Evolution and impact of lymph node dissection during pancreaticoduodenectomy for pancreatic cancer

Reassessment of the Optimal Number of Examined Lymph Nodes in Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma

OBJECTIVE

The aim of this study was to reappraise the optimal number of examined lymph nodes (ELNs) in pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC).

SUMMARY BACKGROUND DATA

The well-established threshold of 15 ELNs in PD for PDAC is optimized for detecting 1 positive node (PLN) per the previous 7th edition of the American Joint Committee on Cancer (AJCC) staging manual. In the framework of the 8th edition, where at least 4 PLN are needed for an N2 diagnosis, this threshold may be inadequate for accurate staging.

METHODS

Patients who underwent upfront PD at 2 academic institutions between 2000 and 2016 were analyzed. The optimal ELN threshold was defined as the cut-point associated with a 95% probability of identifying at least 4 PLNs in N2 patients. The results were validated addressing the N-status distribution and stage migration.

RESULTS

Overall, 1218 patients were included. The median number of ELN was 26 (IQR 17-37). ELN was independently associated with N2-status (OR 1.27, P < 0.001). The estimated optimal threshold of ELN was 28. This cut-point enabled improved detection of N2 patients and stage III disease (58% vs 37%, P = 0.001). The median survival was 28.6 months. There was an improved survival in N0/N1 patients when ELN exceeded 28, suggesting a stage migration effect (47 vs 29 months, adjusted HR 0.649, P < 0.001). In N2 patients, this threshold was not associated with survival on multivariable analysis.

CONCLUSION

Examining at least 28 LN in PD for PDAC ensures optimal staging through improved detection of N2/stage III disease. This may have relevant implications for benchmarking processes and quality implementation.

Comparison of laparoscopic versus open radical antegrade modular pancreatosplenectomy for pancreatic cancer: A systematic review and meta-analysis

BACKGROUND

Laparoscopic radical antegrade modular pancreatosplenectomy (l-RAMPS) provides a new surgical approach for patients with pancreatic cancers of the body and tail. However, whether it can achieve comparable outcomes to the open RAMPS (o-RAMPS) remains an issue.

METHODS

To evaluate the safety and effectiveness of l-RAMPS, the studies in the databases of Medline, Embase, and the Cochrane Library published before September 13, 2021 were searched and a meta-analysis was performed using the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. The perioperative and oncological outcomes were analyzed.

RESULTS

Five retrospective cohorts involving 189 patients were included for final pooled analysis. There were no significant differences in the patients' operation time, intra-abdominal bleeding rate, intra-abdominal infection rate, mild morbidity (Clavien-Dindo classification = 1), moderate to severe morbidity (Clavien-Dindo classification ≥2), overall morbidity, wound infection rate, pancreatic fistula rate, delayed gastric emptying rate, reoperation rate, length of hospital stay, postoperative mortality, R0 resection rate, and 2-year overall survival between the 2 approaches. Besides, l-RAMPS was associated with less blood loss (mean difference (MD) = -232.69, 95% confidence interval (CI) = -316.93 to -148.46, P < 0.00001) and shorter days until oral feeding (MD = -0.79, 95% CI = -1.35 to -0.22, P = 0.006). However, the pooled analysis also indicated a significantly fewer lymph nodes dissected (MD = -3.01, 95% CI = -5.59 to -0.43, P = 0.02) in l-RAMPS approach.

CONCLUSIONS

Although l-RAMPS provides similar outcomes associated with benefits of minimal invasiveness compared to o-RAMPS, it harvested significantly fewer lymph nodes which might have potentially negative influence on the patients' long-term survival. L-RAMPS is still in the infancy stage and further investigation is needed to verify its feasibility.

A Novel Criterion for Lymph Nodes Dissection in Distal Pancreatectomy for Ductal Adenocarcinoma: A Population Study of the US SEER Database

OBJECTIVE

The aim of this study was to clarify the minimum number of examined lymph nodes (MNELNs) required to ensure the quality of lymph node detection and its impact on long-term survival in distal pancreatectomy for pancreatic ductal adenocarcinoma.

METHODS

Clinicopathological characteristics and survival data of patients with resectable pancreatic cancer who underwent distal pancreatectomy between 2004 and 2017 were collected from the Surveillance, Epidemiology, and End Results database. The associations between the number of examined lymph nodes (ELNs) and number of positive lymph nodes (PLNs), stage migration, and overall survival were investigated through adjusted multivariate models with locally weighted scatterplot smoothing smoothing fitting curves and estimation of the structural breakpoints. Kaplan-Meier survival analysis and X-tile software were used to identify the ideal cut-off value for ELNs.

RESULTS

In total, 2610 consecutive patients who underwent distal pancreatectomy between 2004 and 2017 were included in this study. The optimal ELN count according to the associations between the number of ELNs and number of PLNs, odds ratio for stage migration, or hazard ratio for overall survival were 19, 17, and 19, respectively. Furthermore, the optimal division of ELN count for maximum overall survival was divided into three populations (ELN ≤ 8, ELN 9-18, ELN ≥ 19) based on X-tile software.

CONCLUSION

A minimal count of 19 lymph nodes was demanded to guarantee the quality of lymph node examination in patients with distal pancreatectomy. Long-term survival could be delimited by MNELNs. A sufficient number of ELNs could improve the accuracy of cancer staging and reflect a better overall survival.

Original study: The rescue staging for pancreatic ductal adenocarcinoma with inadequate examined lymph nodes

BACKGROUND

In previous studies, it's recommended that the lymph node involvement should be evaluated with enough examined lymph nodes (eLNs) in the 8th American Joint Committee on Cancer (AJCC) staging system for pancreatic cancer. This study aims to put forward a rescue staging system for pancreatic ductal adenocarcinoma (PDAC) patients with inadequate eLNs after pancreatoduodenectomy (PD).

METHOD

11,224 PDAC patients undergoing PD in The Surveillance, Epidemiology, and End Results (SEER) database were included. Another Ruijin Pancreatic Disease Center (RJPDC) database consisted of 821 patients was utilized for external validation.

RESULTS

The proportions of patients with eLNs≥15 were 44.7% and 32.8% in SEER and RJPDC database separately. The rescue staging system was put forward relying on LNR (HR = 1.83, 95% CI 1.74-1.92, P < 0.001) for N staging of eLNs<15 population and pLNs for the rest. The TNM modalities were also rearranged in the rescue system for better survival coordination. The C-index of rescue staging system was 0.638 while that of AJCC 8th staging system was 0.613 in SEER database. Similar phenomena were observed in RJPDC database. Kaplan-Meier analyses revealed reliable internal coherences (SEER: Ib: P = 0.26; IIa: P = 0.063; IIb: P = 0.53; IIIa: P = 0.11.

RJPDC

Ib: P = 0.32; IIa: P = 0.66; IIb: P = 0.76; IIIa: P = 0.66) and significant staging efficiency (SEER: P < 0.001; RJPDC: P = 0.002).

CONCLUSION

A rescue staging system was put forward regardless of the eLNs number. And the novel system manifested better predictive capacity than 8th AJCC staging system.

Significance of Lymph Node Resection After Neoadjuvant Therapy in Pancreatic, Gastric, and Rectal Cancers

OBJECTIVE

Gastrointestinal cancers are increasingly being treated with NAT before surgical resection. Currently, quality metrics are linked to the number of LNs resected to determine subsequent treatment and prognosis. We hypothesize that NAT decreases LN metastasis, downstages patients, and decreases overall lymph node yields (LNY) compared to initial surgical resection. With increasing use of NAT, this brings into question the validity of quality metrics.

METHODS

Gastric (stage II/III), pancreatic (stage I/II/III), and rectal cancers (stage II/III) (2010-2015) treated with surgery with/without NAT were identified in National Cancer Database. We evaluated total LNY and LN metastasis with/without NAT and clinical and pathological stage to evaluate rates of downstaging.

RESULTS

A total of 7934 gastric, 15,908 pancreatic, and 21,354 rectal cancer patients were included of which 61.1%, 21.2%, and 85.7% received NAT, respectively. NAT patients were more likely to be downstaged (39.9% vs 11.1% gastric P< 0.001, 30.6% vs 3.2% pancreatic P< 0.001, 52.0% vs 16.3% rectal P< 0.001), have lower LNYs (18.8 vs 19.1 gastric P = 0.239, 18.4 vs 17.5 pancreatic P< 0.001, 15.7 vs 20.0 rectal P< 0.001) and have N0 pathologic disease (43.6% vs 26.7% gastric P< 0.001, 51.1% vs 30.9% pancreatic P< 0.001, 65.9% vs 49.4% rectal P< 0.001) when compared to initial surgical resection.

CONCLUSION

NAT for gastrointestinal cancers results in overall lower LN yields, lower LN metastases, and significant downstaging of tumors. As all patients undergoing NAT receive multimodality therapy, LN yield recommendations may not be true quality metric changing.

Score for predicting overall survival in pancreatic adenocarcinoma patients with positive lymph nodes after surgery: a novel nomogram-based risk assessment

Background

Pancreatic adenocarcinoma (PaC) patients with positive lymph nodes (PLNs) have a dismal prognosis and lack a specific prognostic stage. This study aimed to construct a nomogram for the prediction of overall survival (OS) in these patients.

Methods

A total of 1,340 patients screened from the Surveillance, Epidemiology, and End Results database were included and randomly divided at a ratio of 7:3 into a training set (n=940) and an internal validation set (n=400). Cox regression analyses were conducted to select independent predictors in the training set, and a nomogram was constructed. The model was verified in the internal validation set and in an external validation set, which comprised 64 patients from a Chinese institute.

Results

Six independent prognostic factors (age at diagnosis, tumor grade, lymph node ratio, T stage, radiotherapy, and chemotherapy) were identified in PaC patients with PLNs and were entered into the nomogram. The final model had a higher C-index for predicting OS than the American Joint Committee on Cancer-8th edition staging system (training set: 0.658 vs. 0.546; internal validation set: 0.661 vs. 0.546; external validation set: 0.691 vs. 0.581). The 1-, 2-, and 3-year area under the receiver operating characteristic curve values indicated better discrimination power for the established nomogram with respect to the prediction of OS in the training, internal validation, and external validation sets than for the American Joint Committee on Cancer-8th edition staging system. Furthermore, the nomogram performed well in both calibration and decision curve analyses (DCA) of clinical applicability. OS in PaC patients with PLNs was significantly distinguished among the three risk groups stratified according to the nomogram score (P<0.001).

Conclusions

The well-calibrated nomogram was determined to be extremely efficient in predicting survival, and defining a high-risk population based on the nomogram score among PaC patients with PLNs after surgery.

Pancreatic Carcinosarcoma Clinical Outcome Analysis of the National Cancer Institute Database

BACKGROUND

Pancreatic carcinosarcomas (PCS) are rare aggressive biphasic malignancies with a poor prognosis. We aimed to improve the understanding of PCS by analyzing variables that influence the mortality of PCS patients.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for cases of PCS from 1973 to 2016. Cases were analyzed for patient demographics, tumor characteristics, and surgical intervention. Kaplan-Meier and Cox regression analyses were applied to investigate the overall survival (OS) and prognostic factors.

RESULTS

Thirty-nine cases of PCS were identified along with the disease demographics and characteristics. The majority of patients had a regionally invasive or metastatic disease. There was a significant decrease in OS with the increase of the tumor extension. Conversely, surgery showed to improve OS in the crude analysis, including patients that underwent lymphadenectomy. In addition, the unadjusted Cox regression results showed decreased hazard ratios with a local disease versus distant metastasis and with cancer-directed surgery versus no surgery. Nevertheless, the adjusted Cox regression results revealed that metastatic disease was the only significant predictor of survival.

CONCLUSIONS

This population-based study provides some insight to a very rare disease by analyzing 39 cases of PCS. Our finding suggests considering PCS as a nonsurgical disease and reserving surgery solely for patients with a localized disease in combination or after neoadjuvant therapy. Consequently, there is a need to further investigate novel therapies for this aggressive malignancy.

Periarterial divestment in pancreatic cancer surgery

BACKGROUND

Modern pancreatic cancer surgery changed with the introduction of effective neoadjuvant therapies. Complete tumor resection is the mainstay for long-term, disease-free, and overall survival and has been a prerequisite for decreasing local recurrence. The medial resection margin in the area of the superior mesenteric vessels limits the radicalness of the resection, especially in borderline and locally advanced cases. Therefore, the periarterial soft tissue around the peripancreatic visceral arteries must be completely cleared. This procedure, namely periarterial divestment, is technically demanding but often represents an alternative to arterial resection.

OBJECTIVE

Here we describe the technique and our initial experience with periarterial divestment along the peripancreatic visceral arteries during pancreatic surgery. This technique, in combination with previously published resection strategies, such as artery first maneuver and mesenterico-portal venous bypass first, enables tumor resection in locally advanced pancreatic cancer.

CONCLUSION

Periarterial divestment can prevent the need for arterial resection in borderline and locally advanced pancreatic cancer, especially after neoadjuvant therapy. The feasibility, improved safety, and oncologic equivalence of arterial divestment versus arterial resection for pancreatic cancer surgery must be evaluated by clinical trials.

Mesopancreas level 3 dissection in robotic pancreaticoduodenectomy

BACKGROUND

There are no reports of performing mesopancreas dissections in robotic pancreaticoduodenectomy. This study evaluated the feasibility and justification for mesopancreas level 3 dissection in robotic pancreaticoduodenectomy.

METHODS

Surgical outcomes after robotic pancreaticoduodenectomy and open pancreaticoduodenectomy were evaluated and compared.

RESULTS

There were 289 robotic pancreaticoduodenectomy and 162 open pancreaticoduodenectomy patients included in the study. Postoperative diarrhea occurred in 34.5% of mesopancreas level 3 dissection cases and was higher than in levels 2 and 1 dissection cases, P < .001. Blood loss in the robotic pancreaticoduodenectomy group was higher for mesopancreas level 3 dissection, with a median loss of 263 mL (P = .015). The rate of R0 resection with margin >1 mm was higher for mesopancreas level 3 dissection (93.8%) than for level 2 dissection (72.2%) (P < .001). The lymph node yield was higher for mesopancreas level 3 dissection in robotic pancreaticoduodenectomy; the median lymph node yield was 21 for level 3, 18 for level 2, and 14 for level 1 (P < .001). Compared with mesopancreas levels 1 and 2 dissections in the robotic pancreaticoduodenectomy groups, level 3 dissection did not show increased surgical mortality or postoperative complications, including postoperative pancreatic fistula, delayed gastric emptying, postpancreatectomy hemorrhage, chyle leakage, bile leakage, or wound infection. Compared with open pancreaticoduodenectomy, mesopancreas level 3 dissection in robotic pancreaticoduodenectomy had less blood loss, no delayed gastric emptying, and lower chyle leakage.

CONCLUSION

Mesopancreas level 3 dissection in robotic pancreaticoduodenectomy is feasible without compromising surgical safety. Therefore, robotic pancreaticoduodenectomy can be recommended as a safe alternative to open pancreaticoduodenectomy for mesopancreas level 3 dissection.

Development of a MUC16-Targeted Near-Infrared Fluorescent Antibody Conjugate for Intraoperative Imaging of Pancreatic Cancer

Surgical resection is currently the only potentially curative option for patients with pancreatic cancer. However, the 5-year survival rate after resection is only 25%, due in part to high rates of R1 resections, in which cells are left behind at the surgical margin, resulting in disease recurrence. Fluorescence-guided surgery (FGS) has emerged as a method to reduce incomplete resections and improve intraoperative assessment of cancer. Mucin-16 (MUC16), a protein biomarker highly overexpressed in pancreatic cancer, is a potential target for FGS. In this study, we developed a fluorescent MUC16-targeted antibody probe, AR9.6-IRDye800, for image-guided resection of pancreatic cancer. We demonstrated the efficacy of this probe to bind human pancreatic cancer cell lines in vitro and in vivo In an orthotopic xenograft model, AR9.6-IRDye800 exhibited superior fluorescence enhancement of tumors and lower signal in critical background organs in comparison to a nonspecific IgG control. The results of this study suggest that AR9.6-IRDye800 has potential for success as a probe for FGS in pancreatic cancer patients, and MUC16 is a feasible target for intraoperative imaging.

The Value of Total Lymph Nodes Examined and Number of Positive Lymph Nodes in Determining the Role of Adjuvant Radiation in Pancreatic Cancer Patients

OBJECTIVES

The aim of this study was to determine the survival benefits by adjuvant radiation therapy (RT) in pancreatic cancer patients with different total lymph nodes examined (TNE), number of positive lymph nodes (NPN), and lymph nodes ratio (LNR).

METHODS

National Cancer Database was queried for nonmetastatic pancreatic cancer patients from 2004 to 2015. Cox models were utilized. Interaction terms were applied to evaluate the effect of RT in different NPN, LNR, and margin strata. Multivariate analysis was performed.

RESULTS

Of 19,759 patients identified, 10,910 patients qualified. Compared with TNE of 1 to 9, TNE of 10 to 14, 15 to 19, 20 to 24, and 25 or greater had progressive overall survival (OS) benefits. Adjuvant RT had similar OS benefits among them. In negative margin patients, adjuvant RT improved OS when NPN was 2 to 3 (hazards ratio [HR], 0.84; P = 0.01) or LNR was 0.15 to 0.25 (HR, 0.79; P = 0.002). In positive margin patients, adjuvant RT nonsignificantly improved OS when NPN was 1 to 3 (HR, 0.89; P = 0.36) or when NPN was 4 or greater (HR, 0.79; P = 0.07).

CONCLUSIONS

Higher TNE correlates with better survival. Adjuvant RT may not compensate for inadequate lymph node dissection. Adjuvant RT improves survival in negative-margin patients with 2 to 3 positive lymph nodes or LNR of 0.15 to 0.25.

Prognostic impact of lymph node status in patients after total pancreatectomy for pancreatic ductal adenocarcinoma: A strobe-compliant study

The optimal number of examined lymph nodes (ELN) for staging and impact of nodal status on survival following total pancreatectomy (TP) for pancreatic ductal adenocarcinoma (PDAC) is unclear. The aim of this study was to evaluate the prognostic impact of different lymph node status after TP for PDAC.The Surveillance, Epidemiology, and End Results (SEER) database was used to identify patients who underwent TP for PDAC from 2004 to 2015. We calculated overall survival (OS) of these patients using Kaplan-Meier analysis and Cox proportional hazards model.Overall, 1291 patients were included in the study, with 869 node-positive patients (49.5%). A cut-off points analysis revealed that 19, 19, and 13 lymph nodes best discriminated OS for all patients, node-negative patients, and node-positive patients, respectively. Higher number of ELN than the corresponding cut-off points was an independent predictor for better prognosis [all patients: hazard ratios (HR) 0.786, P = .002; node-negative patients: HR 0.714, P = .043; node-positive patients: HR 0.678, P < .001]. For node-positive patients, 1 to 3 positive lymph nodes (PLN) correlated independently with better survival compared with those with 4 or more PLN (HR 1.433, P = .002). Moreover, when analyzed in node-positive patients with less than 13 ELN, neither the number of PLN nor lymph node ratio (LNR) was associated with survival. However, when limited node-positive patients with at least 13 ELN, univariate analyses showed that both the number of PLN and LNR were associated with survival, whereas multivariate analyses demonstrated that only number of PLN was consistently associated with survival (HR 1.556, P = .004).Evaluation at least 19 lymph nodes should be considered as quality metric of surgery in patients who underwent TP for PDAC. For node-negative patients, a minimal number of 19 lymph nodes is adequate to avoid stage migration. For node-positive patients, PLN is superior to LNR in predicting survival after TP, predominantly for those with high number of ELN.

Does Neoadjuvant Chemotherapy Change the Role of Regional Lymphadenectomy in Pancreatic Cancer Survival?

OBJECTIVES

The objective of this study was to evaluate the role of lymph node (LN) dissection and staging in outcomes of patients with pancreatic adenocarcinoma (PDAC) who underwent neoadjuvant chemotherapy (NAC).

METHODS

National Cancer Database was queried for patients with stages I to III PDAC diagnosed between 2004 and 2014. Overall survival (OS) was derived from Kaplan-Meier methods, and Cox-regression model was used to evaluate associations between the number of LN examined, number of positive nodes, and LN ratio with OS.

RESULTS

A total 35,599 patients were included, 3395 (9%) underwent NAC, 19,865 (56%) received adjuvant chemotherapy (AC), and 12,299 (35%) underwent surgery alone. Cox-regression showed superior OS in NAC compared with AC and surgery alone (26 vs 23 vs 14 months, P < 0.001). Minimum number of LN examined affecting OS was 8 LNs in NAC (23.8 vs 26.6 months, P = 0.029), and 12 LNs in AC group (22 vs 23.1 months, P = 0.028). Lymph node ratio cutoff of greater than 0.2 was associated with decreased OS (19.4 vs 24.4 months, P < 0.001).

CONCLUSIONS

Neoadjuvant chemotherapy is associated with improved survival in PDAC. Lymph node yield remains a significant prognostic factor after NAC, whereas the minimum number of harvested LNs associated with sufficient staging and survival is decreased.

A Single-Institution Validation Study of Lymph Node Staging By the AJCC 8th Edition for Patients with Pancreatic Head Cancer: A Proposal to Subdivide the N2 Category

BACKGROUND

According to the revised staging of the American Joint Committee on Cancer, 8th edition (AJCC8), the N category in pancreatic ductal adenocarcinoma is classified as N0 (0), N1 (1-3), and N2 (≥ 4) based on the number of metastatic lymph nodes (LNs). This study aimed to validate this classification and analyze cutoff values of metastatic LN numbers.

METHODS

Patients with pancreatic head ductal adenocarcinoma who underwent pancreaticoduodenectomy at our institution between 2005 and 2016 without preoperative therapy were retrospectively analyzed. The patients were staged by AJCC8, and prognostic analyses were performed. The best cutoff value for the metastatic LN number was determined by the minimum P value approach.

RESULTS

In 228 of 309 patients, LN metastases were found (median number of examined LNs, 41). The median survival time (MST) was 56 months in the N0 group, 34 months in the N1 group, and 20 months in the N2 group (N0 vs N1: P = 0.023; N1 vs N2: P < 0.001). The best cutoff number of metastatic LNs was 4 for patients with LN metastases and 7 for patients with N2 disease. The MST for patients with four to six positive nodes (N2a) was significantly longer than for those with seven or more positive nodes (N2b) (24.0 vs 19.1 months: P = 0.012). For N2b patients, conventional adjuvant chemotherapy did not show survival benefits (P = 0.133), and overall survival did not differ significantly from that for patients with para-aortic LN metastasis (P = 0.562).

CONCLUSION

The N staging of AJCC8 was valid. Clinicians should regard N2b as similar to distant LN metastasis, and more intensive adjuvant therapy may be indicated for this group.

Prognostic Value of Metastatic Lymph Node Ratio in Pancreatic Cancer

Lymph node involvement in pancreatic adenocancer is one of the strongest predictors of prognosis. However, the extent of lymph node dissection is still a matter of debate and number of dissected nodes varies widely among patients. In order to homogenize this diverse group of patients and more accurately predict their prognosis, we aimed to analyze the effect of metastatic lymph node ratio as an independent prognostic factor. We retrospectively analyzed medical recordings of 326 patients with pancreatic cancer who were treated in a tertiary medical oncology center over a 10-year period. Both in univariate and multivariate analyses, metastatic lymph node ratio proved to be a strong predictor of prognosis which was unaffected from heterogeneity of our patient population and can be used to facilitate predict prognosis of patients who underwent lymph node dissection to various extents and with future studies it can emerge as a successful tool for creating prognostic subgroups of the disease.

Pancreatic Cancer Lymph Node Resection Revisited: A Novel Calculation of Number of Lymph Nodes Required

BACKGROUND

Pancreatic cancer is the third leading cause of cancer related deaths in the US. Although lymph node (LN) metastasis is a prognostic indicator, the extent of LN resection is still debated. Our goal was to use the distribution of the ratio of positive to negative LNs to derive a more adequate number of necessary examined LNs based on the target LN threshold (TLNT).

STUDY DESIGN

Using the National Cancer Database, we performed a retrospective study of surgically resected pancreatic adenocarcinoma (2010 to 2015). We evaluated the number of positive LNs and total LNs examined and the log of the ratio of positive LNs to negative LNs (LODDS). The distribution of LODDS was examined to determine a target LNs examined threshold sufficient to detect N1 disease. Using the LODDS distribution of N1 cases, target LNs examined threshold were calculated to encompass 90 of the N1 group distribution.

RESULTS

Of the total 24,038 resected patients included in this study, 26% underwent operation only, 18% received neoadjuvant therapy, and 56% underwent adjuvant therapy. In all, 8,144 (34%) patients had N0 disease and 15,894 (66%) had N1 disease. To capture 90% to 95% of the N1 group, the minimum number of LNs examined would be 18 (LODDS -2.74) to 24 (LODDS -3.04), respectively.

CONCLUSIONS

Although previous studies have suggested 11 to 17 LNs required for adequate LN sampling in pancreatic cancer, our findings suggest that to capture 90% of cases with N1 disease, 18 LNs is more appropriate.

Accuracy of Nodal Positivity in Inadequate Lymphadenectomy in Pancreaticoduodenectomy for Pancreatic Ductal Adenocarcinoma: A Population Study Using the US SEER Database

Objectives: The optimal number of the examined lymph nodes (ELNs) in pancreaticoduodenectomy for pancreatic ductal adenocarcinoma has been widely studied. However, the accuracy of nodal positivity for the patients with inadequate lymphadenectomy is still unclear. The purpose of our study was to determine the accuracy of the number of positive nodes reported for patients with 1-3 positive nodes and the probability that 4 or more nodes could be positive along with tumor size and number of nodes examined. Methods: We obtained data on patients who underwent pancreaticoduodenectomy for resectable pancreatic ductal adenocarcinoma diagnosed during 2004-2013 from the US Surveillance, Epidemiology, and End Results registry. An mathematical model based on Hypergeometric Distribution and Bayes' Theorem was used to estimate the accuracy. Results: Among the 9,945 patients, 55.6% underwent inadequate lymphadenectomy. Of them, 1,842, 6,049, and 2,054 had T1, T2, and T3 stage disease, respectively. The accuracy of the number of observed positive nodes increased as the number of ELNs increased and the tumor size decreased. To rule out the possibility of N2 stage (4 and more positive nodes), there should be at least 13 ELNs for the patients with 1 observed positive lymph node and 14 for the patients with 2. Conclusion: Inadequate lymphadenectomy could result in underestimation of the N stage, and this would have adverse impact on recurrence, efficacy of postoperative treatment, and even overall survival. This model combined with the observed positive lymph nodes, the number of ELNs, and tumor size could provide a more accurate determination of nodal positivity of these patients.

Surgical management of periampullary adenocarcinoma: defining an optimal prognostic lymph node stratification schema

Background: Lymph node (LN) metastasis is a strong predictor of unfavorable prognosis for patients with periampullary adenocarcinoma after surgical resection. We sought to assess the prognostic performance of several LN staging systems, including American Joint Committee on Cancer (AJCC)/ International Union Against Cancer (7th edition) N stage, the total number of LN (TLN), the number of metastatic LN (MLN), the lymph node ratio (LNR) and the log odds of MLNs (LODDS), in patients with periampullary adenocarcinoma after surgical resection and identify the optional LN staging system to accurately stratify patients with different prognoses. Methods: We retrospectively analyzed 205 patients with periampullary adenocarcinoma after surgical resection. The predictive effects of several LN staging systems on overall survival (OS) and progression free survival (PFS) for all included patients and patients with more than 12 TLNs examined were evaluated and compared using the time-dependent receive operating characteristic (ROC) curve and decision curve analysis (DCA), respectively. Results: Eighty-nine patients (43.4%) had LN metastasis and their survival was not significantly decreased compared with patients without LN metastasis. LODDS and LNR were able to stratify patients into various subgroups with significant differences of both OS and PFS. When assessed using ROC curve and DCA, LODDS outperformed LNR and other LN staging systems in predicting OS and PFS. In addition, when analyzed in patients with more than 12 TLNs examined, LODDS had a higher value of area under ROC curve (AUC) and showed better performance of DCA. Conclusion: LODDS performs better than other LN staging systems in predicting OS and PFS for patients with periampullary adenocarcinoma after surgical resection. Adequate LN dissection is necessary for curative surgery, as well as to achieve a more accurate staging of the disease and a more precise prediction of survival for these patients.