Low Maruyama index surgery for gastric cancer: blinded reanalysis of the Dutch D1-D2 trial

Postoperative adjuvant chemotherapy in patients with gastric cancer based on the Nationwide Gastric Cancer Registry in Japan

The nationwide registry of the Japanese Gastric Cancer Association contains data related to the efficacy of adjuvant chemotherapy and prognostic factors across this patient population; elderly patients with advanced resectable gastric cancer are especially prevalent. Here, we analyzed data from 34,931 patients, who were treated between 2011 and 2013 at 421 hospitals in Japan. Although adjuvant chemotherapy was effective overall, 75 years or older elderly patients had a worse prognosis compared to younger patients. The most administered adjuvant chemotherapy was S-1 monotherapy. Adjuvant S-1 monotherapy was also effective for patients with pT1N2, pT1N3, and pT3N0 stage II tumors, as well as patients with other stage II and III malignancies. Independent prognostic factors for poor overall and relapse-free survival in patients at both stage II and stage III were age 75 or older, male, preoperative Eastern Cooperative Oncology Group performance status (ECOG-PS) 1 or more, preoperative renal dysfunction, undifferentiated adenocarcinoma, undergoing total gastrectomy, open laparotomy, no adjuvant chemotherapy, D1 lymphadenectomy, residual tumor R1 or R2, and Clavien-Dindo classification grade II or higher. Age 75 or older, renal dysfunction, ECOG-PS 1 and total gastrectomy were also significant risk factors for postoperative complications and lower compliance with adjuvant chemotherapy. Our analysis also revealed that adjuvant chemotherapy after resection of cancer of gastric remnant and postoperative chemotherapy against CY1 gastric cancer were also effective. We conclude that adjuvant chemotherapy is effective for all stage II and III patients including age 75 or older gastric cancer patients, in addition to distal gastrectomy, proximal gastrectomy, and pylorus-preserving surgery to avoid total gastrectomy may improve surgical outcomes and quality of life for elderly patients.

Lymph node metastasis prediction model for each lymph node station in gastric cancer patients

BACKGROUND

Lymph node metastasis (LNM) prediction for each LN station is required for tailored surgery for patient safety or improving quality of life in gastric cancer. This retrospective review was performed to develop a prediction program for calculating the probability of LNM according to LN stations in patients with gastric cancer.

METHOD

Among patients who underwent gastrectomy for primary gastric cancer between 2003 and 2017 at Seoul National University Hospital, 4660 patients up to 2013 were used as the development set, and 2564 patients after 2013 were used as the validation set. Not only the center of tumor but also all locations of stomach by tumor were included in the analysis. A multiple logistic regression analysis was used to develop an LNM prediction program for each LN station in development set. The program was validated using C-statistics and a calibration plot of the validation set.

RESULTS

Multivariate analysis identified tumor depth, gross type, and involved locations as covariates associated with LNM. However, the significant factors differed slightly according to the LN station. The prediction equations were developed for each LN station. In the validation set, the prediction equation exhibited good discriminant C-statistics of over 0.8 for all stations. The calibration plot of the prediction equation predicted the LNM rate, which corresponded closely to the actual rate.

CONCLUSIONS

A program was developed to predict LNM at LN stations. Predictive power was confirmed via internal validation. Predicting the LN metastatic rate for each LN station could help in planning more customized surgery.

Feasibility of Regional Lymphadenectomy for Stomach-Preserving Surgery in Early Gastric Cancer Omitting Sentinel Node Navigation: A Post Hoc Analysis of the SENORITA Trial

BACKGROUND

Sentinel node navigation (SNN) has been known as the effective treatment for stomach-preserving surgery in early gastric cancer; however, SNN presents several technical difficulties in real practice.

OBJECTIVE

This study aimed to evaluate the feasibility of regional lymphadenectomy omitting SNN, using the post hoc analysis of a randomized controlled trial.

METHODS

Using data from the SENORITA trial that compared laparoscopic standard gastrectomy with lymphadenectomy and laparoscopic SNN, 237 patients who underwent SNN were included in this study. Tumor location was divided into longitudinal and circumferential directions. According to the location of the tumor, the presence or absence of lymph node (LN) metastases between sentinel and non-sentinel basins were analyzed. Proposed regional LN stations were defined as the closest area to the primary tumor. Sensitivities, specificities, positive predictive values, and negative predictive values (NPV) of SNN and regional lymphadenectomy were compared.

RESULTS

Metastasis to non-sentinel basins with tumor-free in sentinel basins was observed in one patient (0.4%). The rate of LN metastasis to non-regional LN stations without regional LN metastasis was 2.5% (6/237). The sensitivity and NPV of SNN were found to be significantly higher than those of regional lymphadenectomy (96.8% vs. 80.6% [p = 0.016] and 99.5% vs. 97.2% [p = 0.021], respectively).

CONCLUSIONS

This study showed that regional lymphadenectomy for stomach-preserving surgery, omitting SNN, was insufficient; therefore, SNN is required in stomach-preserving surgery.

A combined approach for individualized lymphadenectomy in gastric cancer patients

Introduction: Gastric cancer ranks as the fifth most common cancer globally. The presence of lymph node metastasis is a significant prognostic factor influencing survival. Postoperative morbidity and nodal staging accuracy are heavily affected by the extent of lymph node dissection. Our study aimed to explore the potential integration of two contemporary methods, sentinel node navigation surgery (SNNS) and the Maruyama Computer Program (MCP), to improve the accuracy of nodal staging. Materials and methods: We conducted a prospective data collection involving patients with gastric adenocarcinoma from 2008 to 2018 at the Department of Surgery, University of Debrecen, Hungary. Data from 100 consecutive patients were collected. The primary and secondary endpoints included evaluating the rate of node-negative patients and the diagnostic accuracy of our combined approach. Results: Sentinel node mapping was successful in 97 out of 100 patients. We found that using the threshold value of the Maruyama Index (MI) ≥ 28, all metastatic stations of sentinel-node-negative patients could be identified. Our method achieved 100% sensitivity and negative predictive value, with a specificity of 60.42% (95% CI = 46.31%-72.98%). Discussion: The combined application of SNNS and MCP has proven to be an effective diagnostic technique in the synergistic approach for identifying metastasis-positive lymph node stations. Despite its limitations, this combination may assist clinicians in customizing lymphadenectomy for gastric cancer patients.

Indications and technical aspects of proximal gastrectomy

According to the World Health Organization, gastric cancer is the fifth most common type of tumor, and is the third most common cause of tumor-associated death. Although gastric cancer incidence rates have decreased in the past few decades, the prevalence of proximal gastric cancer has been steadily rising in developed countries. Techniques regarding the improvement of treatment options must thus be developed. This can be achieved through incorporating both a wider use of endoscopic surgery (endoscopic mucosal resection-EMR, endoscopic submucosal dissection-ESD) and a review of applied surgical interventions. Even though there is no single international consensus available, the Japanese Gastric Cancer Association (JGCA) recommends proximal gastrectomy with D1+ lymphadenectomy in early gastric tumors. Despite recommendations from Asian guidelines and the short term outcomes of the KLASS 05 trial, surgical treatments in Western countries still rely on total gastrectomy. This is mostly due to technical and oncological challenges regarding surgical interventions in a proximal gastrectomy. However, the residual stomach after a proximal gastrectomy has been shown to diminish the incidence of dumping syndrome and anemia, and even improve postoperative quality of life (QoL). Therefore, it is necessary to define the place of proximal gastrectomy in the treatment of gastric cancers.

Optimal extent of lymph node dissection in gastric cancer

Gastric cancer still remains a major cause of cancer-related deaths globally. Stage-adapted, individualized treatment is crucial to achieving optimal oncological outcomes. Postoperative morbidity and accurate nodal staging are heavily influenced by the extent of lymph node dissection. On one hand, insufficient lymphadenectomy may result in understaging and undertreatment of a patient, on the other hand, unnecessary lymph node dissection may result in a higher rate of postoperative complications. Approximately one-third of patients with gastric cancer undergoes an avoidable lymph node dissection. Many of the recent treatment updates in the management of gastric cancer have a major influence on both surgical and oncological approaches. Currently, a wide range of endoscopic, minimally invasive, and hybrid surgical techniques are available. The concept of sentinel node biopsy and utilization of the Maruyama Computer Program are significant components of stage-adapted gastric cancer surgery. Likewise, centralization and application of national guidelines, widespread use of neoadjuvant therapy, and the stage migration phenomenon are serious concerns to be discussed. Our goal is to review the available surgical strategies for gastric cancer, with a primary focus on lymphadenectomy.

Significance of nodal dissection and nodal positivity in gastric cancer

Lymphadenectomy is a central component of surgery for gastric cancer. However, controversies over the optimal extent of lymphadenectomy in gastric cancer surgery have persisted for several decades. In Eastern countries where the incidence of gastric cancer is high, surgeons have performed extensive lymphadenectomy (D2 lymphadenectomy) with low morbidity and mortality, while most Western surgeons have advocated for more limited lymphadenectomies according to the results of Dutch trial and MRC trial. Initially, these trials had failed to show survival benefit of D2 procedure and instead, found pancreaticosplenectomy performed as part of the D2 procedure associated with high incidence of morbidity and mortality. Subsequently, superiority of D2 lymphadenectomy on survival was demonstrated based on updated results. Moreover, spleen and pancreas preserving D2 lymphadenectomy are being performed safely in Western countries. Today, there is an international consensus on performing D2 lymphadenectomy as the standard procedure for advanced gastric cancer and is widely accepted as the standard procedure for gastric cancer surgery. The significance of the extent of lymphadenectomy is intimately associated with the prognostic importance of nodal metastases as the most powerful indicator of recurrence and survival for patients after curative gastrectomy. Maruyama computer program could be used to estimate the risk of lymph node metastasis in each nodal station. The Maruyama Index could be used to assess the adequacy of lymphadenectomy in gastric cancer. Positive lymph node ratio is calculated as the ratio of positive lymph nodes to all harvested lymph nodes, which might be a more precise predictor of prognosis than the absolute number of positive lymph nodes. While D2 lymphadenectomy enables the accurate staging of the disease, reduces the incidence of locoregional recurrences and thus contribute to an improved overall survival; performing lymphadenectomy beyond D2 is unlikely to improve survival. Therapeutic D2+ lymphadenectomy for advanced gastric cancer requires further evaluations, especially for patients receiving neo-adjuvant or conversion treatments.

Surgicopathological Quality Control and Protocol Adherence to Lymphadenectomy in the CRITICS Gastric Cancer Trial

OBJECTIVE

The purpose of this study was to evaluate surgicopathological quality and protocol adherence for lymphadenectomy in the CRITICS trial.

SUMMARY OF BACKGROUND DATA

Surgical quality assurance is a key element in multimodal studies for gastric cancer. In the multicenter CRITICS trial (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach), patients with resectable gastric cancer were randomized for preoperative chemotherapy, followed by gastrectomy with a D1+ lymphadenectomy (removal of stations 1 to 9 and 11), followed by either chemotherapy or chemoradiotherapy.

METHODS

Surgicopathological compliance was defined as removal of ≥15 lymph nodes. Surgical compliance was defined as removal of the indicated lymph node stations. Surgical contamination was defined as removal of lymph node stations that should be left in situ. The Maruyama Index (MI, lower is better), which has proven to be an indicator of surgical quality and is strongly associated with survival, was analyzed.

RESULTS

Between 2007 and 2015, 788 patients were randomized, of whom 636 patients underwent a gastrectomy with curative intent. Surgicopathological compliance occurred in 72.8% (n = 460) of the patients and improved from 55.0% (2007) to 90.0% (2015). Surgical compliance occurred in 41.1% (n = 256). Surgical contamination occurred in 59.6% (n = 371). Median MI was 1 (range 0 to 136).

CONCLUSION

Surgical quality in the CRITICS trial was excellent, with a MI of 1. Surgicopathological compliance improved over the years. This might be explained by the quality assurance program within the study and centralization of gastric cancer surgery in the Netherlands.

Blast from the past: Perioperative use of the Maruyama computer program for prediction of lymph node involvement in the surgical treatment of gastric cancer following neoadjuvant chemotherapy

BACKGROUND

Surgical quality assurance is a key element of gastric cancer treatment. The Maruyama Computer Program (MCP) allows to predict lymph node involvement in stations no. 1-16. The aim of the current study was to evaluate the accuracy of the MCP predictions in GC patients treated with neoadjuvant chemotherapy (nCTH) followed by gastrectomy with adequate lymphadenectomy.

METHODS

101 patients who underwent preoperative nCTH followed by D2 gastrectomy with curative intent were analysed. The response to nCTH was measured using the tumour regression grade system.

RESULTS

Test sensitivity, specificity, PPV, NPV and accuracy of the MCP were 92%, 33%, 41%, 89%, and 53%, respectively. In patients with response to nCTH, number of false positive (FP) results was significantly higher than in patients who did not respond to nCTH both in the N1 (56.3% vs 28.9%, p < 0.0001) and in the N2 (59% vs 41%, p < 0.0001) trier. The risk for FP results was 6 times higher in N1 (OR = 6.50, 95%CI: 3.91-10.82,; p < 0.0001) and N2 (OR = 5.84, 95%CI: 2.85-11.96; p < 0.0001) triers. In patients with intestinal type GC, the risk for FP results was 4 times higher than in other histologic types of GC in both N1 (OR = 4.23, 95%CI: 2.58-6.95; p < 0.0001) and N2 (OR = 4.23, 95%CI: 2.02-9.62; p = 0.0002) triers.

CONCLUSIONS

MCP predictions in the GC patients treated with nCTH have low specificity due to significantly high number of FP results. Noticeably low accuracy level of predictions indicate a need for new prediction models, based on Laurén classification, since it may provide some information on expected regression grade.

Does Noncompliance in Lymph Node Dissection Affect Oncological Efficacy in Gastric Cancer Patients Undergoing Radical Gastrectomy?

BACKGROUND

Few reports have examined the prognosis of or possible remedial treatments for patients with noncompliant D2 lymphadenectomy. We investigated the effect of noncompliance in lymph node (LN) dissection on long-term survival in gastric cancer (GC) patients after radical gastrectomy and explored intervention measures.

METHODS

Clinicopathological data were retrospectively analyzed in 2401 patients who underwent radical gastrectomy for GC. Noncompliance was defined as patients with more than one empty LN station, as described in the protocol of the Japanese GC Association.

RESULTS

The overall noncompliance rate was 49.1%. The 3-year overall survival (OS) rate was significantly better in compliant than noncompliant patients (74.0% vs. 60.1%, P < 0.001). Univariate and multivariate analyses revealed that noncompliance was an independent risk factor for OS. Logistic regression analysis demonstrated that extent of gastrectomy, primary tumor site, history of intraperitoneal surgery, body mass index, and open gastrectomy were independent preoperative predictive factors for noncompliance. Cox analysis demonstrated that age, pT, pN, and extent of gastrectomy independently affected OS in patients with noncompliant lymphadenectomy. However, OS was significantly better in the compliant than noncompliant group regardless of the recommendation for chemotherapy. Stratified analysis demonstrated that OS was significantly better in chemotherapy patients than in patients without chemotherapy and stage II patients (pT1N2/N3M0 and pT3N0M0) in whom chemotherapy was not recommended.

CONCLUSIONS

Noncompliance is an independent risk factor after radical gastrectomy for GC. Adjuvant chemotherapy improved the prognosis of patients with pT1N2/N3M0 and pT3N0M0 disease who underwent noncompliant D2 lymphadenectomy.

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.

Association between hospital volume and quality of gastric cancer surgery in the CRITICS trial

BACKGROUND

Studies investigating the association between hospital volume and quality of gastric cancer surgery are lacking. In the present study, the effect of hospital volume on quality of gastric cancer surgery was evaluated by analysing data from the CRITICS (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach) trial.

METHODS

Patients who underwent gastrectomy with curative intent in the Netherlands were selected from the CRITICS trial database. Annual hospital volume of participating centres was derived from the Netherlands Cancer Registry. Hospital volume was categorized into very low (1-10 gastrectomies per year per institution), low (11-20), medium (21-30) and high (31 or more), and linked to the CRITICS database. Quality of surgery was analysed by surgicopathological compliance (removal of at least 15 lymph nodes), surgical compliance (removal of indicated lymph node stations) and the Maruyama Index. Postoperative morbidity and mortality were also compared between hospital categories.

RESULTS

Between 2007 and 2015, 788 patients were included in the CRITICS study, of whom 494 were analysed. Surgicopathological compliance was higher (86·7 versus 50·4 per cent; P < 0·001), surgical compliance was greater (52·9 versus 19·8 per cent; P < 0·001) and median Maruyama Index was lower (0 versus 6; P = 0·006) in high-volume hospitals compared with very low-volume hospitals. There was no statistically significant difference in postoperative complications or mortality between the hospital volume categories.

CONCLUSION

Surgery performed in high-volume hospitals was associated with better surgical quality than surgery carried out in lower-volume hospitals.

Impact of upfront randomization for postoperative treatment on quality of surgery in the CRITICS gastric cancer trial

BACKGROUND

Preoperative randomization for postoperative treatment might affect quality of surgery. In the CRITICS trial (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach), patients were randomized before treatment to receive chemotherapy prior to a D1 + gastrectomy (removal of lymph node station (LNS) 1-9 + 11), followed by either chemotherapy (CT) or chemoradiotherapy (CRT). In this analysis, the influence of upfront randomization on the quality of surgery was evaluated.

METHODS

Quality of surgery was analyzed in both study arms using surgicopathological compliance (removal of ≥ 15 lymph nodes), surgical compliance (removal of the indicated LNS), and surgical contamination (removal of LNS that should be left in situ). Furthermore, the 'Maruyama Index of Unresected disease' (MI) was evaluated in both study arms, and validated with overall survival.

RESULTS

Between 2007 and 2015, 788 patients with gastric cancer were included in the CRITICS study of which 636 patients were operated with curative intent. No difference was observed between the CT and CRT group regarding surgicopathological compliance (74.8% vs 70.9%, P = 0.324), surgical compliance (43.2% vs 39.2%, P = 0.381), and surgical contamination (59.4% vs 59.9%, P = 0.567). Median MI was 1 in both groups (range CT 0-88 and CRT 0-136, P = 0.700). A MI below 5 was associated with better overall survival (CT: P = 0.009 and CRT: P = 0.013).

CONCLUSION

Surgical quality parameters were similar in both study arms in the CRITICS gastric cancer trial, indicating that upfront randomization for postoperative treatment had no impact on the quality of surgery. A Maruyama Index below five was associated with better overall survival.

Historical assumptions of lymphadenectomy

The role of lymphadenectomy for the treatment of gastric cancer is still very much open to debate. Consequently, Japanese, European and American surgeons perform different typologies of lymphadenectomy because of the absence of randomized clinical trials confirming the superiority of extended lymphadenectomy over less invasive surgery. In Japan, D2 lymphadenectomy has been considered as the gold standard for advanced gastric carcinoma for many years. Although numerous European studies have been conducted in an attempt to find differences between D1 and D2 lymphadenectomy, none has succeeded to date. The decision to wait for results attesting to the fact that D2 guarantees a better outcome than D1 resulted in a long delay in the implementation of D2 as the gold standard treatment in Europe. In the U.S., the study by Macdonald et al. established D1 lymphadenectomy followed by chemoradiotherapy as the treatment of choice for advanced cancer, whereas D2 is officially indicated as the gold standard in the most recent European guidelines [the Italian Research Group for Gastric Cancer (GIRGC), German, British, ESSO]. Interestingly, European guidelines for lymphadenectomy are not based on evidence-based medicine but rather on the experience of the most important centers involved in the treatment of gastric cancer.

Alternative staging of regional lymph nodes in gastric cancer

The TNM pN stage based on the number of metastatic lymph nodes is an independent prognostic factor in gastric cancer. Many studies have highlighted the phenomenon of stage migration and problems in comparing groups of patients with different numbers of total lymph nodes harvested within TNM staging. The current version of UICC/AJCC and JGCA TNM classifications postulates a minimal number of 16 lymph nodes as the base for N stage determination. Alternative systems such as lymph node ratio (LNR), positive to negative lymph node ratio (PNLNR), and LOGODDS (or LODDS), were implemented to increase the quality of LN assessment. These methods have reached the background in the literature, but to date no standard approach according to the cut-offs for the stages has been implemented. LOGODDS is the method that most reflects the number of harvested lymph nodes. The rationale for alternative staging methods, their correlations, and limitations are presented.

Clinical Outcome after D1 vs D2–3 Gastrectomy for Treatment of Gastric Cancer

Background:

Clinical benefit from extended lymphadenectomy for gastric cancer remains controversial as a considerable variation exists between results of different studies.

Methods:

562 patients were treated at HUCH between 1987–2003, whereof 223 underwent gastrectomy with curative intent. Of these, 114 patients underwent subtotal/total gastrectomy with D1 (standard) lymphadenectomy and 109 patients had D2–3 (extended) lymph node dissection. The clinical outcome of these patients was analysed retrospectively.

Results:

The incidence of surgical complications was 33.0% in D2–3 and 16.8% in D1 lymphadenectomy groups (p = 0.008). Abscess was the most common complication (11.0%) among D2–3 operated patients and haemorrhage (4.4%) in D1 group. Hospital mortality was 3.7% in D2–3 and 1.8% in D1 group (p = 0.438). The only statistically significant factor influencing the rate of complications was D2–3 lymphadenectomy (OR 2.620, 95% C.I. 1.375 to 4.991). D2–3 was associated with a longer postoperative hospital stay and operation time, greater blood loss and increased need for blood transfusions compared to D1. The 5-year survival was not statistically different between lymphadenectomy groups.

Conclusion:

It is justified to perform a D2–3 gastrectomy in Europe with a acceptable postoperative mortality but with a significant morbidity. Further studies are needed to assess the value of extended lymphadenectomy in gastric cancer

The Essentials of Locoregional Control in the Treatment of Gastric Cancer

Gastric cancer is the fourth most frequent cancer in the world. For curative treatment and local control of gastric cancer, surgery is essential. The extent of the lymph node dissection is still under debate. Only one available trial showed significantly increased overall survival, whereas in all other randomised trials no significant difference could be found.

As surgery alone often is not sufficient in the curative treatment in gastric cancer, different (neo)adjuvant treatment strategies have extensively been studied. The recently published MAGIC trial showed downstaging, downsizing and an improved overall survival for patients treated with perioperative chemotherapy, compared to surgery alone (difference 13%, p = 0.009). The INT 0116 trial on the other hand, demonstrated the benefit of postoperative chemoradiotherapy compared to surgery alone for patients with a curative resection of gastric cancer. However, the quality of resections in this trial was poor, illustrating the importance of standardisation by quality control. This could be done by the Maruyama index, which quantifies the likelihood of unresected disease.

In the Netherlands, the CRITICS trial has recently been launched, which will be a quality controlled trial comparing postoperative chemoradiotherapy and chemotherapy on survival and/or locoregional control in patients who receive neoadjuvant chemotherapy followed by a D1+ gastric resection.

Gastric cancer: Current status of lymph node dissection

D2 procedure has been accepted in Far East as the standard treatment for both early (EGC) and advanced gastric cancer (AGC) for many decades. Recently EGC has been successfully treated with endoscopy by endoscopic mucosal resection or endoscopic submucosal dissection, when restricted or extended Gotoda's criteria can be applied and D1+ surgery is offered only to patients not fitted for less invasive treatment. Furthermore, two randomised controlled trials (RCTs) have been demonstrating the non inferiority of minimally invasive technique as compared to standard open surgery for the treatment of early cases and recently the feasibility of adequate D1+ dissection has been demonstrated also for the robot assisted technique. In case of AGC the debate on the extent of nodal dissection has been open for many decades. While D2 gastrectomy was performed as the standard procedure in eastern countries, mostly based on observational and retrospective studies, in the west the Medical Research Council (MRC), Dutch and Italian RCTs have been conducted to show a survival benefit of D2 over D1 with evidence based medicine. Unfortunately both the MRC and the Dutch trials failed to show a survival benefit after the D2 procedure, mostly due to the significant increase of postoperative morbidity and mortality, which was referred to splenopancreatectomy. Only 15 years after the conclusion of its accrual, the Dutch trial could report a significant decrease of recurrence after D2 procedure. Recently the long term survival analysis of the Italian RCT could demonstrate a benefit for patients with positive nodes treated with D2 gastrectomy without splenopancreatectomy. As nowadays also in western countries D2 procedure can be done safely with pancreas preserving technique and without preventive splenectomy, it has been suggested in several national guidelines as the recommended procedure for patients with AGC.

Clinical significance of lymphadenectomy in patients with gastric cancer

Approximately thirty percent of patients with gastric cancer undergo an avoidable lymph node dissection with a higher rate of postoperative complication. Comparing the D1 and D2 dissections, it was found that there is a significant difference in morbidity, favoured D1 dissection without any difference in overall survival. Subgroup analysis of patients with T3 tumor shows a survival difference favoring D2 lymphadenectomy, and there is a better gastric cancer-related death and non-statistically significant improvement of survival for node-positive disease in patients with D2 dissection. However, the extended lymphadenectomy could improve stage-specific survival owing to the stage migration phenomenon. The deployment of centralization and application of national guidelines could improve the surgical outcomes. The Japanese and European guidelines enclose the D2 lymphadenectomy as the gold standard in R0 resection. In the individualized, stage-adapted gastric cancer surgery the Maruyama computer program (MCP) can estimate lymph node involvement preoperatively with high accuracy and in addition the Maruyama Index less than 5 has a better impact on survival, than D-level guided surgery. For these reasons, the preoperative application of MCP is recommended routinely, with an aim to perform “low Maruyama Index surgery”. The sentinel lymph node biopsy (SNB) may decrease the number of redundant lymphadenectomy intraoperatively with a high detection rate (93.7%) and an accuracy of 92%. More accurate stage-adapted surgery could be performed using the MCP and SNB in parallel fashion in gastric cancer.

Analysis of surgery for incurable gastric cancer

BACKGROUND

It is important to evaluate the curability of and avoid unnecessary exploratory surgery for gastric cancer preoperatively. However, no related research has been reported until now. The aim of this study was to evaluate the factors influencing surgery for incurable gastric cancer.

METHODS

310 cases of T3-4 gastric cancer patients were analyzed retrospectively, including 141 cases with radical surgery and 169 with surgery for incurable gastric cancer. The incurable factors were categorized as T status (unresectable T4 tumor), N status (unresectable lymph node), peritoneal metastasis, and distant metastasis. χ (2) test and logistic regression were performed to analyze the associations between curability, T status, N status, peritoneal metastasis, or distant metastasis and clinicopathological data.

RESULTS

Esophageal involvement and T grade were associated with curability. Cardia involvement and Borrmann type were associated with T status. Esophageal involvement and T grade were associated with N status. Gastric body involvement, esophageal involvement, and T grade were associated with peritoneal metastasis. Gastric antrum involvement was associated with distant metastasis.

CONCLUSIONS

The influencing factors of surgery for incurable gastric cancer should be analyzed preoperatively. Resectability should be evaluated according to these influencing factors combined with imaging analysis.

Quality control of lymph node dissection in the Dutch Gastric Cancer Trial

BACKGROUND

Current guidelines indicate that D2 resection is the standard of care for patients with locally advanced gastric cancer. To assess the impact of quality assurance of lymph node removal, non-compliance and contamination in the D1 and D2 study arms of the Dutch Gastric Cancer Trial were investigated with respect to recurrence and survival.

METHODS

The location and numbers of lymph nodes detected at pathological investigation in the Dutch Gastric Cancer Trial were compared according to the guidelines of the Japanese Research Society for the study of Gastric Cancer. Non-compliance was defined as inadequate removal of lymph node stations. Contamination was defined as lymph nodes removed outside the intended level of resection. The dissection groups D1 and D2 were divided into non-compliance, compliance and contamination categories. Long-term overall survival was calculated for minor (2 or fewer lymph nodes) and major (more than 2 lymph nodes) non-compliance and contamination in the D1 and D2 group, using Kaplan-Meier plots.

RESULTS

Some 1078 patients were included, of whom 711 with potentially curative surgical resections were evaluated. Overall non-compliance was 80·5 per cent in the D1 and 81·6 per cent in the D2 group. Major non-compliance occurred in 15·3 per cent of the D1 and 26·0 per cent of the D2 group. Major contamination hardly occurred. Overall 15-year survival rates in the randomized groups were 21·2 per cent (D1) and 29·0 per cent (D2) (P = 0·351). After exclusion of patients with major non-compliance and/or major contamination, survival rates were 23·2 per cent (319 patients) and 32·6 per cent (245) respectively (P = 0·261). Where there was major non-compliance, survival rates in the D1 (58 patients) and D2 (86) groups were 10 and 17 per cent respectively (P = 0·302). Survival in the D2 compliant + contaminated group (139 patients) was significantly better than that in the D1 group without contamination (282): 35·7 versus 19·9 per cent (P = 0·041). In the D2 group, there was a significant difference in survival between contaminated (95 patients) and non-contaminated (236) groups: 39 versus 25·1 per cent (P = 0·041).

CONCLUSION

Non-compliance in the D2 dissection group may have obscured a significant difference in survival between the randomized groups. A D2 dissection with contamination was associated with the best survival, suggesting that extended D2 lymph node dissections improve survival.

Surgical management of gastric cancer: the East vs. West perspective

Gastric cancer is a unique malignancy, with definite geographic differences in incidence, pathology, treatment and outcome. While the incidence has been declining in the Western hemisphere, steady rates have been reported in Eastern countries, particularly South Korea and Japan. One of the most profound differences between the East and West centers around treatment strategies, with Western clinicians routinely adopting a neoadjuvant approach, prior to surgical resection. Eastern clinicians, however, favor primary surgical therapy and have pioneered many of the techniques currently used worldwide. From endoscopic therapies to minimally-invasive surgery, including laparoscopic and robotic techniques, the Eastern surgeons have studied their techniques with high-volumes of patients. Western surgeons, practicing in systems where gastric cancer care is not centralized, typically have performed less aggressive surgical resections, although generally see more advanced diseases. In the era where global care is becoming more standardized, however, the differences in surgical practice have lessened. This review compares the surgical techniques and outcomes for gastric cancer practiced in the East with those standard in the West.

Subtotal gastrectomy for gastric cancer

Although a steady decline in the incidence and mortality rates of gastric carcinoma has been observed in the last century worldwide, the absolute number of new cases/year is increasing because of the aging of the population. So far, surgical resection with curative intent has been the only treatment providing hope for cure; therefore, gastric cancer surgery has become a specialized field in digestive surgery. Gastrectomy with lymph node (LN) dissection for cancer patients remains a challenging procedure which requires skilled, well-trained surgeons who are very familiar with the fast-evolving oncological principles of gastric cancer surgery. As a matter of fact, the extent of gastric resection and LN dissection depends on the size of the disease and gastric cancer surgery has become a patient and “disease-tailored” surgery, ranging from endoscopic resection to laparoscopic assisted gastrectomy and conventional extended multivisceral resections. LN metastases are the most important prognostic factor in patients that undergo curative resection. LN dissection remains the most challenging part of the operation due to the location of LN stations around major retroperitoneal vessels and adjacent organs, which are not routinely included in the resected specimen and need to be preserved in order to avoid dangerous intra- and postoperative complications. Hence, the surgeon is the most important non-TMN prognostic factor in gastric cancer. Subtotal gastrectomy is the treatment of choice for middle and distal-third gastric cancer as it provides similar survival rates and better functional outcome compared to total gastrectomy, especially in early-stage disease with favorable prognosis. Nonetheless, the resection range for middle-third gastric cancer cases and the extent of LN dissection at early stages remains controversial. Due to the necessity of a more extended procedure at advanced stages and the trend for more conservative treatments in early gastric cancer, the indication for conventional subtotal gastrectomy depends on multiple variables. This review aims to clarify and define the actual landmarks of this procedure and the role it plays compared to the whole range of new and old treatment methods.

Extent of lymphadenectomy and perioperative therapies: Two open issues in gastric cancer

Gastric cancer is one of the leading causes of death for cancer worldwide, although geographical variations in incidence exist. Over the last decades, its incidence and mortality have gradually decreased in Western countries, while these have increased, or remained stable, in the other world regions. Gastric cancer is often diagnosed at an advanced stage, with the only notable exception of Japan, where nationwide screening programs are enforced, due to local high incidence. Curative- intent surgery (i.e., gastrectomy, total or partial, and lymphadenectomy) remains the cornerstone of treatment of gastric cancer. Much has been debated about the extent of lymph node dissection and, although it is a valuable contribution to staging and cure, operative treatment only represents one aspect of overall effective management, as the risk of both locoregional and distant recurrences are high, and bear a poor prognosis. As a matter of fact, surgery, as a single modality treatment, has probably achieved its maximum efficacy for local control and survival, while other accompanying nonsurgical treatment modalities have to be taken into account, although their role is still the subject of considerable debate. The authors in this review present an update on the outcome of treatment of gastric cancer in relation to the extent of lymphadenectomy and of various nonsurgical preoperative, intraoperative, and postoperative strategies.

Lymph node dissection in resectable advanced gastric cancer

The extent of surgery for gastric cancer has been debated since Billroth performed his first gastrectomy in 1881. This review gives an overview of the available literature on the extent of gastrectomy and lymphadenectomy for advanced resectable gastric cancer. Subtotal gastrectomy is associated with lower morbidity and mortality compared with total gastrectomy, without compromising long-term survival. However, a positive resection margin decreases the chance of curation. Frozen section examination may prevent this. For poorly differentiated singlet ring cell tumors, there may be an argument to perform a total gastrectomy in all cases. In 1981, the Japanese Research Society for the Study of Gastric Cancer provided guidelines for the standardization of surgical treatment and pathological evaluation of gastric cancer. Since then, D2 lymph node dissections have become the standard of care in Japan. Because of the superior stage-specific survival rates in Japan, a D2 dissection was evaluated in several Western randomized controlled trials, but no survival benefit was found for a D2 over a D1 dissection. This might be explained by the increased mortality in the D2 dissection groups which might be the result of a standard pancreaticosplenectomy and low experience with D2 dissections. Adding the removal of the para-aortic nodes to a D2 dissection does not further improve survival. The removal of lymph node stations 10 and 11 by splenectomy showed an increased morbidity, no survival benefit, and a very poor prognosis if lymph nodes were affected. Therefore, pancreaticosplenectomy should only be performed in cases of tumor invasion into these organs. A D2 dissection without routine splenectomy and pancreatic tail resection in experienced hands should be considered standard of care for advanced resectable gastric cancer, both in Asian and in Western patients. Centralization and auditing may further improve outcomes after gastrectomy.

D2 lymphadenectomy with surgical ex vivo dissection into node stations for gastric adenocarcinoma can be performed safely in Western patients and ensures optimal staging

BACKGROUND

The AJCC recommends examination of >16 nodes to stage gastric adenocarcinoma. D2 lymphadenectomy (LAD) followed by surgical ex vivo dissection (SEVD) into nodal stations is standard at many high-volume Asian centers, but potential increases in morbidity and mortality have slowed adoption of D2 LAD in some Western centers.

METHODS

A total of 331 patients with gastric adenocarcinoma who underwent surgical resection at one Western institution from 1995 to 2010 were examined.

RESULTS

Median age of patients was 69 years old, 65% were male, and 84% were white. D1 LAD was performed in 285 patients (86%) and D2 LAD in 46 patients (14%), with SEVD being performed in 17 patients (37%) in the D2 group. D2 LAD with or without SEVD was performed much more commonly between 2006 and 2010. For the D1, D2 without SEVD, and D2 with SEVD groups, the median number of examined nodes and percentage with >16 examined nodes were 16 and 51%, 27 and 93%, and 40 and 100%, respectively. Major complications occurred in 16% of the D1 group and 17% of the D2 group (p>0.05), and 30-day mortality was 3% for the D1 group and 0% for the D2 group. D2 LAD was a positive prognostic factor for overall survival on univariate (p=0.027) and multivariate analyses (p=0.005), but there were several possible confounding variables.

CONCLUSIONS

D2 LAD at our Western institution was performed with low morbidity and no mortality. Optimal staging occurred after D2 LAD combined with SEVD, where a median of 40 nodes were examined and all patients had >16 examined nodes.

Effect of adjuvant chemoradiotherapy on overall survival of gastric cancer patients submitted to D2 lymphadenectomy

BACKGROUND

Adjuvant chemoradiotherapy (CRT) is the standard treatment in Western countries for gastric cancer patients submitted to curative resection. However, the role of adjuvant CRT in gastric cancer treated with D2 lymphadenectomy has not been well defined.

METHODS

We conducted a retrospective study in patients with stage II to IV gastric adenocarcinoma with no distant metastases, who underwent curative resection with D2 lymphadenectomy between January 2002 and December 2007. The present study compared the 3-year overall survival of two treatments (adjuvant CRT according to the INT 0116 trial versus resection alone). Survival curves were estimated by the Kaplan-Meier method and compared with a log-rank test. Multivariate analysis of prognostic factors was performed by the Cox proportional hazards model.

RESULTS

A total of 185 patients were included, 104 patients (56 %) received adjuvant CRT and 81 received resection alone. The 3-year overall survival was 64.4 % in the CRT group and 61.7 % in the resection-alone group (p: 0.415). However, according to the Cox proportional hazards model, adjuvant CRT was a prognostic factor for 3-year overall survival (hazard ratio [HR] 0.46, 95 % confidence interval [CI] 0.26-0.82, p: 0.008).

CONCLUSIONS

In the present study, adjuvant CRT was associated with a lower risk of death over a 3-year period in gastric cancer patients treated with D2 lymphadenectomy.

How many lymph nodes should be assessed in patients with gastric cancer? A systematic review

BACKGROUND

Nodal status is one of the most important prognostic factors in gastric adenocarcinoma (GC). As such, it is important to assess an appropriate number of lymph nodes (LNs) in order to accurately stage patients. However, the number of LNs assessed in each GC case varies, and in many cases the number examined per gastric specimen is less than current recommendations.

PURPOSE

We aimed to identify and synthesize findings from all articles evaluating the association of clinicopathological features and long-term outcomes with the number of LNs assessed among GC patients.

METHODS

Systematic electronic literature searches were conducted using Medline, Embase, and the Cochrane Central Register of Controlled Trials from 1998 to 2009.

RESULTS

Twenty-five articles were included in this review. Extensive resection, increased tumor size, and greater TNM staging were all associated with a greater number of LNs assessed. The disease-free survival was longer and recurrence rate was lower in patients with more LNs assessed. Overall survival, as well as survival by TNM and clinical stage, was improved among patients with an increased number of LNs assessed, but much of this appears to be due to stage migration, with the effect more pronounced in more advanced disease.

CONCLUSION

More LNs assessed resulted in less stage migration and possibly better long-term outcomes. Although current guidelines suggest 16 LNs to be assessed, especially in advanced GC, a higher number of LNs should be assessed.

Surgery for gastric cancer: what the trials indicate

To optimize the therapeutic value of an operation for cancer, surgeons must weigh survival value against mortality/morbidity risk. As a result of several prospective, randomized trials, many surgeons feel that international opinion has reached a consensus. Reflexively radical surgical hubris has certainly given way to a more nuanced, customized approach to this disease. But issues remain. This article critically reviews existing data and emphasizes areas of continued controversy.

Adjuvant chemotherapy: an option for Asian patients only?

Survival rates following curative resection for gastric cancer are higher in East Asia than in Europe and the US. The aggressive surgical approach adopted in East Asia may explain these observations. In Japan and Korea, gastrectomy with extended lymphadenectomy (D2 gastrectomy) has been standard of care for many years, whereas gastrectomy with lymphadenectomy of the perigastric lymph nodes (D1 surgery) has been favored in Europe and the US until recently. D2 surgery is now recommended globally based on the 15-year findings from the large Dutch D1D2 study, which showed a reduction in cancer-related deaths with D2 versus D1 surgery. Improved outcomes are now being reported in the US and Europe as D2 surgery becomes more widely used. In addition to surgery, systemic therapy is also required to control recurrences, although the preferred regimen differs by region. Given that some of the studies on which these preferences are based predate the widespread acceptance of D2 surgery, the optimal regimen should be considered carefully. Recent studies from East Asia support the use of adjuvant chemotherapy after D2 surgery. Adjuvant chemotherapy should also be considered a valid approach in other regions now that the benefits of D2 surgery have been demonstrated unequivocally.

Gastric cancer surgery: an American perspective on the current options and standards

Gastric cancer is prevalent globally, particularly in Asian countries such as Japan and Korea. While the prevalence of gastric cancer is not nearly as high in the United States (U.S.) as in Asia, the treatment armamentarium differs widely between regions. The role of surgery for gastric cancer in the U.S. has changed drastically over the last decade. While the natural history of gastric cancer seen in the U.S. markedly differs from that seen in Asia, the U.S. experience with endoscopic and minimally invasive techniques is beginning to parallel those seen in Japan and Korea. Minimally invasive surgery has truly come into the forefront of our surgical armamentarium, and its role, along with robotic and endoscopic approaches, remains to be defined as standard of care. At present, minimally invasive approaches appear to offer oncologically equivalent outcomes compared with standard open gastrectomy when performed by experienced surgeons. Extended lymphadenectomy does not appear to offer benefit with improved survival in our patient population, although sufficient lymph node sampling is imperative for adequate staging. Despite aggressive approaches to surgical resection for cure, the U.S. population tends to present with more advanced disease and have a worse prognosis than our Asian counterparts. Palliation with resection and possibly stent placement should be offered for improved quality of life in late-stage disease.

Impact of pretherapeutic routine clinical staging for the individualization of treatment in gastric cancer patients

PURPOSE

The usefulness and prognostic impact of a pretherapeutic clinical staging is still a matter of discussion. However, a pretherapeutic estimation of the prognosis would be essential to adjust the patient's therapy. Our aim was to compare clinical and histopathological staging and to analyze the predictive value of routine clinical staging and its significance for the individualization of treatment.

PATIENTS AND METHODS

We analyzed the data of 368 patients treated with gastric cancer in the University of Heidelberg, Department of Surgery, from January 2001 to June 2009. Pretherapeutic parameters including sex, age, cTNM, grading, Laurén classification, tumor localization, as well as posttherapeutic parameters were analyzed, and their impact for survival was evaluated. Follow-up data was obtained for all patients (2.17% lost to follow-up).

RESULTS

The overall accuracy was 64.1% for pT category, 54.5% for pN category, and 80.3% for M category for the primary resected patients. For the patients treated neoadjuvantly, the overall accuracy was 21.8% for the pT category, 58.0% for the pN category, and 80.0% for the M category. The prognosis was associated to the age (p = 0.017), tumor localization (p < 0.001), grading (p = 0.041), cT category (p < 0.001), cN category (p < 0.001), and cM category (p = 0.001). The multivariate analysis, including pre- and postoperative factors, revealed tumor localization (p = 0.002), cN category (p = 0.019), and metastatic lymph node rate (p < 0.001) as independent prognostic factors.

CONCLUSION

The accordance between clinical and histopathological staging is limited, but nevertheless pretherapeutic parameters have a high prognostic impact and could be used for individualized therapy planning. The relevant pretherapeutic prognostic factors can all be determined by routine clinical staging including CT and endoscopy. Consequently pretherapeutic prognostic evaluation and therapy planning seem to be feasible with routine staging methods.

Long-term results of tailored D(2) lymph node dissection after R(0) surgery for gastric cancer

Implementation of extended lymph node dissection for gastric cancer in western non-specialized centers through tailoring its extent upon disease stage and patient comorbidities was suggested as a wise policy to reduce morbidity and mortality rates, albeit with a potential for undertreatment in elderly and/or comorbid patients. Current definition of R(0) resection for gastric cancer lacks consideration of treatment-related variables such as extended lymph node dissection. Few studies to date have tried to fill this gap in such a clinical context. A retrospective evaluation of factors influencing long-term results after R(0) surgery was done in a prospective series of a non-specialized western surgical unit during the implementation of D(2) lymphadenectomy. Univariate and multivariate analysis of 22 variables were performed on a prospective database of 233 consecutive R(0) resections performed by ten different surgeons in 10 years. Endpoint was disease-free survival calculated at 5 and at 10 years. Disease-free survival rates were independently influenced by age, American Society of Anesthesiologists (ASA) status and lymph node ratio. Subset analysis of the status at censor stratified for age and ASA status failed to identify any significant difference in disease recurrence rates. Lymph node ratio was the only treatment-related independent prognostic factor for long-term results after R(0) surgery for gastric cancer in the setting of a non-specialized western unit, where the extent of lymph node dissection needs to be tailored on the presence of comorbidities (ASA status).

Gastric cancer: surgery in 2011

BACKGROUND

Treatment of gastric cancer is more and more becoming an individualized decision. The choice of the optimal approach is based on prognostic factors, on the anatomic site of the tumor, and on expectations about the response to neoadjuvant treatment. Early gastric cancer that is limited to the mucosal layer is the domain of endoscopic resections. As soon as the submucosal layer is invaded, surgical strategies with adequate lymphadenectomy become necessary.

DISCUSSION

In many East Asian Centers and some other centers in the world, these tumors are resected by a laparoscopic approach. With a high experience, this can be done with excellent quality and outcome. In locally advanced gastric cancer, multimodal treatment can improve survival in comparison to surgery alone. However, the strategies differ significantly around the world. While adjuvant chemoradiotherapy is standard in the USA, in Europe, perioperative chemotherapy is the first choice, and in Japan, adjuvant chemotherapy is recommended. In Europe, three randomized phase III studies on the value of preoperative chemotherapy have been performed. Two of them have shown that perioperative chemotherapy does significantly improve the survival of patients with adenocarcinoma of the stomach and of the esophagogastric junction. The one including only preoperative chemotherapy failed to show a survival benefit for the combined treatment arm but showed excellent outcomes in both the surgery alone and the preoperative chemotherapy arms. Based on these studies, patients with stage II or stage III disease are now treated with perioperative chemotherapy. Additionally, it is generally accepted for more than 10 years now that responding patients have a significantly improved prognosis compared to nonresponding patients. The percentage of responding patients varies depending on the applied regimen between 20% and 45%. Therefore, early response evaluation or response prediction is an utmost important field of research. Proximal tumors are treated with a transhiatal extended gastrectomy, tumors in the middle third with a total gastrectomy, and distal tumors with a subtotal gastrectomy, if possible. Modified D2 lymphadenectomy avoiding splenectomy is now accepted as the standard procedure, providing improved prognosis for certain subgroups of patients. Individualized resection and lymphadenectomy techniques for early tumor stages and response-based neoadjuvant concepts for locally advanced tumors are the challenge for the future.

Validation of limited lymphadenectomy for lower-third gastric cancer based on depth of tumour invasion

BACKGROUND

This study aimed to determine the appropriate extent of lymph node (LN) dissection in gastric cancer by analysing LN metastasis patterns from prospectively collected topographical data on nodal status at Seoul National University Hospital, Korea.

METHODS

The metastasis rate for each LN station was analysed according to the depth of tumour invasion in patients with primary lower-third gastric cancer who underwent curative gastrectomy. The Maruyama Index of unresected disease (MI) was calculated using the WinEstimate(®) program with simulation of various extents of LN dissection.

RESULTS

LN metastasis in mucosal cancer was rare; 2·6 per cent of patients had a MI of more than 5 with simulation of D1 plus station 7 dissection, whereas 0·9 per cent had a MI above 5 with D1 plus stations 7 and 8a. In submucosal cancer, 3·3 per cent of tumours metastasized to level 2 LN stations outside the range of D1 plus stations 7, 8a and 9. The proportion of patients with a MI above 5 was 9·0 per cent with D1 plus stations 7, 8a and 9 dissection. The nodal metastasis rate was higher at level 1 and 2 for muscularis propria or deeper cancers.

CONCLUSION

D1 dissection plus stations 7 and 8a for mucosal cancer, and D2 dissection for cancers of the muscularis propria or deeper seems appropriate. For submucosal cancer, an expanded dissection to the D2 level should be considered to ensure complete removal of metastatic LNs.

R0 resection in the treatment of gastric cancer: Room for improvement

Gastric carcinoma is one of the most frequent malignancies in the world and its clinical behavior especially depends on the metastatic potential of the tumor. In particular, lymphatic metastasis is one of the main predictors of tumor recurrence and survival, and current pathological staging systems reflect the concept that lymphatic spread is the most relevant prognostic factor in patients undergoing curative resection. This is compounded by the observation that two-thirds of gastric cancer in the Western world presents at an advanced stage, with lymph node metastasis at diagnosis. All current therapeutic efforts in gastric cancer are directed toward individualization of therapeutic protocols, tailoring the extent of resection and the administration of preoperative and postoperative treatment. The goals of all these strategies are to improve prognosis towards the achievement of a curative resection (R0 resection) with minimal morbidity and mortality, and better postoperative quality of life.

Evaluation of the adequacy of lymph node dissection in pylorus-preserving gastrectomy for early gastric cancer using the maruyama index

BACKGROUND

The Maruyama computer program predicts the percentage likelihood of disease in lymph node stations left undissected by a surgeon, according to the age and sex of the patient and the gross type, size, location, depth of invasion, and histology of the tumor. The Maruyama index (MI) is defined as the sum of the predictions of the percentage likelihood of disease in undissected regional lymph node station (station 1-12). It has been shown that an MI < 5 is a strong predictor of survival and that the MI is an independent predictor of overall survival and relapse risk. We used the MI to evaluate the adequacy of lymph nodes dissection in pylorus-preserving gastrectomy (PPG) for early gastric cancer (EGC) performed at Seoul National University Hospital.

METHODS

From March 2003 to September 2007, PPG was performed for patients with EGC of the middle third of the stomach when the distal resection margin was greater than 2 cm and preservation of 3 cm antral segment was possible. MIs and pathologic data such as TNM stage and the presence of metastatic lymph node for each station were reviewed.

RESULTS

PPG were performed on 24 patients. The mean age of the patients was 55 years. The median tumor size was 2.1 cm. The median and mean MI were 0 and 0.8, respectively. There were 23 cases of T1N0M0 tumor and one case of T2N0M0 tumor postoperatively. There were no recurrences (mean follow-up period: 27.2 months).

CONCLUSIONS

The MI indicates that lymph node dissection during PPG performed in these 24 patients was adequate.

Impact of the extent of surgery and postoperative chemoradiotherapy on recurrence patterns in gastric cancer

PURPOSE

The Intergroup 0116 trial has demonstrated that postoperative chemoradiotherapy (CRT) improves survival in gastric cancer. We retrospectively compared survival and recurrence patterns in two phase I/II studies evaluating more intensified postoperative CRT with those from the Dutch Gastric Cancer Group Trial (DGCT) that randomly assigned patients between D1 and D2 lymphadenectomy.

PATIENTS AND METHODS

Survival and recurrence patterns of 91 patients with adenocarcinoma of the stomach who had received surgery followed by radiotherapy combined with fluorouracil and leucovorin (n = 5), capecitabine (n = 39), or capecitabine and cisplatin (n = 47) were analyzed and compared with survival and recurrence patterns of 694 patients from the DGCT (D1, n = 369; D2, n = 325). For both groups, the Maruyama Index of Unresected Disease (MI) was calculated and correlated with survival and recurrence patterns.

RESULTS

With a median follow-up of 19 months in the CRT group, local recurrence rate after 2 years was significantly higher in the surgery only (DGCT) group (17% v 5%; P = .0015). Separate analysis of CRT patients who underwent a D1 dissection (n = 39) versus DGCT-D1 (n = 369) showed fewer local recurrences after chemoradiotherapy (2% v 8%; P = .001), whereas comparison of CRT-D2 (n = 25) versus DGCT-D2 (n = 325) demonstrated no significant difference. CRT significantly improved survival after a microscopically irradical (R1) resection. The MI was found to be a strong independent predictor of survival.

CONCLUSION

After D1 surgery, the addition of postoperative CRT had a major impact on local recurrence in resectable gastric cancer.

Optimal surgery for advanced gastric cancer

Locoregional control remains a major problem after surgery, although a curative resection is still the only treatment to offer a cure for patients with gastric cancer. Despite the results of major randomized trials, the extent of nodal dissection continues to be debated. If there is a survival benefit to be gained by extended lymphadenectomy, added operative mortality should be eliminated. A pancreas and spleen-preserving D2 lymphadenectomy provides superior staging information and may provide a survival benefit while avoiding its excess morbidity. Splenectomy during gastric resection for tumors not adjacent to or invading the spleen increases morbidity and mortality without improving survival. Therefore, splenectomy should not be performed unless there is direct tumor extension. The Maruyama Index and nomograms that predict disease-specific survival may help to discriminate between patients with a high risk of relapse and select those patients who will be most likely to benefit from tailored multimodality treatment. There is growing evidence that gastric cancer surgery should be performed in high-volume centers with experienced specialists to reduce morbidity and operative mortality and to achieve better survival results.

New metastatic lymph node ratio system reduces stage migration in patients undergoing D1 lymphadenectomy for gastric adenocarcinoma

BACKGROUND

The American Joint Committee on Cancer (AJCC)/International Union Against Cancer (UICC) staging system for gastric cancer incorporates the absolute number of metastatic lymph nodes (N status) and is optimally used when >or=15 nodes are examined. The ratio of metastatic to examined nodes (N ratio) is an effective prognostic tool, but has not been examined in Western patients undergoing primarily D1 lymphadenectomy.

METHODS

Two hundred and fifty seven patients with gastric adenocarcinoma who underwent gastric resection between 1995 and 2005 at our institution were examined. Novel N ratio intervals were determined using the best cutoff approach (Nr0: N ratio = 0 and >or=15 nodes examined; Nr1: 0 <or= N ratio <or= 0.3; Nr2: 0.3 < N ratio <or= 0.7; and Nr3: N ratio > 0.7). Overall survival was examined according to N status and N ratio.

RESULTS

83% of patients underwent D1 lymphadenectomy with a median of 14 lymph nodes examined. Overall survival stratified by N status was significantly different in patients with <15 nodes examined compared with those with >or=15 nodes examined. When we stratified by N ratio intervals, there was no significant difference in overall survival in patients with <15 versus >or= 15 nodes examined. On multivariate analysis, N ratio but not N status was retained as an independent prognostic factor.

CONCLUSIONS

The use of N status for staging patients undergoing primarily D1 lymphadenectomy results in significant stage migration due to varying numbers of nodes examined. Use of N ratio reduces stage migration and may be a more reliable method of staging these patients.

Lymphadenectomy for gastric adenocarcinoma: should west meet east?

The extent of lymphadenectomy that should be performed for gastric adenocarcinoma has been a topic of persistent debate. In countries such as Japan and Korea, where the incidence of gastric adenocarcinoma is high, more extensive (e.g., D2) lymphadenectomies are routinely performed, usually by experienced surgeons with low morbidity and mortality. In western countries such as the U.S., where the incidence of gastric adenocarcinoma is tenfold lower, the performance of more extensive lymphadenectomies is generally limited to specialized centers, and quite possibly the majority of patients are treated at nonreferral centers with less than a D1 lymphadenectomy. There is little disagreement among gastric cancer experts that the minimum lymphadenectomy that should be performed for gastric adenocarcinoma should be at least a D1 lymphadenectomy. Two large, prospective randomized trials performed in the United Kingdom and the Netherlands failed to demonstrate a survival benefit of D2 over D1 lymphadenectomy, but these trials have been criticized for high surgical morbidity and mortality rates in the D2 group. More recent studies have demonstrated that western surgeons can be trained to perform D2 lymphadenectomies on western patients with low morbidity and mortality. Retrospective analyses and one prospective, randomized trial suggest that there may be some benefits to more extensive lymphadenectomies when performed safely, but this assertion requires further validation. This article provides an update on the current literature regarding the extent of lymphadenectomy for gastric adenocarcinoma.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Lymph nodes and gastric cancer

Worldwide, gastric cancer is one of the top three leading causes of cancer mortality, but incidence and presentation vary geographically. Currently, surgery is the only possible cure. Nodal status is an important prognostic indicator for gastric cancer, and despite results of randomized controlled trials, debate continues over the importance of aggressive lymphadenectomy.