Gastric mucosal pathology in Belgian Shepherd dogs with and without clinical signs of gastric disease

Incidence and Heritability of Gastric Carcinoma in the Belgian Shepherd Dog Population in The Netherlands

BACKGROUND

Gastric carcinoma in the Tervueren and Groenendael varieties of the Belgian Shepherd dog is commonly recognized and carries a grave prognosis. Information on incidence and heritability is necessary to design an effective selection strategy against this disease.

METHODS

A database of cases and controls was built including cases with Tier 1 (confirmed via endoscopy or post-mortem) and Tier 2 evidence of gastric carcinoma. From the database, a birth cohort of dogs born in the Netherlands in the period 2000-2010 was used, together with pedigree information to calculate heritability using a mixed models approach. Univariate linear regression was used to test the influence of the gastric carcinoma status of the parents on gastric carcinoma occurrence in offspring.

RESULTS

For Tervueren the 10-year cumulative incidence was 4.7%, and for the Groenendael this was 2.1%. There was no sex predilection. The odds of gastric carcinoma were 5.0 (2.4-11.0) in offspring where at least one parent was known to be affected versus at least one parent was known to be unaffected. Heritability, based on analysis using pedigree information from 338 dogs with gastric carcinoma and 159 controls, was 0.53 (SE 0.15).

CONCLUSIONS

Gastric carcinoma in the Belgian Shepherd Tervueren and Groenendael varieties has a high incidence in the Dutch population and a strong genetic component. Because it is a late onset disease, dogs have often already been used for breeding before they are diagnosed. An effective breeding strategy for reducing disease incidence therefore relies on the identification of genetic risk factors influencing its development.

The Histopathological Characteristic of Gastric Carcinoma in the Belgian Tervueren and Groenendael Dog: A Comparison of Two Classification Methods

Gastric carcinoma is generally considered to be a rare disease in dogs, carrying a grave prognosis. However, in the Tervueren and Groenendael varieties of the Belgian Shepherd dog breed, the disease is highly prevalent. While histopathology is the gold standard for diagnosing gastric carcinoma, there is no general consensus on the methods for histological classification in these cases. Biopsies of a group of 61 dogs with confirmed gastric carcinoma (45 Tervueren and 16 Groenendael) were examined and classified according to World Health Organization (WHO) and Laurén classifications. Kaplan-Meier curves were used to compare survival between the different subtypes and simple and multiple linear regression were used to analyse the association between age of onset and breed variant, sex, neuter status, location of the tumour, inflammation score, and Laurén and WHO classifications. Mean age at diagnosis was significantly different in Groenendael (10.1 ± 2.01) and Tervueren dogs (8.5 ± 1.90). The Laurén classification resulted in 29 (48%) diffuse- and 32 (52%) intestinal-type tumours. Applying the WHO classification resulted in 30 (49%) tubular carcinoma growth patterns and 31 (51%) others. Median survival time was significantly reduced for the diffuse type as compared to the intestinal type according to the Laurén classification, with the same median survival time results for tubular compared to non-tubular subtypes according to the WHO classification (median survival time of 61 vs. 182 days, respectively). Using the WHO and Lauren classification on tumour biopsies may help the practising clinician in the prognostication of gastric carcinoma in Tervueren and Groenendael dogs.

Can Chromoendoscopy Improve the Early Diagnosis of Gastric Carcinoma in Dogs?

Simple Summary

Currently, canine gastric carcinoma is mainly diagnosed in its late, incurable phase, and strategies for early diagnosis are lacking. In human medicine, chromoendoscopic (CE) methods such as staining the gastric mucosal surface with indigo carmine (IC), and narrow band imaging (NBI), have improved the diagnosis of precancerous gastric mucosal changes and early gastric carcinoma. This study aimed at investigating whether IC-CE and NBI-CE can improve the diagnostic yield of endoscopy in dogs. Belgian Shepherd dogs are predisposed to gastric carcinoma; thus, 30 dogs of the breed served as the study population. As a result, the study revealed that especially the combination of standard white light endoscopy (WLE) with NBI-CE allows better recognition of gastric mucosal structural changes than WLE alone. However, CE assessment templates used to predict the type of mucosal change in humans were not applicable in dogs. The value of the study lies in providing evidence that CE can improve the diagnosis of precancerous changes and early gastric carcinoma in dogs. However, current image assessment templates from human medicine need major adjustments to comprehend canine gastric mucosal conditions.

Abstract

Chromoendoscopy has improved the early diagnosis of gastric cancer in humans but its usefulness in dogs is unknown. This study aimed at assessing whether adding narrow band imaging (NBI) or indigo carmine (IC) chromoendoscopy (CE) can improve the diagnostic yield of standard white light endoscopy (WLE). We compared the real-time findings of canine WLE, NBI-CE, and IC-CE and corresponding histology reports with endoscopic mucosal pattern assessment templates used in human medicine. Belgian Shepherd dogs are predisposed to gastric carcinoma. Therefore, 30 dogs of this breed served as the study population. According to histology, 17/30 dogs had mucosal changes (mucous metaplasia, glandular dysplasia, and gastric carcinoma). Diagnostic yield was best when targeted biopsies were taken with WLE and NBI-CE combined (15/17 cases). WLE alone positively identified only 8/17 cases and missed a gastric carcinoma in 3/6 cases. CE assessment templates based on macroscopic mucosal patterns, broadly used in human medicine, were not readily applicable in dogs. In conclusion, the study provides evidence that using CE in dogs has the potential to improve the diagnosis of precancerous gastric mucosal pathology and early gastric carcinoma. However, current image assessment templates from human medicine need major adjustments to the patterns of canine gastric mucosa.