Comparisons of different neoadjuvant chemotherapy regimens with or without stereotactic body radiation therapy for borderline resectable pancreatic cancer: study protocol of a prospective, randomized phase II trial (BRPCNCC-1)

BACKGROUND: Few patients with pancreatic cancer may be candidates for immediate surgical resection at the initial diagnosis. Even if patients with borderline resectable pancreatic cancer (BRPC), micrometastases may occur before surgery. Therefore, neoadjuvant therapy is vital for improved survival, which has been confirmed in previous studies that neoadjuvant chemotherapy with or without radiotherapy provides superior overall compared with upfront surgery. However, question of whether the addition of radiotherapy to neoadjuvant chemotherapy can improve prognosis compared with chemotherapy alone is a challenging matter. Moreover, most of previous studies only adopted conventional radiotherapy as the neoadjuvant modality though stereotactic body radiation therapy (SBRT) has been proven effective and commonly employed in pancreatic cancer. Also, no studies have evaluated the efficacy of S-1 as the neoadjuvant chemotherapy regimen for BRPC albeit similar prognosis has been found between S-1 and gemcitabine in advanced pancreatic cancer. Hence, the aim of this study is to investigate whether neoadjuvant chemotherapy plus SBRT results in better outcomes compared with neoadjuvant chemotherapy alone and also compare the efficacy of gemcitabine plus nab-paclitaxel with SBRT and S-1 plus nab-paclitaxel with SBRT. METHODS: Patients with biopsy and radiographically confirmed BRPC, no prior treatment and severe morbidities are enrolled. They will be randomly allocated into three groups: neoadjuvant gemcitabine plus nab-paclitaxel, neoadjuvant gemcitabine plus nab-paclitaxel with SBRT and neoadjuvant S-1 plus nab-paclitaxel with SBRT. Standard doses of gemcitabine and nab-paclitaxel are used. The radiation dose of SBRT is 7.5-8Gy/f for 5 fractions. Surgical resection will be performed 3 weeks after SBRT. Artery first approach pancreaticoduodenectomy or radical antegrade modular pancreatosplenectomy will be used for the tumor in the head or body and tail of the pancreas, respectively. The primary endpoint is overall survival. The secondary outcomes are disease free survival, pathological complete response rate, R0 resection rate and incidence of adverse effects. DISCUSSION: If results show the survival benefits of neoadjuvant chemotherapy plus SBRT and similar outcomes between S-1 and gemcitabine, it may provide evidence of clinical practice of this modality for BRPC. TRIAL REGISTRATION: The study has been registered in ClinicalTrial.gov (NCT03777462).