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Background: There is paucity of investigations into immunotherapy or targeted therapy for postoperative locally recurrent pancreatic cancer. We aimed to assess the efficacy of stereotactic body radiotherapy (SBRT) plus pembrolizumab and trametinib in these patients.Methods: In this open-label, randomised, controlled, phase 2 study, participants were recruited from Changhai Hospital affiliated to the Naval Medical University, Shanghai, China. Eligible patients were aged 18 years or older with histologically confirmed pancreatic ductal adenocarcinoma characterised by mutant KRAS and positive immunohistochemical staining of PD-L1, Eastern Cooperative Oncology Group performance status of 0 or 1, and documented local recurrence after surgery followed by chemotherapy (mFOLFIRINOX [ie, 5-fluorouracil, oxaliplatin, irinotecan, and folinic acid] or 5-fluorouracil). Eligible participants were randomly assigned (1:1) using an interactive voice or web response system, without stratification, to receive SBRT with doses ranging from 35-40 Gy in five fractions, intravenous pembrolizumab 200 mg once every 3 weeks, and oral trametinib 2 mg once daily or SBRT (same regimen) and intravenous gemcitabine (1000 mg/m2) on day 1 and 8 of a 21-day cycle for eight cycles until disease progression, death, unacceptable toxicity, or consent withdrawal. The primary endpoint was overall survival in the intention-to-treat population. Safety was assessed in the as-treated population in all participants who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02704156, and is now complete.Findings: Between Oct 10, 2016, and Oct 28, 2017, 198 patients were screened, of whom 170 patients were enrolled and randomly assigned to receive SBRT plus pembrolizumab and trametinib (n=85) or SBRT plus gemcitabine (n=85). As of the clinical cutoff date (Nov 30, 2020), median follow-up was 13·1 months (IQR 10·2-17·1). Median overall survival was 14·9 months (12·7-17·1) with SBRT plus pembrolizumab and trametinib and 12·8 months (95% CI 11·2-14·4) with SBRT plus gemcitabine (hazard ratio [HR] 0·69 [95% CI 0·51-0·95]; p=0·021). The most common grade 3 or 4 adverse effects were increased alanine aminotransferase or aspartate aminotransferase (ten [12%] of 85 in SBRT plus pembrolizumab and trametinib group vs six [7%] of 85 in SBRT plus gemcitabine group), increased blood bilirubin (four [5%] vs none), neutropenia (one [1%] vs nine [11%]), and thrombocytopenia (one [1%] vs four [5%]). Serious adverse events were reported by 19 (22%) participants in the SBRT plus pembrolizumab and trametinib group and 12 (14%) in the SBRT plus gemcitabine group. No treatment-related deaths occurred.Interpretation: The combination of SBRT plus pembrolizumab and trametinib could be a novel treatment option for patients with locally recurrent pancreatic cancer after surgery. Phase 3 trials are needed to confirm our findings.Funding: Shanghai Shenkang Center and Changhai Hospital.Translation: For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Purpose/Objectives: Locally recurrent pancreatic cancer is a therapeutic challenge, and aggressive approaches are needed to improve its clinical outcomes. Stereotactic body radiotherapy (SBRT) is a promising treatment for pancreatic cancer with an excellent local control and acceptable toxicity. However, the safety and efficacy of SBRT for in-field recurrence after initial SBRT remain unknown. The aim of the study was to investigate the feasibility of re-irradiation with SBRT for locally recurrent pancreatic cancer after prior definitive SBRT. Material/Methods: Twenty-four consecutive patients with pancreatic cancer received two courses of SBRT in our center between January 2014 and December 2016. The median prescription dose of the initial and second courses of SBRT was 35.5 Gy/5–7f and 32 Gy/5–8f, respectively. Clinical outcomes including overall survival (OS), disease control, and toxicity were evaluated after treatment. Results: The median interval between two courses of SBRT was 13 months (range: 6–29 months). From the first SBRT, the median OS of 18 patients with limited diseases was 26 months (95% CI: 19.1–32.95 months). The median OS of 12 patients without metastasis was 14 months (95% CI: 10.6–17.4 months) from re-irradiation of SBRT. The overall response rate and disease control rate were 50% and 13%, and 100% and 86.9% after each SBRT, respectively. Carbohydrate antigen 19-9 (CA19-9) levels declined dramatically after re-irradiation within 1 month (p = 0.002) and 3 months (p = 0.028). Twelve (75%) out of 16 patients had pain relief after re-irradiation. None of the patients experienced gastrointestinal toxicity. Conclusions: Re-irradiation with SBRT can provide favorable outcomes and effective analgesia with mild toxicity after prior SBRT for in-field recurrent pancreatic cancer, which might be feasible for locally relapsed pancreatic cancer. [ABSTRACT FROM AUTHOR]

• No studies about optimal treatment for patients with LAPC and poor performance status. • SBRT and S-1 showed favorable outcomes and acceptable toxicity in those patients. • Improvement of quality of life and significant pain relief were found after treatment. The optimal treatment for a particularly neglected group of patients with locally advanced pancreatic cancer (LAPC) and poor performance status, who are usually excluded from most clinical trials, is required. Therefore, we aim to investigate the efficacy and safety of stereotactic body radiation therapy (SBRT) with sequential S-1 for those patients. Eligible patients had histologically and radiographically confirmed LAPC and ECOG performance status of 2 or more points determined by two independent physicians. Radiation doses ranged from 35-40 Gy/5f. S-1 was taken orally, twice daily, at a dose of 80 mg/m2 for 28 days, followed by a 14-day interval, which repeated for 6 cycles and was initiated one month after SBRT. The primary endpoint was 1-year overall survival (OS). The secondary endpoints were OS, progression free survival (PFS), treatment-related toxicity and quality of life. The study was registered at ClinicalTrials.gov: NCT02704143. Sixty-three patients were enrolled. At the time of data cut-off, all patients died. No patients were lost to follow-up. Median follow-up was 15.8 months (95%CI 12.9–18.7 months). One-year OS was noted in 46 of 63 patients (73.0%, 95%CI 67.4%-78.6%). The median OS and PFS was 14.4 (95%CI 13.2–15.6 months) and 10.1 months (95%CI 9.7–10.5 months) respectively. Eighteen patients (28.6%) had grade 3 toxicity. According to Quality of Life Questionnaire-Core 30, significant improvements of abdominal pain were found, and patients with poorer baseline global health status had greater improvement of health status and pain relief after treatment. SBRT with sequential S-1 shows promising efficacy and acceptable toxicity in poor performance status patients with LAPC. [ABSTRACT FROM AUTHOR]

Background: There is paucity of investigations into immunotherapy or targeted therapy for postoperative locally recurrent pancreatic cancer. We aimed to assess the efficacy of stereotactic body radiotherapy (SBRT) plus pembrolizumab and trametinib in these patients.Methods: In this open-label, randomised, controlled, phase 2 study, participants were recruited from Changhai Hospital affiliated to Naval Medical University, Shanghai, China. Eligible patients were aged 18 years or older with histologically confirmed pancreatic ductal adenocarcinoma characterised by mutant KRAS and positive immunohistochemical staining of PD-L1, Eastern Cooperative Oncology Group performance status of 0 or 1, and documented local recurrence after surgery followed by chemotherapy (mFOLFIRINOX or 5-fluorouracil). Eligible participants were randomly assigned (1:1) using an interactive voice or web response system, without stratification, to receive SBRT with doses ranging from 35-40 Gy in five fractions, intravenous pembrolizumab 200 mg once every 3 weeks, and oral trametinib 2 mg once daily or SBRT (same regimen) and intravenous gemcitabine (1000 mg/m2) on day 1 and 8 of a 21-day cycle for eight cycles until disease progression, death, unacceptable toxicity, or consent withdrawal. The primary endpoint was overall survival in the intention-to-treat population. Safety was assessed in the as-treated population in all participants who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT02704156, and is now complete.Findings: Between Oct 10, 2016, and Oct 28, 2017, 198 patients were screen, of whom 170 patients were enrolled and randomly assigned to receive SBRT plus pembrolizumab and trametinib (n=85) or SBRT plus gemcitabine (n=85). As of the clinical cutoff date (Nov 30, 2020), median follow-up was 23·3 months (IQR 20·5-27·4). Median overall survival was 24·9 months (23·3-26·5) with SBRT plus pembrolizumab and trametinib and 22·4 months (95% CI 21·2-23·6) with SBRT plus gemcitabine (hazard ratio [HR] 0·60 [95% CI 0·44-0·82]; p=0·0012). The most common grade 3 or 4 adverse effects were increased alanine aminotransferase or aspartate aminotransferase (ten [12%] of 85 in SBRT plus pembrolizumab and trametinib group vs six [7%] of 85 in SBRT plus gemcitabine group), increased blood bilirubin (four [5%] vs none), neutropenia (one [1%] vs nine [11%]), and thrombocytopenia (one [1%] vs four [5%]). Serious adverse events were reported by 19 (22%) participants in the SBRT plus pembrolizumab and trametinib group and 12 (14%) in the SBRT plus gemcitabine group. No treatment-related deaths occurred.Interpretation: The combination of SBRT plus pembrolizumab and trametinib could be a novel treatment option for patients with locally recurrent pancreatic cancer after surgery. Phase 3 trials are needed to confirm our findings.Funding: Shanghai Shenkang Center and Changhai Hospital.Translation: For the Chinese translation of the abstract see Supplementary Materials section. [ABSTRACT FROM AUTHOR]

Objective: Due to common practice of hypofractionated radiotherapy in pancreatic cancer and heterogeneous chemotherapy regimens in previous studies, modified nomograms are required. Therefore, we aim to develop and validate prognostic nomograms for locally advanced pancreatic cancer (LAPC) after stereotactic body radiation therapy (SBRT) and chemotherapy. Methods: The development cohort comprised 925 patients with LAPC receiving SBRT and gemcitabine-based chemotherapy in our center, while 297 patients from another two centers formed the validation cohort. Nomograms were created from COX models and internally validated by bootstrap. Model discriminations were evaluated by calibration plots and concordance index (C-index). A decision curve analysis (DCA) was performed to evaluate clinical benefits of nomograms. Additionally, recursive partitioning analysis (RPA) was used for stratifications of survival probability based on the total score of each patient calculated by nomograms. Results: Weight loss, tumor diameter, radiation dose, CA19-9 kinetics after treatment and surgical resection were included in the nomogram for overall survival (OS), while the five factors plus performance status formed the nomogram for progression free survival (PFS). The corrected C-indexes for estimated 1-year and 2-year OS of the development cohort were 0.88 (95% CI: 0.85-0.91) and 0.86 (95% CI: 0.83-0.90). For those of the validation cohort, it was 0.88 (95% CI: 0.82-0.94) and 0.83 (95% CI: 0.74-0.91). Additionally, the corrected C-index for predicted 1-year PFS in the development and validation cohort was 0.83 (95% CI: 0.81-0.86) and 0.82 (95% CI: 0.78-0.87), respectively. The calibration plots showed good agreement of 1- and 2-year OS and 1-year PFS between the estimations and actual observations. Potential clinical benefits were demonstrated with DCA. Additionally, for 1- and 2-year OS and 1-year PFS, patients were stratified into four groups with different survival probability by RPA. Conclusion: The validated nomograms provided useful predictions of OS and PFS for LAPC with chemoradiotherapy. [ABSTRACT FROM AUTHOR]

• Longer survival in patients with PD-L1+/TIL + having immunotherapy-based regimens. • Similar outcomes in PD-L1+/TIL + and PD-L1+/TIL- groups regarding chemoradiotherapy. • No increased toxicity in PD-L1+/TIL + compared with PD-L1+/TIL- group in two regimens. Immunotherapy alone offered limited survival benefits in pancreatic cancer, while the role of immunotherapy-centric combined therapy remains controversial. Therefore, it is required to develop biomarkers to precisely deliver immunotherapy-based multimodality for pancreatic cancer. This is a secondary analysis of an open label, randomized, phase 2 trial, whereas patients with locally recurrent pancreatic cancer after surgery were enrolled. Eligible patients with mutant KRAS and positive immunohistochemical staining of PD-L1 were randomly assigned to receive stereotactic body radiation therapy (SBRT) plus pembrolizumab and trametinib (SBRT + K + M) or SBRT and gemcitabine (SBRT + G). Meanwhile, patients were classified into PD-L1+/tumor infiltrating lymphocytes [TIL(s)]- and PD-L1+/TIL + group for each arm. A total of 170 patients were enrolled and randomly assigned to receive SBRT + K + M (n = 85) or SBRT + G (n = 85). The improved outcomes have been reported in patients with SBRT + K + M in the previous study. In this secondary analysis, the median overall survival (OS) was 17.2 months (95% CI 14.6–19.8 months) in patients with PD-L1+/TIL + and 12.7 months (95% CI 10.8–14.6 months) in patients with PD-L1+/TIL- (HR 0.62, 95% CI 0.39–0.97, p = 0.036) receiving SBRT + K + M. In SBRT + G group, the median OS was 13.1 months (95% CI 10.9–15.3 months) in patients with PD-L1+/TIL- and 12.7 months (95% CI 9.2–16.2 months) in patients with PD-L1+/TIL+ (HR 0.97, 95% CI 0.62–1.52, p = 0.896). Grade 3 or 4 adverse events were found in 16 patients (30.8%) and 10 patients (30.3%) with PD-L1+/TIL- and PD-L1+/TIL + in SBRT + K + M group respectively; whereas 9 (16.7%) and 8 patients (25.8%) with PD-L1+/TIL- and PD-L1+/TIL + in SBRT + G group. PD-L1, TILs and mutant KRAS may be a biomarker to guide clinical practice of radiotherapy and immunotherapy-based regimens in pancreatic cancer if further combined with MEK inhibitors as targeted therapy. [ABSTRACT FROM AUTHOR]

This study aims to identify postoperative recurrence patterns of pancreatic cancer with different molecular profiles, which provides evidence for personalized target volumes of adjuvant radiotherapy. Patients with pathologically confirmed resectable pancreatic ductal adenocarcinoma were included. Recurrences were treated with stereotactic body radiation therapy. Immunohistochemical staining of Ki‐67, P53, and programmed cell death‐ligand 1 (PD‐L1) was carried out. Both of the intensities of Ki‐67 and P53 were classified as 10% or less, 11%‐49%, and 50% or more. Eighty‐nine patients had PD‐L1 tested, stratified as TC0 and IC0, and TC1/2 or IC1/2. Distances with significant differences among different levels or beyond 10 mm were of interest. With the increasing intensity of Ki‐67, the distance from the superior and posterior border of 80% recurrences to the celiac axis (CA) ranged from 10.1 to 13.8 mm and 9.2 to 11.0 mm. The distance from the inferior and posterior border of 80% recurrences to the superior mesenteric artery (SMA) ranged from 9.4 to 9.9 mm and 9.4 to 11.0 mm. Similarly, with the increasing intensity of P53, the distance from the superior and posterior border of 80% recurrences to the CA ranged from 9.7 to 13.2 mm and 10.1 to 10.6 mm. The distance from the inferior and anterior border of 80% recurrences to the SMA ranged from 9.5 to 9.9 mm and 8.6 to 9.4 mm. Regarding the increasing level of PD‐L1, the distance from the superior border of 80% recurrences to the CA ranged from 10.9 to 13.5 mm. A biologically effective dose of more than 65 Gy to local recurrences was predictive of favorable outcomes in all levels of Ki‐67, P53, and PD‐L1. Nonuniform expansions of regions of interest based on different levels of molecular profiles to form target volumes could cover most recurrences, which might be feasible for adjuvant radiotherapy. [ABSTRACT FROM AUTHOR]

Objective: This study aims to compare recurrence patterns and outcomes of biologically effective dose (BED10, α/β = 10) of 60–70 Gy with those of a BED10 >70 Gy for locally advanced pancreatic cancer (LAPC). Methods: Patients from three centers with a biopsy and a radiographically proven LAPC were retrospectively included and data were prospectively collected from June 2012 to June 2019. Radiotherapy was delivered by stereotactic body radiation therapy. Recurrences were categorized as in-field, marginal, and outside-the-field recurrence. Patients in two groups were required to receive abdominal enhanced contrast CT or MRI every 2–3 months and CA19-9 examinations every month during follow-up. Treatment-related toxicities were evaluated every month. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. Results: After propensity score matching, there were 486 patients in each group. The median prescription dose of the two groups was 37 Gy/5–8 f (range: 36–40.8 Gy/5–8 f) and 42 Gy/5–8 f (range: 40–49.6 Gy/5–8 f), respectively. The median OS of patients with a BED10 >70 Gy and a BED10 60–70 Gy was 20.3 months (95% CI: 19.1–21.5 months) and 18.2 months (95% CI: 17.8–18.6 months) respectively (p < 0.001). The median PFS of the two cohorts was 15.4 months (95% CI: 14.2–16.6 months) and 13.3 months (95% CI: 12.9–13.7 months) respectively (p < 0.001). A higher incidence of in-field and marginal recurrence was found in patients with BED10 of 60–70 Gy (in-field: 97/486 versus 72/486, p = 0.034; marginal: 109/486 versus 84/486, p = 0.044). However, more patients with BED10 >70 Gy had grade 2 or 3 acute (87/486 versus 64/486, p = 0.042) and late gastrointestinal toxicities (77/486 versus 55/486, p = 0.039) than those with BED10 of 60–70 Gy. Conclusion: BED10 >70 Gy was found to have the best survival benefits along with a higher incidence of acute and late gastrointestinal toxicities. Therefore, a higher dose may be required in the case of patients' good tolerance. [ABSTRACT FROM AUTHOR]

The passive targeting via nanomedicine to pancreatic tumor microenvironment (TME) is identified as an optimized therapeutic strategy for pancreatic ductal adenocarcinoma (PDAC) because lacking specific biomarkers and the intractable anatomical position. Herein, an in vitro 3D PDAC model was set up to evaluate the regulation of extracellular matrix (ECM) by an intelligent gemcitabine@nanogel system (GEM@NGH). This GEM@NGH system consisting of a reduction-sensitive core, the payloads of gemcitabine, and the coronal of hyaluronidase arrayed on the cationic surface was fabricated to improve intratumoral penetration and antitumor efficacy. The physicochemical properties, reduction sensitivity, cellular biocompatibility and cytotoxicity, intracellular distribution and therapeutic effects were all evaluated. Particularly, the GEM@NGH system showed excellent ECM eradication and in vitro/vivo solid tumor penetration ability as evaluated by home-built equipment and in vitro 3D PDAC model, which confirmed that GEM@NGH could be disintegrated in the tumoral reductive cytoplasm after internalization and release gemcitabine to exhibit promoted cytotoxicity. In the in vivo therapy, GEM@NGH displayed the highest tumor growth inhibition in PANC-1 tumor-bearing mice with the remarkably increased tumor penetration ability by TME regulation. The results obtained in this study indicate that specifically regulating TME by a well-designed intelligent gemcitabine@nanogel is promising way for the pancreatic cancer therapy. Unlabelled Image • An in vitro 3D model successfully set-up for evaluation of TME regulation. • Intelligent nanogel responsive to the TEM with high tumor penetration ability. • The reduction sensitive property synergistically promoted PDAC therapy. [ABSTRACT FROM AUTHOR]

Highlights • This study focuses on the re-irradiation for pancreatic cancer, which is rarely investigated, yet an important treatment option for recurrence of pancreatic cancer. Besides, it is the largest series of two courses of stereotactic body radiation therapy for pancreatic cancer. • To the best of our knowledge, a novel prognostic score was firstly developed for selecting patients amenable to re-irradiation for pancreatic cancer. • This scoring system may provide insights for individualized treatment. Abstract Purpose To develop a predictive model for stratification of patients with pancreatic cancer who may achieve survival benefits from re-irradiation with stereotactic body radiation therapy (SBRT). Methods The score was developed based on clinical predictors of OS in 31 patients receiving two courses of SBRT with Cox proportional hazards model. Results were then validated in another cohort with 11 participants to assess the performance of the score. Results In the training cohort, the median BED 10 of the first and second SBRT was 59.5 Gy (48–85.5 Gy) and 50.2 Gy (43.7–66.9 Gy) in 5–8 fractions, while in the validation cohort, the median BED 10 of the first and second SBRT was 59.5 Gy (52.5–66.9 Gy) and 47.7 Gy (40.6–54.8 Gy) in 5–8 fractions. The interval between the first and second SBRT of the training cohort and validation cohort was 10.5 months (6.1–24.3 months) and 12.8 months (6.5–29.1 months), respectively. Multivariable analysis showed that tumor stage (P = 0.005), BED 10 (P = 0.006) and CA19-9 response (P = 0.04) were significantly predictive of overall survival, which formed SCAD score (named after the initials of factors). Patients with the score < 3 points had a superior OS compared with those with the score ≥ 3 points in the validation cohort (median OS has not been reached vs. 15.9 months, P = 0.032). Conclusions The SCAD score may have the potential to identify individuals benefiting from re-SBRT and be a step toward more personalized medicine. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of gemcitabine and nab-paclitaxel (GT) plus stereotactic body radiation therapy (SBRT) or gemcitabine and S-1 (GS) plus SBRT on health-related quality of life (HRQOL) of metastatic pancreatic cancer. Methods: Patients with biopsy-proven and radiographically metastatic pancreatic cancer were included. HRQOL was assessed using the Chinese version of Brief Pain Inventory (BPI) and 5-level European quality of life 5-dimensions (EQ-5D-5L). Data were analyzed with Spearman's rank correlation, ordinal regression, and propensity score-matched analysis. Results: A total of 75 and 89 patients received GT and GS, respectively. The median biological effective dose of GT group and GS group was 59.5 Gy (range 48–85.5 Gy) and 64.4 Gy (range 52.48–85.5 Gy) in 5–8 fractions, respectively. More patients in the GS group had improvement in BPI and EQ-5D-5L compared with those in the GT group (n=38 vs n=15, P<0.001; n=42 vs n=20, P<0.001). No differences of BPI scores were found between pre- and post-treatment in each group, while only the post-treatment EQ-5D-5L score was higher than that at baseline in GS the group (P<0.001). Compared with GS group, it was unlikely for patients receiving GT to have better BPI and EQ-5D-5L. After propensity-matched analysis, more patients in GS group had improvement in BPI and EQ-5D-5L (n=24 vs n=12, P=0.002; n=28 vs n=16, P=0.002). Furthermore, patients with GS had a superior overall survival than those with GT (11.1 months [95% CI: 10.6–11.6 months] vs 9.9 months [95% CI: 8.8–11.0 months]; P=0.005). Both incidences of grade 3 hematological (P=0.024) and gastrointestinal (P=0.049) toxicities were higher in the GT group. Conclusion: GS may achieve better HRQOL than GT. Therefore, GS may be an alternative of GT for metastatic pancreatic cancer, especially for Asians. [ABSTRACT FROM AUTHOR]

The role of stereotactic body radiation therapy for the elderly with advanced or medically inoperable pancreatic cancer was still debated. Therefore, we evaluated the value of stereotactic body radiation therapy and its association with survival of those patients. A total of 417 elderly patients were retrospectively reviewed from 2012 to 2015. Overall survival ( OS), progression-free survival ( PFS), local recurrence-free survival ( LRFS), distant metastasis-free survival ( DMFS), and toxicities were analyzed. Prescription doses ranged from 30-46.8 Gy in 5-8 fractions. Median age was 73 years old. Median OS, PFS, LRFS, and DMFS were 10, 8, 10, and 9.5 months, respectively. One-year OS, PFS, LRFS, and DMFS rate were 35.5%, 18.2%, 26.6%, and 27.1%, respectively. Tumor stage and tumor response at 6 months and CA19-9 levels normalization at 3 months after treatment were independent predictors of OS, PFS, LRFS, and DMFS. Patients with early-stage cancer, better tumor response, and normalization of CA19-9 levels had significantly longer OS, PFS, LRFS, and DMFS. Patients with the prodrug of 5- FU and radiotherapy had longer survival than those with gemcitabine-based chemotherapy and radiotherapy. Patients who received BED10 ≥ 60 Gy achieved better tumor response compared with those who received BED10 < 60 Gy. Two patients had grade 4 intestinal strictures. No grade 3 or higher hematologic toxicities occurred. Stereotactic body radiation therapy is safe and effective for elderly patients with advanced or medically inoperable pancreatic cancer. Early efficacy could be predictive of prognosis. Higher doses may be associated with efficacy but need further investigation. [ABSTRACT FROM AUTHOR]

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 ). [ABSTRACT FROM AUTHOR]