Extended Lymphadenectomy for Gastric Cancer in the Neoadjuvant Era: Current Status, Clinical Implications and Contentious Issues

Despite its decreasing incidence, gastric cancer remains an important global healthcare problem due to its overall high prevalence and high mortality rate. Since the MAGIC and FNLCC/FFCD trials, the neoadjuvant chemotherapy has been recommended throughout Europe in gastric cancer. Potential benefits of preoperative treatments include a higher rate of R0 resection achieved by downstaging the primary tumor, a likely effect on micrometastases and isolated tumor cells in the lymph nodes, and, as a result, improved cancer-related survival. Nevertheless, distortion of anatomical planes of dissection, interstitial fibrosis, and sclerotic tissue changes may increase surgical difficulty. The collection of at least twenty-five lymph nodes after neoadjuvant therapy would seem to ensure removal of undetectable node metastasis and reduce the likelihood of locoregional recurrence. It is not what you take but what you leave behind that defines survival. Therefore, para-aortic lymph node dissection is safe and effective after neoadjuvant chemotherapy, in both therapeutic and prophylactic settings. In this review, the efficacy of adequate lymph node dissection, also in a neoadjuvant setting, has been investigated in the key studies conducted to date on the topic.

Extensive Dissection at No. 12 Station During D2 Lymphadenectomy Improves Survival for Advanced Lower-Third Gastric Cancer: A Retrospective Study From a Single Center in Southern China

BACKGROUND

D2 lymphadenectomy including No. 12a dissection has been accepted as a standard surgical management of advanced lower-third gastric cancer (GC). The necessity of extensive No. 12 nodes (No. 12a, 12b, and 12p) dissection remains controversial. This study aims to explore its impact on long-term survival for resectable GC.

METHODS

From 2009 to 2016, 353 advanced lower-third GC patients undergoing at least D2 lymphadenectomy during a radical surgery were included, with 179 patients receiving No. 12a, 12b, and 12p dissection as study group. A total of 174 patients with No. 12a dissection were employed as control group. Surgical and long-term outcomes including 90-day complications incidence, therapeutic value index (TVI), 3-year progression-free survival (PFS), and 5-year overall survival (OS) were compared between both groups.

RESULTS

No. 12 lymph node metastasis was observed in 20 (5.7%) patients, with 10 cases in each group (5.6% vs. 5.7%, p = 0.948). The metastatic rates at No. 12a, 12b, and 12p were 5.7%, 2.2%, and 1.7%, respectively. The incidence of 90-day complications was identical between both groups. Extensive No. 12 dissection was associated with increased TVI at No. 12 station (3.9 vs. 0.6), prolonged 3-year PFS rate (67.0% vs. 55.9%, p = 0.045) and 5-year OS rate (66.2% vs. 54.0%, p = 0.027). The further Cox-regression analysis showed that the 12abp dissection was an independent prognostic factor of improved survival (p = 0.026).

CONCLUSION

Adding No. 12b and 12p lymph nodes to D2 lymphadenectomy might be effective in surgical treatment of advanced lower-third GC and improve oncological outcomes compared with No. 12a-based D2 lymphadenectomy.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2021

There exist differences in the epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selections between gastric cancer patients from the Eastern and Western countries. The Chinese Society of Clinical Oncology (CSCO) has organized a panel of senior experts specializing in all sub-specialties of gastric cancer to compile a clinical guideline for the diagnosis and treatment of gastric cancer since 2016 and renews it annually. Taking into account regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted expert consensus judgment on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes in China. The 2021 CSCO Clinical Practice Guidelines for Gastric Cancer covers the diagnosis, treatment, follow-up, and screening of gastric cancer. Based on the 2020 version of the CSCO Chinese Gastric Cancer guidelines, this updated guideline integrates the results of major clinical studies from China and overseas for the past year, focused on the inclusion of research data from the Chinese population for more personalized and clinically relevant recommendations. For the comprehensive treatment of non-metastatic gastric cancer, attentions were paid to neoadjuvant treatment. The value of perioperative chemotherapy is gradually becoming clearer and its recommendation level has been updated. For the comprehensive treatment of metastatic gastric cancer, recommendations for immunotherapy were included, and immune checkpoint inhibitors from third-line to the first-line of treatment for different patient groups with detailed notes are provided.

Current status of extended 'D2 plus' lymphadenectomy in advanced gastric cancer

The extent of lymph node (LN) dissection has been a topic of interest in gastric cancer (GC) surgery. D2 lymphadenectomy is considered the standard surgical procedure for most resectable advanced GC cases. The value and indications of more extended lymphadenectomy than D2 remain unclear. Currently, the controversial stations beyond the D2 range are mainly focused on no. 14v, no. 16a2/b1 and no. 13 LN stations. The metastatic rate of no. 14v LN is relatively high in advanced distal GC, particularly in patients with suspicious no. 6 LN metastasis. D2 plus no. 14v LN dissection may be attributed to improved survival outcomes for patients with obvious no. 6 LN metastasis. Although GC with para-aortic lymph node (PALN) metastases is considered an M1 disease beyond surgical cure, patients with limited PALN metastases may benefit from the treatment strategy of adjuvant chemotherapy followed by D2 plus no. 16a2-b1 LN dissection. In addition, D2 plus no. 13 LN dissection may be an option in a potentially curative gastrectomy for GC with duodenal invasion. The present review discusses the current status and future perspectives of D2 plus lymphadenectomy.

Current status of lymph node dissection in gastric cancer

Gastrectomy with lymph node (LN) dissection has been regarded as the standard surgery for gastric cancer (GC), however, the rational extent of lymphadenectomy remains controversial. Though gastrectomy with extended lymphadenectomy beyond D2 is classified as a non-standard gastrectomy, its clinical significance has been evaluated in many studies. Although hard evidence is lacking, D2 plus superior mesenteric vein (No. 14v) LN dissection is recommended when harbor metastasis to No. 6 nodes is suspected in the lower stomach, and dissection of splenic hilar (No. 10) LN can be performed for advanced GC invading the greater curvature of the upper stomach, and D2 plus posterior surface of the pancreatic head (No. 13) LN dissection may be an option in a potentially curative gastrectomy for cancer invading the duodenum. Prophylactic D2+ para-aortic nodal dissection (PAND) was not routinely recommended for advanced GC patients, but therapeutic D2 plus PAND may offer a chance of cure in selected patients, preoperative chemotherapy was considered as the standard treatment for GC with para-aortic node metastasis. There has been no consensus on the extent of lymphadenectomy for the adenocarcinoma of the esophagogastric junction (AEG) so far. The length of esophageal invasion can be used as a reference point for mediastinal LN metastases, and the distance from the esophagogastric junction to the distal end of the tumor is essential for determining the optimal extent of resection. The quality of lymphadenectomy may influence prognosis in GC patients. Both hospital volume and surgeon volume were important factors for the quality of radical gastrectomy. Centralization of GC surgery may be needed to improve prognosis.

"D2 plus" lymphadenectomy is associated with improved survival in distal gastric cancer with clinical serosa invasion: a propensity score analysis

The aim of this study was to elucidate the potential impact of “D2 plus” lymphadenectomy on the long-term survival of distal gastric cancer (GC) patients with clinical serosa invasion. A total of 394 distal GC patients with clinical serosa invasion who underwent at least standard D2 lymphadenectomy were enrolled. Patients were categorized into two groups according to the extent of lymphadenectomy: D2 group and “D2 plus” group. Propensity score matching was used to adjust for the differences in baseline characteristics. In the multivariate analysis for the whole study series, extent of lymphadenectomy was an independent prognostic factor for GC patients (P = 0.011). With the strata analysis, the significant prognostic differences between the two groups were only observed in patients at the IIIa-b or N1-3a stages. After matching, patients in “D2 plus” group still demonstrated a significantly higher 5-year overall survival rate than those in D2 group (55.3% versus 43.9%, P = 0.042). The common therapeutic value index of No. 12b, No. 12p, No. 14v and No. 13 LNs was 4.6, which was close to that of No. 5 LN station. In conclusion, “D2 plus” lymphadenectomy may be associated with improved overall survival in distal GC with clinical serosa invasion.

Evaluation of D2-plus radical resection for gastric cancer with pyloric invasion

Background

The optimal lymphadenectomy for gastric cancer (GC) with pyloric invasion is controversial because the pattern of lymph node metastasis is different from that of distal GC. The rate of lymph node metastasis into the posterior area of the pancreatic head and hepatoduodenal ligament is high. This study evaluated the estimated benefit of radical gastrectomy with D2-plus lymphadenectomy in patients with pyloric invasion.

Methods

All patients with GC invading the pylorus who underwent curative surgical resection with D2-plus lymphadenectomy between February 2013 and September 2015 were enrolled in the study. The index of estimated benefit from lymph node dissection (IEBLD) was calculated by multiplying the incidence of metastasis to each lymph node station by the 3-year overall survival (OS) rate of patients with metastasis to that station.

Results

In total, 128 patients were eligible. The rate of lymph node metastasis and the 3-year OS rate (and IEBLD) of the patients with metastasis to lymph nodes were 14.3 and 44.4% (5.56) for No. 8p, 10.9 and 35.7% (3.89) for No. 12b, 9.5 and 33.3% (3.13) for No. 12p, 18.8 and 54.2% (10.19) for No. 13, and 21.8 and 53.6% (11.68) for No. 14v, respectively.

Conclusions

In radical gastrectomy for GC with pyloric invasion, some survival benefit was observed with dissection of the No. 13 and No. 14 lymph nodes, but there was no survival benefit with dissection of the No. 8p lymph nodes. The No. 12b and No. 12p lymph nodes may be better to dissect in cT3 GC patients with pyloric invasion.

Trial registration

http://ClinicalTrials.gov Identifier: NCT01836991. Date of registration: April 17, 2013.

In Patients with Localized and Resectable Gastric Cancer, What is the Optimal Extent of Lymph Node Dissection-D1 Versus D2 Versus D3?

BACKGROUND

Despite advances in the treatment of patients with gastric cancer, the debate over the optimal extent of lymphadenectomy continues.

METHOD

A review of the classification, rationale for, and boundaries of lymphadenectomy is presented. A review of the available literature comparing D1 versus D2 versus D3 lymphadenectomy was performed and included randomized controlled trials, and prospective and retrospective comparative and non-comparative studies.

RESULTS

Earlier studies demonstrated increased morbidity with D2 compared with D1 lymphadenectomy, with no significant survival benefit. More recent studies have demonstrated survival benefit of a pancreas and spleen-sparing D2 lymphadenectomy in patients with advanced, node-positive tumors. Para-aortic/D3 dissections contribute to increased morbidity, with no survival benefit.

CONCLUSIONS

In patients with resectable gastric adenocarcinoma, a D2 lymph node dissection preserving the pancreas and spleen should be considered standard for optimal staging and treatment, provided it is performed by surgeons with sufficient expertise. Extended lymph node dissections beyond D2 should not be routinely performed as it has been shown to have increased morbidity, with no improvement in outcomes. While systemic chemotherapy should be considered standard in patients undergoing D2 lymphadenectomy, the role of adjuvant radiation continues to evolve.

Comparison of D2 and D2 plus radical surgery for advanced distal gastric cancer: a randomized controlled study

BACKGROUND

The optimal extent of lymph node (LN) dissection for advanced distal gastric cancer remains controversial. The present study compared the safety and efficacy of extended LN dissection (D2 plus) with standard D2 radical surgery for advanced distal gastric cancer.

METHODS

Eligible patients were enrolled and randomly assigned into two groups: D2 group and D2 plus group. Patients in the D2 group received standard D2 LN dissection, while patients in the D2 plus group received an additional nos. 8p, 12b, 13, and 14v LNs dissection. The clinicopathological and surgical data of these two groups were compared, and the factors that may influence survival were analyzed.

RESULTS

Seventy patients were enrolled, out of which 64 patients were analyzed. There were no significant differences in the operative time, blood loss, and complications between the two groups. In the D2 plus group, the positive rate of the nos. 12b, 13, and 14v LN was 3.1%, 9.4%, and 12.5%, respectively. The positive rate of the no. 13 LN correlated with the duodenal involvement, while the positive rate of the no. 14v LN correlated with no. 6 LN metastasis. The survival analysis indicated that among patients with duodenum involvement, the 3-year disease-free survival rate of the D2 plus group was significantly better than that of the D2 group.

CONCLUSION

Duodenum involvement and positive no. 6 LN were high-risk factors of advanced distal gastric cancer. D2 plus radical surgery turned out to be safe and feasible, and may improve the prognosis of these patients. However, further clinical trials are still warranted.

TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov as NCT01836991 , registered on 22 April 2013.

Surgical Margin Status of Patients with Pancreatic Ductal Adenocarcinoma Undergoing Surgery with Radical Intent: Risk Factors for the Survival Impact of Positive Margins

BACKGROUND

For pancreatic ductal adenocarcinoma (PDAC), surgical margin status is an important pathological factor for evaluating surgical adequacy. In this study, we attempted to investigate predictive factors for the survival impact of positive surgical margins.

MATERIALS AND METHODS

From February 2004 to December 2013, 204 patients were diagnosed with PDAC and underwent surgery with radical intent; 189 patients fulfilled our selection criteria and were enrolled for analysis.

RESULTS

For the 189 enrolled patients with PDAC, we found male predominance (112/189, 59%) and a median age of 64 years; most patients were diagnosed with stage IIB disease (n=115, 61%). The positive surgical margin rate was 21% (n=40). Carbohydrate antigen 19-9 (CA19-9) level higher than 246 U/ml (odds ratio (OR)=2.318; 95% confidence interval (CI)=1.037-5.181 p=0.040) and lesion location in the uncinate process (OR=2.996; 95% CI=1.232-7.284 p=0.015) were the only two independent risk factors for positive surgical margins. Positive retroperitoneal soft-tissue margins were the most frequently observed (24/40, 60%). Overall, positive surgical margins had no survival impact in the 189 patients with PDAC who underwent surgery; however, positive surgical margins had an unfavorable survival impact on patients with stage IIA PDAC who underwent surgery.

CONCLUSION

Retroperitoneal soft-tissue was the most common site for positive surgical margins. Additionally, surgical margin positivity was more likely for tumors located in the uncinate process than for other tumors. Positive surgical margins had an unfavorable survival impact on patients with stage IIA PDAC who underwent surgery.

Clinical impact of molecular classifications in gastric cancer

Treatment options to gastric cancer (GC) have been changing in recent years from a standard to a tailored approach. Different individualized procedures can range from endoscopic resection, D2 with open or minimally invasive approach, to neo-adjuvant therapy followed by extended surgery. In more advanced stages, a combined approach with the inclusion of intraperitoneal chemo-hyperthermia (HIPEC) may represent a new advanced option. The inclusion of histological type according to Laurén classification in the flowchart of treatment could increase both accuracy and effectiveness of such tailored approach. New molecular classifications of GC have been introduced recently and translational clinical studies are ongoing. These classifications are expected to be included in multidisciplinary treatment of GC. In particular, in the group with microsatellite instability a less extended lymphadenectomy may be proposed. Also tailored neo-adjuvant treatment may be proposed according to molecular classifications. The group of patients with epithelial-to-mesenchymal transition shows very high propensity to peritoneal dissemination, as well as N-metastases, and may benefit from prophylactic HIPEC and extended lymphadenectomy when confirmed in prospective trials.

Satisfactory surgical outcome of T2 gastric cancer after modified D2 lymphadenectomy

Objective

Though D2 lymphadenectomy has been increasingly regarded as standard surgical procedure for advanced gastric cancer (GC), the modified D2 (D1 + 7, 8a and 9) lymphadenectomy may be more suitable than D2 dissection for T2 stage GC. The purpose of this study is to elucidate whether the surgical outcome of modified D2 lymphadenectomy was comparable to that of standard D2 dissection in T2 stage GC patients.

Methods

A retrospective cohort study with 77 cases and 77 controls matched for baseline characteristics was conducted. Patients were categorized into two groups according to the extent of lymphadenectomy: the modified D2 group (mD2) and the standard D2 group (D2). Surgical outcome and recurrence date were compared between the two groups.

Results

The 5-year overall survival (OS) rate was 71.4% for patients accepted mD2 lymphadenectomy and 70.1% for those accepted standard D2, respectively, and the difference was not statistically significant. Multivariate survival analysis revealed that curability, tumor size, TNM stage and postoperative complications were independently prognostic factors for T2 stage GC patients. Patients in the mD2 group tended to have less intraoperative blood loss (P=0.001) and shorter operation time (P<0.001) than those in the D2 group. While there were no significant differences in recurrence rate and types, especially lymph node recurrence, between the two groups.

Conclusions

The surgical outcome of mD2 lymphadenectomy was equal to that of standard D2, and the use of mD2 instead of standard D2 can be a better option for T2 stage GC.

Incidence and Prognostic Value of Metastases to "Posterior" and Para-aortic Lymph Nodes in Resectable Gastric Cancer

BACKGROUND

The purpose of this retrospective study was to evaluate the incidence and prognostic value of metastases to "posterior" (8p, 12b/p, 13) and para-aortic lymph nodes in a large cohort of Western patients submitted to D2 plus lymphadenectomy.

METHODS

Removal of "posterior" nodes was performed in 743 patients, and para-aortic lymphadenectomy in a subgroup of 390 patients. After lymph node mapping and retrieval on the fresh specimen, a median number of 41 total lymph nodes were analyzed. The median follow-up period was 37 months for the entire series and 68 months for survivors.

RESULTS

Of 743 included patients, 23 (3.1%) had metastases in station 8p, 12 (1.6%) in station 12b/p, and 19 (2.6%) in station 13. On the whole, 47 of 743 patients (6.3%) had positive "posterior" nodes. Para-aortic metastases were present in 42 of 390 patients (10.8%). Metastases to "posterior" stations were significantly related to depth of invasion, number of positive nodes, and surgical radicality. Distal tumors showed higher trend to metastasize to "posterior" nodes than upper third, whereas for para-aortic metastases it was the reverse. 5-year survival in patients with positivity to "posterior" nodes was 17%, with no significant difference according to 8p, 12b/p, and 13 stations; long-term outcome was overlapping to pN3b stage. 5-year survival in para-aortic positive cases was 11%, and a trend to better outcome was observed in proximal tumors.

CONCLUSIONS

Although metastases to "posterior" and para-aortic nodes are expression of an advanced nodal stage, not negligible survival rates are observed in subgroups of patients.

Risk factors and prognostic significance of retropancreatic lymph nodes in gastric adenocarcinoma

Background. The studies on risk factors and metastatic rate of retropancreatic (number 13) lymph nodes in gastric adenocarcinoma were few and the results were still controversial. The aim of this study was to elucidate risk factors and prognostic significance of number 13 lymph nodes in gastric adenocarcinoma. Method. From January 2000 to December 2011, 114 patients who underwent gastrectomy with number 13 lymph nodes dissection were enrolled and followed up to January 2014. Patients were grouped according to whether number 13 lymph nodes were positive or negative. Results. The metastatic rate of number 13 lymph nodes was 22.8%. In multivariate analysis, pT stage (P = 0.027), pN stage (P = 0.005), and number 11p (P = 0.015) lymph nodes were independent risk factors of positive number 13 lymph nodes. In all patients (P < 0.001) and subpopulation with TNM III stage (P = 0.007), positive number 13 lymph nodes had significantly worse prognosis than those of patients with negative number 13 LNs in Kaplan-Meier analysis. Conclusion. Number 13 lymph nodes had relatively high metastatic rate and led to poor prognosis. pT stage, pN stage, and number 11p lymph nodes were independent risk factors of positive number 13 lymph nodes.