Pathway for Pancreatic Cancer across a Geographically Large and Diverse Healthcare System

Abstract

<h3>Purpose/Objective(s)</h3> The role of SBRT as part of a neoadjuvant therapy pathway (NATP) is actively being defined in the setting of growing multidisciplinary approach to pancreatic cancer (PC). A standardized approach to neoadjuvant therapy (NAT) has been shown to improve outcomes. We evaluated whether patients who received SBRT as part of our standardized NATP had better outcomes than patients in our institution who were not enrolled in our NATP. <h3>Materials/Methods</h3> The NATP was established at Northwell Health in June 2019, consisting of a single-day pancreas multi-disciplinary clinic (PMDC) visit, followed by neoadjuvant chemotherapy with interval scans and PMDC re-reviews prior to consideration of radiation and/ or surgical resection. Prior to consideration for resection, SBRT was standardized for borderline resectable PC (BRPC) and locally advanced PC (LAPC) patients after completion of chemotherapy. We retrospectively analyzed patients undergoing neoadjuvant SBRT in the last 5 years prior and after the establishment of NATP. Primary endpoints included resection rates, quality assurance (QA) measures and overall survival (OS). Kaplan-Meier analysis was used to estimate OS. <h3>Results</h3> A total of 38 non-metastatic patients were identified between January 2017 and December 2021 undergoing neoadjuvant SBRT after completion of at least 1 cycle of chemotherapy with 19 (50%) enrolled in the newly established NATP. Between NATP and non-NATP SBRT, mean age was 66.3 vs 63.3 years (p=.519) and additional baseline characteristics listed in Table 1 were comparable. SBRT BED (10) was 87.4Gy in NATP vs 68.8Gy in non-NATP (p<0.001). NATP patients underwent surgery at 47% vs. 26% in non-NATP (p=.179). Median OS was 19.7 months for all patients undergoing SBRT, with median follow-up (FU) of 13.0 mo (IQR: 9.2-18.8 mo). With Median FU of 10.0 mo vs 18.5 mo (p<0.001), NATP Median OS was 16.0 mo vs. non-NATP 22.8 mo (p=0.157). Surgery was the only significant predictor of OS, Median OS 28.3 mo vs. 18.5 mo (p=0.047). Implementation of NATP showed QA improvements in time of biopsy to start of chemotherapy (NATP 21 days (d) vs. 28 d) and time of radiation to surgery (NATP 35 d vs. 68d). <h3>Conclusion</h3> Implementation of a NATP with standardized incorporation of SBRT increased the percentage of PC patients who underwent timely radiation therapy and surgical resection. Further follow-up is required for assessing OS benefit. A standardized NATP increases access for patients to radiation therapy and sets the groundwork for multi-disciplinary care in PDAC.