AIMS: This interim safety/toxicity analysis aims to assess toxicity of adjuvant stereotactic body radiation therapy (SBRT) after surgery of pancreatic cancer (PC) with high risk features across an ongoing prospective phase II trial, allowing better integration of chemotherapy and surgery. METHODS: The study started in 2021 and this paper represents an interim safety analysis. Enrollment will last 36 months, followed by 12 months of follow-up for a duration of 4 years and 50 patients. Inclusion criteria are: pT1-T4 adenocarcinoma with or without positive resection margin and/or N1 at lymphadenectomy. Chemotherapy can be administered in neoadjuvant and adjuvant setting. The primary endpoint is local relapse. The secondary endpoints are disease-free survival, overall survival, patterns of failure, acute and late toxicity. Radiation dose is 40 Gy in 5 fractions. Toxicities are recorded according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0. The study protocol was approved by the institutional research ethics committee on May 18th 2021 and registered on ClinicalTrials.gov (NCT05043857). RESULTS: This preliminary analysis was focused on 50 patients. The median follow-up at the time of the analyses was 16.5 months (range 3-35). Neoadjuvant chemotherapy was administered to 23 patients (46%) and 30 (60%) received adjuvant chemotherapy. No patients experienced ≥ G3 toxicity. The most frequent toxicities during SBRT were: nausea (G1, 18%; G2, 8%), asthenia (G1, 10%), abdominal pain (G1, 12%; G2, 2%) and diarrhea (G1, 6%; G2, 2%). After 3 and 6 months abdominal pain (16%) and diarrhea (12%) remained the most G1-G2 toxicities. At 6 and 12 months, we observed two cases of G2 malabsorption. At 1 year, we recorded G2 abdominal pain (4%) and G1 diarrhea (4%). CONCLUSIONS: In this series, adjuvant SBRT in PC was associated with acceptable tolerability with no ≥G3 toxicity. A longer follow-up is needed to fully characterize late toxicity. The final results are awaited to confirm the safety and efficacy of SBRT as a new therapeutic option for patients with resected PC. TRIAL REGISTRATION: The study protocol was approved by the institutional research ethics committee (Comitato Etico Indipendente IRCCS Humanitas Research Hospital) on May 18th 2021 and registered on ClinicalTrials.gov (NCT05043857) on September 14th 2021.
Massaro et al. (Wed,) studied this question.