Search

680 Background: Multidisciplinary treatment of borderline resectable (BR)/unresectable locally advanced (UR-LA) pancreatic adenocarcinoma (PDAC) has not yet been established. The purpose of this study is to explore factors that improve prognosis in radical surgery after multidisciplinary treatment for pancreatic cancer. Methods: We evaluated the following prognostic factors in 240 PDAC patients who underwent radical resection after multidisciplinary treatment. Patients were classified into 3 groups according to NCCN guidelines (BR PDAC invading the portal vein (BR-PV), BR pancreatic cancer in contact with the major arteries such as the hepatic artery, celiac axis and superior mesenteric artery (BR-A), and UR-LA), and prognostic factors were investigated. Patients with BR PDAC were treated with chemotherapy followed by surgery, while radiation therapy was added preoperatively in most cases with arterial invasion. All patients with UR-LA underwent surgery after nab-paclitaxel plus gemcitabine (GnP) followed by chemoradiotherapy (CRT) with S-1. Results: BR-PV/BR-A/UR-LA patients were 88/111/41, respectively. Prognosis was significantly better in the NAT group than in the upfront surgery group for both BR-PV/A (P=0.004/42.5 (P=0.022). In univariate analysis in 39 patients with BR-A, the following factors were significantly favorable prognostic factors; TM normalization (P=0.033), preoperative PNI>42.5 (P=0.013), intraoperative blood loss>830 ml (P=0.013). Multivariate analysis revealed that high preoperative PNI was an independent prognostic factor (hazard ratio 0.15 [0.02-0.85]; P=0.014) in BR-A patients. In patients with UR-LA who underwent radical resection after GnP and subsequent CRT, median duration of NAT was 8.8 months, and R0 resection was achieved in 36 patients (88%). 3-year OS was 77.4%, and 5-year OS 58.6%. Multivariate analysis revealed that CA19-9 normalization (hazard ratio 0.23 [0.02-0.88]; P=0.032) and PNI≥41.7 (HR 0.05 [0.01-0.62]; P=0.021) were independent prognostic factors. Conclusions: In both BR/UR-LA pancreatic cancer, normalization of TM and maintenance of good nutritional status during NAT until surgery may contribute to prolonged prognosis.

674 Background: Positive peritoneal cytology has been reported to indicate a poor prognosis in patients with pancreatic cancer even if the primary tumor is surgically resected. This study investigated the clinical implications of peritoneal cytology by staging laparoscopy for patients with potentially resectable pancreatic cancer for whom initial treatment will be started. Methods: We retrospectively reviewed 113 consecutive patients with pancreatic cancer diagnosed as resectable by computed tomography in whom peritoneal cytology was evaluated by staging laparoscopy between December 2018 and August 2022. Patients with positive cytology received induction chemotherapy, and those in whom cytology converted to negative underwent surgical resection as needed when possible. We set best tumor marker cutoff values for predicting positive cytology by maximizing the Youden index. Results: Seventy-three patients were men and the mean age was 72 years. Thirty patients (26.5%) had positive cytology at initial staging laparoscopy. Minimal peritoneal metastases were detected in seven of these patients and liver metastases in two. Larger tumor diameter ( > 30 mm), location in the pancreatic body or tail, an elevated CA19-9 level ( > 138.5 U/ml), an elevated CA125 level ( > 13.5 U/ml), and an elevated CEA level ( > 5.1 ng/ml) were associated with a significantly increased risk of positive cytology (odds ratio 4.71 [confidence interval 1.87–12.2] P = 0.001, 2.49 [1.07–6.05] P = 0.038, 2.95 [1.26–7.12] P = 0.014, 3.89 [1.57-10.7] P = 0.005, and 3.52 [1.23–10.2] P = 0.018, respectively). Eighteen patients (60%) who received induction chemotherapy converted from positive to negative cytology; seven (38%) of these patients underwent surgery and all remain alive without recurrence. Interestingly, median overall survival in patients with negative cytology was not necessarily inferior to that in those with positive cytology (23.4 months vs. 24.2 months, P = 0.33). Conclusions: Over a quarter of patients with pancreatic cancer that is diagnosed as resectable by computed tomography may have positive peritoneal cytology at the initial assessment. These patients tend to have higher CA19-9, CA125, and CEA levels, larger tumors, and tumors located in the body or tail of the pancreas. A more favorable prognosis may be achieved by administering induction chemotherapy until cytology converts to negative than by upfront surgery.

530 Background: For borderline resectable pancreatic ductal adenocarcinoma (BR-PDAC), upfront surgery was standard in the past, and the usefulness of neoadjuvant treatment (NAT) has been reported in recent years. However, few studies have been conducted to date on whether there is a difference in optimal treatment between BR-PDAC invading the portal vein (BR-PV) or abutting major arteries (BR-A). The objective of this study was to investigate the optimal treatment for BR-PV and BR-A. Methods: We retrospectively analyzed 199 patients with BR-PDAC (88 BR-PV and 111 BR-A). For each BR-PV and BR-A, we analyzed the following points. 1) Comparison of prognosis of upfront surgery vs. NAT, 2) Comparison of regimens in patients who underwent NAT, 3) Prognostic factors in patients who underwent resection after NAT. Results: 1) In BR-PV patients who underwent upfront surgery (n = 46)/NAT (n = 42), survival was significantly better in the NAT group (3-year overall survival (OS): 5.8%/35.5%, p = 0.004). In BR-A patients who underwent upfront surgery (n = 48)/NAT (n = 63), survival was also significantly better in the NAT group (3-year OS:15.5%/41.7%, p < 0.001). 2) The prognosis tended to be better in patients who received newer chemotherapeutic regimens, such as FOLFIRINOX and gemcitabine with nab-paclitaxel than older regimens such as gemcitabine and/or S-1, in each BR-PV and BR-A patients. The R0 rate was significantly higher (100%) when radiotherapy was used in combination with chemotherapy, regardless of the chemotherapeutic regimen. 3) In 36 BR-PV patients who underwent surgery after NAT, univariate analysis revealed that normalization of tumor marker levels ( p = 0.028) and preoperative high prognostic nutritional index (PNI) ( p = 0.022) were significantly associated with a favorable prognosis. In 39 BR-A patients who underwent surgery after NAT, multivariate analysis revealed that preoperative PNI > 42.5 was an independent prognostic factor (hazard ratio: 0.15, p = 0.014). The length of NAT was not a prognostic factor for either BR-PV or BR-A. Conclusions: NAT using newer chemotherapy is essential for improving the prognosis of BR pancreatic cancer. These findings suggest that prognosis may be improved by maintaining good nutritional status during preoperative treatment, not by the length of preoperative treatment. In addition, surgery after normalization of tumor markers levels by preoperative treatment contributes to the prolongation of survival.

658 Background: Early studies raised concerns over whether preoperative treatment led to postoperative complications or even death. In contrast, recent studies have reported that initial treatment (IT) prior to resection of pancreatic ductal adenocarcinoma (PDAC) is safe, with no significant increase in overall morbidity or mortality, despite evidence for more advanced disease. In this study, we analyzed the clinical impact of chemotherapy or chemoradiotherapy as IT, focusing on treatment duration, on morbidity and mortality in patients with resected PDAC. Methods: We enrolled 509 consecutive patients, with 417 in the upfront surgery group and 92 in the IT group. The IT group was subdivided into 72 patients treated for < 8 months and 20 treated ≥8 months. We compared rates of postoperative Clavien–Dindo grade ≥III complications between the groups. Multivariate logistic regression analysis was used to find independent predictors of complications. Results: The upfront surgery and IT groups did not significantly differ in overall postsurgical complications. The rate of postoperative pancreatic fistula was significantly less in the IT group. Rates of other complications did not significantly differ, except for severe infection and delayed gastric emptying. Initiation of adjuvant chemotherapy was later in the IT group than in the upfront surgery group (43.2 vs 57.8 days, P < 0.001). In contrast, rates of overall complications significantly differed between the < 8 months and ≥8 months IT groups, although their background clinical factors did not differ. In multivariate analysis, operative procedure (distal pancreatectomy and distal pancreatectomy with celiac axis resection) (odds ratio [OR] 6.950, P = 0.0416) and IT ≥8 months (OR: 4.508, 95%, P = 0.0156) were independent predictive factors for postoperative complications. Conclusions: The incidence of postoperative complication was similar between the upfront surgery group and the IT group, however, it was significantly higher in the ≥8 months IT group in patients who underwent PDAC resection.

219 Background: Recently, several nutritional and inflammatory markers have been reported to be involved in cancer progression. The aim of this study is to evaluate whether nutritional and inflammatory biomarkers such as the modified Glasgow prognostic score (mGPS), the neutrophil‐to-lymphocyte ratio (NLR), the platelet‐to-lymphocyte ratio, the systemic-immune-inflammation index (SIII), controlling nutritional status (CONUT) score, prognostic nutritional index, and the lymphocyte‐to-monocyte ratio (LMR) could predict the prognosis in patients with unresectable pancreatic ductal adenocarcinoma (UR-PDAC) who underwent chemotherapy as first-line therapy, using disease-specific survival as the primary outcome. Methods: All UR-PDAC patients were retrospectively evaluated between January 2011 and May 2017 at Toyama University Hospital. Baseline clinicopathological characteristics and pre-treatment laboratory values such as absolute neutrophil, lymphocyte and platelet counts, C-reactive protein, albumin and CA19-9 levels, were collected. Results: A total of 184 patients were diagnosed as UR-PDAC. Among them, 151 patients who underwent chemotherapy were enrolled in this study. There were significant relationships between survival and elevated mGPS, elevated NLR, elevated SIII, decreased LMR, decreased serum cholinesterase level, and low CONUT score (p < 0.001, p < 0.001, p = 0.001, p < 0.001, p = 0.026 and p < 0.001, respectively, by log-rank test). The median survival time of patients with metastatic lesions was significantly shorter than that of patients with unresectable locally advanced PDAC (9.0 vs 15.5 months, respectively; p = 0.033). There was no significant difference in survival in pre-treatment CA19-9 level and tumor location. Multivariate analysis using Cox regression model revealed that NLR and CONUT score were independent prognostic factors. Conclusions: Pre-treatment NLR and CONUT score may predict clinical outcome in patients with UR-PDAC undergoing chemotherapy as first-line therapy.