Protective immunity induced by concurrent intradermal injection of porcine circovirus type 2 and Mycoplasma hyopneumoniae inactivated vaccines in pigs

Vaccines against porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae (Mhp) are routinely used by intramuscular injection. However, since intramuscular vaccination causes stress and increases the risk of cross-contamination among pigs, research on intradermal vaccination is currently being actively conducted. This study was designed to evaluate the efficacy of intradermally administered inactivated vaccines against PCV2 and Mhp in pigs. Three-week-old specific pathogen-free pigs were divided into three groups (5 pigs per group). Pigs in the two groups were intradermally vaccinated with the PCV2 or Mhp vaccine using a needle-free injector. Pigs in the third group were kept as nonvaccinated controls. At 21 days post-vaccination, pigs in one of these vaccinated groups and the nonvaccinated group were intranasally challenged with PCV2b and Mhp, while the other vaccinated group pigs were maintained as vaccine controls. Vaccine efficacy was evaluated by observing weight gain, pathogen load, pathological changes, and humoral or cellular immune responses. As a result, vaccinated pigs revealed significantly higher body weight gain, with lower clinical scores. Vaccinated pigs also showed higher antibody responses but lower PCV2b or Mhp loads in sera, nasal swabs, or lungs than nonvaccinated pigs. Intriguingly, vaccinated pigs upregulated cytotoxic T cells (CTLs), helper T type 1 cells (Th1 cells), and helper T type 17 cells (Th17 cells) after immunization and showed significantly higher levels of CTLs, Th1 and Th17 cells at 14 days post-challenge than nonvaccinated and challenged pigs. This study demonstrated that protective immune responses against PCV2 and Mhp could be efficiently induced in pigs using a relatively small volume of intradermal vaccines, probably due to effective antigen delivery to antigen-presenting cells in the dermis.

Characterization of Clostridium novyi isolated from a sow in a sudden death case in Korea

Background

Multifocal spherical nonstaining cavities and gram-positive, rod-shaped, and endospore-forming bacteria were found in the liver of a sow that died suddenly. Clostridium novyi type B was identified and isolated from the sudden death case, and the isolate was characterized by molecular analyses and bioassays in the current study.

Results

C. novyi was isolated from the liver of a sow that died suddenly and was confirmed as C. novyi type B by differential PCR. The C. novyi isolate fermented glucose and maltose and demonstrated lecithinase activity, and the cell-free culture supernatant of the C. novyi isolate exhibited cytotoxicity toward Vero cells, demonstrating that the isolate produces toxins. In addition, whole-genome sequencing of the C. novyi isolate was performed, and the complete sequences of the chromosome (2.29 Mbp) and two plasmids (134 and 68 kbp) were identified for the first time. Based on genome annotation, 7 genes were identified as glycosyltransferases, which are known as alpha toxins; 23 genes were found to be related to sporulation; 12 genes were found to be related to germination; and 20 genes were found to be related to chemotaxis.

Conclusion

C. novyi type B was isolated from a sow in a sudden death case and confirmed by biochemical and molecular characterization. Various virulence-associated genes were identified for the first time based on whole-genome sequencing.

Incidence of fall accident in Suseong district of Daegu Metropolitan City, Republic of Korea

Background:

Among the various types of injuries in the world, falls are one of the most important health problem related issues, especially for modern societies with aged populations. Korea, a country where industrialization and urbanization have made building structures and living spaces complex, has also been facing the emerging danger of falls. So, among the causes of death due to unintended injury accidents, falls are second reason of injury worldwide following traffic accidents. Falls are important causes in increase of morbidity rates, hospitalization rates, death rates and medical fees. Falls are not unfortunate accidents rather, they are preventable and predictable. Therefore, we needs to identify the incidence and causes of falls. Objectives The purposes of this study are to identify the incidence of fall accident in Suseong district of Daegu metropolitan city and to develop the evidence based fall accident program for Suseong district.

Methods:

In order to identify the incidence of falls of the citizens of Suseong district, authors analyzed the annual report on the causes of death statistics from the National Statistical Office and the injury data from Fire Station 119 Rescue Activity Daily Record. As well, in order to understand the current state of falls in households, an epidemiological survey was conducted to people from 1,977 households in Suseong district by home visited. The collected data were analyzed using SPSS WIN 17.0 based on the research objectives, and the frequency and percentages were investigated.

Results:

According to the data from the National Statistical Office, the death rate due to falls was 4.1 people (per 100,000 persons). In terms of age, elders aged 65 and over was the highest death rate with 17.0 out of 100,000 persons. In the injury transfer rate analyzed from rescue records of 119, accidents due to falls were highest with 2.3 cases out of 1,000 persons. In terms of age, elders aged 65 and over was the highest injury rate with 9.2 out of 1000 persons. After analyzing the injury causes of the citizens of Suseong district through household visits, the highest rate of falls was 43.7%, followed by traffic accidents (24.9%) and bump injuries (21.1%). Therefore, we were able to confirm once again that the fall prevention program is a very important program for improving the safety of citizens. Housework (29.4%) was the most common cause of falls. The most common places for falls were living rooms (22.6%), followed by restrooms and entrance.

Conclusions:

Mortality due to falls can be reduced through education, environmental improvements, and safety policies. It is necessary to conduct preventive education for elderly people who are vulnerable to falls, and to apply gymnastic exercises that can enhance balance and lower extremity muscle strength. In addition to, it is necessary to strengthen regulations on safety facilities at the senior community center. Therefore the government and related organizations should put fall prevention as the primary task and spread an effective evidence-based fall prevention program based on result of research.

Keywords:

Fall, Injury, Safety, Safety promotion

Influence of a ring-shaped pump beam on temperature distribution and thermal lensing in end-pumped solid state lasers

A simple method for reducing thermal lensing in an end-pumped solid state laser using a ring-shaped pump beam is reported. Analytical expressions for the temperature distribution and the thermal lensing focal length in a laser medium end-pumped by a beam with a ring-shaped intensity profile are derived. The results indicate that thermal effects including thermal lensing can be significantly reduced due to a more uniform temperature distribution. This approach has been applied to a Nd:YVO₄ amplifier operating at 1064 nm confirming that the brightness of the output beam can be remarkably improved at high power levels due to the better beam quality for the ring-shaped pumping compared to the conventional quasi-top-hat pumping. The prospects for power scaling and further improvement in laser performance will be discussed.

Locoregional relapse after gastrectomy with D2 lymphadenectomy for gastric cancer

BACKGROUND

Risk for and site of locoregional relapse have not been well studied in patients undergoing gastrectomy with D2 lymphadenectomy for gastric cancer.

METHODS

Patients who had undergone gastrectomy with D2 lymphadenectomy for gastric cancer between 2004 and 2007 were identified from an institutional database. The locoregional relapse rate was estimated by competing risk analysis, and risk groups were derived according to locoregional relapse risk using recursive partitioning analysis (RPA). The locations of nodal relapses were evaluated according to Japanese Classification of Gastric Carcinoma criteria.

RESULTS

Some 2618 patients were included. With a median follow-up of 78·0 (range 28·5-122·6) months, relapse was diagnosed in 471 of 2618 patients (18·0 per cent). The cumulative incidence of locoregional relapse at 5 years was 8·5 (95 per cent c.i. 7·4 to 9·6) per cent. The 5-year locoregional recurrence rates for high-risk (N3), intermediate-risk (N1-2) and low-risk (N0) groups were 32·4, 12·3 and 1·7 per cent respectively (P < 0·001). Among patients with regional relapse, 90·4 per cent had involvement outside the D2 dissected area, and the most commonly involved site was station 16b1. This pattern was maintained in the RPA risk groups (P = 0·329).

CONCLUSION

Locoregional relapse at 5 years after gastrectomy with D2 lymphadenectomy was 8·5 per cent, and was most often seen outside the D2 dissected area.

Risk factors for double primary malignancies and their clinical implications in patients with sporadic gastric cancer

AIMS

We carried out a large scale study to identify the risk factors for double primary malignancy (DPM) development in gastric cancer patients and to evaluate the clinical implications for these patients.

METHODS

A total of 2593 patients who underwent gastrectomy for primary gastric cancer from January 2005 to November 2010 were reviewed with regard to DPM. We compared the clinicopathological characteristics, risk factors for developing DPM, and prognosis between the DPM+ group and the DPM- group.

RESULTS

Of the 2593 patients, 152 (5.9%) were diagnosed with DPM. The most common accompanying malignancies were colorectal, lung and thyroid. Multivariate analysis indicated that age (p = 0.016) and MSI status (p = 0.002) were associated with a higher frequency of DPM. 30.3% of patients were diagnosed with DPM within 1 year around perioperative period and 53.3% of patients had DPM detected during 5 years of post-operative follow up periods. Although there was no significant difference in overall survival between the DPM+ and DPM- group, DPM+ patients had a worse prognosis than DPM- patients in stage I gastric cancer.

CONCLUSIONS

Gastric cancer patients over the age of 60 or with a MSI-high status had an increased risk for developing DPM. Further, in stage I gastric cancer, the presence of DPM was associated with a worse prognosis. Therefore, careful pre- and postoperative surveillance is especially important in these patients.

Minimally invasive surgery for serosa-positive gastric cancer (pT4a) in patients with preoperative diagnosis of cancer without serosal invasion

BACKGROUND

Although surgeons normally use minimally invasive surgery (MIS) for patients with early gastric cancer, in Korea and Japan the procedure is also indicated for serosa-negative tumors. Serosal invasion is regarded to be a potential risk factor for peritoneal dissemination as a result of the effect of pneumoperitoneum and tumor manipulation during the operation. We compared operative outcomes between MIS and conventional open surgery for serosa-involved advanced gastric cancer patients who had a preoperative diagnosis of cancer without serosal invasion.

METHODS

A total of 61 patients (39 patients treated by MIS and 22 by open surgery) treated between 2003 and 2009 who were first diagnosed preoperatively as serosa negative on the basis of computed tomography, endoscopy, and endoscopic ultrasound but then diagnosed as serosa positive upon final pathology were studied. We retrospectively compared recurrence and survival between the two treatment groups.

RESULTS

Clinicopathologic characteristics, clinical stage, extent of surgery, and short-term operative outcome did not differ between the groups. 5-year overall survival (73.5 vs. 67.5 %, p = 0.518, respectively) and disease-free survival (67.8 vs. 54.2 %, p = 0.296, respectively) were comparable between the MIS and open surgery groups. There were recurrences in 12 patients in the MIS group and 11 patients in the open surgery group, with a median follow-up period of 64 months. Recurrence patterns did not differ between the groups; moreover, MIS did not increase peritoneal recurrences compared to open surgery (42.0 vs. 54.5 %, p = 0.537, respectively). In multivariate analyses, the type of surgery was not an independent prognostic factor.

CONCLUSIONS

Similar survival and recurrence patterns were observed in advanced gastric cancer patients preoperatively diagnosed as serosa negative who were treated either by MIS or open surgery. MIS may be safely applied in patients with serosa-positive tumors.

Major early complications following open, laparoscopic and robotic gastrectomy

BACKGROUND

Laparoscopic and robotic gastrectomy have been adopted rapidly despite lack of evidence concerning technical safety and controversy regarding additional benefits. This study aimed to compare clinically relevant complications after open, laparoscopic and robotic gastrectomy.

METHODS

This was a retrospective analysis of prospectively collected data on surgical complications in patients undergoing gastrectomy with curative intent for histologically proven adenocarcinoma between 2005 and 2010 at the Department of Surgery, Yonsei University College of Medicine in Seoul, Korea. Complications were categorized into wound infection, bleeding, anastomotic leak, obstruction, fluid collection and other.

RESULTS

In a total of 5839 patients (4542 open, 861 laparoscopic and 436 robotic gastrectomies), overall complication, reoperation and mortality rates were 10·5, 1·0 and 0·4 per cent respectively. There were no significant differences between the three groups. Ileus (P = 0·001) and intra-abdominal fluid collections (P = 0·013) were commoner after conventional open surgery. However, tumour stage was higher and more complex resections were performed in the open group. Anastomotic leak, the leading cause of death, occurred more often after a minimally invasive approach (P = 0·017).

CONCLUSION

Laparoscopic and robotic gastrectomy had overall complication and mortality rates similar to those of open surgery, but anastomotic leaks were more common with the minimally invasive techniques.

Impact of pretreatment thrombocytosis on blood-borne metastasis and prognosis of gastric cancer

BACKGROUND

Thrombocytosis has been associated with malignancies and poor prognostic implications in cancer patients. In the present study the prognostic significance of pretreatment platelet (PLT) level was assessed with regard to recurrence and survival in patients with primary gastric adenocarcinoma.

METHODS

The authors reviewed the prospective data of 1593 gastric cancer patients who received curative gastrectomy with extended lymphadenectomy. The correlations of PLT level with recurrence and overall survival were evaluated by both univariate and multivariate analyses.

RESULTS

Thrombocytosis (≥ 40 × 10(4)/ μL), present in 6.4% of the patients prior to curative surgery, was more frequently associated with advanced T and N classification, larger tumor size, anemia, and leukocytosis (p < 0.05). In patients with pretreatment thrombocytosis compared to those without it, five-year survival rate was worse (56.9% vs. 65.5%; p = 0.043), and recurrence rate was higher mainly due to the frequent hematogenous spread (51.0% vs. 34.5%; p < 0.001). Furthermore, risk of blood-borne metastasis was almost three-fold higher in patients with pretreatment thrombocytosis (Odds ratio 2.83 [95% CI 1.67-4.77], p < 0.001).

CONCLUSIONS

Pretreatment thrombocytosis correlated significantly with poor prognosis and can be used as an independent predictor of recurrence by blood-borne metastasis in gastric cancer.

External validation of nomogram for the prediction of recurrence after curative resection in early gastric cancer

BACKGROUND

Nomograms are statistics-based tools that provide the overall probability of a specific outcome. In our previous study, we developed a nomogram that predicts recurrence of early gastric cancer (EGC) after curative resection. We carried out this study to externally validate our EGC nomogram.

PATIENTS AND METHODS

The EGC nomogram was established from a retrospective EGC database that included 2923 consecutive patients. This nomogram was independently externally validated for a cohort of 1058 consecutive patients. For the EGC nomogram validation, we assessed both discrimination and calibration.

RESULTS

Within the follow-up period (median 37 months), a total of 11 patients (1.1%) experienced recurrence. The concordance index (c-index) was 0.7 (P = 0.02) and the result of the overall C index was 0.82 [P = 0.006, 95% confidence interval (CI) 0.59-1.00]. The goodness of fit test showed that the EGC nomogram had significantly good fit for 1- and 2-year survival intervals (P = 0.998 and 0.879, respectively). The actual and predicted survival outcomes showed good agreement, suggesting that the survival predictions from the nomogram are well calibrated externally.

CONCLUSIONS

A preexisting nomogram for predicting disease-free survival (DFS) of EGC after surgery was externally validated. The nomogram is useful for accurate and individual prediction of DFS, patient prognostication, counseling, and follow-up planning.

Relevance of lymph node metastasis along the superior mesenteric vein in gastric cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic value of lymph node metastasis along the superior mesenteric vein (station 14v) to determine the need for 14v dissection in gastric cancer surgery.

METHODS

A total of 1104 patients with gastric cancer who underwent gastrectomy including 14v dissection were enrolled. Patients were categorized into two groups: those with and those without 14v lymph node involvement by metastasis.

RESULTS

Of the total study population, 73 patients (6·6 per cent) had 14v-positive gastric cancer. These patients were more likely to have advanced tumour (T), node (N) and distant metastatic (M) status, and histologically undifferentiated gastric cancers. The 3- and 5-year survival rates of patients with 14v-positive disease were 24 and 9 per cent respectively. Survival in this group was similar to that of patients who had gastric cancer with distant metastasis (M1). Multivariable analysis demonstrated that 14v status was a significant prognostic factor for gastric cancer (hazard ratio 2·13; P < 0·001). After histologically complete (R0) resection, the overall survival of 14v-positive patients with any stage of cancer was significantly worse than that for 14v-negative patients with stage IV cancer (P = 0·006).

CONCLUSION

14v status is an independent prognostic factor for gastric cancer, with 14v-positive gastric cancer having a poor prognosis, similar to that of M1 disease. The exclusion of 14v in regional lymph node dissection should be considered.

Lymph node dissection around the splenic artery and hilum in advanced middle third gastric carcinoma

AIM

To evaluate the clinicopathological factors influencing lymph node metastasis around the splenic artery and hilum and the effect of spleen-preserved lymphadenectomy in advanced middle third gastric carcinoma.

METHODS

We retrospectively studied 131 patients with advanced middle third gastric carcinoma who had received D2 lymphadenectomy and lymph node dissection around the splenic artery and hilum, from 2000 to 2004. Of these patients, 62 simultaneously underwent splenectomy and 69 underwent spleen-preserved lymphadenectomy.

RESULTS

The incidences of Nos. 10 and 11 lymph node metastases were 21% and 15%, respectively, in advanced middle third gastric carcinoma. A tumor size larger than 5 cm, metastases of Nos. 1 and 7-9 lymph node were independent risk factors for metastasis of No. 10 and/or No. 11 lymph node. The spleen-preserved group had a slightly better survival rate and a relatively lower rate of postoperative complications than the splenectomy group. No. 10 and/or No. 11 lymph node metastasis was an independent prognostic factor, while splenectomy was not.

CONCLUSIONS

It is necessary to remove the lymph nodes around the splenic artery and hilum to achieve radical resection in advanced middle third gastric carcinoma patients with risk factors. Our results demonstrate that spleen-preserved lymphadenectomy is a good option for those patients.

Phase III trial of adjuvant 5-fluorouracil and adriamycin versus 5-fluorouracil, adriamycin, and polyadenylic-polyuridylic acid (poly A:U) for locally advanced gastric cancer after curative surgery: final results of 15-year follow-up

BACKGROUND

This phase III trial was to compare 5-fluorouracil (5-FU), adriamycin, and polyadenylic-polyuridylic acid (poly A:U) against 5-fluorouracil plus adriamycin (FA) for operable gastric cancer.

PATIENTS AND METHODS

From 1984 to 1989, patients who had D(2-3) curative resection were randomly assigned to receive chemotherapy or chemoimmunotherapy. Chemotherapy consisted of 12 mg/kg 5-FU every week for 18 months and 40 mg/m2 adriamycin every 3 weeks for 12 cycles. Chemoimmunotherapy consisted of FA plus 100 mg of poly A:U weekly for six cycles and was followed 6 months later by six weekly 50-mg booster injections.

RESULTS

A total of 292 patients were enrolled. After excluding 12 ineligible patients, 142 and 138 patients were allocated to each treatment. Patients were balanced with prognostic variables: age, sex, tumor location, differentiation, degree of tumor invasion (T2-T4a), and lymph node status (N0-N2). During the 15-year follow-up, chemoimmunotherapy significantly prolonged overall (P = 0.013) and recurrence-free (P = 0.005) survivals compared with chemotherapy alone. The survival benefits were prominent in the subset of patients with T3/T4a, N2, or stage III. Treatments were generally well tolerated in both arms.

CONCLUSIONS

These results indicate a survival advantage of chemoimmunotherapy with a regimen of FA and poly A:U in curatively resected gastric adenocarcinoma.

A phase II study of S-1 monotherapy administered for 2 weeks of a 3-week cycle in advanced gastric cancer patients with poor performance status

Systemic chemotherapy for gastric cancer is often associated with treatment-related toxicity, which is particularly severe in patients with a poor performance status. In this paper, we describe the first study to evaluate S-1 monotherapy as an option for advanced gastric cancer patients who are not candidates for combination chemotherapy due to poor clinical condition. Fifty-two patients with Eastern Cooperative Oncology Group (ECOG) performance scale 2-3, whose general condition had made use of combination chemotherapy impossible, were enrolled. S-1 was administered to 30 patients as second- or third-line therapy. The initial dose of S-1 was 35 mg m(-2), administered b.i.d for 14 days every 3 weeks. With a median follow-up period of 33 weeks, the median progression-free survival, and overall survival were 11 weeks (95% CI, 8-14) and 33 weeks (95% CI, 19-47), respectively. The overall 1-year survival rate was 29% by intent-to-treat analysis. The overall response rate was 12% (95% CI, 3-21), and the percentage of stable disease was 35%, resulting in the disease control rate of 47% (95% CI, 32-60). Significant drug-related toxicity included grade 3 diarrhoea (14%), anorexia (14%), fatigue (10%), neutropenia (10%), and leucopenia (6%). In conclusion, this study indicated the modest activity of S-1 in gastric cancer patients with poor performance status.

Factors influencing operation time of laparoscopy-assisted distal subtotal gastrectomy: Analysis of consecutive 100 initial cases

AIMS

There is little information on patient selection criteria for laparoscopy-assisted distal gastrectomy (LADG) that would facilitate a successful initial experience for a surgeon new to the procedure. This study aimed to establish patient selection criteria that will allow increased proficiency and shorter operation times for the LADG procedure.

METHOD

One hundred LADG with lymphadenectomy and no other combined procedures were consecutively performed by one surgeon. These 100 consecutive LADG procedures were analyzed retrospectively from a prospectively designed computer database. Uni- and multivariate analyses were performed to identify factors influencing operation time.

RESULTS

According to univariate analysis, operation time was influenced by sex, BMI, surgical experience, and tumor location, whereas multivariate analysis indicated that operation time was significantly influenced only by BMI and surgical experience. The same analyses of only the first 50 cases showed that sex, BMI, surgical experience, and tumor location were independently associated with operation time. As BMI increased, so did operation time, whereas operation time decreased with increasing surgical experience.

CONCLUSION

This study suggests that surgeons who have limited experience with this advanced procedure may shorten operation time by considering patient and tumor characteristics in their early attempts at LADG. With a shortened operation time, surgeon with limited experience may become proficient to LADG rapidly.

Metastasis in para-aortic lymph nodes in patients with advanced gastric cancer, treated with extended lymphadenectomy

BACKGROUND/AIMS

Lymph node dissection is an essential component of curative resection for advanced gastric cancer. To improve the survival of N2 patients, Asian surgeons have been performing D2+para-aortic lymph node dissection. The current study presents the results of lymph node status from multicenter trial of D2 and D2 + para-aortic nodal (No.16) dissection (D4 dissection).

METHODOLOGY

Patients enrolled in the study had potentially curable gastric adenocarcinoma in an advanced stage, T2, T3 or T4/N1 or N2. Patients were randomized to undergo either D2 or D4 gastrectomy.

RESULTS

Two hundred and seventy patients were registered and 136 and 134 patients were allocated into the D2 or D4 group, respectively. The average nodal yield of No.16 in D4 group was 18.4 +/- 14.1, ranging from 2 to 84. No.16 metastasis was detected in 12 (9.0%) of 134 D4 patients. One, 9 and 2 patients had simultaneous involvement in N1, N2, and N3 (No.8p, 12, 13 or 14). Namely, in 39 patients who were diagnosed as N2 from the lymph node status in N1 and N2 levels, nine (23.0%) patients had No.16 metastasis. The stage migration by D4 was found in 10 (7.5%). Logistic regression analysis revealed that the stations of No.7 and No.8 were the significant predictors of No.16 involvement.

CONCLUSIONS

The present study may strongly suggest that prophylactic D4 dissection may be indicated for patients with N2 involvement, and that No.7 and No.8 are the junctional nodes for D4 dissection.

The effect of epidural sufentanil in ropivacaine on urinary retention in patients undergoing gastrectomy

BACKGROUND

Although epidural opioids have excellent analgesic property, their side-effects limit its use in patient-controlled epidural analgesia (PCEA). This study was designed to compare side-effects of epidural sufentanil in ropivacaine with that of morphine in ropivacaine focusing on lower urinary tract function after major abdominal surgery.

METHODS

In total 60 patients undergoing gastrectomy were randomly allocated to receive either sufentanil in ropivacaine (Group S, n=30) or morphine in ropivacaine (Group M, n=30) for their PCEA. Epidural catheter was inserted between the 7th and 8th thoracic spine. Visual analogue pain score and side-effects such as nausea, vomiting, pruritus, hypotension and urinary retention were evaluated during postoperative days (PODs) 1 and 2 in the postanaesthetic care unit.

RESULTS

The incidence of serious to major micturition problem in Group S was lower than that in Group M (P<0.001). The incidence of pruritus, nausea and vomiting was also lower in Group S than in Group M on POD 1.

CONCLUSIONS

The lower incidence of major/serious micturition problem in patients receiving sufentanil in ropivacaine thoracic epidural analgesia suggests that continuation of urinary drainage may not be necessary from POD 1 onwards.

Operative morbidity and mortality after D2 and D4 extended dissection for advanced gastric cancer: a prospective randomized trial conducted by Asian surgeons

BACKGROUND/AIMS

A randomized study was performed to evaluate morbidity and mortality after D2 (level 1 and 2 lymphadenectomy) and D4 (D2 plus lymphadenectomy of para-aortic lymph nodes) dissection for advanced gastric cancer.

METHODOLOGY

Two hundred and fifty-six patients with advanced gastric adenocarcinoma were enrolled (128 to each group). Patients were randomly allocated into D2 (N = 128) or D4 (N = 128) group. The first and second tiers of lymph nodes are removed in D2 dissection. In D4 gastrectomy, the paraaortic lymph nodes were additionally removed.

RESULTS

There was no indication of significant distribution bias with regard to age, sex, T-grade, and N-grade between the two groups. Operation time of D4 gastrectomy (369 +/- 120 min) was significantly longer than that of D2 gastrectomy (273 +/- 1103 min), and blood loss of the D4 group (872 +/- 683 mL) was significantly greater than that of the D2 group 571 +/- 527 mL (P < 0.001). Five (4%) and two (2%) medical complications developed in the D2 and D4 groups, respectively. Surgical complications developed in 28 (22%) and 48 patients (38%) after D2 and D4 gastrectomy. The most common complications were anastomotic leakage, pancreatic fistula, and abdominal abscess. Pancreatic fistula developed in 6 (19%) of 32 patients after D4 plus pancreatosplenectomy, but the incidence of pancreatic fistula after D2 gastrectomy plus pancreatosplenectomy was low (6%, 1/16). Two patients died within 30 days of operation (0.8%, 2/256), and each patient belonged to the D2 and D4 group.

CONCLUSIONS

Although there is a significantly higher surgical complication rate in D4 dissection, D4 dissection can be done safely as D2 dissection when performed by well-trained surgeons.

Intraoperative tumor localization using laparoscopic ultrasonography in laparoscopic-assisted gastrectomy

BACKGROUND

During laparoscopic-assisted gastrectomy, it is impossible to identify early gastric cancer (EGC) lesions; therefore, a precise localization technique is needed. In this study, we used laparoscopic ultrasonography (LUS) after endoscopic clipping as a method of localizing EGC and evaluated the effectiveness of this method.

METHODS

A prospective study of 17 patients who had undergone laparoscopic-assisted gastrectomy was performed. Three endoscopic clips were applied just proximal to the tumor during the preoperative endoscopy. The applied clips were detected from the serosal side of the stomach using LUS. The serosal surface of the lesion was marked with dye.

RESULTS

In all patients, endoscopic clips were applied proximal to the lesion without complications, and the applied clips were confirmed by plain abdominal radiography. The clips were successfully detected by LUS in all patients. In the resected specimen, the serosal surface, marked with dye, was always just above the clips in the anterior wall or on the anterior wall opposite the clips applied in the posterior wall. The mean detection time was 4.7 min (range, 2-8). With this procedure, two patients underwent total gastrectomy and 15 patients underwent distal subtotal gastrectomy with gastroduodenostomy or gastrojejunostomy. Histological examination confirmed that the resection margins were tumor free in all patients. There was no operative morbidity related to the LUS procedure.

CONCLUSIONS

Using LUS to detect endoscopic clips is an easy, safe, and accurate method to localize EGC lesions in laparoscopic-assisted gastrectomy.

A phase II trial of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer

BACKGROUND

Capecitabine (Xeloda) is a novel, oral, selectively tumor-activated fluoropyrimidine with proven activity in the treatment of advanced colorectal cancer. This trial was conducted to evaluate the efficacy, safety and feasibility of capecitabine in previously untreated patients with advanced and/or metastatic gastric cancer, with a view to replacing 5-fluorouracil (5-FU) in such patients.

PATIENTS AND METHODS

Forty-four patients received capecitabine 1250 mg/m2 twice daily (2500 mg/m2/day) for 14 days followed by 7 days of rest, for up to six cycles.

RESULTS

Capecitabine produced an objective response rate of 34% (all partial responses) and stable disease in 14 patients (30%). The median time to disease progression (TTP) was 3.2 months [95% confidence interval (CI) 2.7-6.4 months] and median overall survival was 9.5 months (95% CI 6.9-13.2 months). Hand-foot syndrome (HFS), nausea, anorexia, diarrhea and vomiting were the most common adverse events. While HFS was the most frequent grade 3/4 toxicity (National Cancer Institute Common Toxicity Criteria), only 9% of patients experienced grade 3 HFS. Severe myelosuppression was not reported during the study.

CONCLUSIONS

Capecitabine monotherapy is active and well tolerated as first-line therapy in patients with advanced/metastatic gastric cancer. Larger comparative trials investigating capecitabine-based combination regimens in patients with advanced gastric cancer are warranted.

Treatment of advanced gastric cancer by palliative gastrectomy, cytoreductive therapy and postoperative intraperitoneal chemotherapy

BACKGROUND

The treatment options for the 10-20 per cent of patients with gastric cancer who present with peritoneal dissemination are extremely limited and no standard approach exists.

METHODS

The feasibility of using intraperitoneal chemotherapy to treat gastric cancer with intra-abdominal gross residual lesions after palliative gastrectomy with maximal cytoreduction was investigated. Early postoperative intraperitoneal chemotherapy started on the day of operation with 5-fluorouracil 500 mg/m2 and cisplatin 40 mg/m2 (days 1-3) over a 4-week interval.

RESULTS

Of the 53 patients enrolled between July 1994 and December 1998, 49 were eligible. The progression-free survival (PFS) was 7 months and the overall survival was 12 months. In multivariate analysis, performance status was the only significant defining factor for PFS (P = 0.009). The predominant toxicity was neutropenia and nausea/vomiting. The relative dose intensity of 5-fluorouracil and cisplatin was 89 and 63 per cent respectively.

CONCLUSION

Performance status emerged as a major determining factor for prognosis and patient selection for early postoperative intraperitoneal chemotherapy in patients with advanced gastric cancer after maximally cytoreductive surgery.

The prognosis of stage IV gastric carcinoma patients after curative resection

BACKGROUND/AIMS

In the UICC staging system, stage IV contains not only those patients with distant metastasis but also patients with far-advanced T and N status but without distant metastasis. We investigated the prognostic factors of stage IV gastric carcinoma patients, without distant metastasis after curative resection and the role of surgery.

METHODOLOGY

One hundred and ninety stage IV gastric carcinoma patients, without distant metastasis were reviewed after curative resection in our hospital from January 1987 to December 1996.

RESULTS

Male sex, distal third location, diffuse or infiltrative type and histologically undifferentiated type were common. Of the 190 patients, 52 (27.4%) patients lived more than 3 years. The lymph node ratio (positive lymph node/retrieved lymph node) and combined resection independently affected survival (P = 0.0013, 0.0061, respectively). The perigastric lymph node ratio was well correlated with overall lymph node ratio (r = 0.794, P < 0.001).

CONCLUSIONS

With the involvement of an adjacent organ and knowing the perigastric lymph node ratio, the surgeon can decide upon the extent of dissection and postoperative treatment. However, a prospective study is warranted.

DNA ploidy patterns in advanced gastric carcinoma; is it a clinically applicable prognosticator?

BACKGROUND/AIMS

The purpose of this study was to evaluate the prognostic significance of ploidy patterns as determined by flow cytometry in terms of clinical usefulness.

METHODOLOGY

270 patients with a diagnosis of advanced gastric carcinoma were studied with fresh specimens obtained from multiple site avoiding nonviable or nonneoplastic tissues by DNA flow cytometry. DNA ploidy and clinicopathologic factors were compared and survival was analyzed.

RESULTS

The mean age of the patients was 56.1 +/- 11.6 years (25-80 years). There were 195 males and 75 females. Aneuploidy was shown in 93 (35.9%) patients. Male sex and differentiated tumor were more frequent in aneuploidy than diploidy (P = 0.011, < 0.001, respectively). By univariate analysis, tumor location, size, extent of resection, curative resection, serosa invasion, lymph node involvement, and distant metastasis significantly affected survival but not aneuploidy. Significant independent prognostic factors by multivariate analysis were curative resection, serosa invasion and lymph node involvement (P = 0.0001, 0.0114, 0.0262, respectively).

CONCLUSIONS

DNA ploidy patterns of advanced gastric carcinoma are of limited clinical significance, therefore not a clinically applicable prognosticator.

Apical membrane of native OMCD(i) cells has nonselective cation channels

The purpose of this study was to examine cation channel activity in the apical membrane of the outer medullary collecting duct of the inner stripe (OMCD(i)) using the patch-clamp technique. In freshly isolated and lumen-opened rabbit OMCD(i), we have observed a single channel conductance of 23.3 +/- 0.6 pS (n = 17) in cell-attached (c/a) patches with high KCl in the bath and in the pipette at room temperature. Channel open probability varied among patches from 0.06 +/- 0.01 at -60 mV (n = 5) to 0.31 +/- 0.04 at 60 mV (n = 6) and consistently increased upon membrane depolarization. In inside-out (i/o) patches with symmetrical KCl solutions, the channel conductance (22.8 +/- 0.8 pS; n = 10) was similar as in the c/a configuration. Substitution of the majority of Cl- with gluconate from KCl solution in the pipette and bath did not significantly alter reversal potential (E(rev)) or the channel conductance (19.7 +/- 1.1 pS in asymmetrical potassium gluconate, n = 4; 21.4 +/- 0.5 pS in symmetrical potassium gluconate, n = 3). Experiments with 10-fold lower KCl concentration in bath solution in i/o patches shifted E(rev) to near the E(rev) of K+. The estimated permeability of K+ vs. Cl- was over 10, and the conductance was 13.4 +/- 0.1 pS (n = 3). The channel did not discriminate between K+ and Na+, as evidenced by a lack of a shift in the E(rev) with different K+ and Na+ concentration solutions in i/o patches (n = 3). The current studies demonstrate the presence of cation channels in the apical membrane of native OMCD(i) cells that could participate in K+ secretion or Na+ absorption.

Impact of splenectomy for lymph node dissection on long-term surgical outcome in gastric cancer

BACKGROUND

In the treatment of gastric cancer, splenectomy is performed for effective lymph node dissection around the splenic artery and splenic hilum. The purpose of this study was to clarify the long-term outcome of splenectomy in the treatment of gastric cancer.

METHODS

The effect of splenectomy on recurrence and prognosis was examined in a retrospective analysis of 665 patients who had undergone curative total gastrectomy for gastric carcinoma from 1987 to 1996. The risk factors associated with recurrence and prognosis were investigated by univariate and multivariate analysis.

RESULTS

The splenectomy group showed more advanced lesions and a higher recurrence rate than the spleen-preserved group. However, after adjusting for the TNM (tumor, node, metastasis) stage, there was no significant difference in recurrence rate and pattern between the two groups. Logistic regression analysis revealed that gross type, serosal invasion, and nodal metastasis were independent risk factors for recurrence while splenectomy was not. When comparing patients with the same TNM (tumor, node, metastasis) stages, no significant difference in the 5-year survival rates was apparent. Multivariate analysis demonstrated that age, serosal invasion, and nodal metastasis were independent prognostic factors whereas splenectomy was not.

CONCLUSIONS

These data suggest that splenectomy for lymph node dissection in gastric cancer is not effective regarding long-term patient prognosis.

Adjuvant 5-fluorouracil plus doxorubicin in D2-3 resected gastric carcinoma: 15-year experience at a single institute

BACKGROUND

The authors evaluated the efficacy of adjuvant chemotherapy with 5-fluorouracil (5-FU) plus doxorubicin in gastric carcinoma after D2-3 curative resection. They also evaluated the effect of dose-related factors (delivered total dose/m(2), actual dose intensity [ADI], relative dose intensity [RDI]) of this regimen on patient survival.

METHODS

A total of 301 patients with Stage II to IV (en bloc resected T4b; 1984 American Joint Committee on Cancer staging) were accrued between 1984 and 1996. Chemotherapy was started within 4 weeks of surgery according to the following schedule: intravenous bolus injection of doxorubicin 40 mg/m2 every 3 weeks for 12 cycles and 5-FU 400 mg/m2 weekly for 60 weeks. The toxicity and survival were evaluated.

RESULTS

The median follow-up duration was 58 months. Sixty-four percent of the total patients and 71.7% of the patients who did not experience recurrence during the chemotherapy finished the protocol completely with acceptable toxicities. The 5- and 10-year disease free survival rates of total 301 patients were 58.4% and 46.5%, and the overall survival rates were 62.1% and 50.5%, respectively. Treatment completion group showed survival benefit over the early termination group in 5-year survival (75.2% vs. 52.9%; P = 0.0005). The median ADI of 5-FU and doxorubicin were 349 and 11 mg/m2/week, and the median RDIs of 5-FU and doxorubicin were 0.87 and 0.83, respectively. Multivariate analysis demonstrated that completion of chemotherapy is an independent prognostic factor of both disease free and overall survival. However, ADI and RDI did now show any effect on survival.

CONCLUSIONS

Adjuvant chemotherapy with 5-FU plus doxorubicin for 60 weeks after D2-3 dissection induced promising survival duration with acceptable toxicities. Full administration of the planned dosage of the combined drugs is recommendable as opposed to early termination of the chemotherapy in gastric carcinoma.

Early postoperative intraperitoneal chemotherapy with mitomycin C, 5-fluorouracil and cisplatin for advanced gastric cancer

OBJECTIVE

The long-term survival of patients who undergo surgery for stage IV gastric cancer is poor, due to metastatic spread of the tumor. Intraperitoneal chemotherapy (IPT) as a possible treatment for peritoneal dissemination has been investigated in a number of different tumors. The aim of this study was to investigate the toxicity and impact of early postoperative IPT on the survival of patients with advanced gastric cancer.

METHODS

Between 1993 and 1997, a total of 91 patients with stage IV gastric cancer who underwent potentially curative or palliative resection received intraperitoneal mitomycin C before closure of the abdominal wound. 5-Fluorouracil and cisplatin were administered intraperitoneally on postoperative days 1-4, and this was repeated at 4-week intervals.

RESULTS

All patients received a median of 3 IPT perfusions. There were 24 (26.4%) postoperative complications and 1 (1.1%) mortality. The most frequent hematologic toxicity (grade 3-4) was leukopenia. The major nonhematologic toxicities (grade 3-4) were emesis and nephrotoxicity. After a median follow-up period of 26 months, 14 patients remain alive without evidence of recurrence, whereas 75 patients died due to recurrence or progression of disease. The median survival period for all 91 patients was 15.4 months. When survival according to the residual tumor was analyzed, median survival was 36.0 months in the R0 (curative resection) group, 20.6 months in the R1 group (margins of resected specimens showing microscopic residual tumor or diameter of each residual tumor less than 3 mm) and 9.0 months in the R2 group (macroscopic residual tumor larger than 3 mm) (p < 0.001).

CONCLUSIONS

IPT was found to be safe, and it appears to improve the prognosis in patients with minimal residual tumors. However, complete cytoreductive surgery is mandatory for achieving the beneficial effect of IPT.

Follicular dendritic cell sarcoma presenting as a submucosal tumor of the stomach

Follicular dendritic cell (FDC) sarcomas, especially those of extranodal origin, are extremely rare, and this entity could easily be missed without a high index of suspicion. We report a case of FDC sarcoma presenting as a submucosal tumor of the stomach in a 45-year-old man. The mass was a spindle and epithelioid mesenchymal tumor with many individually scattered and perivascular aggregates of lymphocytes. Immunohistochemical and ultrastructural studies confirmed the diagnosis. Although more than 50 cases of this tumor have been documented in the English literature, to our knowledge the presentation of FDC sarcoma as a submucosal tumor of the stomach has never been recorded. This case highlights the occurrence of FDC sarcoma as a submucosal tumor of the gastrointestinal tract. We believe that FDC sarcoma should be included in the differential diagnosis of spindle or epithelioid cell tumors of the gastrointestinal hollow viscus to prevent this still under-recognized tumor from being overlooked.

Clinicopathologic characteristics of early gastric cancer in Korea

Gastric cancer is the most common cause of cancer related death in Korea. Early gastric cancer (EGC), confined to mucosa or submucosa, regardless of lymph node metastasis, is known to have a favorable prognosis. From 1976 to 1995, four thousand nine hundred and twenty eight gastric cancer patients underwent operation at the Severance Hospital, Yonsei University, College of Medicine, Seoul, Korea. Of these, 1,117 patients (22.6%) were diagnosed as EGC and underwent curative operation. Clinicopathologic characteristics were reviewed and survival data was analyzed. The proportion of EGC has increased during the last two decades, from 14.9% during 1976-1985 to 25.8% for 1986-1995. EGC has a wide age distribution range from the thirties to the sixties, with highest incidence in the sixties. The male to female ratio is 1.8:1, without any significant change in last two decades. Most lesions are located in the lower third of stomach (52.3%), and the lesser curvature (52.2%) was the most frequent site in the transverse axis. Macroscopically, the depressed type was the most common (66.1%) followed by the elevated, flat and mixed types, in that order. Tumor confined to the mucosa layer was seen in 52.5%, and lymph node involvement in 11.7%. The depth of tumor invasion correlated with tumor size and regional lymph node involvement. On histopathologic examination, signet ring cell type accounted for 29.6% of all EGCs. Overall 5-year survival rate was 92.7% and the presence of lymph node metastasis significantly affected survival (84.6% versus 96.2%) (p<0.05). In conclusion, the proportion of EGC, in terms of the gastric cancers operated upon, has been increasing in Korea over the last two decades. The introduction of active diagnostic approaches and diagnostic modalities could improve early diagnosis and the cure rate of gastric cancer in Korea.

Recurrence following curative resection for gastric carcinoma

BACKGROUND

The diagnosis and treatment of recurrent gastric cancer remains difficult. The aim of this study was to determine the risk factors for recurrence of gastric cancer and the prognosis for these patients.

METHODS

Of 2328 patients who underwent curative resection for gastric cancer from 1987 to 1995, 508 whose recurrence was confirmed by clinical examination or reoperation were studied retrospectively. The risk factors that determined the recurrence patterns and timing were investigated by univariate and multivariate analysis.

RESULTS

The mean time to recurrence was 21.8 months and peritoneal recurrence was the most frequent (45.9 per cent). Logistic regression analysis showed that serosal invasion and lymph node metastasis were risk factors for all recurrence patterns and early recurrence (at 24 months or less). In addition, independent risk factors involved in each recurrence pattern included younger age, infiltrative or diffuse type, undifferentiated tumour and total gastrectomy for peritoneal recurrence; older age and larger tumour size for disseminated, haematogenous recurrence; and older age, larger tumour size, infiltrative or diffuse type, proximally located tumour and subtotal gastrectomy for locoregional recurrence. Other risk factors for early recurrence were infiltrative or diffuse type and total gastrectomy. Reoperation for cure was possible in only 19 patients and the mean survival time after conservative treatment or palliative operation was less than 12 months.

CONCLUSION

The risk factors for each recurrence pattern and timing of gastric cancer can be predicted by the clinicopathological features of the primary tumour. Since the results of treatment remain dismal, studies of perioperative adjuvant therapy in an attempt to reduce recurrence are warranted.

Putative chromosomal deletions on 9P, 9Q and 22Q occur preferentially in malignant gastrointestinal stromal tumors

To characterize the type of genetic alterations in gastrointestinal stromal tumors (GISTs), we performed a comprehensive allelotype study of 14 GISTs (2 benign, 7 borderline and 5 malignant) by polymerase-chain-reaction and loss-of-heterozygosity (PCR-LOH) analysis using 102 microsatellite markers, and compared the results with comparative-genomic-hybridization (CGH) analysis. Among the 38 evaluated chromosomal arms, 16 (42.1%) showed LOH in at least one patient. Most frequent LOH was observed at chromosome 14p and 14q (9/14, 64%) and this was demonstrated in all types of GISTs (50% in benign, 71% in borderline and 80% in malignant). Additional chromosomal deletions were found in several chromosomal arms. Among them, deletions on chromosomal arms of 22q (3/14, 21.4%), 9p (2/14, 14.3%) and 9q (2/14, 14.3%) were the most frequent, and were detected only in malignant GISTs both by PCR-LOH and by CGH analysis. Additionally, 2 malignant GISTs with LOH on 9p showed homozygous deletions in the restricted area of 9p by multiplex PCR-LOH analysis. Thus, several putative chromosomal changes were preferentially present in malignant GISTs but rare in benign and borderline GISTs. These findings suggest that accumulated chromosomal changes may contribute to the progression and/or malignant transformation of GISTs.

Putative chromosomal deletions on 9P, 9Q and 22Q occur preferentially in malignant gastrointestinal stromal tumors

To characterize the type of genetic alterations in gastrointestinal stromal tumors (GISTs), we performed a comprehensive allelotype study of 14 GISTs (2 benign, 7 borderline and 5 malignant) by polymerase-chain-reaction and loss-of-heterozygosity (PCR-LOH) analysis using 102 microsatellite markers, and compared the results with comparative-genomic-hybridization (CGH) analysis. Among the 38 evaluated chromosomal arms, 16 (42.1%) showed LOH in at least one patient. Most frequent LOH was observed at chromosome 14p and 14q (9/14, 64%) and this was demonstrated in all types of GISTs (50% in benign, 71% in borderline and 80% in malignant). Additional chromosomal deletions were found in several chromosomal arms. Among them, deletions on chromosomal arms of 22q (3/14, 21.4%), 9p (2/14, 14.3%) and 9q (2/14, 14.3%) were the most frequent, and were detected only in malignant GISTs both by PCR-LOH and by CGH analysis. Additionally, 2 malignant GISTs with LOH on 9p showed homozygous deletions in the restricted area of 9p by multiplex PCR-LOH analysis. Thus, several putative chromosomal changes were preferentially present in malignant GISTs but rare in benign and borderline GISTs. These findings suggest that accumulated chromosomal changes may contribute to the progression and/or malignant transformation of GISTs.

Recurrence following curative resection for gastric carcinoma

BACKGROUND

The diagnosis and treatment of recurrent gastric cancer remains difficult. The aim of this study was to determine the risk factors for recurrence of gastric cancer and the prognosis for these patients.

METHODS

Of 2328 patients who underwent curative resection for gastric cancer from 1987 to 1995, 508 whose recurrence was confirmed by clinical examination or reoperation were studied retrospectively. The risk factors that determined the recurrence patterns and timing were investigated by univariate and multivariate analysis.

RESULTS

The mean time to recurrence was 21.8 months and peritoneal recurrence was the most frequent (45.9 per cent). Logistic regression analysis showed that serosal invasion and lymph node metastasis were risk factors for all recurrence patterns and early recurrence (at 24 months or less). In addition, independent risk factors involved in each recurrence pattern included younger age, infiltrative or diffuse type, undifferentiated tumour and total gastrectomy for peritoneal recurrence; older age and larger tumour size for disseminated, haematogenous recurrence; and older age, larger tumour size, infiltrative or diffuse type, proximally located tumour and subtotal gastrectomy for locoregional recurrence. Other risk factors for early recurrence were infiltrative or diffuse type and total gastrectomy. Reoperation for cure was possible in only 19 patients and the mean survival time after conservative treatment or palliative operation was less than 12 months.

CONCLUSION

The risk factors for each recurrence pattern and timing of gastric cancer can be predicted by the clinicopathological features of the primary tumour. Since the results of treatment remain dismal, studies of perioperative adjuvant therapy in an attempt to reduce recurrence are warranted.

Differential expression of nitric oxide synthase in human stomach cancer

The level of expression and cellular localization of isoenzymes of nitric oxide synthase (NOS) was detected in human stomach tumor tissues. Tumor tissues showed 70% higher activity of NOS than that of normal tissues (P < 0.01). Poorly differentiated adenocarcinoma tend to have higher activity (P < 0.05) than well differentiated and moderately differentiated tumor tissues. Aminoguanidine (AG), 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), NG-monomethyl-L-arginine (L-NMMA), and Nomega-nitro-L-arginine (L-NNA) inhibited NOS activity in tumor tissues by 18, 14, 11 and 13%, respectively. The TNF-alpha mRNA expression was correlated with the inducible NOS (iNOS) level, which was high in adenocarcinomas and low in normal tissues. Tumor tissues showed higher expression of iNOS in gland epithelial cells but the level of eNOS was significantly decreased with an exception of concentrated localization in the proliferating capillary endothelium. These results revealed that isoforms of NOS might contribute differentially to growth and progression of human stomach tumor.

Accumulated frameshift mutations at coding nucleotide repeats during the progression of gastric carcinoma with microsatellite instability

Microsatellite instability (MSI) and frameshift mutations in genes containing nucleotide repeats have been reported in a subset of gastric carcinomas, but the mutational profiles in precancerous lesions have not been characterized. To characterize the genetic events during gastric carcinogenesis, we analyzed DNA from 56 gastric adenomas and 167 gastric carcinomas for MSI using five microsatellite markers and for frameshift mutations at coding nucleotide repeats of the type II transforming growth factor beta receptor, BAX, hMSH3, hMSH6, IGF II receptor, and E2F-4 genes. On the basis of the number of markers displaying instability per tumor, the tumors were divided into three groups: those with two or more of the five markers showing instability (high MSI [MSI-H]), those with one of the five markers showing instability (low MSI [MSI-L]), and those with no instability. MSI-H was found in 8 adenomas (14%) and 19 carcinomas (11%), and MSI-L was found in 8 adenomas (14%) and 9 carcinomas (5%). These groups were tested for correlations with several clinicopathologic parameters. MSI-H gastric adenomas were related to the high histologic grade of composing dysplastic glands (p = 0.004), and MSI-H gastric carcinomas were associated with exophytic tumor growth (p = 0.005). We found 48 frameshift mutations at coding nucleotide repeats of the six genes, and all mutations except one were found in MSI-H gastric tumors. Only one of the 17 MSI-L tumors showed frameshift mutations at coding nucleotide repeats of the transforming growth factor beta receptor II gene. Compared with MSI-H gastric carcinomas, MSI-H adenomas had no mutations in the hMSH6 and the IGF II receptor genes, less frequent mutations in the transforming growth factor beta receptor II (38% versus 63%), BAX (13% versus 37%), and hMSH3 (13% versus 37%) genes, and more frequent mutations in the E2F-4 (50% versus 37%) gene. Our findings suggest that MSI and E2F-4 mutations are early genetic events and that mutations of the other five genes are accumulated during the progression of gastric carcinomas with MSI.

Modulation of biological phenotypes for tumor growth and metastasis by target-specific biological inhibitors in gastric cancer

For tumor progression, a cascade of linked sequential biological events is essential. We tried to test whether biological therapy can modulate specific biological phenotypes and increase the anti-tumor effect when combined with chemotherapy. Five human gastric cancer cell lines (YCC-1, YCC-2, YCC-3, YCC-7, AGS) were used in these studies. Pentosan polysulfate (PPS) as a heparin-binding growth factor inhibitor, Tranexamic acid as a plasmin inhibitor, Lovastatin as an adhesion inhibitor and Adriamycin as a chemotherapeutic agent were selected. The effects of each drug on colony formation and tumor cell proliferation were evaluated by soft agar assay and cell proliferation assay, respectively to test direct anti-tumor effect. The expression of uPA, PAI-1 was determined by ELISA, while MMPs activity was evaluated by zymography. PPS suppressed the colony-forming activity as much as Adriamycin did, but it showed only cytostatic effects in cell proliferation assay. Migration capacity using Boyden chamber assay was more closely correlated with adhesive capacity than uPA or MMP-2 expression. The motility inhibitory effect of Tranexamic acid was observed in the YCC-7 cell line, which expressed all the required biological phenotypes for migration. In AGS, with high cell motility and adhesiveness, the adhesion was inhibited by Lovastatin and most of the inhibitory effect was recovered by Mevalonate. When PPS was combined with Adriamycin on the Adriamycin-resistant, midkine (MK) gene expressing YCC-7 cell line, the growth inhibition rate increased up to 84%, while that for a single treatment of PPS or Adriamycin was 40% and 22%, respectively (p=0.001). When we combined Tranexamic acid and Adriamycin, we observed the synergistic effect in YCC-3 and YCC-7, while no combined effect was found in YCC-1. The combination of Lovastatin and Adriamycin did not show any combined effects in any of the cell lines. In conclusion, a synergistic anti-proliferative effect (chemo-sensitization) with combined chemo-biotherapy was found in cancer cells with specific biological target, MK. The anti-motility effect was the greatest when the gastric cancer cells expressed all the specific biological phenotypes.

Prognostic significance of CD44 and nm23 expression in patients with stage II and stage IIIA gastric carcinoma

BACKGROUND AND OBJECTIVES

Predicting the prognosis in gastric carcinoma patients with intermediate stages is difficult. We investigated the prognostic impacts of CD44 and nm23 expression in a homogeneous group of patients with stage II and IIIA gastric carcinoma who had undergone curative resections.

METHODS

A total of 261 paraffin-embedded gastric carcinomas were stained with the monoclonal antibodies CD44 and nm23 using the labeled streptovidin biotin method.

RESULTS

The expression of CD44 and nm23 was detected, respectively, in 31.0% (81/261) and 70.1% (183/261) of all tumors. There was no correlation between CD44 expression and clinicopathological variables. However, nm23 was more frequently expressed in older patients with differentiated adenocarcinoma. A significant difference in 5-year survival rates was found between patients with CD44-positive (43.2%) and CD44-negative tumors (63.4%), (P = 0.0018). However, there was no significant difference in 5-year survival rates between patients with nm23-positive (54.7%) and nm23-negative tumors (62.7%) (P = 0.2734).

CONCLUSIONS

CD44 expression was a significant adverse prognostic factor in gastric carcinoma and may be a predictor of metastatic potential of the primary tumor. By contrast, immunohistochemical detection of nm23 expression was not a predictor of outcome of patients with gastric carcinoma.

Prognostic significance of CD44 and nm23 expression in patients with stage II and stage IIIA gastric carcinoma

BACKGROUND AND OBJECTIVES

Predicting the prognosis in gastric carcinoma patients with intermediate stages is difficult. We investigated the prognostic impacts of CD44 and nm23 expression in a homogeneous group of patients with stage II and IIIA gastric carcinoma who had undergone curative resections.

METHODS

A total of 261 paraffin-embedded gastric carcinomas were stained with the monoclonal antibodies CD44 and nm23 using the labeled streptovidin biotin method.

RESULTS

The expression of CD44 and nm23 was detected, respectively, in 31.0% (81/261) and 70.1% (183/261) of all tumors. There was no correlation between CD44 expression and clinicopathological variables. However, nm23 was more frequently expressed in older patients with differentiated adenocarcinoma. A significant difference in 5-year survival rates was found between patients with CD44-positive (43.2%) and CD44-negative tumors (63.4%), (P = 0.0018). However, there was no significant difference in 5-year survival rates between patients with nm23-positive (54.7%) and nm23-negative tumors (62.7%) (P = 0.2734).

CONCLUSIONS

CD44 expression was a significant adverse prognostic factor in gastric carcinoma and may be a predictor of metastatic potential of the primary tumor. By contrast, immunohistochemical detection of nm23 expression was not a predictor of outcome of patients with gastric carcinoma.

Comparison of prognostic significance of nodal staging between old (4th edition) and new (5th edition) UICC TNM classification for gastric carcinoma. International Union Against Cancer

The description of nodal staging for gastric cancer was changed in the new fifth edition of the International Union Against Cancer (UICC) TNM classification from the anatomic sites of metastatic lymph nodes to the number of metastatic lymph nodes, as pN1 is metastasis in 1 to 6 lymph nodes, pN2 is in 7 to 15 lymph nodes, and pN3 is in 16 or more lymph nodes. The purpose of this study was to investigate the prognostic significance of the new staging system based on the number of metastatic lymph nodes compared to the old staging system by anatomic site. From 1987 to 1994 a total of 2108 patients who underwent potentially curative resections with D2 or D3 lymph node dissection and with 15 or more lymph nodes retrieved were studied retrospectively. Lymph node metastases were found in 1018 patients (48.3%). A mean of 37.9 lymph nodes were retrieved per patient, and a mean of 7.2 lymph nodes were invaded by tumor cells. We found that the new nodal staging based on the number of metastatic lymph nodes closely correlated with the depth of cancer invasion and with the old nodal staging based on the anatomic site of the metastatic nodes, with statistical significance. The 5-year survival rates after gastrectomy decreased significantly by increasing the extent of the pN classification in both nodal staging methods. In a subgroup analysis of survivals between the old and new nodal staging, the new classification showed more homogeneous survival at the same stage than the old one. With a multivariate analysis of prognostic factors, including the old and new nodal staging, the depth of invasion and the new nodal stage were the most significant prognostic factors, followed by the old nodal stage. Our data suggested that the new nodal staging based on the number of metastatic lymph nodes is not only a reliable and objective method for nodal classification, but it is also a significant prognostic determinant for gastric cancer that can be used in practice.

Clinicopathologic characteristics of mucinous gastric adenocarcinoma

There has been considerable controversy over the prognosis of mucinous gastric adenocarcinoma (MGC). In this study we analyzed the clinicopathologic differences between MGC and non-mucinous gastric carcinoma (NMGC). In addition, the relationship between mucin content and other clinicopathologic variables, including prognosis in MGC, was also investigated. We reviewed 2118 patients with pathologically-confirmed gastric cancer who underwent gastrectomy at the Department of Surgery, Yonsei University College of Medicine, during the period between Jan. 1987 and Dec. 1993. Among them, 130 patients had gastric carcinoma with extracellular mucin (MGC) and 1988 patients had gastric carcinoma without extracellular mucin (NMGC). We placed the MGC patients into two groups according to mucin content: mucin content involving over 50% of the tumor (dominant type, n = 94) and mucin content involving less than 50% of the tumor area (partial type, n = 36). The results were as follows: MGC was more common in males than NMGC. The size of the tumor in MGC (mean 5.3 cm) was larger than that of NMGC (mean 4.4 cm). The patients with MGC had a higher incidence of Borrmann type IV (MGC: 16.1%, NMGC: 9.9%), more frequent serosal invasion (MGC: 75.4%, NMGC: 48.6%), lymph-node metastasis (MGC: 75.4%, NMGC: 50.7%), and peritoneal metastasis (MGC: 10.0%, NMGC: 3.5%) than patients with NMGC. The patients with MGC were more advanced in stage at the time of diagnosis and had a worse overall 10-year survival rate (44.9%) than patients with NMGC (54.7%). However, the 10-year survival rate according to the stage of MGC was similar to that of NMGC. There were no significant differences between the mucin content and other pathologic variables, including prognosis, i.e. similar biologic behavior between dominant type MGC and partial type MGC. In conclusion, we suggest that MGC was more frequently diagnosed in advanced stage than NMGC with a poorer prognosis and that it is reasonable to consider the carcinoma with mucin content involving more than 30% of the tumor area as MGC.

An unusual case of gastric carcinoma with synchronous non-Hodgkin's lymphoma

We report a case of synchronous gastric adenocarcinoma and abdominal non-Hodgkin's lymphoma in a 56-year-old man. An explo-laparotomy was performed for the purpose of palliative resection of the stomach and to evaluate the nature of splenic and peri-pancreatic mass lesions. The pathologic stage of the gastric carcinoma was stage IB (T2N0M0) and the clinical stage of the diffuse large cell type lymphoma was IIA2S. Following surgery and chemotherapy, the patient is now in a disease-free state.

Telomerase activity and telomere lengths in various cell lines: changes of telomerase activity can be another method for chemosensitivity evaluation

For the cancer cells which have overcome the second mitotic clock (M2), activated telomerase is essential and used as another marker of immortality. Many trials had been initiated to target telomerase, which is known to be specific to tumors. To determine the best in vitro cell system for testing the efficacy of telomerase inhibitors, we evaluated the telomerase activity of various cancer cell lines and measured their telomere lengths. We also treated some cancer cell lines with adriamycin and measured the changes of telomerase activity. Telomerase activity was evaluated in various cell lines with the TRAP (telomeric repeat amplification protocol) assay. Telomerase activity was calculated and translated into arbitrary units by computer-assisted densitometry with the control of telomerase activity in the 293 control cell line. Also, terminal restriction fragment lengths were measured using Southern blotting. We also measured telomerase activity and telomere lengths in 11 benign breast tumor tissues and 19 paired stomach cancer and normal tissues. Cancer cell lines treated with adriamycin we evaluated for changes of telomerase activity and the cell proliferation by MTT assay and dye exclusion test. Telomerase activity of cell lines was 95.3 24.1 unit with a range of 27.6-129.6 unit, while the telomere lengths of those cell lines were variable from 5.0 to 10.4 kbp with a median of 6 kbp. In 11 cancer cell lines which were not yet firmly established, we could not detect any telomerase activity. Low telomerase activity was detected in only 2 benign tumor tissues of breast with a median telomere length of 8.8 (7-10.5) kbp. Among paired 19 gastric cancer and normal tissues, only 7 cancer tissues showed weak telomerase activity. After adriamycin treatment, telomerase activity in YCC-S-1, YCC-S-3, MCF-7 and MCF-7/ADR was decreased in accordance with the changes of the cell numbers. Telomerase is specific to cancer tissues and is expressed differently from organ to organ. Telomerase activity by TRAP assay could be used as a chemosensitivity assay.

Alpha-fetoprotein-producing gastric cancer

We measured the sero-positivity rate of serum alpha-fetoprotein (alphaFP) of gastric cancer patients by ELISA assay; forty-two curatively resected patients, 14 palliatively resected patients, 8 who received explo-laparotomy or bypass surgery and 18 patients with systemic metastasis. The sero-positive rate was 9.8% (8/82) and the positivity increased with cancer progression. Sex, age and pathological type were similar between alphaFP-positive and -negative patients. The overall synchronous hepatic metastasis rates in alphaFP-positive and alphaFP-negative groups were 37.5% (3/8) and 12.2% (9/74), respectively (p=0.08). The predictability of synchronous liver metastasis in eight alphaFP-positive patients were as follows: 37. 5% of total patients (3/8), 50.0% (3/6) of unresectable patients, and 60.0% (3/5) of patients with systemic metastasis. In three alphaFP-positive patient with liver metastasis, all the hepatic lesions were intrahepatic and multiple, while in alphaFP-negative patients, 67% (6/9) of the hepatic lesions was single intrahepatic lesion or surface nodule. The predictability of both synchronous and metachronous liver metastasis in alphaFP-positive gastric cancer patients was 75%. These findings suggested that, in advanced stomach cancer patients, especially in stage IV, alphaFP can be used in predicting liver metastasis during follow-up.

Farnesylcysteine methyltransferase activity and Ras protein expression in human stomach tumor tissue

The processing pathway of G-proteins and Ras family proteins includes the isoprenylation of the cysteine residue, followed by proteolysis of three terminal residues and alpha-carboxyl methyl esterification of the cysteine residue. Farnesylcysteine methyltransferase (FCMT) activity is responsible for the methylation reaction which play a role in the membrane attachment of a variety of cellular proteins. Four kinds of Ras protein (c-Ha-ras, c-N-Ras, c-Ki-Ras, pan-Ras) expression were detected in adenocarcinoma of human tissue by immunohistochemical method, and hematoxylin and eosin staining. The level of Ras protein in human stomach tumor tissues was much higher than in normal and peritumoral regions of the same biopsy samples. The FCMT activities of each cellular fractions were high in mitochondrial fraction followed by microsomal fraction, whole homogenate and cytosolic fraction. The inhibitory effect on FCMT activity on stomach tumor tissue was determined after treatment with 0.25 microM of S-adenosyl-L-homocysteine. S-adenosyl-L-homocysteine inhibited FCMT activity from 11.2% to 30.5%. These results suggested that FCMT might be involved in Ras proteins activity.

Synchronous elevation of soluble intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) correlates with gastric cancer progression

Soluble forms of ICAM-1 (sICAM-1) and VCAM-1 (sVCAM-1) have been reported from the supernatant of cytokine-activated endothelial cells, cancer cells and from sera of cancer patients. We measured sICAM-1 and sVCAM-1 from the serum of 20 healthy volunteers and 142 gastric cancer patients by ELISA assay. Ninety-five patients were operable and 47 patients were in-operable at the time of this study. Particularly in the 28 operable patients, we sampled both portal and peripheral blood simultaneously and measured the levels of the soluble forms of cell adhesion molecules (sCAMs). The sCAMs level and sero-positivity rate increased with cancer progression in order of the healthy controls, operable patients, and inoperable patients. In in-operable cancer, the sICAM-1 level increased more with liver metastasis. sICAM-1 and sVCAM-1 did not correlate with each other in either portal or peripheral blood. A total of 58.3% of patients with liver metastasis and 22.9% of patients without liver metastasis showed synchronous expression of both sCAMs (p = 0.03). Synchronous sero-positivity of sCAMs and alpha FP was higher with liver metastasis (p = 0.01). The median overall survival duration which co-expressed both sCAMs was 9 months. This showed a significant difference compared with the sICAMs non-expressing group, where the median survival was not reached until 24 months follow-up (p = 0.002). The synchronous expression of sCAMs was an independent risk factor in gastric cancer patients. We raise the possibility that synchronous sICAM-1 and sVCAM-1 elevation may be a useful monitor to determine tumor burden in gastric cancer.

Retrospective comparison of infusional 5-fluorouracil, doxorubicin, and mitomycin-C (modified FAM) combination chemotherapy versus palliative therapy in treatment of advanced gastric cancer

About one-third of patients with gastric cancer are unresectable at the time of diagnosis. Their median survival is < 6 months, with a grave prognosis. The purpose of this study was to assess the efficacy of a modified FAM (mFAM) regimen in advanced gastric cancer. We retrospectively reviewed the clinical records of 409 advanced gastric cancer patients who had not received curative surgery. Among 409 patients, 202 patients were treated with an mFAM regimen (infusional 5-FU + doxorubocin + mitomycin-C), and 207 patients received no chemotherapy (control group). No differences were found in clinical parameters between the two groups. The 1-year survival rates were 34.1% for the mFAM-treated group and 22.5% for the control group (p = 0.0135). In subset analysis, a higher 1-year survival rate was demonstrated in patients with mFAM and palliative surgery. Of the 154 evaluable patients in the mFAM-treated group, the response rate was 17.5%. In these patients, median response duration was 30 weeks, and progression-free survival was 23 weeks. Overall toxicity of mFAM regimen was relatively tolerable and reversible. In conclusion, FAM combination chemotherapy, which has been used as a standard therapy, prolonged survival after modification of the administration schedule and combination with palliative surgery. A prospective randomized study is warranted to confirm this conclusion from our retrospective study.

Comparison of biological phenotypes according to midkine expression in gastric cancer cells and their autocrine activities could be modulated by pentosan polysulfate

We studied biological phenotypes of gastric cancer cell lines based on a novel heparin-binding growth/differentiation factor (midkine (MK)) expression. MK expression was found in 67% (6/9) of the gastric cancer cell lines and 56% (14/25) of the primary cancer tissues. Gastric cancer cell lines with MK expression showed higher colony forming activity in soft agar assay and endothelial cell growth stimulatory effect in cross-feeding assay than cells which did not express MK. However, urokinase-type plasminogen activator (uPA) expression and tumor invasiveness did not correlate with MK expression. Growth of MK expressing cells was inhibited by a heparin-binding blocking agent, pentosan polysulfate (PPS). In cancer tissues, MK expression correlated with tumor size, suggesting in vivo autocrine and paracrine activity. This proliferation promoting activity of MK can be targeted by an anti-heparin binding agent as a biotherapy model in gastric cancer.

High level of urokinase-type plasminogen activator is a new prognostic marker in patients with gastric carcinoma

BACKGROUND

Prognosis of gastric carcinoma is related to invasion and metastasis. Evidence has accumulated that invasion and metastasis in solid tumors require the action of tumor-associated proteases, which promote the dissolution of the surrounding tumor matrix and the basement membrane. The serine protease urokinase-type plasminogen activator (uPA) and its inhibitor, plasminogen activator inhibitor-1 (PAI-1), appear to have a major function in these processes. Recent reports have demonstrated that expression of these proteolytic enzymes is elevated in breast and colon carcinoma and that it can be associated with invasiveness and poor prognosis. Therefore, the authors evaluated whether the expression and activation of uPA and PAI-1 might be of clinical value as a tumor/biologically defined risk factor in patients with gastric carcinoma.

METHODS

Enzyme-linked immunoadsorbent assays were used to test for uPA antigens and PAI-1 in tissue extracts of normal and cancerous tissue from 160 gastric carcinoma patients who were enrolled in the Yonsei Cancer Center Study Group.

RESULTS

Both uPA and PAI-1 levels were significantly higher in cancerous tissues than in normal tissues (uPA: 9.4 +/- 8.7 vs. 5.3 +/- 3.1 ng/mg protein cytosol; PAI-1: 10.9 +/- 9.1 vs. 5.8 +/- 2.9 ng/mg protein cytosol), (P < 0.001, respectively). Both high uPA and PAI-1 levels were associated with differentiation of the tumor (P = 0.04 and P = 0.004, respectively), and a high PAI-1 level was associated with lymph node metastasis at an advanced stage (P = 0.003 and P = 0.04, respectively). There was a correlation between the levels of uPA and PAI-1 expression in cancerous tissues (correlation coefficient = 0.57). In univariate analysis, a high level of uPA or PAI-1 was associated with a short relapse free survival, but in multivariate analysis only a high level of uPA was an independent prognostic parameter for a short relapse free survival for gastric carcinoma patients.

CONCLUSIONS

These data indicate that uPA is a new independent variable for the identification of high risk gastric carcinoma patients. Therefore, therapy targeting uPA can be applied as a new biologic treatment modality for these individuals.

Relationship between p53 overexpression and gastric cancer progression

The relationship between p53 overexpression and clinicopathologic variables in gastric cancer was evaluated using 304 paraffin-embedded gastric tumor tissues. DO7, a murine monoclonal antiserum to p53 protein, was used for the immunohistochemical analysis. Positive staining was found in 129 tumors (42.2% of all tumors). Overexpression of p53 was not associated with sex, location of the tumor in the stomach or the type of Borrman's tumor. The overexpression rate of p53 protein was 30.4% (28/92) in stage II and 47.6% (101/212) in stage III (p = 0.007). While there was no significant association between p53 protein accumulation and T stage, there was a significant association with N stage, i.e. p53 overexpression was 27.4% (17/62) in the node-negative group and 46.3% (112/242) in the node-positive group (p = 0.011). In 79 patients, in whom corresponding primary gastric tumor and regional lymph node metastases were available, overexpression was found in 34 (43%) primary tumors and in 38 (48.1%) node samples, with a concordance rate of 67.1% in terms of p53 expression. Mean numbers of regional lymph node involvement by the tumor were 6.1 in the group with p53 overexpression and 5.2 in the group showing no immunoreactivity (p = 0.051). These findings suggest that p53 overexpression is related to gastric cancer progression and that immunoreactivity in the metastatic lymph nodes show the dependency on p53 expression in the primary tumor.