Evaluation of the Maruyama computer program accuracy for preoperative estimation of lymph node metastases from gastric cancer

Extent of gastrectomy and lymphadenectomy for gastric adenocarcinoma

Gastric adenocarcinoma is one of the most common and lethal cancers worldwide and is associated with a high frequency of nodal metastasis. The value of multimodality therapy is well-established, but gastric resection and locoregional lymph node dissection are important mainstays in potentially curative therapy. However, there has been considerable regional variation in surgical approach and debate regarding the ideal extent of gastric resection, gastric reconstruction, and extent of lymphadenectomy. This chapter outlines the current evidence in the surgical management of gastric adenocarcinoma. The advent of minimally invasive approaches to gastric operations is also discussed.

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.

A prediction model for lymph node metastasis in early-stage gastric cancer: Toward tailored lymphadenectomy

BACKGROUND

The aim of this study was to develop a prediction model for the presence and location of lymph node metastasis (LNM) in early gastric cancer.

METHOD

We reviewed medical records of 4 929 patients who underwent radical gastrectomy for early gastric cancer. Variables of age, sex, lymphatic invasion, depth of invasion, location, gross type, differentiation, and tumor size were analyzed. Logistic regression analysis was used to determine independent predictors of LNM at each LN station.

RESULT

Overall incidence of LNM was 9.1% (448/4 929 patients). For the presence of LNM, risk factors of age, sex, lymphatic invasion, depth of invasion, anatomical part, gross ulceration, size, and tumor differentiation were significantly associated with LNM. The area under the curve (AUC) for predicting LNM after validation was 0.834 for the test set. For the location of LNM, age, sex, lymphatic invasion, depth of invasion, anatomical part, circumferential portion, gross type, differentiation, and tumor size were significantly associated with LNM. The AUC of each LN station was favorable with the test set.

CONCLUSION

Predicting the location of metastatic LNs appeared to be possible in patients with early gastric cancer.

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.

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.

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.

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.

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.

[Adjuvant chemoradiotherapy in gastric adenocarcinoma: about 34 cases and review of the literature]

Notre étude consistera en l’évaluation du pronostic des patients porteurs d'un adénocarcinome gastrique opérés et traités par radio-chimiothérapie adjuvante en technique conformationnelle. Entre Janvier 2007 et Décembre 2011, 34 patients ont reçu après une chirurgie radicale (R0 ou R1), un à trois cycles de 5-Fluoro-uracile associé à de l'Elvorine en adjuvant, suivi d'une radio-chimiothérapie selon le même protocole à la dose de 45Gy, puis de deux cycles de chimiothérapie à un mois d'intervalle après la radio-chimiothérapie concomitante. Dans le groupe d’étude, il y avait 34 patients d’âge médian 50 ans (47-58), avec un sexe ratio (H/F) de 2,4. Une chirurgie de type R1 a été réalisée dans 26,5% des cas, et 53% des patients étaient de stade III-IV. Le rapport nombres de ganglions positifs, sur nombre de ganglions prélevés étaient > 0,4 dans 26,5% des cas. Durant le traitement mené à terme, une neutropénie de grade III a été observée chez quatre patients, avec des troubles digestifs (nausées, vomissement, ou diarrhée) de grade I/II dans la majorité des cas. Après un suivi médian de 20 mois, 70,6% des patients étaient en survie sans rechute, et 29,4% ont présenté une récidive métastatique; la survie globale à 5 ans était de 35,4% et la survie sans progression de 58,7%. La radio-chimiothérapie concomitante postopératoire pourrait être un régime efficace et sûre chez les patients ayant bénéficié d'une gastrectomie à visée curative dans le cancer de l'estomac localement avancé.

Pathological factors affecting gastric adenocarcinoma survival in a Caribbean population from 2000-2010

AIM: To investigate pathological factors related to long term patient survival post surgical management of gastric adenocarcinoma in a Caribbean population.

METHODS: This is a retrospective, observational study of all patients treated surgically for gastric adenocarcinoma from January 1^st 2000 to December 31^st 2010 at The University Hospital of the West Indies, an urban Jamaican hospital. Pathological reports of all gastrectomy specimens post gastric cancer resection during the specified interval were accessed. Patients with a final diagnosis other than adenocarcinoma, as well as patients having undergone surgery at an external institution were excluded. The clinical records of the selected cohort were reviewed. The following variables were analysed; patient gender, patient age, the number of gastrectomies previous performed by the lead surgeon, the gross anatomical location and appearance of the tumour, the histological appearance of the tumour, infiltration of the tumour into stomach wall and surrounding structures, presence of Helicobacter pylori and the presence of gastritis. Patient status as dead vs alive was documented for the end of the interval. The effect of the aforementioned factors on patient survival were analysed using Logrank tests, Cox regression models, Ranksum tests, Kruskal-Wallis tests and Kaplan-Meier curves.

RESULTS: A total of 79 patients, 36 males and 43 females, were included. Their median age was 67 years (range 36-86 years). Median survival time from surgery was 70 mo with 40.5% of patients dying before the termination date of the study. Tumours ranged from 0.8 cm in size to encompassing the entire stomach specimen, with a median tumour size of 6 cm. The median number of nodes removed at surgery was 8 with a maximum of 28. The median number of positive lymph nodes found was 2, with a range of 0 to 22. Patients’ median survival time was approximately 70 mo, with 40.5% of the patients in this cohort dying before the terminal date. An increase in the incidence of cardiac tumours was noted compared to the previous 10 year interval (7.9% to 9.1%). Patients who had serosal involvement of the tumour did have a significantly shorter survival than those who did not (P = 0.017). A significant increase in the hazard ratio (HR), 2.424, for patients with circumferential tumours was found (P = 0.044). Via Kaplan-Meier estimates, the presence of venous infiltration as well as involvement of the circumferential resection margin were found to be poor prognostic markers, decreasing survival at 50 mo by 46.2% and 36.3% respectively. The increased HR for venous infiltration, 2.424, trended toward significant (P = 0.055) Age, size of tumour, number of positive nodes found and total number of lymph nodes removed were not useful predictors of survival. It is noted that the results were mostly negative, that is many tumour characteristics did not indicate any evidence of affecting patient survival. The current sample, with 30 observed events (deaths), would have about 30% power to detect a HR of 2.5.

CONCLUSION: This study mirrors pathological factors used for gastric cancer prognostication in other populations. As evaluation continues, a larger cohort will strengthen the significance of observed trends.

N-myc downstream-regulated gene 1 promotes tumor inflammatory angiogenesis through JNK activation and autocrine loop of interleukin-1α by human gastric cancer cells

The expression of N-myc downstream-regulated gene 1 (NDRG1) was significantly correlated with tumor angiogenesis and malignant progression together with poor prognosis in gastric cancer. However, the underlying mechanism for the role of NDRG1 in the malignant progression of gastric cancer remains unknown. Here we examined whether and how NDRG1 could modulate tumor angiogenesis by human gastric cancer cells. We established NU/Cap12 and NU/Cap32 cells overexpressing NDRG1 in NUGC-3 cells, which show lower tumor angiogenesis in vivo. Compared with parental NU/Mock3, NU/Cap12, and NU/Cap32 cells: 1) induced higher tumor angiogenesis than NU/Mock3 cells accompanied by infiltration of tumor-associated macrophages in mouse dorsal air sac assay and Matrigel plug assay; 2) showed much higher expression of CXC chemokines, MMP-1, and the potent angiogenic factor VEGF-A; 3) increased the expression of the representative inflammatory cytokine, IL-1α; 4) augmented JNK phosphorylation and nuclear expression of activator protein 1 (AP-1). Further analysis demonstrated that knockdown of AP-1 (Jun and/or Fos) resulted in down-regulation of the expression of VEGF-A, CXC chemokines, and MMP-1, and also suppressed expression of IL-1α in NDRG1-overexpressing cell lines. Treatment with IL-1 receptor antagonist (IL-1ra) resulted in down-regulation of JNK and c-Jun phosphorylation, and the expression of VEGF-A, CXC chemokines, and MMP-1 in NU/Cap12 and NU/Cap32 cells. Finally, administration of IL-1ra suppressed both tumor angiogenesis and infiltration of macrophages by NU/Cap12 in vivo. Together, activation of JNK/AP-1 thus seems to promote tumor angiogenesis in relationship to NDRG1-induced inflammatory stimuli by gastric cancer cells.

Evaluation of focused sentinel lymph node RT-qPCR screening for micrometastases with the use of the Maruyama computer program

Background

In this preliminary study, we investigated the sensitivity and specificity of reverse transcriptase (RT)-qPCR lymph node (LN) metastases detection, the accuracy of intraoperative dye navigation, and the incidence of micrometastasis (MM) detection with this protocol, compared to other published studies.

Methods

A total of 23 patients were enrolled in the study. The first stained LN was analyzed using RT-qPCR for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20) expression, as markers for MM involvement. The Maruyama computer program was used to determine the most likely first metastatic site. These results were compared with the actual staining patterns to evaluate whether the first draining LN was extracted. We analyzed the correlations between MM and tumor characteristics. The incidence of MM detected with the present method was compared to other studies, as markers of the accuracy of the present protocol.

Results

At 35 threshold cycles, the RT-qPCR had a negative predictive value of 100 % and a positive predictive value of 83.3 %. MM were detected in 4 out of 14 node-negative patients (28.6 %). The extracted sentinel LN coincided in 76.9 % of cases with the most probable first metastatic LN predicted by the Maruyama program. MM were found more frequently in these ‘high-risk’ LNs. Significant differences were found in the Lauren’s histological type distribution and the age distribution among the MM-positive and MM-negative groups.

Conclusion

Our preliminary results confirm that RT-qPCR is an accurate method of MM detection, that the dye navigation enables the determination of the first draining LN, and that the incidence of MM detection with this focused sentinel LN protocol is comparable to other studies.

Prospective, comparative study for the evaluation of lymph node involvement in gastric cancer: Maruyama computer program versus sentinel lymph node biopsy

BACKGROUND

Stage-adapted surgery guarantees the best outcome for patients with gastric cancer. Successful identification of lymph node involvement may help to reduce the number of extended lymphadenectomies. Preoperative diagnostic tools have low sensitivity and specificity for determining lymph node involvement. Evaluation of sentinel lymph nodes (SLNs) intraoperatively has good results, while the accuracy of the Maruyama computer program (MCP) is controversial.

METHODS

We investigated 40 patients by the Maruyama computer model and labeled lymph nodes with blue dye for SLN mapping. To compare the probability calculations by MCP and the results of SLN mapping, we had to define a cutoff level; we did this using receiver-operating characteristics analysis. Sentinel lymph nodes were examined in frozen sections intraoperatively and by standard hematoxylin and eosin staining postoperatively.

RESULTS

A total of 795 lymph nodes were removed and examined. The Maruyama computer model had a sensitivity of 91.3 %, specificity of 64 %, and accuracy of 80 % by the best cutoff point. The false-negative rate was 8.7 %. The sensitivity of SLN mapping was 95.7 %, the false-negative rate was 4.3 %, and the specificity was 100 %. The accuracy of SLN mapping was 97.4 %. Only the sensitivity of MCP and SLN biopsy was proven equivalent.

CONCLUSIONS

Our results suggest that intraoperative SLN examination is superior to preoperative estimation with the MCP. Correct definition of lymph node involvement helps in planning the best stage-adapted surgery in gastric cancer.

D1 versus D2 lymphadenectomy for gastric cancer

Significant variability exists throughout the world in the extent of lymphadenectomy that is performed for gastric adenocarcinoma. D2 lymphadenectomy is the standard lymphadenectomy performed in high incidence countries such as Japan and South Korea, and less extensive lymphadenectomies are often performed in lower incidence countries such as the Unites States. This article reviews the evidence on the extent of lymphadenectomy that should be performed for gastric adenocarcinoma.

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.

A risk score system to preoperatively predict TNM stages in gastric cancer

BACKGROUND

To improve the estimation of tumor status and facilitate the stage-dependent treatment planning, we developed a reliable and easy-to-use risk score for prediction of tumor-node-metastasis stages in gastric cancer.

METHODS

Clinicopathological data were collected prospectively from 108 curatively resected patients with gastric cancer. The risk score was established on the basis of independent predictive factors for tumor stages, and its performance was evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

The following 4 independent factors were included in our score: serum albumin levels, tumor size, T and N categories determined by helical computed tomography. Using ROC analysis, we chose a score at 7 as the optimal cut point for differentiating the more advanced disease (stage III/IV) from the less advanced one (stage I/II). With the defined cut point, our score allowed predicting stage III/IV with sensitivity of 79.6%, specificity of 85.2%, and accuracy of 82.4%. The discriminative ability of this score was good (the area under the ROC curve, 0.861-0.965).

CONCLUSIONS

The risk score may be helpful to preoperative gastric cancer staging. It probably assists surgeons in deciding the extent of surgery and in choosing the appropriate perioperative adjuvant therapies.

An evidence-based review of the surgical treatment of gastric adenocarcinoma

The management of gastric adenocarcinoma continues to evolve. Chemotherapy is being increasingly used in both the neoadjuvant and adjuvant setting. Surgical resection of the stomach and regional lymph nodes remains the mainstay of potentially curative therapy, but significant regional differences persist in the surgical management. This review provides an update on the current literature regarding the preoperative evaluation and staging, extent of gastric resection, extent of lymph node resection, and adjuvant therapy for patients with gastric adenocarcinoma.

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).

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.

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.

Improved regional control and survival with "low Maruyama Index" surgery in gastric cancer: autopsy findings from the Dutch D1-D2 Trial

Based on more than 11 years of follow-up, autopsy-based analysis of recurrence in the Dutch D1-D2 Trial permits meaningful assessment of patterns of failure with respect to the Maruyama Index (MI). We previously reported that a low Maruyama Index was an independent predictor of both overall and disease-specific survival. Autopsy results are available for 441 deaths on study. Distant-only failure (15% vs 13%) was no different between the MI categories, but isolated "regional" failure (8% for MI < 5 group vs 21%) and "regional + distant" failure (19% for MI < 5 group vs 36%) occurred less frequently in the MI < 5 group (P < 0.001). We conclude that "low Maruyama Index" surgery enhances regional control and survival but does not alter the occurrence of isolated distant metastases unassociated with regional failure. Our results speak to the substantial survival value of local-regional control in this disease.

Gastric cancer: D2 dissection or low Maruyama Index-based surgery--a debate

This article provides perspectives on the surgical approaches required optimally to manage patients with respectable gastric adenocarcinoma. The status of techniques of surgical resection in the management of gastric cancer is reviewed. The premise of this approach is that extended gastrectomy with D2 lymph node dissection is good. Also addressed are prognostic and predictive factors in the surgical treatment of stomach cancer.

Low maruyama index surgery for gastric cancer

BACKGROUND

Japanese definitions and treatment guidelines have dominated extent-of-surgery concepts in gastric cancer for over 4 decades, despite the fact that such definitions/guidelines have changed considerably over time, and the fact they have largely failed to improve survival in prospective, randomized clinical trials.

AIM

To briefly review lessons from previous surgical trials in gastric cancer, and, more specifically, to review data validating the concept of "low Maruyama Index surgery" as a data-driven guide to surgical treatment.

METHODS

Review of results from blinded multivariate analyses of two separate, prospective, randomized clinical trials: (a) the Macdonald Trial of adjuvant postoperative chemo-radiation, Intergroup 0116, conducted in North America; and (b) the Dutch D1-D2 Trial.

RESULTS

Blinded univariate and multivariate analysis of both trials establish "Maruyama Index of Unresected Disease" (MI) <5 as a strong independent predictor of better disease-free and overall survival in gastric cancer. Moreover, a strong "dose response" effect for MI versus survival is apparent.

CONCLUSIONS

In contrast to surgery focused on achievement of a particular Japanese-defined D-level, "low Maruyama Index surgery" is associated with increased disease-free and overall survival. Further, the dose-response effect suggests MI can be used to quantify the adequacy of lymphadenectomy for a given patient. Low MI surgery can be prospectively planned by using the Maruyama Computer Program pre-operatively or intraoperatively.

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

A quantitative estimate of residual nodal disease after gastric cancer surgery, the Maruyama index of unresected disease (MI), proved to be a strong independent predictor of survival in a large U.S. adjuvant chemoradiation study in which surgical undertreatment was frequent. Data from the Dutch D1-D2 Lymphadenectomy Trial permit an opportunity to assess the prognostic value of this variable in a cohort with lower-stage disease treated with minimum D-1 lymphadenectomy and no adjuvant chemoradiation. Blinded to survival, and excluding those cases with missing information, the MI was calculated for 648 of the original 711 patients treated with curative intent. Survival was assessed by log-rank and multivariate Cox regression analysis. All patients have been followed for a minimum of 11 years. Overall Dutch trial findings were not affected by the absence of 63 cases with incomplete data. As expected, the median MI was 26, much lower than in the previous U.S. study. In contrast to the D level, MI < 5 proved to be a strong predictor of survival by both univariate and multivariate analysis. The MI was an independent predictor of both overall survival [P = 0.016; hazard ratio (HR) = 1.45; 95% confidence interval (CI) 1.07-1.95] and relapse risk (P = 0.010; HR = 1.72; 95% CI 1.14-2.60). A strong dose-response reaction with respect to the MI and survival was also observed. We conclude that in this trial low-MI surgery is associated with enhanced survival, whereas outside of certain subgroups routine D2 lymphadenectomy is not. This observation suggests that surgeons might have more of an impact on patient survival by achieving a low-MI operation than a particular D level. A compelling dose-response effect reveals that the MI is a quantitative yardstick for assessing the adequacy of lymphadenectomy in gastric cancer.

A practical scoring system based upon ROC analysis for evaluating potential lymph nodes metastasis during gastric surgery

BACKGROUND AND OBJECTIVES

Current preoperative N staging does not offer an accurate estimation of lymph node involvement. We establish a new scoring system for predicting N stages to guide a rational lymphadenectomy for gastric cancer.

METHODS

Variables correlated with N stages were selected by multivariate stepwise logistic regression analysis. Variables granted the different scores according to the odds ratio (OR). Receiver operating characteristic (ROC) analysis was used to generate scoring ranges from N0 to N3. The agreement between predicted N staging and actual pN classification was analyzed using kappa statistics.

RESULTS

Tumor size, depth of invasion, and histological types were selected to establish the scoring system. Scores 0-4, 5-7, 8-9, and 10-13 were postulated to predict N0-3, respectively. The predicted N stage has good agreement with the actual pN classifications. The negative predictive values for N0-3 were 87.0, 86.4, 90.4, and 90.2%; the positive predictive values were 74.7, 62.8, 57.3, and 69.6%, respectively. The accuracy is 82% for N0-1, and 83.7% for N2-3.

CONCLUSIONS

The new scoring system can predict the N stage of gastric cancer. With its good negative predictive value, it is possible to minimize the potential hazards of applying a more extensive lymph node dissection than necessary.

Changing gastric cancer treatment in the United States and the pursuit of quality

The low incidence of gastric cancer in the US presents various quality challenges. For most US practitioners, individual experience is inadequate. Accrual to clinical trials testing new treatments can be daunting. However, through the use of nationally available clinical trials sponsored by many trial groups working in concert, and the use of national registries for treatment and outcome surveillance, a path to increased gastric cancer survival has been charted. Moreover, systems for continuous quality improvement at the institutional level are in place. Quality assurance is an increasing concern of both private and governmental groups. In this article, we summarize recent national US clinical trial findings concerning gastric cancer treatment, highlight national assessment systems for cancer outcomes, and describe what these systems tell us about the current status of gastric cancer care in the US, highlighting challenges and areas for potential improvement.

Prediction of gastric cancer lymph node status by sentinel lymph node biopsy and the Maruyama computer model

AIMS

The extent of lymph node dissection in gastric cancer remains controversial. The Maruyama computer model and the sentinel lymph node biopsy (SLNB) are compared for their value to predict the nodal status and lead to stage-adapted surgery.

METHODS

Thirty four patients with stage I-IV gastric cancer underwent both staging procedures. For SLNB, 15 patients underwent endoscopic, peri-tumoural injection of (99m)Tc-colloid, and 19 patients were injected of Patent blue V. All 'hot' or blue sentinel lymph nodes (SLNs) were separately excised and histopathologically assessed. If the SLN was negative after routine staining by H&E, it was processed completely and reanalysed after immunohistochemistry.

RESULTS

At least, one SLN was detected by means of SLNB in 33/34 of the patients. The sensitivity to identify a positive nodal status was 22/33 and the specificity/positive predictive value was 10/10 and 22/22. Additional micrometastases or isolated tumour cells in the SLN led to 'upstaging' of 5/15, initially classified as nodal negative by H&E-staining. Using the Maruyama computer model, a sensitivity of 22/23 for the correct prediction of the lymph node involvement was associated with a specificity of 2/10 and a positive predictive value of 22/30.

CONCLUSIONS

The clinical impact of the Maruyama computer model is limited due to low specificity and a low positive predictive value, rendering the method less useful as an indicator for individualised surgery.

Artificial neural network for prediction of lymph node metastases in gastric cancer: a phase II diagnostic study

BACKGROUND

Extension of lymphadenectomy in gastric cancer is controversial, and preoperative diagnosis of lymph node metastases (LNM) is difficult. Therefore, knowledge-based systems such as the Maruyama computer program (MCP) are being developed. MCP shows good prognostic value for the compartments; however, for different lymph node groups (LNG) there are a large number of false positives. The aim of this study was to evaluate artificial neural networks (ANN) for predicting LNM in patients with gastric cancer and to compare the predictive power with that of MCP.

METHODS

A total of 135 consecutive patients who underwent D2 gastrectomy were included. We applied a single-layer perceptron to the data of 4302 patients from the National Cancer Center, Tokyo, and compared the results with those from the MCP.

RESULTS

Prediction of N(+) or N0 with ANN-1 (Borrmann classification, T category, and tumor size and location) had an accuracy of 79%. The predictive value for LNM in each of the LNG varied: ANN-1, 64% to 86%; MCP, 42% to 70%. We constructed another ANN by using the additional parameter of metastases in LNG 3 as an example of sentinel node. The accuracy of this ANN was 93%.

CONCLUSIONS

Using an ANN, LNM in each LNG can be accurately predicted. Additional knowledge about one lymph node improves the results.

Expression of vascular endothelial growth factor C and chemokine receptor CCR7 in gastric carcinoma and their values in predicting lymph node metastasis

AIM: To study the expression of vascular endothelial growth factor C (VEGF-C) and chemokine receptor CCR7 in gastric carcinoma and to investigate their associations with lymph node metastasis of gastric carcinoma and their values in predicting lymph node metastasis.

METHODS: The expression of VEGF-C and CCR7 in gastric carcinoma tissues obtained from 118 patients who underwent curative gastrectomy was examined by immunohistochemistry. Among these patients, 39 patients underwent multi-slice spiral CT (MSCT) examination.

RESULTS: VEGF-C and CCR7 were positively expressed in 52.5 and 53.4% of patients. VEGF-C expression was more frequently found in tumors with lymph node metastasis than those without it (P < 0.001). VEGF-C expression was also closely related to lymphatic invasion (P < 0.001), vascular invasion (P < 0.01), and TNM stage (P < 0.001). However, there was no significant correlation between VEGF-C expression and age at surgery, gender, tumor size, tumor location, Lauren classification, and depth of invasion. CCR7 expression was significantly higher in patients with lymph node metastasis compared with those without lymph node metastasis (P < 0.001) and was also associated with tumor size (P < 0.01), depth of invasion (P < 0.001), lymphatic invasion (P < 0.001), and TNM stage (P < 0.001). However, the presence of CCR7 had no correlation to age at surgery, gender, tumor location, Lauren classification, and vascular invasion. Among the 39 patients who underwent MSCT examination, only CCR7 expression was related to lymph node metastasis determined by MSCT (P < 0.05). In the current retrospective study, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of VEGF-C and CCR7 expression in the diagnosis of lymph node metastasis for patients with gastric carcinoma were 73.8%, 70.2%, 72.6%, 71.4% and 72.0%, and 82.0%, 77.2%, 79.4%, 80.0% and 79.7%, respectively. After subdivision according to the combination of VEGF-C and CCR7 expression, receiver operating characteristic (ROC) analysis showed that the accuracy of the combined examination of VEGF-C and CCR7 expression in predicting lymph node metastasis was relatively high (area under ROC curve [Az] = 0.83).

CONCLUSION: The expression of VEGF-C and CCR7 is related to lymph node metastasis of gastric carcinoma and both of them may become new targets for the treatment of gastric carcinoma. Furthermore, the combined examination of VEGF-C and CCR7 expression in endoscopic biopsy specimens may be useful in predicting lymph node metastasis of gastric carcinoma and deciding the extent of surgical lymph node resection.

Comparison of complications after D2 and D3 dissection for gastric cancer

BACKGROUND

D3 dissection is accepted as having higher rates of mortality and morbidity than D2 dissection. In this study, we aimed to evaluate the mortality and morbidity rates of D3 dissection in our department and to compare these with mortality and morbidity after D2 dissection.

PATIENTS AND METHODS

All patients who underwent radical gastric resection with lymph node dissection for gastric adenocarcinoma between June 1999 and June 2002 were evaluated. Clinicopathologic features of the tumour, the resection and lymphadenectomy, the postoperative mortality and morbidity were analysed.

RESULTS

There were 359 patients admitted for the treatment of gastric cancer. One hundred twenty four underwent palliative resection and 134 underwent resection with curative intent. Of 34/134 patients, underwent gastric resection with D3 dissection, and 100 underwent D2 dissection. The overall operative mortality rate of D2 and D3 dissections was 1 and 8.8%, respectively (p<0.05). The relaparotomy rate was almost doubled in D3 dissection group (11.8% vs. 6%) but this difference was not statistically significant. D3 dissection was also associated with an increase in morbidity (35.3% vs. 10%, p<0.05).

CONCLUSIONS

This study indicates that D3 dissection can be performed with reasonable safety. It may be a useful alternative procedure in advanced cases for which additional risks of surgical morbidity and mortality are felt to be outweighed by potential benefits to patients.

Role of computer analysis in gastric cancer surgery: evaluation of the WinEstimate v. 2.5 computer program

To identify the group of patients with gastric cancer who can benefit from extensive lymphadenectomy and to offer a rational approach to lymph node dissection, it is important to know the incidence of metastases at each lymph node station. A computer program was developed for assessment of lymph node involvement and survival time in each individual case according to preoperative variables. In patients who have undergone R0 resection with D2 lymphadenectomy, differences between the individual results generated by the computer and the actual data were compared. A cutoff point of 10% in the prediction of metastases was used as a positive result. The computer program made false predictions in 9% of patients for the pN status (3% lower and 6% higher than the actual status). Computerized prediction of 5-year survival was close to the rate calculated by the Kaplan-Meier method (55.5% vs 56.1%). Preoperative computer analysis of patient data and tumor characteristics offers a rational approach to individualizing tumor therapy] where the extent of lymph node dissection is tailored to the type, site, and stage of the tumor, thereby minimizing the disadvantages (morbidity, mortality) associated with the extensive operative procedure.

Gastric cancer

The past decade has seen many advances in knowledge about gastric cancer. Notably, tumour biology and lymphatic spread are now better understood, and treatment by surgical and medical oncologists has become more standardised. Since refrigerators have replaced other methods of food conservation, Helicobacter pylori has become a factor in the cause of gastric cancer. Cancers that arise at the oesophagogastric junction might be further examples of wealth-associated disease. To tailor treatment better, the western hemisphere needs to borrow from the East by establishing screening programmes for early diagnosis, through careful surgical resection, and through detailed analysis of tumour spread. In Europe and the USA, most patients reach treatment with cancers already at an advanced stage. For these patients, three important randomised trials are underway that evaluate combined therapy. Cytostatic drugs, especially angiogenesis inhibitors have proved disappointing; however, basic research efforts to detect familial gastric cancers and to assess minimally residual disease look more hopeful.