Oncologic outcomes according to the location and status of resection margin in pancreas head cancer: role of radiation therapy in R1 resection

Changing Clinical Meaning of Resection Margin Status According to the Treatment Paradigm and the Potential Role of Perioperative Radiotherapy for Patients with Pancreatic Ductal Adenocarcinoma: An Updated Multicenter Retrospective Cohort Study

BACKGROUND

Surgeons have focused on obtaining microscopically negative margins and developing perioperative treatment strategies for pancreatic head cancer. However, the clinical significance of resection margin and radiotherapy remains unclear, particularly in neoadjuvant chemotherapy (NAC) settings. Therefore, this study aimed to evaluate the prognostic impact of margin status and perioperative radiotherapy.

METHODS

Between 2014 and 2019, the study enrolled 307 patients with pancreatic head cancer who underwent upfront pancreaticoduodenectomy (PD) and 97 patients who underwent NAC followed by PD at three tertiary referral hospitals. The margin status was divided into a three-tier system as follows: R0-wide (tumor-free margin, ≥ 1 mm), R0-narrow (0 mm < margin < 1 mm), and R1 (margin = 0 mm).

RESULTS

In the upfront surgery setting, the groups were arranged in descending order of the 5-year overall survival (OS) rates as follows: R0-wide (39.1%), R0-narrow (25.6%), and R1 (12.5%). In the NAC setting, the groups also could be arranged in descending order of 5-year OS rates as follows: R0-wide (52.2%), R0-narrow (45.5%), and R1 (8.3%). However, the differences in OS between the R0-wide and R0-narrow groups did not reach statistical significance (P = 0.587), in contrast to the upfront surgery setting. In the multivariate analyses, concurrent chemo-radiotherapy after surgery was significantly associated with a decreased risk of locoregional recurrence in both treatment settings.

CONCLUSIONS

Obtaining a wide margin could enhance prognosis in upfront surgery settings, and obtaining only a narrow margin could be appropriate in NAC settings. In addition, adjuvant radiotherapy could be considered, particularly for patients with margin involvement.

Prognostic implications of resection margin status in distal pancreatectomy for pancreatic ductal adenocarcinoma

BACKGROUND

Curative resection is a well known prognostic factor in pancreatectomy. However, definition and clinical significance of resection margin in distal pancreatectomy remains controversial.

METHODS

From 2010 to 2018, 203 patients with pancreatic cancer undergoing distal pancreatectomies were included. Patients were classified into three groups: R0-wide (tumor-free margin ≥1 mm), R0-narrow (0 mm < tumor-free margin <1 mm), and R1 margin (tumor-free margin = 0 mm). We also evaluated the prognostic impact of individual margins (transection, anterior, and posterior).

RESULTS

Patients with an R0-wide margin (36.6 %) exhibited superior 5-year disease free survival rate compared to those with R0-narrow (30.4 %, p = 0.059) or R1 margin (0.1 %, p = 0.014). However, in multivariate analyses, only R1 margin (hazard ratio [95 % confidence interval], 2.02 [1.32-3.12]; p = 0.001), unlike R0-narrow margin (1.17 [0.78-1.77]; p = 0.446), was linked to shorter overall survival compared to R0-wide margin. In multivariate analyses, posterior margin involvement was uniquely identified as a poor prognostic factor (1.83 [1.07-3.13]; p = 0.027).

CONCLUSIONS

The 0 mm rule seems more suitable than the 1 mm rule for predicting prognosis in performing distal pancreatectomy, and especially, achieving microscopically negative posterior margin is crucial.

Postoperative complications and surgical outcomes of robotic versus laparoscopic pancreaticoduodenectomy: a meta-analysis of propensity-score-matched studies

BACKGROUND

Robotic pancreaticoduodenectomy (RPD) is used more commonly, but high-level evidence is still scarce. This meta-analysis aimed to compare the short-term outcomes between RPD and laparoscopic pancreaticoduodenectomy (LPD) using data collected from propensity score-matched (PSM) studies.

MATERIALS AND METHODS

We searched PubMed, Cochrane Library, Embase, and Web of Science databases for PSM studies comparing RPD and LPD. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals were calculated.

RESULTS

Ten PSM studies were included, encompassing 8106 patients (RPD group: 3695 patients; LPD group: 4411 patients). Compared with LPD, RPD was associated with a lower conversion rate (RR, 0.56) and blood transfusion rate (RR, 0.49), as well as a higher number of harvested lymph nodes (MD, 2.15). There were no significant differences observed in 30-day readmission (RR, 1.02), 90-day mortality (RR, 1.01), overall morbidity (RR, 0.94), major complications (RR, 1.06), operative time (MD, -8.00 min), blood loss (MD, -19.37 mL), reoperation (RR, 0.95), bile leak (RR, 0.93), chylous leak (RR, 1.40), postoperative pancreatic fistula (RR, 1.06), delayed gastric emptying (RR, 0.92), wound infection (RR, 1.12), length of stay (MD, -0.32 days), and R0 resection (RR, 0.98) between the groups.

CONCLUSIONS

Although LPD and RPD had similar surgical outcomes, RPD had the perioperative advantage over LPD in decreasing conversion rates and blood transfusion rates and increasing the number of lymph nodes harvested. Further randomized controlled trials evaluating the potential advantages of RPD over LPD are warranted.

Comparison of short-term outcomes of robotic versus open pancreaticoduodenectomy: a meta-analysis of randomized controlled trials and propensity-score-matched studies

BACKGROUND

Robotic pancreaticoduodenectomy (RPD) is used more commonly, but this surge is mostly based on observational data. This meta-analysis aimed to compare the short-term outcomes between RPD and open pancreaticoduodenectomy (OPD) using data collected from randomized controlled trials (RCTs) and propensity-score-matched (PSM) studies.

METHODS

We searched PubMed, Cochrane Library, Embase, and Web of Science databases for RCTs and PSM studies comparing RPD and OPD. Risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Twenty-four studies, encompassing two RCTs and 22 PSM studies, were included, with a total of 9393 patients (RPD group: 3919 patients; OPD group: 5474 patients). Although RPD was associated with a longer operative time (MD, 61.61 min), patients may benefit from reduced blood loss (MD, -154.05 ml), shorter length of stay (MD, -1.60 days), lower blood transfusion rate (RR, 0.85), and wound infection rate (RR, 0.61). There were no significant differences observed in 30-day readmission (RR, 0.99), 90-day mortality (RR, 0.97), overall morbidity (RR, 0.88), major complications (RR, 1.01), reoperation (RR, 1.08), bile leak (RR, 1.01), chylous leak (RR, 0.98), postoperative pancreatic fistula (RR, 0.97), post-pancreatectomy hemorrhage (RR, 1.15), delayed gastric emptying (RR, 0.88), number of harvested lymph nodes (MD, -0.12), and R0 resection (RR, 1.01) between the groups.

CONCLUSIONS

Although some short-term outcomes were similar between RPD and OPD, RPD exhibited reduced intraoperative blood loss, shorter hospital stays, lower wound infection, and blood transfusion rates. In the future, RPD may become a safe and effective alternative to OPD.

Prognostic impact of the distance from the anterior surface to tumor cells in pancreatoduodenectomy with neoadjuvant chemoradiotherapy for pancreatic ductal adenocarcinoma

PURPOSE

Several reports have shown the importance of margins in pancreatoduodenectomy (PD) specimens; however, whether anterior surfaces are included as margins varies among reports. In this study, we aimed to examine the impact of the anterior surface on disease-free survival (DFS) and overall survival (OS).

METHOD

In total, 98 patients who underwent PD after chemoradiotherapy for pancreatic ductal adenocarcinoma at Mie University Hospital between January 1, 2012, and December 31, 2019, were included. We investigated the prognostic impact of the distance from the anterior surface to tumor cells on DFS and OS using a log-rank test. Multivariate analysis was performed using Cox proportional hazards analysis.

RESULTS

A significant difference in DFS and OS was observed up to a distance of 5 mm from the anterior surface of tumor cells. The multivariate analysis revealed that the distance from the anterior surface to tumor cells (≤5 mm) was an independent poor prognostic factor for DFS and OS.

CONCLUSION

In patients with PD treated with neoadjuvant therapy, the distance from the anterior surface to tumor cells is an important assessment and should be included in the pathology report.

Prognostic significance of margin clearance in pancreaticoduodenectomy specimens with pancreatic ductal adenocarcinoma in a Danish population-based nationwide study

BACKGROUND

In this nationwide population-based cohort study, we investigated the overall minimum margin width that is independently associated with improved survival following pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC) and evaluated whether certain margins or surfaces hold independent prognostic significance.

METHODS

Data from 367 patients who underwent PD for PDAC in the period 2015-2019 were retrieved from the Danish Pancreatic Cancer Database. Missing data were obtained by review of pathology reports and re-microscopy of resection specimens. Surgical specimens were evaluated using a standardised pathological protocol involving multicolour inking, axial slicing and exact reporting of circumferential margin clearances in 0.5 mm increments.

RESULTS

When categorised according to margin widths of <0.5, <1.0, <1.5, <2.0, <2.5 and <3.0 mm, R1 resections were detected in 34%, 57%, 75%, 78%, 86% and 87% of cases, respectively. In multivariable analyses, an overall margin clearance of ≥1.5 mm was associated with improved survival compared with a clearance of <1.5 mm (HR 0.70 95% CI 0.51-0.97 (p = 0.031)). When evaluating the margins separately, no margin had independent prognostic significance.

CONCLUSION

Margin clearance of at least 1.5 mm was independently associated with improved survival following PD for PDAC.

The effectiveness of adjuvant chemotherapy for Stage I pancreatic cancer based on the UICC 8th edition

BACKGROUND

Adjuvant chemotherapy is recommended for patients with pancreatic cancer after curative resection. However, there is limited evidence regarding the efficacy and prognostic factors for adjuvant chemotherapy in patients with stage I pancreatic cancer. This study aimed to identify patients in whom chemotherapy was effective and to detect prognostic factors for stage I pancreatic cancer based on guidelines of the 8^th edition of the Union for International Cancer Control (UICC).

METHODS

Between 2009 and 2017, 108 patients diagnosed with stage I pancreatic cancer were enrolled in this study. They were distributed into invasion (n = 68) and non-invasion (n = 40) groups. The relationship between clinicopathological variables, including various prognostic factors, disease-free survival (DFS), and overall survival (OS), were investigated by univariate and multivariate analyses.

RESULTS

Five-year survival in all patients with stage I pancreatic cancer was 38.9%. Adjuvant chemotherapy failed to improve DFS or OS in patients with stage I cancer (DFS, p = 0.26; OS, p = 0.30). In subgroup analysis, adjuvant chemotherapy significantly improved DFS (multivariate-adjusted hazard ratio (HR), 0.40; 95% confidence interval [CI], 0.21-0.78; p = 0.007) and OS (multivariate-adjusted HR, 0.32; 95% CI, 0.15-0.68; p = 0.003) in the invasion group than in non-invasion group. In contrast, in the non-invasion group, adjuvant chemotherapy failed to improve DFS and OS in univariate analysis (DFS, p = 0.992; OS, p = 0.808).

CONCLUSION

For stage I pancreatic cancer, based on guidelines of the UICC 8^th edition, adjuvant chemotherapy may benefit patients with extrapancreatic invasion.

Prognostic Impact of Resection Margin Status on Distal Pancreatectomy for Ductal Adenocarcinoma

Pancreatic cancer is associated with a poor prognosis. While surgical resection is the only treatment option with curative intent, most patients die of locoregional and/or distant recurrence. The prognostic impact of the resection margin status has received much attention. However, the evidence is almost exclusively related to pancreatoduodenectomies, while corresponding data for distal pancreatectomy specimens are limited. The key data, such as the rate of microscopic margin involvement (“R1”), the site of margin involvement, and the impact of R1 on patient outcome, are divergent between studies and do not currently allow any general conclusions. The main reasons for the variability in the published data are the small size of the study cohorts and their heterogeneity, as well as the marked divergence in pathology examination practices. The latter is a consequence of the lack of concrete guidance, both for grossing and microscopic examination. The increasing administration of neoadjuvant chemo(radio)therapy introduces a further factor of uncertainty as the conventional definition of a tumour-free margin (“R0”) based on 1 mm clearance is inadequate for these specimens. This review discusses the published data regarding the prognostic impact of margin status in distal pancreatectomy specimens along with the challenges and uncertainties that are related to the assessment of the margins.