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Gastric cancer has quite a long
history in the long-haired Belgian Shepherds (Groenendael and Tervueren). One
of the first documented victims is the well-known and highly respected
grey-beige Tervueren male Vici des Hauts de Bievre. “Vici des Hauts de Bievre
is no more” was the announcement of his death in the 1979 edition of Berger
Belge. Dr. Vet. Y. Surget wrote an account of his death, which can be roughly
translated and paraphrased as: “Vici des Hauts de Bievre was euthanized April
5, 1979 on the operating table following the discovery of a large tumor of the
lining of the stomach with many ganglion metastases. His condition had declined
over the course of several weeks. Vici des Hauts de Bievre died in exactly the
same conditions as his mother, Riane du Donjon de Vincennes. But the latter was
nearly 10, which is not very old; Vici had not yet turned 7 and the evil
evolved very quickly.”1
Vici was an influential male in
Tervueren breeding of the mid 1970s and many of today’s dogs are still
line-bred on him. At that time, it was not known that gastric cancer was
hereditary. In addition, veterinary diagnostics were not as advanced as today,
which may have led to many dogs dying of an “unknown cause” when in fact they
may have been suffering from gastric cancer or other diseases that we are more
aware of today.
The first indication of a genetic link for gastric cancer
was published in 1989 when an Italian study suggested a genetic mechanism in
the occurrence of gastric cancer in 8 Belgian Shepherd dogs (7 Groenendael and
1 Tervueren)2. In 1991 the same group reported 7 more cases (all
Tervueren)3, building more evidence for a genetic basis for gastric
cancer in Belgian Shepherds.
In 2009, a retrospective study in the Netherlands looked at the incidence of gastric carcinoma in Dutch Tervueren shepherd dogs born between 1991 and 20024. The researchers found an incidence rate of 1.18%, which is higher than reported for the larger population of dogs. A study based on the Norwegian canine cancer register confirmed a breed predisposition in Tervueren and Groenendael5. Both studies indicate a genetic susceptibility to gastric carcinoma.
Current Status
The exact pattern of heritability for gastric cancer
remains unclear. It may be a normal autosomal recessive trait, but it is
probably more complicated than that. At least one study in the Netherlands has
suggested that gastric carcinoma is not the result of a single genetic
mutation.
Types of Gastric Cancer
Although gastric cancer can have various forms and can be
found in different locations, most commonly it is located in the lesser
curvature and pylorus of the stomach. Extension throughout the stomach is
possible. Due to the location of the tumor, surgery generally is not possible.
Endoscopy is the most reliable method of diagnosis. Other methods like
ultrasound may give biased results as they often can’t distinguish between
ulcers, gastritis and cancer.
On average, gastric cancer is diagnosed at an age of 9-10
years, with a higher incidence in Tervueren than in Groenendael, with males
being slightly more likely to be affected4,6,7. In the Dutch study a
questionnaire was used to investigate environmental factors7. No
relationship could be found between the occurrence of gastric cancer and type
of food eaten by the affected dogs (kibble or raw meat). However, environmental
influences, including food, are not well investigated and therefore cannot be
excluded.
The most common clinical signs are vomiting (40–95% of
cases), anorexia (48–52%), weight loss (23–52%), and lethargy (25–28%)8.
The prognosis is very poor. Medication can sometimes stretch the lifetime of
the dog, but mostly dogs die within weeks or a few months. At the time gastric
cancer is diagnosed, metastasis has generally occurred, meaning that the cancer
has already spread to other organs. Usually it spreads to the regional lymph
nodes, liver, lung, duodenum, adrenal glands, pancreas, omentum and spleen.
Considerations for Breeding
Belgian Shepherd Health Project considers the following
items relevant to breeding decisions:
As the exact inheritance is
unknown and no tests are available yet to identify carriers or affected dogs,
it is very hard to provide any considerations that are specific to gastric
cancer. However, all general principles should be reviewed.
When breeding, one should take
into account that gastric cancer mostly shows up at an older age.
Unfortunately, dogs may not show signs before being bred. Therefore, knowledge
of the health status of related dogs is often very important. For that, one
should specifically look at the parent/grandparent/great grandparent level, as siblings
and half siblings will probably be too young to gain any useful information.
Great care should be taken to
minimize the risk of producing dogs with a genetic predisposition for gastric
cancer. At the present time, the following strategies are considered to be high
risk:
Breedings in which both dogs have
at least one parent that has been diagnosed with gastric cancer
Breedings of 2 dogs that are
closely line-bred or inbred on dogs known to have offspring with gastric cancer
with more than one partner
Males have the potential to impact
the breed more than females due simply to the number of offspring they might
produce. This is frequently referred to as the “Popular Sire Effect”. A breeder
might choose to use a male for a very limited number of breedings, thereby
minimizing the impact of the male on the overall frequency of any deleterious
mutation while still ensuring the contribution of his genetics to the gene
pool. This is also an appropriate strategy for conditions that might show up
after a dog has been used for breeding. In general, limiting the number of
breedings for males is also a preferred strategy for promoting genetic
diversity within any breed9.
Leading Academic Resources
Research is ongoing in several countries to find the
genetic factor(s) that is (are) responsible for the susceptibility to gastric
cancer in Belgian Shepherds.
Netherlands: University Clinic,
Utrecht, led by Dr. Paul Mandigers, MVM, DVM, PhD, DipECVN, DipRNVA
USA: NHGRI/NIH, Cancer Genetics
and Comparative Genomics, led by Dr. Elaine Ostrander, Ph.D.
Finland: University of Helsinki,
Small Animal Gastroenterology group, led by Professor Thomas Spillmann,
Diplomate ECVIM-CA
Belgian Shepherd Health Project Involvement
The Belgian Shepherd Health Project Involvement supports
the research carried out by the groups pursuing active research into the cause
of gastric cancer in Belgian Shepherds. Recently collaborations have been
formed between some of these labs and Embark. We encourage all those interested
in supporting research into the cause of gastric cancer in Belgian Shepherds to
contact the research groups nearest them and submit samples from their dogs, as
appropriate.
In addition, those people that choose to have their dog(s)
tested with Embark may elect to have the results shared with the lab of Dr.
Ostrander (U.S.). The Embark data can be directly incorporated into the ongoing
gastric cancer study. However, owners are also encouraged to submit their dogs’
blood samples for the gastric cancer study to the Ostrander lab when possible.
Closing Remarks
Gastric cancer is a very serious issue for Belgian
Shepherds. It takes far too many of our dogs far too young. If you are
unfortunate enough to encounter it with one of your dogs, we hope that you will
contact one of the leading academic researchers to submit
the appropriate samples as soon as reasonably
possible, even if that occurs after your dog has already died. Every bit of
information that we can provide them may prove to be useful in their research.
It may be too late to help your dog, but hopefully, it will help someone
else’s dog in the future.
We hope that you have found this article to be useful. We
anticipate providing updates as additional information becomes available.
Referenced Sources
Berger
Belge, 1979 pp 184-185
Fonda D, Gualtieri M and Scanziani E. Gastric carcinoma in the dog: a clinicopathological study of 11 cases. Journal of Small Animal Practice 1989; 30: 353–360.
Scanziani E, Giusti
AM, Gualtieri M and Fonda D. Gastric carcinoma in the Belgian
shepherd dog. Journal of Small
Animal Practice 1991; 32:
465–469.
Lubbes D, Mandigers
PJ, Heuven HC and Teske E. Incidence of gastric carcinoma in Dutch
Tervueren shepherd dogs born between 1991 and 2002. Tijdschrift voor Diergeneeskunde 2009; 134: 606–610.
Seim‐Wikse T, Jorundsson E, Nodtvedt A, Grotmol T, Bjornvad CR,
Kristensen AT, et al. Breed predisposition
to canine gastric carcinoma – a study based on the Norwegian
canine cancer register. Acta
Veterinaria Scandinavica 2013; 55: 25. Doi: 10.1186/1751-0147-55-25
Marcus Vinicius Candido, Pernilla Syrjä, Susanne Kilpinen and
Thomas Spillmann.
Canine breeds associated with gastric carcinoma, metaplasia and dysplasia
diagnosed by histopathology of endoscopic biopsy samples. Journal: Acta Veterinaria Scandinavica,
2018, Volume 60, Number 1. DOI: 10.1186/s13028-018-0392-6
Genealogy
research of the Groenendael and the Tervueren Belgian Shepherd diagnosed
with gastric carcinoma. Faculty of Veterinary Medicine Theses (Master
thesis). https://dspace.library.uu.nl/handle/1874/299326
Hugen,
S, Thomas, RE, German, AJ, Burgener, IA, Mandigers, PJJ. (2017) Gastric
carcinoma in canines and humans, a review. Vet Comp Oncol, 15: 692-705.
doi:10.1111/vco.12249
The views and opinions expressed in this educational/informational media product, including articles, analyses, and slide shows, are the informed opinion of the author(s) and do not necessarily reflect the official policy or opinion of their employer(s), or any other organization, agency, or company. Assumptions made in any data analysis are not reflective of any position other than the author(s). Please keep in mind the constant availability of new data means that views and opinions are always subject to change, revision or rethinking.
