Pathogenesis of adenocarcinoma induced by gastrojejunostomy in Wistar rats: role of duodenogastric reflux

Clinicopathological features and prognosis of gastric tube cancer after esophagectomy for esophageal cancer: a nationwide study in Japan

BACKGROUND

Survivors of esophageal cancer post-esophagectomy may sometimes develop gastric tube cancer (GTC). However, its clinical characteristics have not been elucidated. We conducted a retrospective nationwide survey of GTCs to clarify them.

METHODS

A questionnaire on GTCs was sent by e-mail and mail to 116 institutions certified by the Japan Esophageal Society. A total of 608 GTC cases diagnosed and treated between 2001 and 2015 were registered from 62 institutions.

RESULTS

The median age at diagnosis was 71 years, with 88.9% being diagnosed with stage I. Sixty percent of GTC cases were in the anal third of the gastric tube and 79.7% were differentiated adenocarcinomas. The median interval between esophagectomy and GTC diagnosis was 6 years, with approximately 25% of patients being diagnosed more than 10 years later. The 5-year overall survivals (5-OSs) after endoscopic and surgical treatments for GTC were 75.9% and 52.7%, respectively. Patients whose GTC was diagnosed without symptoms or by regular follow-up examination showed better 5-OSs compared to others (69.7% vs. 41.2%, p < 0.0001; and 71.4% vs. 41.8%, p < 0.0001, respectively). The prognosis of GTC cases diagnosed within 2 years of the preceding upper gastrointestinal endoscopy (UGI) was better than that in cases diagnosed longer than 2 years (5-OS: 73.4% vs. 48.8%, p < 0.05).

CONCLUSION

This nationwide survey revealed the clinicopathological features of GTCs for the first time. Early detection is important in improving the prognosis of GTC, and it is recommended that UGI endoscopy be continued every 2 years for 10 or more years after esophagectomy.

Carcinoma in the Remnant Stomach During Long-Term Follow-up After Distal Gastrectomy for Gastric Cancer: Analysis of Cumulative Incidence and Associated Risk Factors

BACKGROUND

The number of patients with remnant gastric cancer following resection of gastric cancer may increase. The aims of this study were to investigate the development of remnant gastric cancer after distal gastrectomy for gastric cancer and to examine its cumulative incidence, clinicopathological characteristics, and risk factors.

METHODS

We examined 437 patients with relapse-free survival for 5 years or more after distal gastrectomy with Billroth I reconstruction for gastric cancer performed between 1985 and 2005.

RESULTS

A total of 17 patients suffered from remnant gastric cancer. The cumulative incidence was 3.7% at 10 years and 5.4% at 20 years. The median time until development of remnant gastric cancer was 79 months (range 30-209 months). The presence of synchronous multiple gastric cancers was a significant independent risk factor for remnant gastric cancer (hazard ratio 4.036; 95% confidence interval 1.478-11.02; P = 0.006). Of the 17 patients, the 13 whose remnant gastric cancer was detected via regular endoscopy showed better prognoses than the patients detected by other means (P < 0.001).

CONCLUSION

The cumulative incidence of remnant gastric cancer was 5.4% at 20 years. In particular, patients who had multiple gastric cancers at initial gastrectomy were at higher risk for remnant gastric cancer. Therefore, long-term endoscopic surveillance is important.

[Gastric stump carcinoma: frequency, treatment, complications and prognosis]

BACKGROUND

Gastric stump carcinoma develops in the gastric remnant after partial gastrectomy. While the frequency of gastric cancer is declining, the incidence of gastric stump carcinoma has remained stable due to the long latency period. As the surgical treatment of gastric ulcers by partial gastrectomy has become much less important, more and more gastric stump carcinomas develop after oncological resection.

AIM

This study compared the surgical therapy of gastric stump carcinoma with the therapy of primary gastric cancer.

MATERIAL AND METHODS

From 2001 to 2014 a total of 24 patients were surgically treated for gastric stump carcinoma in the University Hospital of Heidelberg. In the same time 428 patients underwent resection due to primary gastric cancer. Both groups were analyzed and compared with a focus on preoperative therapy, intraoperative differences, complications and overall survival.

RESULTS

Patients with gastric stump carcinoma were older at disease onset (68 years vs. 62 years, p = 0.003). Compared with primary gastric cancer, patients with gastric stump carcinoma were more often suspected of having lymph node (cN+) involvement (51.4 % vs. 41.7 %, p < 0.001) but neoadjuvant therapy was applied less often (48.7 % vs. 14.3 %, p < 0.01). For resection of gastric stump carcinoma, extended resections were more often necessary (54.5 % vs. 28.2 %, p < 0.001). There were no significant differences in mean overall survival between the two patient groups (64.4 months vs. 45.8 months, p = 0.34) CONCLUSION: Despite the differences described, the treatment of gastric stump carcinoma does not essentially differ from that of primary gastric cancer. Carcinomas of the gastric stump are more often locally advanced and in our opinion a neoadjuvant therapy should be applied analogue to gastric cancer even if evidence-based data on this point are limited.

Gastric remnant cancer patients had a better prognosis than upper-third gastric cancer patients in a case-control study after surgical treatment

Background

The aim was to compare the clinicopathological features and prognostic outcomes of gastric remnant carcinoma patients with those of patients with upper-third gastric cancer.

Methods

Clinical data extracted from 112 gastric remnant carcinomas and 367 upper-third gastric cancer patients were analyzed to explore the clinicopathologic differences between two groups. After radical resection, prognostic difference between them was evaluated through a 1:2 matched case-control study.

Results

The pattern of gastric remnant carcinomas showed a male predominance. Undifferentiated type histology, depth at T4 stage and distant metastases were more frequent in gastric remnant carcinomas than in upper-third gastric cancers (P <0.05). The radical resectability of gastric remnant carcinomas was lower and the multi-visceral resectabilitiy was relatively higher than the other group (P = 0.00). Gastric remnant carcinomas trended to have a higher incidence of metastases to either mesojejunum or lower mediastinal lymph nodes than upper-third gastric cancers, but patient survival was not significantly different. In the case-control study, gastric remnant carcinomas had a better prognosis than upper-third gastric cancers after radical resection when the clinicopathologic features and surgical treatment were matched.

Conclusions

Although there was no significant prognostic distinction between gastric remnant carcinomas and upper-third gastric cancer, after radical surgical treatment, patients with the former had an even better prognosis.

Large-cell neuroendocrine carcinoma arising from a gastritis cystica polyposa

Gastritis cystica polyposa is a polypoid lesion that arises from the gastric mucosa at the gastrojejunal anastomotic site and is characterized by cystic dilation of the gastric glands. A 78-year-old man who underwent distal gastrectomy for a gastric ulcer with Billroth II reconstruction approximately 40 years previously, exhibited a gastritis cystica polyposa at the anastomotic site. Ulceration was observed on an annual endoscopic examination. Endoscopic ultrasonography revealed a submucosal hypoechoic mass with multiple cystic lesions. Gastrectomy was performed and histological examination revealed a large-cell neuroendocrine carcinoma with cystic dilation of the gastric glands. Here, we report the first case of a large-cell neuroendocrine carcinoma arising from a gastritis cystica polyposa. Endoscopic ultrasonography was effective at diagnosing a submucosal hypoechoic mass with cystic dilation of the gastric glands.

Current status in remnant gastric cancer after distal gastrectomy

Remnant gastric cancer (RGC) and gastric stump cancer after distal gastrectomy (DG) are recognized as the same clinical entity. In this review, the current knowledges as well as the non-settled issues of RGC are presented. Duodenogastric reflux and denervation of the gastric mucosa are considered as the two main factors responsible for the development of RGC after benign disease. On the other hand, some precancerous circumstances which already have existed at the time of initial surgery, such as atrophic gastritis and intestinal metaplasia, are the main factors associated with RGC after gastric cancer. Although eradication of Helicobacter pylori (H. pylori) in remnant stomach is promising, it is still uncertain whether it can reduce the risk of carcinogenesis. Periodic endoscopic surveillance after DG was reported useful in detecting RGC at an early stage, which offers a chance to undergo minimally invasive endoscopic treatment or laparoscopic surgery and leads to an improved prognosis in RGC patients. Future challenges may be expected to elucidate the benefit of eradication of H. pylori in the remnant stomach if it could reduce the risk for RGC, to build an optimal endoscopic surveillance strategy after DG by stratifying the risk for development of RGC, and to develop a specific staging system for RGC for the standardization of the treatment by prospecting the prognosis.

Gastritis cystica profunda in a previously unoperated stomach: A case report

Gastritis cystica profunda is a relatively rare disease, usually observed at anastomotic sites in stomachs of patients that have undergone gastric procedures. We present the rare case of an elevated lesion in the anterior wall of the gastric antrum of a 43-year-old Chinese woman who had never undergone gastric surgery and had no gastrointestinal tract symptoms. Although the physical examination and laboratory data showed no abnormalities, endoscopic ultrasonography revealed an anechoic cystic structure. Abdominal computed tomography and magnetic resonance imaging showed the gastric wall of the greater curvature of the antrum was markedly and irregularly thickened, and mild to moderate enhancement was observed around the lesion with no enhancement in the central portion, suggestive of a gastrointestinal stromal tumor. The patient underwent a distal gastric resection of the 2.5 cm × 1.5 cm lesion. A postoperative pathologic examination showed dilated cystic glands in the muscularis mucosa and submucosal layers and erosion of the mucosal surface of the tumor, confirming the diagnosis of gastritis cystica profunda without malignancy.

Function-preserving gastrectomy for early gastric cancer

The number of early gastric cancer (EGC) cases has been increasing because of improved diagnostic procedures. Applications of function-preserving gastric cancer surgery may therefore also be increasing because of its low incidence of lymph node metastasis, excellent survival rates, and the possibility of less-invasive procedures such as laparoscopic gastrectomy being used in combination. Pylorus-preserving gastrectomy (PPG) with radical lymph node dissection is one such function-preserving procedure that has been applied for EGC, with the indications, limitations, and survival benefits of PPG already reported in several retrospective studies. Laparoscopy-assisted proximal gastrectomy has also been applied for EGC of the upper third of the stomach, although this procedure can be associated with the 2 major problems of reflux esophagitis and carcinoma arising in the gastric stump. In the patient with EGC in the upper third of the stomach, laparoscopy-assisted subtotal gastrectomy with a preserved very small stomach may provide a better quality of life for the patients and fewer postoperative complications. Finally, the laparoscopy endoscopy cooperative surgery procedure combines endoscopic submucosal dissection with laparoscopic gastric wall resection, which prevents excessive resection and deformation of the stomach after surgery and was recently applied for EGC cases without possibility of lymph node metastasis. Function-preserving laparoscopic gastrectomy is recommended for the treatment of EGC if the indication followed by accurate diagnosis is strictly confirmed. Preservation of remnant stomach sometimes causes severe postoperative dysfunctions such as delayed gastric retention in PPG, esophageal reflux in PG, and gastric stump carcinoma in the remnant stomach. Moreover, these techniques present technical difficulties to the surgeon. Although many retrospective studies showed the functional benefit or oncological safety of function-preserving gastrectomy, further prospective studies using large case series are necessary.

Modelo de carcinogênese gástrica utilizando piloroplastia de Finney: estudo experimental em ratos

RACIONAL: O refluxo duodenogástrico tem sido implicado como potencial carcinógeno para o estômago e esôfago e é um dos fatores que podem explicar o desenvolvimento de câncer no coto gástrico. Modelos experimentais de carcinogênese no estômago ressecado ou nas gastrojejunoanastomoses estão bem definidos. OBJETIVOS: Desenvolver um modelo experimental de carcinogênese gástrica através de piloroplastia à Finney, avaliar a influência da ingestão de nitrito de sódio nesse modelo, analisar as concentrações de ácidos biliares e o valor do pH gástrico. MÉTODOS: Foram operados 110 ratos Wistar divididos em quatro grupos: Grupo I (15 ratos) submetidos à laparotomia (grupo Sham); Grupo II (15 ratos) submetidos à laparotomia (Sham) e à ingestão de nitrito de sódio na água de beber; Grupo III (40 ratos) submetidos à piloroplastia à Finney; Grupo IV (40 ratos) submetidos à piloroplastia à Finney e à ingestão de nitrito de sódio na água de beber. Após 50 semanas da operação, os ratos foram sacrificados, coletadas amostras de suco gástrico para análise do pH, dosagem dos ácidos biliares, e realizada análise histológica. RESULTADOS: A mortalidade pós-operatória imediata foi de 9% e, ao longo do experimento, 10 ratos morreram. O grupo controle (I) não apresentou lesões gástricas; o grupo controle com nitrito de sódio (II) desenvolveu papilomas no pré-estômago em 16.6%; os grupos operados com piloroplastia apresentaram adenomas em 10,3% no Grupo III e 14,2% no Grupo IV, e adenocarcinoma em 55,1%, no grupo III e 14,2% no Grupo IV. A implantação de glândulas para dentro da submucosa e muscular, na zona de anastomose (implantação mucosa), não foi critério suficiente para decidir sobre a malignidade das lesões, sendo necessária a presença simultânea de atipias celulares. A concentração de ácidos biliares do suco gástrico foi maior nos Grupos III e IV. A medida do pH gástrico não foi diferente nos grupos estudados. CONCLUSÃO: 1) A piloroplastia à Finney é modelo experimental adequado de carcinogênese gástrica; 2) ela induziu refluxo duodenogástrico; 3) o refluxo duodenogástrico atuou como carcinógeno para o estômago; 4) não houve relação entre o pH gástrico e o desenvolvimento de carcinoma; 5) o nitrito de sódio não atuou como carcinógeno para o estômago dos ratos.

Treatment and outcome of patients with gastric remnant cancer after resection for peptic ulcer disease

BACKGROUND

To study the pathology, treatment, and outcome of patients with gastric remnant cancer (GRC) after resection for peptic ulcer disease (PUD).

METHODS

Review of a prospective gastric cancer database identified patients with GRC after gastrectomy for PUD. Clinicopathologic and treatment-related variables were obtained. Multivariate analysis was performed for factors associated with disease-specific survival (DSS).

RESULTS

From January 1985 to April 2010, 4402 patients with gastric adenocarcinoma were treated at our institution and 105 patients (2.4%) had prior gastrectomy for PUD. Prior resections were most often Billroth II (N = 97, 92%). The median time from initial resection to development of GRC was 32 years (3-60 years), and the majority of tumors were located at the gastrointestinal anastomosis (N = 72, 69%). Median DSS was 1.3 years (0.6-2.1 years). Patients who had resection had a significantly better outcome than patients who did not have resection (median DSS 5 vs 0.35 years, P < .0001). Factors associated with DSS on multivariate analysis included advanced T-stage (HR 16.5 (CI 2.2-123.4), P = .0006) and lymph node metastasis (HR 1.1 (CI 1.0-1.2), P < .0001). Stage-specific survival following R0 resection was similar to patients with conventional gastric cancer.

CONCLUSIONS

Patients have a lifetime risk for the development of GRC following resection for PUD. As with conventional gastric cancer, determinants of survival of patients with GRC include advanced T stage and nodal metastasis. Patients with GRC amenable to curative resection exhibit the best DSS and have stage-specific outcomes similar to patients with conventional gastric cancer.

A clinicopathological study of gastric stump carcinoma following proximal gastrectomy

BACKGROUND

We aimed to clarify the frequency and clinicopathological characteristics of gastric stump carcinoma following proximal gastrectomy.

METHODS

Three-hundred and sixteen patients who had undergone curative proximal gastrectomy over a 21-year period from January 1984 through December 2004 were reviewed.

RESULTS

Gastric stump carcinoma was observed in 17 patients (5.4%). The time interval between the initial gastrectomy and the treatment of gastric stump cancer was within 5 years in 3 patients, within 5-10 years in 8, and after 10 years in 6. Treatment included endoscopic resection (n = 4), completion total gastrectomy of the remnant stomach (n = 11), pancreatoduodenectomy (n = 1), and nonsurgical resection (n = 1). Pathologically, 9 carcinomas were differentiated and 8 were undifferentiated. In a review of reconstruction methods associated with disease stage, stage I was found in 6 of the 7 patients with esophagogastrostomy or short-segment jejunal interposition. On the other hand, stage I was found in only 3, but stage II-IV was found in 7 of the 10 patients with reconstruction by double-tract or long-segment jejunal interposition; thus, the tumor was more likely to be detected at an advanced stage after long-segment interposition (P = 0.049).

CONCLUSION

Gastric stump carcinoma following proximal gastrectomy occurred at a high frequency of 5.4% of initial resections. It is necessary to select a reconstruction method that facilitates postoperative endoscopic examination, as well as to follow up the patients after proximal gastrectomy in the long term for the early detection and early treatment of gastric stump carcinoma.

Gastric remnant cancer: an old problem with novel concerns

BACKGROUND AND AIMS

The patients with cancers in the remnant stomachs after previous partial resections for benign diseases constitute a peculiar subset of the patients with gastric cancer. They are generally at advanced stages on admissions due to disregarding the symptoms related to cancer.

PATIENTS AND METHODS

Twenty six patients with cancer arising from the remnant stomach were analyzed. Clinicopathologic features such as age, gender, time interval between the initial operation and diagnosis of gastric remnant cancer, preoperative symptoms, surgical management, and tumor characteristics like size, location, histopathology, depth of invasion, lymph node involvement, presence of distant metastasis, and stages were documented.

RESULTS

None of the cancers were diagnosed by routine surveillance and all the patients were symptomatic at the time of diagnosis. Twenty five patients were qualified for surgery. The resectability rate was 61% (n = 16). The ability to perform a curative resection and tumor location at the anastomotic site were determined as the factors significantly influencing survival (p < 0.05).

CONCLUSION

Curative resection has to be the goal of surgical management in patients with gastric remnant cancer. Concerning clinician should be sceptical about a newly developing cancer in order to detect it in an early stage and enhance resectability.

Treatment and prognosis of gastric stump carcinoma in comparison with primary proximal gastric cancer

BACKGROUND

The intention of this study was to evaluate the outcome of patients with gastric stump cancer (GSC) in comparison with patients treated for primary proximal gastric cancer (PPGC).

METHODS

Nineteen patients with GSC undergoing surgery between January 1989 and August 2005 were compared with 194 PPGC patients treated during the same time period. Various factors such as epidemiologic data, type of treatment, and histopathologic data were evaluated in the analysis.

RESULTS

The overall 5-year disease-specific survival was 42% for resected GSC patients in comparison with 37% for resected PPGC patients. There was no statistically significant difference in the survival rate detected between these 2 groups. On multivariate analysis the infiltration of the gastrojejunal anastomosis by the carcinoma was shown to be a significant predictor for the outcome of patients with GSC.

CONCLUSIONS

In summary, no significant difference in the outcome between GSC and PPGC has been detected.

Bile salts inhibit growth and induce apoptosis of culture human normal esophageal mucosal epithelial cells

AIM: To investigate the effect of six bile salts: glycocholate (GC), glycochenodeoxycholate (GCDC), glycodeoxycholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and their mixture on cultured human normal esophageal mucosal epithelial cells.

METHODS: Human normal esophageal mucosal epithelial cells were cultured with serum-free keratinocyte medium. 3-[4,5-Dimethylthiaolyl]-2,5-diphenyl-tetrazolium bromide assay was applied to the detection of cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptotic cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptotic DNA ladders on agarose gel electrophoresis were observed.

RESULTS: Except for GC, GCDC, GDC, TC, TCDC, TDC and their mixture could initiate growth inhibition of esophageal mucosal epithelial cells in a dose- and time-dependent manner. TUNEL and FCM assays demonstrated that the bile salts at 500 μmol/L and their mixture at 1 500 μmol/L induced apoptosis except for GC. The percentage of sub-G1 detected by FCM with PI staining was 83.5% in cells treated with 500 μmol/L TC for 2 h, and 19.8%, 20.4%, 25.6%, 13.5%, and 75.8% in cells treated with 500 μmol/L GCDC, TCDC, GDC, TDC, and 1 500 μmol/L mixture for 24 h, respectively, which were higher than that of the control (1.5%). The percentage was 1.4% in cells with 500 μmol/L GC for 24 h. DNA ladders on agarose gel electrophoresis were seen in cells treated with 500 μmol/L TC for 2 h and 1 500 μmol/L mixture for 24 h.

CONCLUSION: All GCDC, GDC, TC, TCDC, TDC and their mixture can inhibit growth and induce apoptosis of cultured human normal esophageal mucosal epithelial cells, but GC is well tolerated by the cells.

Bile salts inhibit growth and induce apoptosis of human esophageal cancer cell line

AIM: To explore the effect of six bile salts, including glycoc-holate (GC), glycochenodeoxycholate (GCDC), glycodeoxy-cholate (GDC), taurocholate (TC), taurochenodeoxycholate (TCDC), taurodeoxycholate (TDC), and two bile acids including cholic acid (CA) and deoxycholic acid (DCA) on esophageal cancer Eca109 cell line.

METHODS: Eca109 cells were exposed to six bile salts, two bile acids and the mixed bile salts at different concentrations for 24-72 h. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to detect the cell proliferation. Apoptotic morphology was observed by phase-contrast video microscopy and deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Sub-G1 DNA fragmentations and early apoptosis cells were assayed by flow cytometry (FCM) with propidium iodide (PI) staining and annexin V-FITC conjugated with PI staining. Apoptosis DNA ladders on agarose were observed. Activation of caspase-3 was assayed by FCM with FITC-conjugated monoclonal rabbit anti-active caspase-3 antibody and expressions of Bcl-2 and Bax proteins were examined immunocytochemically in 500 μmol/L-TC-induced apoptosis cells.

RESULTS: Five bile salts except for GC, and two bile acids and the mixed bile salts could initiate growth inhibition of Eca109 cells in a dose- and time-dependent manner. TUNEL, FCM, and DNA ladder assays all demonstrated apoptosis induced by bile salts and bile acids at 500 μmol/L, except for GC. Early apoptosis cell percentages in Eca109 cells treated with GCDC, GDC, TC, TCDC, TDC, CA at 500 μmol/L for 12 h, DCA at 500 μmol/L for 6 h, and mixed bile salts at 1 000 μmol/L for 12 h were 7.5%, 8.7%, 14.8%, 8.9%, 7.8%, 9.3%, 22.6% and 12.5%, respectively, all were significantly higher than that in control (1.9%). About 22% of the cell population treated with TC at 500 μmol/L for 24 h had detectable active caspase-3, and were higher than that in the control (1%). Immunocytochemical assay suggested that TC down-regulated Bcl-2 protein level and up-regulated Bax protein level.

CONCLUSION: GCDC, GDC, TC, TCDC, TDC, CA and DCA, except for GC, can inhibit growth and induce apoptosis of esophageal cancer Eca109 cells. Activation of caspase-3, decreased Bcl-2 protein and increased Bax protein are involved in TC-induced apoptosis of Eca109 cells.

Gastritis cystica polyposa concomitant with gastric inflammatory fibroid polyp occurring in an unoperated stomach

The endoscopic examination of a 61-year-old male patient revealed a protruding lesion in the greater curvature of the lower third area of the stomach. The lesion, 17 mm in size, was resected completely with endoscopic submucosal dissection using an insulated-tip diathermic knife (IT-ESD). Histological examination of the protruding lesion revealed proliferation of fibroblasts and infiltration of inflammatory cells in the mucosa and submucosa, and it was diagnosed as an inflammatory fibroid polyp (IFP). Gastritis cystica polyposa (GCP) was presented adjacent to the IFP. This may be the first report of GCP concomitant with gastric IFP occurring in an unoperated stomach.

Ulceration as a possible link between duodenogastric reflux and neoplasms in the stomach of rats

BACKGROUND

Duodenogastric reflux predisposes to gastric cancer. This study investigates whether ulceration induced by duodenogastric reflux is associated with the development of neoplasms in the stomach.

MATERIALS AND METHODS

In a rat experiment, duodenal fluid was directed into the corpus (jejunal reflux) or through the pylorus into the antrum (pyloric reflux). Sham-operated animals served as controls. The animals were sacrificed after 24, 36, or 52 weeks.

RESULTS

Ulcerations and neoplasms occurred more frequently in the corpus than in the antrum. In the corpus, ulceration was observed significantly more often in animals with jejunal reflux (62, 55, and 53% at 24, 36, and 52 weeks, respectively) than in animals with pyloric reflux (15, 21, and 30%). The incidence of neoplasm in the corpus increased significantly with time from 38% at 24 weeks to 89% at 52 weeks in animals with jejunal reflux and from 12 to 33% in animals with pyloric reflux. Ulceration and neoplasms shared location in the corpus adjacent to the gastrojejunostomy and by 24 weeks, all but one neoplasm in the jejunal reflux and one in pyloric reflux groups occurred adjacent to ulceration. In the antrum, 37% of the animals had a prepyloric ulceration after 24 weeks of pyloric reflux and only one of these animals had a neoplasm. By 52 weeks 20% of animals with pyloric reflux had a neoplasm that appeared in the prepyloric area.

CONCLUSIONS

Ulceration and neoplasm occurred at the same sites in the stomach, and ulcerations preceded the development of neoplasms in the antrum and very likely in the corpus. The results suggest that ulceration plays an important role in the genesis of neoplasms in the stomach and that the vulnerability to duodenogastric reflux is more pronounced in the corpus than in the antrum mucosa.

Duodenogastric reflux increases the penetration of N-3H-methyl-N-nitro-N-nitrosoguanidine into the antral mucosa of rats: a possible role for mucosal erosions and increased cell proliferation in gastric carcinogenesis

Duodenogastric reflux is a risk factor for gastric carcinogenesis, but the pathogenesis is not fully understood. We studied the risk of N-methyl-N-nitro-N-nitrosoguanidine (MNNG)-induced carcinogenesis in the antrum of rats with duodenogastric reflux. Duodenal fluid was directed into the stomach through the pylorus (pyloric reflux group) or through a gastrojejunostomy (jejunal reflux group). After twenty-four weeks, 5-bromo-2-deoxyuridine (BrdU) was injected intravenously and the stomach was exposed to N-(3)H-methyl-N-nitro-N-nitrosoguanidine ((3)H-MNNG). The antral mucosa was examined with immunohistochemistry and autoradiography for identification of proliferating cells (BrdU labelled) and cells at risk of MNNG-induced carcinogenesis ((3)H-MNNG and BrdU-labelled cells). Duodenogastric reflux increased the number of double-labelled cells in the antral mucosa from 4.8 +/- 0.6 per mm in the control group to 11.3 +/- 1.9 in the jejunal reflux group (P < 0.05) and 12.7 +/- 0.9 in the pyloric reflux group (P < 0.05). Mucosal erosions were observed in 15 of 28 animals with pyloric reflux and the number of double-labelled cells in the erosion area (4.3 +/- 0.7) was higher than in the same area of animals without erosion (1.4 +/- 0.5) (P < 0.05). Duodeno-gastric reflux increased the cell proliferation and significantly changed the distance between the surface epithelial lining and the proliferating cells when compared to the controls. These results indicate that duodenogastric reflux increases the penetration of (3)H-MNNG into the antrum mucosa of rats. Increased cell proliferation and erosions increase the number of cells at risk of an initiation process from a penetrating gastric carcinogen.