Cancer and the Cavalier King Charles Spaniel
While many cavalier King Charles spaniels develop cancer, and it is one of the breed’s leading causes of death, there does not appear to be any particular form of cancer which is much more common in the CKCS than in other purebred breeds of dogs.
This webpage is designed to familiarize the reader with some basic information about cancer in general, as well as particular types of cancer most common in dogs. We do not include all of the current means of detecting or treating various cancers, as there are several other websites with far more detailed information on those topics. See Related Links below.
If and when research is published about any cancer for which the cavalier is considered pre-disposed, we will update this webpage with that information.
What It Is
Cancer is a mutation of genes which normally control the growth of cells in the dog’s body. Cancer appears as the uncontrolled growth and division of abnormal cells and which are able to invade other tissues.
There are several types of cancer, including carcinoma (which begins in the skin or in tissues that line or cover internal organs), sarcoma (which begins in connective or supportive tissue, such as bone, muscle, cartilage, and blood vessels), leukemia (which begins in the bone marrow or other blood cell producing tissues and causes abnormal blood cells to enter the blood), lymphoma and myeloma (which begin in the cells of the immune system), mastocytoma (which begins on the skin), and central nervous system cancers (which begin in the brain and spinal cord), such as meningioma and neuroblastoma. There are other forms in addition to these.
A cancer often is named for the organ in which it first appears, but it can spread to other parts of the body through the blood system and lymph system. It starts as a mutation of a cell, likely due to radiation or chemical damage or a change in the cell’s genetic material. A mutation can affect the normal growth of that cell and its division into new cells, which also are mutated.
The mutated cells may form a mass, called a tumor (a neoplasm), which could be either malignant or benign. A benign tumor is not cancerous and often can be removed and not grow back or spread to other organs. A malignant tumor is one which continues to grow, often rapidly, invading the function of the organ, and which may spread to other parts of the body (metastasis). These cells also are regressive, non-specialized, and display a loss of structural and functional differentiation of normal cells.
Not all cancerous cells form tumors. Leukemia, for example, spreads through the blood system without creating a tumor.
Forms of Dog Cancers
Some forms of cancer are more common among dogs than others. They include:
•Osteosarcoma: This bone cancer may be discovered as a painful swelling within a bone, and is visible on an x-ray. However, it may already have grown so rapidly that it has spread to other organs, such as the lungs, by the time the swelling is first noticed. Osteosarcoma cells lack the strength of normal bone cells, and as they grow and replace the normal bone structure, they weaken the bone to the point that it will collapse.
•Lymphosarcoma: A cavalier was included in a 2003 study of 25 dogs diagnosed with canine multicentric lymphoma, which also had chromosome imbalances.
•White blood cell
•Mast cell tumor: histiocytic mastocytoma, mast cell sarcoma, mastocystosis.
•Mammary tumor: tubular adenocarcinoma, papillary adenocarcinoma, papillary cystic adenocarcinoma, solid carcinoma, anaplastic carcinoma, fibrosarcoma. This is found largely in females. It appears as a lump beneath the skin on the breast.
•Adrenal cortical tumor: This is a tumor of the cortisol-producing cells of the adrenal gland. It is known to cause a form of Cushing's Disease.
•Pituitary tumor: This tumor produces excessive amounts of ACTH -- adrenocorticotrophic hormone, the hormone which causes the adrenal glands to produce cortisol). It also is known to cause a form of Cushing's Disease.
•Anal sac gland carcinoma: A couple of studies of this form of cancer in cavaliers has been reported. One 2005 report and another in 2009. In the 2009 report, the author states that "English Cocker spaniels (and to a lesser extent Springer and Cavalier King Charles spaniels) are at higher risk of developing anal sac tumours than other dogs. This conclusion is based upon the analysis of large numbers of cases of anal sac tumours using data from veterinary pathology laboratories and breed registration data from The British Kennel Club."
•Squamous cell carcinoma: In both a 2008 study and a 2011 study of this cancer in the cornea, which included three CKCSs, the authors found that it was related to chronic dry eye, which is a very common disorder in this breed. This form of carcinoma also is known to develop within the mouths and throats of cavaliers. Also, see this 2011 report of a study of 44 dogs with tonsillar squarmous cell carcinoma, including four cavaliers.
•Conjunctival hemangioma and hemangiosarcoma: In a 2006 study in which cavaliers were included, the authors concluded that ultraviolet light played a significant role in the cancer's development.
•Meningioma: In a 2010 report, a cavalier was found to have a meningioma in a post-mortem examination. The authors noted that, "isolated unilateral facial myokymia preceding diagnosis of a meningioma affecting facial nerve function within the caudal cranial fossa and the remarkably long duration of neurological signs (75 months) attributable to the neoplasm."
•Sebaceous gland adenocarcinoma.
Causes
The primary causes associated with the development and growth of cancerous cells are wide-ranging. They include:
•Exposure to certain forms and quantities of radiation.
•Exposure to certain chemicals which can damage cells’ genetic structure (mutagens and carcinogens in the environment and diet).
•Certain hormones, such as oestrogen and testosterone.
•Certain viruses.
•Genetic pre-disposition.
•Excessive stress and depression (yes, dogs can suffer both).
•A confused immune system.
•Some medications. In both a 2008 study and a 2011 study, the researchers concluded that dogs (including cavaliers) treated with cyclosporine for dry eye are at risk to develop axial corneal squamous cell carcinoma.
•Possibly a consequence of surgery. In a 2010 report, a cavalier developed multiple inverted papilloma, which were benign tumors, following an ovariohysterectomy.
To some extent, dogs living longer lives are at greater risk of cancer eventually developing.
Treatment
The form of treatment depends upon the form of the cancer. The options include:
•Chemotherapy, which consists of doses of toxic active ingredients that are intended to destroy rapidly dividing cancer cells but to spare the normal cells.
•Radiation therapy, which is a beam of radiation aimed at the cancerous tumor.
•Surgery to remove tumors.
•Electrocautery and cryosurgery.
•Hyperthermy.
•Cryotherapy.
•Immunotherapy.
•Prescriptive medications.
•Palliative care, to manage the cancer and its symptoms, and improve quality of life, when cure is not an option.
Current Research
4February 2011: TGen needs spaniel DNA samples. The Translational Genomics Research Institute (TGen) seeks DNA samples from healthy spaniels to establish a genetic backdrop of healthy bloodlines against which genetic signatures of disease susceptibility can be deciphered and to perform periodic population surveys. Details are at http://www.tgen.org/research/canine-spaniel-frm.cfm
4January 2009: Researchers seek DNA samples of cavaliers for anal sac gland carcinoma study. University of Cambridge veterinary oncologists are soliciting blood samples of cavaliers (and other spaniel breeds) either affected with anal sac gland carinoma or non-affected. Details are at http://www.vet.cam.ac.uk/news-and-events/gsd/CScarcinoma.html
Related Links
Cushing's Disease
Dry Eye Syndrome
CanineCancer.com
CanineCancerAwareness.org
DogCancerBlog.com
Book: The Dog Cancer Survival Guide
Veterinary Resources
Chromosome aberrations in canine multicentric lymphomas detected with comparative genomic hybridisation and a panel of single locus probes. R Thomas, K C Smith, E A Ostrander, F Galibert, and M Breen. Brit J Cancer; Oct. 2003;89(8):1530–1537. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2394339/?tool=pmcentrez Quote: "Malignant lymphoma (lymphosarcoma) represents one of the most frequently encountered canine neoplasms, most commonly affecting middle-aged to older dogs of a wide range of breeds. The disease originates from the malignant transformation of developing lymphocytes, and in the absence of chemotherapy, survival beyond one month after diagnosis is uncommon. Although generally considered a chemoresponsive form of malignancy in the dog, .. the disease is highly heterogeneous at both the clinical and histological level. A proportion of cases demonstrate more favourable response to therapy, and longer overall survival time, than others receiving the same initial diagnosis. ... Since humans and dogs demonstrate extensive genome homology, it is likely that canine lymphoma will also be associated with recurrent chromosome aberrations. However, few reports exist describing chromosome abnormalities detected in canine lymphoma and at present insufficient data are available from which to draw significant conclusions on their findings. ... The development of comparative genomic hybridisation (CGH) as a technique for indirect analysis of chromosomal copy number changes in human tumour cells now provides a means by which imbalanced genomic aberrations can be identified accurately and efficiently without the need to generate tumour chromosome preparations. The application of CGH to the dog, the advent of novel molecular cytogenetic resources for this species, the development of comparative cytogenetic maps and the generation of an integrated canine genome map now provide a means by which to overcome prior practical difficulties and embark on more comprehensive studies of tumour karyotypes in this species. ... We have used CGH analysis to identify chromosome imbalances in 25 cases [including one cavalier King Charles spaniel] of canine multicentric lymphoma. The resulting range and distribution of aberrations observed indicates that, as with the human counterpart of this disease, the cytogenetic profiling of canine lymphoma as a potential aid to diagnosis and clinical management warrants more detailed investigation."
Anal sac tumours of the dog and their response to cytoreductive surgery and chemotherapy. S.G. Emms. Austr Vet J; June 2005;83(6):340-343. Quote: "A retrospective study of anal sac tumours without pulmonary metastases, from the author's clinical records for the period July 1989 to July 2002, was conducted to establish the response to treatment with surgery and melphalan chemotherapy. Of 21 dogs [including cavalier King Charles spaniels] with tumours of the anal sacs 19 had apocrine gland adenocarcinomas of anal sac origin, one had a benign papillary cystadenoma and another had a malignant melanoma. Two of the 19 dogs had bilateral anal sac adenocarcinomas. Ten of the 19 dogs with apocrine gland adenocarcinomas of anal sac origin had sublumbar lymphadenopathy. Five dogs were excluded by their owners from recommended treatment. Fourteen dogs with apocrine gland adenocarcinomas of anal sac origin were treated by surgical cytoreduction and chemotherapy with melphalan. Seven of the 14 dogs had regional lymph node metastases. Cytoreduction was by local excision of the anal sac in all 14 dogs and concurrent removal of the sublumbar retroperitoneal lymph nodes in the seven dogs with regional lymph node metastases. The median survival time of dogs with sublumbar nodal metastasis was 20 months and for dogs with tumour localised to the anal sac the median survival time was 29.3 months. There was no difference in median survival of those dogs with sublumbar metastases compared to those without. This study suggests there is a role for melphalan in the treatment of dogs with anal sac adenocarcinoma when combined with cytoreductive surgery, with treatment survival times and the local recurrence rate of the primary tumour comparing favourably with previously published treatment regimes."
Primary Renal Neoplasia of Dogs. Jeffrey N. Bryan, Carolyn J. Henry, Susan E. Turnquist, Jeff W. Tyler, Julius M. Liptak, Scott A. Rizzo, Gabriella Sfiligoi, Steven J. Steinberg, Annette N. Smith, and Tarraca Jackson. J Vet Intern Med 2006;20:1155–1160. Quote: "Background: Primary renal tumors are diagnosed uncommonly in dogs. Hypothesis: Signs and survival will differ among different categories of primary renal tumors. Animals: Data were collected from the medical records of 82 dogs [including a cavalier King Charles spaniel] with primary renal tumors diagnosed by examination of tissue obtained by ultrasound-guided biopsy, needle aspiration, surgery, or at postmortem examination. Results: Forty-nine dogs had carcinomas, 28 had sarcomas, and 5 had nephroblastomas. The dogs were geriatric (mean 8.1 years; range: 1–17) with a weight of 24.9 kg (range: 4.5–80). Tumors occurred with equal frequency in each kidney with 4% occurring bilaterally. Initial signs included one or more of hematuria, inappetance, lethargy, weight loss, or a palpable abdominal mass. Pain was reported more frequently in dogs with sarcomas (5/28). The most common hematologic abnormalities were neutrophilia (22/63), anemia (21/64), and thrombocytopenia (6/68). Polycythemia was present in 3 dogs and resolved with treatment. Hematuria (28/49), pyuria (26/49), proteinuria (24/50), and isosthenuria (20/56) were the most frequently observed abnormalities on urinalysis. Pulmonary metastases were noted on thoracic radiographs in 16% of dogs at diagnosis. Seventy-seven percent of dogs had metastatic disease at the time of death. Median survival for dogs with carcinomas was 16 months (range 0–59 months), for dogs with sarcomas 9 months (range 0–70 months), and for dogs with nephroblastomas 6 months (range 0–6 months). Conclusions and Clinical Importance: Primary renal tumors in dogs are generally highly malignant with surgery being the "only treatment that improves survival."
Canine conjunctival hemangioma and hemangiosarcoma: a retrospective evaluation of 108 cases (1989–2004). Chris G. Pirie, Amy M. Knollinger, Chet B. Thomas, Richard R. Dubielzig. Vet Ophth; July 2006;9(4):215-226. Quote: "Canine conjunctival tumors of vascular endothelial origin are common, although under-reported. The purpose of this study was to evaluate the epidemiology of and potential risk factors for these tumors. This study evaluated 108 cases [including cavalier King Charles spaniels] (70 hemangiomas, 38 hemangiosarcomas) from 8300 canine submissions between 1989 and 2004. Signalment, location, pigmentation, size, duration, diagnosis, margins, ancillary therapy, and geographic location were recorded. Follow-up information was available for 49 cases. Each case was matched with two unaffected controls and compared using logistic regression analysis. Average age upon presentation was 8.6 years; there was no sex predilection. Risk of conjunctival tumors was statistically different among breed groups (P = 0.0010), demonstrating a propensity to occur in groups likely to have increased outdoor activity. Primary involvement occurred within nonpigmented epithelium along the leading edge of the nictitating membrane (41/108) and temporal bulbar conjunctiva (33/108). The etiology remains unknown; however, the strong site predilection, involvement of nonpigmented epithelium, and development within specific breed classes strongly suggest ultraviolet (UV) light as a significant risk factor. In a full-logistic model including breed, gender, age, and UV exposure, UV was not a statistically significant variable (P = 0.1215). In a reduced-model including UV only, significance was approached (P = 0.0696) and posthoc contrast demonstrated a significant linear trend with increasing UV exposure (P = 0.0147). In separate analysis of risks associated with hemangiosarcoma, compared with hemangioma, breed was not significant while increasing UV exposure was significant (P = 0.0381). Early surgical therapy is recommended and may be curative; however, recurrence is possible and more likely with hemangiosarcomas (11/20)."
Breed, gender and neutering status of British dogs with anal sac gland carcinoma. G. A. Polton, V. Mowat, H. C. Lee, K. A. Mckee, T. J. Scase. Vet & Comp Oncology; Sept 2006;4(3):125-131. Quote: "This study details the breed, gender and neutering status of a large cohort of British canine patients suffering from histologically confirmed anal sac gland carcinoma. Estimates of the relative risk for the development of this disease attributable to these factors are calculated. To reduce the impact of sampling errors, cases were selected from veterinary histopathology laboratories rather than referral hospital databases, and multiple estimates of the general British canine population were used. The weaknesses of the statistical assumptions made are discussed. There was no evidence to support a gender predisposition for the development of this condition. English cocker spaniels are significantly over-represented, with a mean relative risk estimate of 7.3. The mean relative risk estimate associated with being neutered was 1.4; the effect of neutering appeared to be more significant in male dogs compared with that in female dogs."
Corneal squamous cell carcinoma in dogs with a history of chronic keratitis. R. R. Dubielzig, C. S. Schobert and J. Dreyfus. Vet Ophth; 2008;11(6):413–429 (Abstract 101). Quote: "Purpose: Corneal squamous cell carcinoma (SCC) is a rare tumor in dogs. The COPLOW has seen a recent increase in primary SCC in the axial cornea. We report here on 25 cases. Methods: Twenty-five cases of primary axial corneal SCC were selected from the COPLOW collection which includes more that 6000 neoplastic specimens. ... Results: The number of canine corneal SCC has risen in the past several years from 1 case per year from 1998 to 2004, jumping to 6 cases in 2005, 8 cases in 2006, and 7 cases in 2007. Brachycephalic breeds are overrepresented. The breed distribution included 8 Pugs, 5 Bulldog, 2 Boxers, 2 Greyhound, 2 Shi Tzu, 2 Border Collie, 2 Pekinese, 1 Bassett, 1 Chow, 1 Cocker, and 1 Cavalier King Charles Spaniel. No correlation to sex was found. Out of the 25 cases, 21 showed signs of chronic keratitis prior to developing SCC. In the remaining 4 cases the prior corneal history was unknown. Within the group of 25, 10 cases had been treated with cyclosporine alone, 4 with tacrolimus alone, 5 with both cyclosporine and tacrolimus, and 6 treated with other drugs or unknown. Follow-up information was obtained from 23 cases with a follow-up interval of between 5 days and 31 months (mean: 7.9 months). Three dogs had died for reasons unrelated to the ocular disease. One dog had recurrent disease extending deeply into the cornea. Conclusions: Brachycephalic dogs with a background of chronic keratitis that are treated with nonsteroidal antiinflammatory drugs are at risk to develop axial corneal SCC. The increase in annual cases of SCC suggests that this phenomenon is a developing problem."
Examining the heritability of anal sac gland carcinoma in cocker spaniels. Gerry Polton. J Sm Animal Prac; Jan 2009;50(1):57. Quote: "English cocker spaniels, and to a lesser extent springer and cavalier King Charles spaniels, are at higher risk of developing anal sac gland tumours than other dogs. ... If colleagues have encountered this tumour in an English cocker spaniel, a springer spaniel or a cavalier King Charles spaniel, it would be of great value to this project if a blood sample and/or the affected patient’s pedigree certificate could be submitted for inclusion in the analyses. ... For further information or to submit blood or pedigrees please contact Gerry Polton at North Downs Specialist Referrals, Friesian Building 3&4, Brewerstreet Dairy Business Park, Brewer Street, Bletchingley, Surrey RH1 4QP, UK. Tel: +44 (0) 1883 741440, Fax: +44 (0) 1883 347030. E-mail: gerrypolton@gmail.com website: www.ndsr.co.uk"
Association between anal sac gland carcinoma and dog leukocyte antigen-DQB1 in the English Cocker Spaniel. J Aguirre-Hernández; G Polton; L J Kennedy; D R Sargan. Tissue antigens 2010;76(6):476-81. Quote: "Anal sac gland carcinomas occur frequently in English Cocker Spaniels and, to a lesser extent, in other spaniel breeds. The disease typically presents in dogs aged 8 years or older and frequently metastasises to the local lymph nodes. The association between anal sac gland carcinoma in English Cocker Spaniels and the major histocompatibility complex class II loci (the dog leukocyte antigen loci DLA-DRB1, -DQA1, -DQB1) was investigated in 42 cases and 75 controls. Based on a corrected error rate of 0.017 for each test, the allele distribution in DLA-DRB1 showed no significant difference between cases and controls (P value = 0.019), while a significant difference was obtained for DLA-DQA1 and -DQB1 alleles (P values are 0.010 and 3.3 × 10⁻⁵). The DLA-DQB1*00701 allele was the most common in both cases and controls, but it had a higher frequency among the former (0.89) than in the latter (0.61), while the second most common allele had a higher frequency in the controls (0.23) than in the cases (0.07). Haplotype distributions were also significantly different between the two groups (P value = 1.61 × 10⁻⁴). This is the second disease in English Cocker Spaniels for which the most common DLA-DQB1 allele in the breed has been shown to have a higher frequency in cases than controls, while the second most common allele in the breed (*02001) has a significantly higher frequency in the controls, compared with the cases."
The development of multiple cutaneous inverted papilloma following ovariohysterectomy in a dog. Munday, J.S.; French, A.F.; MacNamara, A.R. N.Zeal. Vet. J.; June 2010;58(3):168-171(4). Quote: "Case History: Ovariohysterectomy was performed on an adult Cavalier King Charles Spaniel. The skin that had been clipped for surgery was noticed to be erythematous 8 days later. Clinical and Pathological Findings: Poorly defined patches containing multiple papules were visible bilaterally within the clipped skin. These became larger over the following 2 weeks, and samples were collected for histology. Seven days later, the lesions were multiple raised masses, up to 5 cm in diameter. Histology revealed numerous cup-shaped epidermal proliferations extending into the dermis. The presence of keratin ocytes with increased quantities of blue-grey cytoplasm, and koilocytosis suggested papillomaviral infection; Canis familiaris papillomavirus (CfPV-2) DNA was amplified from two separate samples. Complete regression was observed 8 weeks after the lesions had been initially observed. Diagnosis: Multiple inverted papilloma confined to skin that had been clipped for surgery. Clinical Relevance: This is the first time that the development of canine cutaneous papillomas has been associated with surgery. The nature of the association between surgery and development of the papillomas is uncertain. However, it is possible that damage to superficial skin could promote the formation of papillomas. This is the first identification of CfPV-2 in New Zealand."
Unilateral facial myokymia in a dog with an intracranial meningioma. Holland, CT; Holland, JT; Rozmanec, M. Austr Vet J; Sept 2010;88(9):357-361(5). Quote: "A 23-month-old castrated male Cavalier King Charles spaniel was evaluated because of a 6-month history of unusual rippling/undulating movements of the right facial muscles that were continuous and persisted during sleep. Neurological examination revealed narrowing of the right palpebral fissure and unilateral right-sided facial myokymia that was characterised by myokymic, and to a lesser degree, neuromyotonic discharges on concentric needle electromyographic examination. After persisting unchanged for almost 2.5 years from its onset, the facial myokymia gradually disappeared over a 6-month period concomitant with the emergence of a persistent ipsilateral facial paralysis and head tilt. At 5 years and 9 months after the first examination, signs of ipsilateral lacrimal, pharyngeal and laryngeal dysfunction became evident and the dog was euthanased. Postmortem examination identified a malignant (WHO grade III) meningioma in the right cerebellopontomedullary angle that compressed the ventrolateral cranial medulla, effaced the jugular foramen and internal acoustic meatus and extended into the facial canal of the petrous temporal bone. Novel findings were the unique observation of isolated unilateral facial myokymia preceding diagnosis of a meningioma affecting facial nerve function within the caudal cranial fossa and the remarkably long duration of neurological signs (75 months) attributable to the neoplasm."
Superficial corneal squamous cell carcinoma occurring in dogs with chronic keratitis. Jennifer Dreyfus, Charles S. Schobert, Richard R. Dubielzig. Vet Ophth; May 2011;14(3):161-168. Quote: "Objective: Canine corneal squamous cell carcinoma (SCC) is a rare tumor, with only eight cases previously published in the veterinary literature. The Comparative Ocular Pathology Lab of Wisconsin (COPLOW) has diagnosed 26 spontaneously occurring cases, 23 in the past 4 years [three of which were cavalier King Charles spaniels]. This retrospective study describes age and breed prevalence, concurrent therapy, biologic behavior, tumor size and character, and 6-month survival rates after diagnosis. Results: A search of the COPLOW database identified 26 corneal SCC cases diagnosed from 1978 to 2008. There is a strong breed predilection (77%) in brachycephalic breeds, particularly those prone to keratoconjunctivitis sicca. The mean age was 9.6 years (range 6–14.5 years). Follow-up information >6 months was available for 15 of 26 cases. Recurrence occurred in the same eye in nine cases, seven of which were incompletely excised at the time of first keratectomy. No cases were known to have tumor growth in the contralateral eye and no cases of distant metastases are known. Where drug history is known, 16 of 21 dogs had a history of treatment with topical immunosuppressive therapy (cyclosporine or tacrolimus) at the time of diagnosis. Conclusion: Chronic inflammatory conditions of the cornea and topical immunosuppressive therapy may be risk factors for developing primary corneal SCC in dogs. SCC should be considered in any differential diagnosis of corneal proliferative lesions. Superficial keratectomy with complete excision is recommended, and the metastatic potential appears to be low."
Canine tonsillar squamous cell carcinoma - a multi-centre retrospective review of 44 clinical cases. A Mas, L Blackwood, P Cripps, S Murphy, J De Vos, N Dervisis, M Martano, G A Polton. J Small Anim Pract. 2011 Jul ;52 (7):359-364. Quote: " Objectives: To review the presenting clinical signs, treatment and survival of dogs with tonsillar squamous cell carcinoma and, if possible, to identify useful prognostic indicators. Methods: Medical records of 44 dogs were reviewed retrospectively. ... The breeds included: ... cavalier King Charles spaniel (four) ... Clinical signs, clinical stage, time of diagnosis, treatment and outcome were recorded. Data were analysed using the Kaplan-Meier, log-rank, Student's t test, Kruskal-Wallis test and Chi-square/Fisher Exact test as appropriate. Results: The most frequent clinical signs were cough (12 dogs, 27%), enlarged lymph nodes (11 dogs, 25%) and dysphagia (11 dogs, 25%). Anorexia and lethargy were less common but were significantly associated with a poor outcome. No matter what treatment modalities were used, survival times were short and median survival time for all the dogs in the study was 179 days. However, there were a small number of long-term survivors. Clinical Significance: Dogs with tonsillar squamous cell carcinoma that suffered anorexia and lethargy had shorter survival times than patients without these clinical signs. Although surgery, chemotherapy and radiotherapy seem to increase the median survival time of dogs diagnosed with tonsillar squamous cell carcinoma, there is no highly effective treatment for canine tonsillar squamous cell carcinoma."
Dog models of naturally occurring cancer. Jennie L. Rowell, Donna O. McCarthy, Carlos E. Alvarez. Trends in Molecular Med. July 2011;17(7):380-388. Quote: "Studies using dogs provide an ideal solution to the gap in animal models for natural disease and translational medicine. This is evidenced by approximately 400 inherited disorders being characterized in domesticated dogs, most of which are relevant to humans. There are several hundred isolated populations of dogs (breeds) and each has a vastly reduced genetic variation compared with humans; this simplifies disease mapping and pharmacogenomics. Dogs age five- to eight-fold faster than do humans, share environments with their owners, are usually kept until old age and receive a high level of health care. Farseeing investigators recognized this potential and, over the past decade, have developed the necessary tools and infrastructure to utilize this powerful model of human disease, including the sequencing of the dog genome in 2005. Here, we review the nascent convergence of genetic and translational canine models of spontaneous disease, focusing on cancer."
Malocclusion associated with macroglossia in a dog. Gerhard Putter. Comp. Anim. Nov/Dec 2011;16(9):12-19. Quote: "Macroglossia (defined as enlargement of the tongue but not indicating the cause) is a rare condition in dogs. The association with malocclusion has not been described before. It has been reported that resection of as much as 60% of the body of the tongue is well tolerated by dogs. Although the tongue is a very vascular organ, intraoperative haemorrhage during tongue amputation can be effectively controlled by a tourniquet at the base of the tongue. Healing of the amputation wound is usually rapid and uneventful. ... A five year old, 12 kg neutered male Cavalier King Charles Spaniel was presented with a complaint of an excessively long tongue."
Identification of genetic variation in 11 candidate genes of canine mammary tumour. K. S. Borge, A. L. Børresen-Dale, F. Lingaas. Vet. & Comp. Oncology; Dec 2011;9(4):241-250. Quote: "The incidence of canine mammary tumours (CMTs) differs significantly between breeds [cavalier King Charles spaniels are identified as being at low-risk for CMT], strongly supporting an influence of genetic risk factors. We aimed at identifying germline genetic variations in mammary tumour-associated genes in dogs and survey whether these might alter the encoded proteins. We sequenced 11 genes (BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EGFR, ESR1, HER2, PTEN, STK11 and TP53) and screened for genetic variations. Sixty-four single nucleotide polymorphisms (SNPs) were identified. Nine of the coding SNPs were non-synonymous, of which four were located in gene regions conserved across four species. Three of the non-synonymous SNPs might be damaging according to PolyPhen predictions. One of the indels identified has previously been associated with CMTs. Because of the founder effects, genetic drift and inbreeding in many dog breeds the allele frequencies of the genes studied are likely to vary significantly between breeds and contribute to the considerable difference in genetic risk associated with cancer."
Thymidine kinase assay in canine lymphoma. J. W. Elliott, P. Cripps, L. Blackwood. Vet. & Comp. Oncology; Dec 2011. Quote: "The aim of the study was to evaluate if thymidine kinase (TK) correlated with duration of first remission (DFR) or survival in dogs with lymphoma and if initial TK levels correlated with stage and substage; and also to assess if TK level at diagnosis correlated with immunophenotype. TK was assayed in 73 dogs with treatment naïve lymphoma, then again after treatment; 47% had an initial TK above the reference interval. Dogs with B-cell lymphoma had higher initial TK activities than dogs with T-cell lymphoma. TK levels were not higher in dogs with higher stage disease and TK activity prior to treatment was not associated with DFR or survival. Where TK was elevated at diagnosis, it fell into the reference range during remission. TK was normal in 53% dogs at diagnosis, which is higher than previously reported. Further studies are warranted to assess the utility of TK in dogs with lymphoma."
