Impact of the Number of Lymph Nodes Examined on Differences in Survival for Surgically Treated Gastric Cancer Patients Between the US and Japan Using Nationwide Databases

Background: Although incidence and mortality have decreased, gastric cancer (GC) is still a public health issue globally. The international collaborative study for cancer survival using population-based cancer registry showed that the survival of GC was higher in Korea and Japan than other countries, including the United States of America (US). Aim: We examined the determinant factors of the high survival in Japan, compared with the US, with particular focus on the impact of the number of lymph nodes (LNs) examined for surgically treated patients. Methods: We obtained data on 88,447 cases from the nationwide GC registration project, the Japanese Gastric Cancer Association (JGCA), from 2004-2007. We also obtained 18,995 GC cases from US population-based cancer registry data from the Surveillance, Epidemiology, and End Results Program (SEER), diagnosed from 2004-2010. We estimated five-year relative survival and applied a multivariate excess hazard model to compare the two countries. We considered the effect of LNs examined on differences in survival. Results: Five-year relative survival in Japan was 79.8%, compared with 40.1% in the US. After controlling for confounding factors, we still observed significantly higher survival in Japan. The distribution of number of LNs examined showed notable differences between two countries. In over 50% of patients in the US, only 1 to 15 LNs were examined. A higher number of LNs examined showed better survival in both countries. The differences in excess death from cancer between countries were reduced in the category when more than 30 LNs were examined. Conclusion: Although it is difficult to remove biases to compare the two countries, stage migration, related to the more detailed retrieving strategy for LNs in Japan, is a key explanation for high survival in Japan.

Prognostic factors for survival in patients with pT1 N+ or T2–3 N0 gastric cancer in Japan

Background

The outcome for pT1 N+ or pT2–3 N0 gastric cancer is favourable, but some patients suffer from recurrent disease. The aim of this study was to identify prognostic factors in patients with pT1 N+ or pT2–3 N0 gastric cancer.

Methods

This was a multicentre, retrospective cohort study. All patients with pT1 N+ or pT2–3 N0 gastric cancer who underwent curative gastrectomy at five high-volume, specialized cancer centres in Japan between 2000 and 2008 were included. Demographic, clinical, surgical and pathological data were collected. Independent prognostic factors were identified using a Cox proportional hazards regression model.

Results

Some 1442 patients were included. The 5-year overall survival rate for patients with pT1 N+ or pT2–3 N0 gastric cancer was 92·0 per cent. Multivariable analysis for overall survival identified age (hazard ratio (HR) 2·67, 95 per cent c.i. 2·09 to 3·43), sex (HR 0·57, 0·39 to 0·83) and clinical tumour depth (cT) (HR 1·45, 1·06 to 1·98) as independent prognostic factors.

Conclusion

Survival of patients with pT1 N+ or pT2–3 N0 gastric cancer is good. Age 65 years or above, male sex and cT2-4 category are associated with worse overall survival.

The clinical significance of para-aortic nodal dissection for advanced gastric cancer

BACKGROUND

Advanced gastric cancer with the risk of extensive nodal involvement has a poor prognosis even after radical surgery. We aimed to comprehensively review the clinical significance of extended radical dissection.

METHODS

Between 1990 and 1999, 232 patients underwent radical gastrectomy with D2 plus para-aortic lymph node dissection at the National Cancer Center Hospital in Tokyo. We analyzed the short-term surgical and long-term oncological outcomes of these operations.

RESULTS

Major complications occurred in 34 patients (14.7%). Median operation time was 325 min (range: 182-555) and median blood loss was 715 ml (range: 95-4457). There were 2 (0.9%) hospital deaths. Nodal involvement of the para-aortic area was seen in 33 patients (14.2%). The overall 5- and 10-year survival rates in patients with para-aortic node involvement were 21.2 and 15.2%, respectively. Multivariate analysis of patients with para-aortic node involvement revealed advanced age and metastasis in the interaorticocaval lymph nodes above the left renal vein to be independent risk factors impacting overall survival.

CONCLUSIONS

PAN dissection has limited applicability and effectiveness to the patients with advanced gastric cancer. Above all, advanced age and metastasis in the interaorticocaval lymph nodes above the left renal vein are significant poor prognostic factor even after radical resection.

Surgical treatment of gastric cancer in Japan, trend from standardization to individualization

Japan has a huge number of patients with gastric cancer and has developed various surgical treatments for this disease.This paper intends to introduce our strategies against gastric cancer. The Japanese Gastric Cancer Association was established in 1962. Its major purposes are promotion of basic and clinical researches and popularization of the latest knowledge and technologies. For the purposes, the association organized the annual scientific meeting and the nationwide registry by member hospitals, and published the Japanese Classification of Gastric Cancer (1) and the Treatment Guide Line (2). The nationwide registry reported that proportion of Stage-I cancer was 22.5% in 1963-66,which increased to 59.3% in 2008 (3,4,5). 11,261 patients with gastric resection were registered by 187 hospitals in 2008. 63 patients were died within 30 postoperative days and the direct death rate was 0.55%. 5 year survival rate (5YSR) was 37.5% for resected cases in 1963-66, which was improved to 70.1% in 2008. 5YSR was improved from 55.1% to 74.1% for Stage-II, and from 39.1% to 48.8% for Stage-III in the period. According to remarkable increase of early stage cancer, principle of surgical treatments was shifted from "€œextended and standardized surgery for radicality" €to "€œreasonable and individual surgery considering safety and quality of life"€. This trend produced a large variation in surgical treatments; namely 1) minimally invasive surgeries,2) function preserving surgeries, 3) optimal extent of lymph node dissection, and 4) aggressive but safe surgeries.Intention of this paper is to explain these procedures, the intentions, the indications, and the treatment results.

Development and external validation of a nomogram for overall survival after curative resection in serosa-negative, locally advanced gastric cancer

BACKGROUND

Few nomograms can predict overall survival (OS) after curative resection of advanced gastric cancer (AGC), and these nomograms were developed using data from only a few large centers over a long time period. The aim of this study was to develop and externally validate an elaborative nomogram that predicts 5-year OS after curative resection for serosa-negative, locally AGC using a large amount of data from multiple centers in Japan over a short time period (2001-2003).

PATIENTS AND METHODS

Of 39 859 patients who underwent surgery for gastric cancer between 2001 and 2003 at multiple centers in Japan, we retrospectively analyzed 5196 patients with serosa-negative AGC who underwent Resection A according to the 13th Japanese Classification of Gastric Carcinoma. The data of 3085 patients who underwent surgery from 2001 to 2002 were used as a training set for the construction of a nomogram and Web software. The data of 2111 patients who underwent surgery in 2003 were used as an external validation set.

RESULTS

Age at operation, gender, tumor size and location, macroscopic type, histological type, depth of invasion, number of positive and examined lymph nodes, and lymphovascular invasion, but not the extent of lymphadenectomy, were associated with OS. Discrimination of the developed nomogram was superior to that of the TNM classification (concordance indices of 0.68 versus 0.61; P < 0.001). Moreover, calibration was accurate.

CONCLUSIONS

We have developed and externally validated an elaborative nomogram that predicts the 5-year OS of postoperative serosa-negative AGC. This nomogram would be helpful in the assessment of individual risks and in the consideration of additional therapy in clinical practice, and we have created freely available Web software to more easily and quickly predict OS and to draw a survival curve for these purposes.

Integrated genomic and functional analyses reveal glyoxalase I as a novel metabolic oncogene in human gastric cancer

Chromosomal abnormalities are good guideposts when hunting for cancer-related genes. We analyzed copy number alterations of 163 primary gastric cancers using array-based comparative genomic hybridization and simultaneously performed a genome-wide integrated analysis of copy number and gene expression using microarray data for 58 tumors. We showed that chromosome 6p21 amplification frequently occurred secondary to ERBB2 amplification, was associated with poorer prognosis and caused overexpression of half of the genes mapped. A comprehensive small interfering RNA knockdown of 58 genes overexpressed in tumors identified 32 genes that reduced gastric cancer cell growth. Enforced expression of 16 of these genes promoted cell growth in vitro, and six genes showing more than two-fold activity conferred tumor-forming ability in vivo. Among these six candidates, GLO1, encoding a detoxifying enzyme glyoxalase I (GLO1), exhibited the strongest tumor-forming activity. Coexpression of other genes with GLO1 enhanced growth-stimulating activity. A GLO1 inhibitor, S-p-bromobenzyl glutathione cyclopentyl diester, inhibited the growth of two-thirds of 24 gastric cancer cell lines examined. The efficacy was found to be associated with the mRNA expression ratio of GLO1 to GLO2, encoding glyoxalase II (GLO2), another constituent of the glyoxalase system. GLO1 downregulation affected cell growth through inactivating central carbon metabolism and reduced the transcriptional activities of nuclear factor kappa B and activator protein-1. Our study demonstrates that GLO1 is a novel metabolic oncogene of the 6p21 amplicon, which promotes tumor growth and aberrant transcriptional signals via regulating cellular metabolic activities for energy production and could be a potential therapeutic target in gastric cancer.

An integrated analysis of two phase II trials (JCOG0001 and JCOG0405) of preoperative chemotherapy followed by D3 gastrectomy for gastric cancer (GC) with extensive lymph node metastasis (ELM)

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Background: GC with ELM (bulky N2 metastasis and / or para-aortic lymph node metastases [PAN]) is commonly regarded unresectable, while in JCOG combined modality treatment has been tested since 2000 (JCOG0001 and JCOG0405). Both trials met their primary endpoints (i.e., 3 year-survival of 27.3% in JCOG0001 and R0 resection of 82.4% in JCOG0405). The survival and the toxicity profile were quite different between the trials despite the similar eligibility with an outstanding 3-year survival of 58.8% in JCOG0405. This study is conducted to explore if survival is still better in JCOG0405 after adjusting baseline factors and if there is a subset of patients (pts) who benefit more from either treatment.

Methods: Eligibility criteria for both included histologically proven gastric adenocarcinoma; bulky nodal involvement around major branched arteries to the stomach and/or PAN; cM0 (except PAN); negative lavage cytology; not linitis plastica type; PS of 0 or 1. Pts received two or three cycles of induction chemotherapy of IP: irinotecan (70 mg/m2 on day 1 and day 15) and cisplatin (80 mg/m2 on day 1) in JCOG0001, or SP: S1 (80 mg/m2 from day 1 to 21) and cisplatin (60 mg/m2 on day 8) in JCOG0405, followed by D3 gastrectomy. Multivariate analysis for overall survival adjusting baseline factors and treatment (IP/SP) was performed with a Cox regression model. Interaction tests were also carried out between baseline factors and treatment.

Results: After adjusting baseline factors, SP was superior than IP for overall survival (HR=0.335: 0.184 – 0.612). There was only interaction effect between treatment and the status of lymph node metastases (bulkyN+/PAN- vs bulkyN-/PAN+ vs bulkyN+/PAN+; p=0.1306).

Conclusions: SP was shown to be the favorable treatment for GC with ELM by multivariate analysis, while poor prognosis in pts having both bulky N+ and PAN+ may necessitate further treatment improvement.

No significant financial relationships to disclose.

A phase II study of preoperative chemotherapy with S-1 (S) and cisplatin (P) followed by D3 gastrectomy for gastric cancer (GC) with extensive lymph node metastasis (ELM): Survival results of JCOG0405

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Background: GC with ELM, especially in case of M1(LYM), is regarded unresectable in many countries, while challenge is ongoing in Japan to treat them by intensive chemotherapy followed by super extended surgery. In our previous phase II study (JCOG0001) for the same population, iritotecan plus P (IP) chemotherapy followed by surgery showed remarkable survival of 27.0% at 3 years but its toxicity led to rather high treatment related death (TRD). Development of safer and more effective treatment is urged.

Methods: Eligibility criteria included histologically proven gastric adenocarcinoma; bulky nodal involvement around major branched arteries to the stomach and/or para-aortic nodal metastases; cM0 (except para-aortic nodes); negative lavage cytology; not linitis plastica type; PS of 0 or 1. Patients (pts) received two or three 28- day cycles of induction chemotherapy of S (80 mg/m2 from day 1 to 21) and P (60 mg/m2 on day 8), and then underwent D3 gastrectomy. Primary endpoint was R0 resection and key secondary endpoint was 3-year survival. Other secondary endpoints included response rate and adverse events.

Results: Between 02/2005 and 06/2007, 53 pts were enrolled and 2 pts were ineligible. Only surrogate endpoints of efficacy and feasibility were reported in ASCO-GI 2008, which included clinical response of 64.7%, R0 of 82.4%, pathological response of 51.0%, and no TRD with low toxicities. The 3-year overall survival, which we first clarified in this report, was 58.8% (95% CI, 44.1-70.9%).

Conclusions: Preoperative SP followed by D3 gastrectomy demonstrated excellent 3-year survival with low mortality compared with preoperative IP, which was far better result than expected against this unresectable population. This multimodal treatment is highly promising for GC with ELM.

[Table: see text]

Feasibility study of adjuvant chemotherapy with S-1 plus cisplatin for gastric cancer

PURPOSE

To evaluate the feasibility of S-1 plus cisplatin as adjuvant chemotherapy for stage III gastric cancer after curative resection.

METHODS

Japanese patients with stage III gastric cancer who underwent gastrectomy with D2 lymph node resection were enrolled. Treatment consisted of 3 cycles of S-1 (80 mg/m(2)/day, b.i.d.) for 21 days followed by a 14-day rest, and cisplatin (60 mg/m(2) iv) on day 8. After that, S-1 monotherapy was given on days 1-28 every 6 weeks until 1-year postsurgery. After protocol amendment, the first chemotherapy cycle consisted of S-1 monotherapy; cisplatin was added to cycles 2, 3, and 4, followed by S-1 monotherapy up to 1-year postsurgery. The primary endpoint was the completion rate of three cycles of S-1 plus cisplatin.

RESULTS

A total of 63 enrolled patients have been evaluated. Grade 3/4 toxicities included neutropenia (40%), anorexia (28%), and febrile neutropenia (4%) before protocol amendment (n = 25), and neutropenia (37%), anorexia (8%), and febrile neutropenia (3%) after amendment implementation (n = 38). Excluding ineligible cases, treatment completion rates were 57% (12/21) before and 81% (30/37) after the protocol amendment.

CONCLUSIONS

The amended S-1 plus cisplatin is more feasible than the original protocol because of early dose reduction of S-1 prior to cisplatin addition and greater recovery time from surgery prior to cisplatin. This treatment should be considered as a feasible experimental arm for the next postoperative adjuvant phase III trial.

Long-term results of gastrectomy for alpha-fetoprotein-producing gastric cancer

BACKGROUND

alpha-Fetoprotein (AFP)-producing gastric cancer is a rare tumour. It is said to have a high incidence of liver metastasis and poor prognosis. This study sought to evaluate long-term outcomes in such patients.

METHODS

Records of consecutive patients with gastric carcinoma who underwent preoperative measurement of serum AFP levels and gastrectomy were reviewed to identify those who satisfied the following criteria: preoperative AFP level exceeding 40 ng/ml with a decrease after gastrectomy, or raised preoperative AFP level (10-39 ng/ml) and resected tumour showing histologically characteristic features or immunohistochemically positive AFP production.

RESULTS

Of 3374 patients with gastric cancer, 53 (1.6 per cent) met the selection criteria. Tumours were characterized by a high incidence of nodal (79 per cent) or liver (53 per cent) metastasis. Preoperative serum AFP levels showed no correlation with tumour size, depth of invasion, disease stage or survival. The 5-year survival rate was 34 per cent. Five patients survived after recurrence following multimodal treatment. A rising AFP level during follow-up always led to tumour recurrence, but the level remained normal in 11 of 31 patients with recurrence.

CONCLUSION

AFP-producing tumours represent a small subgroup of gastric cancer with high metastatic potential. Postoperative serum AFP level can help predict recurrence but a normal level does not mean absence of recurrence. Prognosis is not as poor as previously thought, and multimodal treatment may be worthwhile even in patients with recurrent tumour.

Long-term outcome after proximal gastrectomy with jejunal interposition for suspected early cancer in the upper third of the stomach

Background

Proximal gastrectomy was introduced as a function-preserving operation for early gastric cancer (EGC). The aim of this study was to investigate long-term outcomes after this procedure.

Methods

Between 1993 and 2005, patients with suspected EGC in the upper third of the stomach underwent proximal gastrectomy. The long-term oncological and surgical outcomes were assessed.

Results

Of 128 patients thought to have EGC, 14 had advanced disease. Nodal involvement was seen in 13 patients (10·2 per cent). Postoperative complications developed in 20 (15·6 per cent). Anastomotic stricture was the most frequent complication, occurring in 13 patients (10·2 per cent). There were no postoperative deaths. During follow-up, nine patients (7·0 per cent) were hospitalized owing to bowel obstruction. Eight (6·3 per cent) developed a second primary gastric carcinoma. The overall 5-year survival rate was 90·5 per cent.

Conclusion

Proximal gastrectomy is well tolerated, with excellent outcomes in patients with suspected EGC. It is recommended as a standard procedure for the treatment of EGC in the upper third of the stomach.

Predictive factors of outcome and clinical management of adjuvant S-1 chemotherapy for gastric cancer

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Background: Adjuvant S-1 chemotherapy has become a standard treatment for stage II and III gastric cancer, following the Adjuvant Chemotherapy Trial of TS-1 for Gastric Cancer (ACTS-GC). This study was designed to identify factors that can be used for predicting the outcome and clinical management of adjuvant S-1 chemotherapy in patients with stage II and III gastric cancer. Methods: We retrospectively examined 97 consecutive patients with stage II or III gastric cancer who received S-1 chemotherapy after gastrectomy to investigate factors associated with outcome and clinical management. S-1 (80 mg/m2/day) was orally administered twice daily for 28 consecutive days, followed by a 14-day rest period. As a rule, this protocol was continued for one year after gastrectomy. According to toxicity profiles, dose reduction or dose schedule modification was performed. Results: Patients consisted of 63 males and 34 females (median age, 59 years; range, 35–80 years), and those undergoing total gastrectomy/subtotal gastrectomy = 40/57. The median follow-up period after gastrectomy was 43.0 months (range, 5.3–73.4 months). As for adjuvant S-1 chemotherapy, dose reduction and dose schedule modification were conducted in 59% and 40% of the patients, respectively. Of the patients needing dose reduction, 79% underwent reduction within three months of treatment. The most common reason for dose reduction during the treatment period was anorexia (47%), followed by diarrhea (32%), leukopenia (24%) and rash (16%) with overlapping reasons. The duration period of the treatment was at least 3 months in 88%, at least 6 months in 82%, and scheduled 12 months in 73%. Twenty six patients discontinued treatment due to adverse event (20 patients), recurrent disease (2 patients) and other reasons (4 patients). The median duration until treatment discontinuation was 4.0 months. To date, 15 patients have recurrent disease. Significant predictive factors for recurrence were not statistically identified. Conclusions: Most patients (73%) could complete the scheduled treatment duration by dose reduction and dose schedule modification.

No significant financial relationships to disclose.

The prognostic impact of isolated tumor cells in lymph nodes of T2N0 gastric cancer: comparison of American and Japanese gastric cancer patients

BACKGROUND

The clinical significance of immunohistochemically detected isolated tumor cells (ITC) in lymph nodes of gastric cancer patients is controversial. This study examined the prognostic impact of ITC on patients with early-stage gastric cancer in two large volume centers in the United States and Japan.

METHODS

Fifty-seven patients with T2N0M0 gastric carcinoma who underwent gastric resection between January 1987 and January 1997 at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York and 107 patients resected at National Cancer Center Hospital (NCCH) in Tokyo between January 1984 and December 1990 were studied. The sections were newly prepared from each lymph node for immunohistochemical staining for cytokeratin. Lymph nodes and original specimens from MSKCC were examined by pathologists in NCCH. The prognostic significance of the presence of ITC in lymph nodes was investigated in patients of both institutions.

RESULTS

ITC were identified in 30 of 57 patients (52.6%) at MSKCC and in 38 of 107 patients (35.5%) at NCCH. In both institutions, there was no significant difference in the prognosis of the studied patients with or without ITC (P= .22, .86 respectively).

CONCLUSIONS

The presence of ITC detected by immunohistochemistry in the regional lymph nodes did not affect the prognosis of American and Japanese patients with T2N0M0 gastric carcinoma who underwent gastrectomy with D2 lymph node dissection.

Treatment strategy after non-curative endoscopic resection of early gastric cancer

BACKGROUND

Endoscopic resection (ER) is indicated for patients with early gastric cancer who have a negligible risk of lymph node metastasis (LNM). Histological examination of the resected specimen may indicate a possible risk of LNM or a positive resection margin. These patients are considered to have undergone non-curative ER. The aim of this study was to determine the appropriate treatment strategy for such patients.

METHODS

A total of 298 patients who had non-curative ER were classified into those with a positive lateral margin only (group 1; 72 patients) and those with a possible risk of LNM (group 2; 226 patients).

RESULTS

Surgery was performed within 6 months of non-curative ER in 19 patients in group 1 and 144 in group 2. In group 1, nine patients were found to have local residual tumours, all limited to the mucosal layer without LNM. In Group 2, 13 patients had residual disease, including four local tumours without LNM, two local tumours with LNM and seven cases of LNM alone. The rate of LNM after surgery was 6.3 per cent in group 2.

CONCLUSION

Surgery remains the standard treatment after non-curative ER in patients with a possible risk of LNM.

Outcome of pylorus-preserving gastrectomy for early gastric cancer

Background

Pylorus-preserving gastrectomy has been introduced as a function-preserving operation for early gastric cancer in Japan. The aim of this study was to investigate the safety and radicality of the procedure.

Methods

Between 1995 and 2004, 611 patients with apparent early gastric cancer in the middle third of the stomach had pylorus-preserving gastrectomy. The short-term surgical and long-term oncological outcomes of these operations were assessed.

Results

The accuracy of preoperative diagnosis of early gastric cancer was 94·3 per cent. Nodal involvement was seen in 62 patients (10·1 per cent). There were no postoperative deaths. Complications developed in 102 patients (16·7 per cent). Major complications, such as leakage and abscess, were observed in 19 (3·1 per cent). The most common complication was gastric stasis, occurring in 49 (8·0 per cent). The overall 5-year survival rate in patients with early gastric cancer was 96·3 per cent.

Conclusion

Pylorus-preserving gastrectomy is a safe operation with an excellent prognosis in patients with early gastric cancer. It is recommended as the standard procedure for early gastric cancer in the middle third of the stomach.

Identification of the high-risk group for metastasis of gastric cancer cases by vascular endothelial growth factor receptor-1 overexpression in peripheral blood

Identification of an isolated tumour cell with metastatic ability is important for predicting the recurrence and prognosis of gastric cancer. A biological marker for evaluating the metastatic ability of gastric cancer cells has not yet been identified. We assessed vascular endothelial growth factor receptor-1 mRNA expression by quantitative real-time reverse transcriptase-polymerase chain reaction. Vascular endothelial growth factor receptor-1 mRNA in peripheral blood was more highly expressed in perioperative metastasis-positive and postoperative recurrence cases than in normal control cases, early cancer cases and nonmetastatic advanced cancer cases. The peripheral blood vascular endothelial growth factor receptor-1 mRNA-positive group was associated with advanced clinical stage, deep invasion beyond the muscularis propria, lymphatic involvement, vascular involvement, lymph node metastasis, positive peritoneal lavage cytology, preoperative metastasis and postoperative recurrence. Flow cytometry analysis disclosed that vascular endothelial growth factor receptor-1 expressing cells in the peripheral blood were more abundant in cancer cases with metastases than in cases without metastases. Our data suggest that the amount of positive cells may provide information on the clinical features of gastric cancer, especially in regard to gastric cancer metastasis.

Surgical treatment of advanced gastric cancer: Japanese perspective

The results of clinical trials regarding surgery of curable advanced gastric cancer and esophagogastric junction (EGJ) tumors are reviewed and summarized. Four clinical trials have evaluated D2 dissection for curable gastric cancer in the West. Two large trials in the UK and the Netherlands failed to prove the efficacy of D2 dissection. However, these trials had critical weak points. As they were carried out in a number of hospitals where there was no experience with this surgery, the quality of surgery and postoperative care were very poor making the hospital mortality unacceptably high. After these trials, an Italian group started a phase II study in 8 hospitals with a relatively high volume to confirm the safety of this procedure for Caucasians. They achieved 3% mortality, which was much smaller than that of even D1 in the former trials. These results first highlighted the importance of learning and hospital volume in D2 dissection. Survival results of the Dutch trial showed some difference between D1 and D2, but the difference was not statistically significant. This was attributed to the high hospital mortality and poor quality of surgery, especially low compliance of D2 and the high rate of extension of D1, making this comparison similar to that between D1.3 and D1.7. The results of the phase III study by the Italian group are awaited. Recently a Taiwanese trial proved the benefit of D2 dissection over D1 in a phase III trial. This was a single institutional trial with a sample size of 221 patients. The 5-year survival rate of D2 and D1 was 59.5 and 53.6%, respectively (p = 0.04). The Dutch trials for EGJ tumors showed a large difference in overall survival between the transthoracic and transhiatal approach for Siewert type 1 and 2 tumors, but this was not statistically significant, most likely due to the small sample size. In the subgroup analysis, they demonstrated that there was no survival difference in Siewert type 2 but a large difference in Siewert type 1. A Japanese study showed that there is no benefit to the thoraco-abdominal approach over the transhiatal approach for EGJ tumors whose invasion in the esophagus is 3 cm or less. These two trials clearly demonstrated that mediastinal dissection through a right thoracotomy is recommendable for Siewert type 1, while the transhiatal approach should be considered as standard for Siewert type 2.

Cancer of the gastric stump following distal gastrectomy for cancer

BACKGROUND

Cancer of the gastric stump (CGS) after distal gastrectomy for cancer has not been characterized in a large study. The aim of this study was to investigate the clinicopathological features and outcome of CGS following distal gastrectomy for cancer.

METHODS

Patients with CGS following distal gastrectomy for gastric cancer diagnosed between 1970 and 2002 were reviewed retrospectively.

RESULTS

A total of 108 patients was identified. The median interval between the initial gastrectomy and resection for CGS was 7.5 (range 1-41) years. The depth of tumour invasion was T1 in 67 patients, T2 in 16, T3 in eight and T4 in 17 patients. Endoscopic mucosal resection was performed in 25 patients with T1 tumours. R0 resection was achieved in 103 patients. The overall 5-year survival rate was 53.1 per cent. The 5-year survival rates for patients with T1, T2, T3 and T4 disease were 76, 40, 13 and 9 per cent respectively.

CONCLUSION

The outcome for patients with non-early CGS was poor. Early detection of CGS is important following distal gastrectomy for gastric cancer and strict surveillance is recommended for at least 10 years after the initial gastrectomy.

Extranodal metastasis is an indicator of poor prognosis in patients with gastric carcinoma

BACKGROUND

The aim of this study was to determine the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma.

METHODS

The study included 1023 patients who underwent gastrectomy with lymphadenectomy for primary gastric carcinoma between January 1993 and December 1996. EM was defined as the presence of tumour cells in extramural soft tissue that was discontinuous with either the primary lesion or locoregional lymph nodes.

RESULTS

EM was detected in 146 (14.3 per cent) of the 1023 patients and in 1060 (3.0 per cent) of the 35 811 nodules that were retrieved as 'lymph nodes' from adipose connective tissues. The incidence of EM was significantly higher in patients with tumours that were large (diameter 10 cm or more), infiltrative, deeply invading or undifferentiated and in those with lymph node, peritoneal or liver metastases, or lymphatic or vascular involvement. After curative operation overall survival was significantly worse for patients with EM than those without (P < 0.001). Multivariate analysis identified EM as an independent prognostic factor (hazard ratio 1.82 (95 per cent confidence interval 1.23 to 2.71); P = 0.003).

CONCLUSION

EM is an independent prognostic factor and should therefore be included in the tumour node metastasis (TNM) staging system.

Extranodal metastasis is an indicator of poor prognosis in patients with gastric carcinoma

BACKGROUND

The aim of this study was to determine the clinical significance and prognostic impact of extranodal metastasis (EM) in gastric carcinoma.

METHODS

The study included 1023 patients who underwent gastrectomy with lymphadenectomy for primary gastric carcinoma between January 1993 and December 1996. EM was defined as the presence of tumour cells in extramural soft tissue that was discontinuous with either the primary lesion or locoregional lymph nodes.

RESULTS

EM was detected in 146 (14.3 per cent) of the 1023 patients and in 1060 (3.0 per cent) of the 35 811 nodules that were retrieved as 'lymph nodes' from adipose connective tissues. The incidence of EM was significantly higher in patients with tumours that were large (diameter 10 cm or more), infiltrative, deeply invading or undifferentiated and in those with lymph node, peritoneal or liver metastases, or lymphatic or vascular involvement. After curative operation overall survival was significantly worse for patients with EM than those without (P < 0.001). Multivariate analysis identified EM as an independent prognostic factor (hazard ratio 1.82 (95 per cent confidence interval 1.23 to 2.71); P = 0.003).

CONCLUSION

EM is an independent prognostic factor and should therefore be included in the tumour node metastasis (TNM) staging system.

Prospective study of proximal gastrectomy for early gastric cancer in the upper third of the stomach

BACKGROUND

Total gastrectomy with D2 dissection is the standard treatment in Japan for early upper-third gastric cancer. The purpose of this study was to confirm the safety and radicality of proximal gastrectomy as an alternative operation.

METHODS

Between 1993 and 1999, 45 patients with an apparent primary early gastric cancer in the upper third of the stomach were treated by proximal gastrectomy with jejunal interposition. The spleen was preserved, but the suprapancreatic nodes were cleared.

RESULTS

Histology confirmed early gastric cancer in 37 patients while eight had advanced disease. Nodal metastasis was observed in six patients. There was no hospital death and no early postoperative complications. One patient died from nodal recurrence and two from unrelated causes. Two patients had reflux symptoms without endoscopic oesophagitis. Mean weight loss was 11.5 per cent of initial bodyweight.

CONCLUSION

Proximal gastrectomy for early upper-third gastric cancer can be performed safely with an excellent cure rate. This procedure deserves further clinical evaluation to assess patients' quality of life.

[Problems of international standardization of gastric cancer surgery]

Treatment results of gastric cancer patients differ considerably between Japan and the West, even at the same stage of disease. This may be partly explained by the varying extent of local control and the "stage-migration" theory. There is an important conceptual difference concerning lymphadenopathy and lymphadenectomy: Japanese surgeons believe that lymph nodes are the governors of metastatic disease and thus that lymphadenectomy will result in cure, while in the West lymph nodes are seen merely as the indicators of systemic metastasis and thus lymphadenectomy serves only for staging. The UICC TNM system has recently abandoned the anatomical N-classification and adopted the numeric N-classification. Although this is a good prognostic indicator, it does not provide surgeons with any information for surgical decision-making. Japanese surgeons will continue to use the Japanese classification that has served as a guideline for standard D2 lymphadenectomy. To establish an international standard for gastric cancer treatment, both sides should make efforts to understand each other and discuss most practical and beneficial treatment modalities for patients in the respective medical environments.

Immunohistochemically detected micrometastases of the lymph nodes in patients with gastric carcinoma

BACKGROUND

Lymph node status is a major determinant of disease recurrence after patients undergo curative resection for gastric carcinoma. A proportion of patients without lymph node metastasis develop systemic recurrences. Recent studies in a range of solid tumors have found a high incidence of micrometastases in the regional lymph nodes of patients with apparently negative lymph nodes. In patients with breast and colorectal carcinoma, the presence of micrometastases has been associated with a poorer prognosis. In patients with gastric carcinoma, the significance of micrometastases in lymph nodes remains controversial. Most published reports on this subject suffer from the problems of small sample size and selection bias.

METHODS

One hundred seven patients with pathologic T2N0M0 (tumor invades muscularis propria or subserosa [T2], no regional lymph node metastasis [N0], and no distant metastasis [M0]; pT2N0M0) gastric carcinoma who underwent gastric resection between 1984 and 1990 at the National Cancer Center Hospital were studied. Two consecutive sections were newly prepared from each lymph node for hematoxylin and eosin staining and immunohistochemical staining (IHC) with antibody against cytokeratin. Associations between clinicopathologic factors and the presence of micrometastases as well as micrometastases and survival were sought.

RESULTS

Micrometastases were identified in 38 of 107 patients (35.5%) and in 87 of 4484 lymph nodes (1.94%) by IHC. The incidence of micrometastases was significantly higher in patients with infiltrative tumors than in patients with expansive, growing tumors (P = 0.02). Other clinicopathologic findings had no statistically significant correlation with the incidence of micrometastases. The 5-year survival rates of patients with and without micrometastases were 94% and 89%, respectively. Similarly, the 10-year survival rates were 79% and 74%, respectively. The survival curves of patients with or without micrometastasis were nearly superimposed (P = 0.86).

CONCLUSIONS

The presence of immunohistochemically detected micrometastases in the regional lymph nodes did not affect the survival of Japanese patients with pT2N0M0 gastric carcinoma who had undergone gastrectomy with D2 lymph node dissection.

Immunohistochemically detected micrometastases of the lymph nodes in patients with gastric carcinoma

BACKGROUND

Lymph node status is a major determinant of disease recurrence after patients undergo curative resection for gastric carcinoma. A proportion of patients without lymph node metastasis develop systemic recurrences. Recent studies in a range of solid tumors have found a high incidence of micrometastases in the regional lymph nodes of patients with apparently negative lymph nodes. In patients with breast and colorectal carcinoma, the presence of micrometastases has been associated with a poorer prognosis. In patients with gastric carcinoma, the significance of micrometastases in lymph nodes remains controversial. Most published reports on this subject suffer from the problems of small sample size and selection bias.

METHODS

One hundred seven patients with pathologic T2N0M0 (tumor invades muscularis propria or subserosa [T2], no regional lymph node metastasis [N0], and no distant metastasis [M0]; pT2N0M0) gastric carcinoma who underwent gastric resection between 1984 and 1990 at the National Cancer Center Hospital were studied. Two consecutive sections were newly prepared from each lymph node for hematoxylin and eosin staining and immunohistochemical staining (IHC) with antibody against cytokeratin. Associations between clinicopathologic factors and the presence of micrometastases as well as micrometastases and survival were sought.

RESULTS

Micrometastases were identified in 38 of 107 patients (35.5%) and in 87 of 4484 lymph nodes (1.94%) by IHC. The incidence of micrometastases was significantly higher in patients with infiltrative tumors than in patients with expansive, growing tumors (P = 0.02). Other clinicopathologic findings had no statistically significant correlation with the incidence of micrometastases. The 5-year survival rates of patients with and without micrometastases were 94% and 89%, respectively. Similarly, the 10-year survival rates were 79% and 74%, respectively. The survival curves of patients with or without micrometastasis were nearly superimposed (P = 0.86).

CONCLUSIONS

The presence of immunohistochemically detected micrometastases in the regional lymph nodes did not affect the survival of Japanese patients with pT2N0M0 gastric carcinoma who had undergone gastrectomy with D2 lymph node dissection.

Node-positive mucosal gastric cancer: a follow-up study

BACKGROUND

Lymph node metastasis from mucosal gastric carcinoma is rare and the prognosis of the patients has seldom been reported.

METHODS

Forty-five patients with node-positive mucosal gastric cancer were studied. They accounted for 2.5% of 1770 patients with mucosal gastric cancer who underwent gastrectomy with lymphadenectomy at the National Cancer Center Hospital, Tokyo. The clinicopathological features were studied and the current clinical status was sought.

RESULTS

The majority of patients (87%) were treated with D2 lymphadenectomy. The metastasis was confined to the perigastric nodes (pN1 by Japanese classification) in 30 patients (67%). The number of positive nodes was less than seven (pN1 by TNM) in 42 patients (93%). Two patients had para-aortic nodal metastasis. The median follow-up period was 11 years. Four patients died of definite or possible recurrent disease and the disease-specific 5- and 10-year survival rates were 95 and 89%, respectively.

CONCLUSIONS

Although nodal metastasis is an important prognostic factor for gastric cancer, the prognosis was excellent as long as the primary tumor was confined to the mucosa and was treated with gastrectomy and lymphadenectomy.

Evaluation of the necessity for gastrectomy with lymph node dissection for patients with submucosal invasive gastric cancer

BACKGROUND

When cancer cells are found in the submucosal layer of an endoscopically resected specimen, patients are recommended to undergo gastrectomy with lymph node dissection. If it were possible to identify those patients in whom the risk of lymph node metastasis was negligible, it might be possible to avoid surgery.

METHODS

Among those who underwent gastrectomy for gastric cancer from 1980 to 1999, 1091 patients with a cancer invading the submucosa were studied. Clinicopathological factors (sex, age, tumour location, macroscopic type, size, ulceration, histological type, lymphatic-vascular involvement and degree of submucosal penetration) were investigated for their possible association with lymph node metastasis.

RESULTS

Lymph node metastases were found in 222 patients (20.3 per cent). Univariate analysis showed that larger tumour size (more than 30 mm), undifferentiated histological type, lymphatic-vascular involvement and massive submucosal penetration had a significant association with lymph node metastasis. Tumour size, histological type and lymphatic-vascular involvement were independent risk factors for lymph node metastasis. By combining these three factors with submucosal penetration of less than 500 microm, 117 patients could be selected as having a minimal risk of lymph node metastasis (95 per cent confidence interval 0-3.1 per cent).

CONCLUSION

Lymphadenectomy may not be necessary for patients with gastric cancer invading the submucosa who fulfil the above conditions

Gastric lymphography and detection of sentinel nodes

The lymphatic drainage system of the stomach was studied using lymphography with various dyes, and several major routes have been shown. Gastric lymph channels are multidirectional and form complex networks. We conducted a retrospective study to know the first site of metastasis from small gastric cancers by examining 89 cases with only one lymph node metastasis. The perigastric nodal area close to the primary tumor was the first site of metastasis in only 62% of the cases. N2 metastasis without N1 involvement was seen in 13%. In order to identify sentinel nodes for local resection of gastric cancer, a novel method needs to be developed.

[Current status and problem of adjuvant chemotherapy for curatively resected gastric cancer]

Randomized controlled trials (RCT) on adjuvant chemotherapy for gastric cancer published in the West and Japan were reviewed. Although several small trials showed positive data, adjuvant chemotherapy for curatively resected gastric cancer has been thought to be ineffective in western countries. Results of Japanese RCTs also have not become evidence of its benefit. Despite this, suggestive data by non-predefined subset analyses of old RCTs have been misread as definitive evidence of benefit because of less understanding of clinical statistics in Japan. As a result most Japanese patients have received postoperative adjuvant chemoimmunotherapy. Recently understanding of clinical trial has spread gradually and well designed RCTs with sufficient sample size have been reported. First of all we have to determine the efficacy of adjuvant chemotherapy by carefully designed RCT using surgery alone arm as control.

Absence of germline CHK2 mutations in familial gastric cancer

Recently, the CHK2 gene was identified as being a candidate gene responsible for Li-Fraumeni syndrome (LFS). Gastric cancer is often clustered in families with LFS, so it is possible that germline CHK2 mutation is also present in familial gastric cancer (FGC). We therefore defined the genomic structure of the CHK2 gene, designed intronic primers, and searched for germline CHK2 mutations in 25 FGC cases by polymerase chain reaction-single strand conformational polymorphism analysis of the entire coding region. In all of the 25 cases, at least two siblings had histories of gastric cancer. There were no FGC cases that showed germline CHK2 mutations. Thus, it was indicated that germline CHK2 mutations do not contribute to the familial clustering of gastric cancer.

Evaluation of the New International Union Against Cancer TNM staging for gastric carcinoma

BACKGROUND

The lymph node (N) classification in the International Union Against Cancer (UICC) TNM staging system for gastric adenocarcinoma has been revised. The new classification is based on the number of positive regional lymph nodes instead of the anatomic location of the regional lymph node metastasis. Both classification systems were compared for prognostic significance.

METHODS

A total of 4362 gastric carcinoma patients who underwent resection between 1969 and 1990 were analyzed.

RESULTS

Thirteen percent of patients could not be staged according to the new system. Based on the previous classification, 647 patients were classified as pN1 and 711 patients as pN2. When reclassified, 587 patients remained pN1, 54 patients became pN2, and 6 patients became pN3. Of the 711 pN2 patients, 333 became pN1, 267 remained pN2, and 111 patients became pN3. Both lymph node classification methods defined groups with widely differing prognoses. The prognoses of patients classified as new pN2 were more homogeneous than those of the group classified as old pN2. Survival of new pT4/pN1 patients was significantly better than that of other subgroups in Stage IV. Nine potential prognostic factors, including lymph node metastasis, were studied in multivariate analysis. The hazard ratios were 1.38 (1.16-1.64) for pN1 and 2.55 (2.16-3.01) for pN2, based on the old classification. They were 1.51 (1.29-78) for pN1, 3.11 (2.56-3.78) for pN2, and 3.88 (2.98-5.05) for pN3, based on the new classification.

CONCLUSIONS

The new N classification is superior as a prognostic factor to the old N classification, although there is inadequacy in stage grouping. [See editorial on pages 1763-5, this issue.]

Evaluation of the New International Union Against Cancer TNM staging for gastric carcinoma

BACKGROUND

The lymph node (N) classification in the International Union Against Cancer (UICC) TNM staging system for gastric adenocarcinoma has been revised. The new classification is based on the number of positive regional lymph nodes instead of the anatomic location of the regional lymph node metastasis. Both classification systems were compared for prognostic significance.

METHODS

A total of 4362 gastric carcinoma patients who underwent resection between 1969 and 1990 were analyzed.

RESULTS

Thirteen percent of patients could not be staged according to the new system. Based on the previous classification, 647 patients were classified as pN1 and 711 patients as pN2. When reclassified, 587 patients remained pN1, 54 patients became pN2, and 6 patients became pN3. Of the 711 pN2 patients, 333 became pN1, 267 remained pN2, and 111 patients became pN3. Both lymph node classification methods defined groups with widely differing prognoses. The prognoses of patients classified as new pN2 were more homogeneous than those of the group classified as old pN2. Survival of new pT4/pN1 patients was significantly better than that of other subgroups in Stage IV. Nine potential prognostic factors, including lymph node metastasis, were studied in multivariate analysis. The hazard ratios were 1.38 (1.16-1.64) for pN1 and 2.55 (2.16-3.01) for pN2, based on the old classification. They were 1.51 (1.29-78) for pN1, 3.11 (2.56-3.78) for pN2, and 3.88 (2.98-5.05) for pN3, based on the new classification.

CONCLUSIONS

The new N classification is superior as a prognostic factor to the old N classification, although there is inadequacy in stage grouping. [See editorial on pages 1763-5, this issue.]

Expression of SART3 tumor-rejection antigen in gastric cancers

We previously reported SART3 as a tumor-rejection antigen recognized by histocompatibility leukocyte antigen (HLA)-A24-restricted cytotoxic T lymphocytes (CTLs). In this study, we investigated the expression of the SART3 antigen in gastric cancers, as a candidate for use in specific immunotherapy. The SART3 antigen was detected in 9 of 10 (90%) gastric cancer cell lines, 35 of 52 (67.3%) gastric cancer tissues, and 0 of 20 non-tumorous gastric tissues. SART3-derived peptides corresponding to positions 109- 118 and 315-323 induced HLA-A24-restricted and tumor-specific CTLs from peripheral blood mononuclear cells (PBMCs) of gastric cancer patients. These peptide-induced CTLs recognized HLA-A24(+) SART3(+) gastric cancer cells, but not HLA-A24(+) SART3(-) or HLA-A24(-) SART3(+) gastric cancer cells. Therefore, the SART3 peptides could be useful in specific immunotherapy of gastric cancer patients.

[Practice guidelines in western countries]

The concept of clinical practice guidelines was established in the 1960's to reduce medical costs that had been increasing dramatically in the US. To reduce medical expenses without lowering the quality of medical care, thorough control of medical practices was undertaken by rationalization of these practices. Guidelines were started initially for social and economical reasons, but were eventually accepted widely by society for several reasons. First, the concept of patients' autonomy was widely accepted after 1970, which supported full disclosure of information to patients. Second, there was too much information, necessitating ranking by scientific certainty. Third, the risk of litigation for doctors in the USA increased dramatically during these years. Whether a medical practice follows the guidelines or not has become one of the most important issues in medical lawsuits. Fourth, there is a constant demand for the effective use of social resources. Methods for developing clinical practice guidelines are already established in many societies. The first step is an intensive review of relevant articles to generate evidence-based recommendations (EBR). Then, to formulate practice guidelines, these EBR are ratified and modified by clinicians to whom they apply. They are then reviewed by independent experts. After final adjustment of the EBR or guidelines for administrative reasons, they are adopted with a future expiry date. Practice guidelines are not actually adopted in European countries. However, the concept of guidelines is well appreciated and medical practice is based on scientific evidence. In socialistic European countries like Sweden, Denmark or the Netherlands, there is huge pressure to control limited social resources, leading to aggressive efforts to reduce unexplained and inappropriate variations in medical practice.

Can sentinel node biopsy indicate rational extent of lymphadenectomy in gastric cancer surgery? Fundamental and new information on lymph-node dissection

Lymph-node dissection has been regarded as an effective surgical treatment for gastric cancer in Japan. It reduces local recurrence and improves survival rate. Japanese-style systematic D2 lymphadenectomy is now being introduced in western countries for treatment of gastric cancer. This surgical procedure, however, is not simple and should be performed by experienced surgeons. And it is too early to apply sentinel node biopsy for reducing extent of lymphadenectomy because of so complicated lymphatic streams from the stomach and frequent skip- and micrometastases.

Surgical treatment for gastric leiomyosarcoma

BACKGROUND

Gastric leiomyosarcoma is an uncommon disease, and the optimal treatment has not been established. In order to better define the optimal surgical treatment, we retrospectively analyzed our experience with these tumors.

METHODS

Records of 103 patients, who underwent surgery between 1972 and 1997 were reviewed.

RESULTS

The upper third of stomach was the most frequent site of disease (66 cases). Seventy one tumors were smaller than 50 mm. Forty patients had ulcerated tumors. Twenty nine of 33 tumors had an inhomogeneous pattern on endoscopic ultrasonography. Nodal involvement was not observed in our series. The most common surgery was wedge resection, performed in 68 patients. The 5-year disease-specific survival rate after curative resection was 93.0% overall, 87.5% after gastrectomy, and 95.0% after wedge resection. 5 year survival rate was worse in patients with ulcer than those without ulcer (87.1% vs. 96.3%, p < 0.01). No patient with a tumor smaller than 3 cm died from the disease. The dominant mode of recurrence was liver and peritoneal metastasis. No lymph node recurrence was observed.

CONCLUSIONS

Surgery is indicated for tumors larger than 3 cm, with rapid growth, with inhomogeneous US pattern, or with ulceration. Wedge resection is the preferred treatment.