The study was carried out on 2500 canine cases referred to the department of Surgery and Radiology. Out of 2,500 cases, 50 were diagnosed as tumours on the basis of cytology or histopathology of excision/needle biopsy. The overall prevalence of canine tumours during the one year study period was 2%. The prevalence of benign tumours and malignant tumours was 46% and 54% respectively. Out of 50 canines diagnosed with tumours, 24 were males (48%) and 26 were females (52%). Organ-wise distribution of tumours included, mammary gland tumour (24%), skin and adnexa (20%), venereal (16%), female reproductive tract (14%), male reproductive tract (8%), melanoma and oral cavity (8%), appendicular skeleton (6%), spleen (2%) and Liver (2%). Breed-wise occurrence of neoplasms was found higher in Labrador dogs and Mongrels (non-descript) as compared to other breeds. Labrador breed of dog had 17 tumour cases followed by non-descript dogs (15), Spitz (7), German Shepherd (5), Neapolitan Mastiff (2), Rottweiler, Dalmatian, Cocker Spaniel, and Pointer, one tumour case each. Age wise prevalence of canine tumours was observed as 0-5 year age group (24%; 12 cases), 6-10 year age group (60%; 30 cases), and 10-15 year old dogs (16%; 8 cases).
With the increased use of vaccines and antibiotics in domestic and pet animals, death due to infectious diseases has decreased dramatically in the last two decades and cancer has now emerged as leading cause of pet animal deaths (Withrow, 2001). As compared to humans, canines neoplasms has been observed more frequent and are one of the major cause of mortality in canines. Consequently, more time of the practicing veterinarian’s, present days, are employed in the diagnosis, prognosis and treatment of tumours in canine patients. Malignant tumours are potentially life-threatening where as benign tumours grow slowly without invading or destroying the neighbouring tissue, and do not spread to other parts of the body and are not usually life threatening. During the last several years canine tumours have raised great interest in human and veterinary surgery. Pre-operative determination of tumour type and differentiation between malignant and benign tumours is of importance in judging patient’s prognosis and in designing therapy (Simon et al., 2009). Many neoplasms are known to affect the dogs and cats; the two most common household pets with mixed type of tumours which could be either benign or malignant. Dogs tend to get cancer at a higher rate than cats. Epidemiological studies considering canine tumours are beneficial in understanding the patterns of tumour occurrence in different organs of various breeds and age group dogs. The present study was aimed to know the prevalence of different neoplastic conditions in Jammu.
Materials and Methods
The present study was carried out on dogs which were presented at the Teaching Veterinary Clinical Complex (TVCC) of SKUAST- Jammu. Complete history of the dogs suspected for neoplasia was recorded and clinical examination comprising of observation, palpation, percussion, recording of physiological parameters was performed. The consistency of visible growth or swelling, if any, their size, their attachment to the skin and the tissues underneath, whether ulcerated or not, engorgement of the blood vessels and lymphatics draining the affected area etc. were recorded. The tumours were diagnosed on the basis of histopathological and cytological studies after representative tissue pieces were collected from multiple (at least 3) sites in tumour suspected cases and fixed in 10% neutral buffered formalin followed by processing of the sample and then histopathological studies.
Radiograph of the region involved, chest and abdomen were performed to know the extent of the lesion and to find out the metastatic lesions. Ultrasonography (USG) of the growth/swelling was performed to record the echotexture, blood supply, invasion of the surrounding tissues and whether cystic or solid. USG of abdomen was performed to find out metastatic lesions in the liver, lymph nodes, peritoneum and other visceral organs.
Results and Discussion
Out of 2,500 cases, fifty were diagnosed as tumours on the basis of cytology or histopathology of excision/needle biopsy. The overall incidence of canine tumours during the one year study period was 2%. The incidence of benign tumours and malignant tumours was 46% and 54% respectively. Out of 50 canines diagnosed with tumours, 24 were males (48%) and 26 were females (52%) (Fig. 1).
Fig.1: Sex wise prevalence of canine tumours (N=50)
Rungsipipat et al.(2003) as well had reported the menace of neoplasms in canines in Bangkok through a retrospective study conducted in the year 1982 and found a total of 2425 neoplasms among dogs in Bangkok, Srivastava et al. (2009) reported 407 neoplasms in dogs, Bronden et al. (2010) in a study found 1878 cases of neoplasms in dogs, in Denmark, Mukaratirwa et al. (2005) recorded 540 skin tumours in dogs in the year 2000-2001, among which 45% were benign; Gupta and Tiwari (2009) reported 109 neoplasms in dogs among which 47.7% were benign and 52.3% were malignant, Srivastva et al.(2009) recorded 45.7% benign and 54.3% malignant tumours out of 407 neoplasms cases of dogs and Sostaric-Zuckermann et al. (2013) recorded 59.1% malignancy condition out of 1568 tumour cases observed in a study. Nair et al. (2007) in a study also reported 68.75% benign and 31.25% malignant tumours out of 48 clinical cases. Overall incidence of mammary tumours was 0.48%, tumours of male reproductive tract 0.16%, female reproductive tract tumours (excluding TVT) 0.28%, skin tumours 0.4%, tumours of oral cavity 0.16%, tumours of appendicular skeleton 0.12% , tumours of visceral organs 0.08%, and TVT 0.32% (Table 1).
Table 1: System wise incidence canine tumours (N=50)
|Male reproductive system tumor||0.16|
|Female reproductive system tumor||0.28|
|Tumors of the oral cavity tumor||0.16|
|Tumors of the appendicular system tumor||0.12|
|Tumors of the visceral organs||0.08|
Among all tumour cases, the prevalence of mammary tumour was highest (24%) and they constituted 46% of all the tumours of female dogs. Out of 12 mammary tumours, adenocarcinoma constituted 41.66% (5 cases), fibroadenoma 33.33% (4 cases), and myoepithelioma 25% (3 cases) (Fig. 2, 3 and 4) (Table 2).
|Fig. 2: HP of Mammary adenocarcinoma showing ducts partially occluded with in growth of tumour cells and presence of extensive fibrous stroma.||Fig. 3: HP of Mammary fibroadenoma showing myoepithelium mixed with stromal elements and highly cellular stroma.|
Table 2: Incidence among mammary tumours (N=12)
|Tumor||n= no. of cases||Incidence (%)|
Sertoli cell tumours formed 75% (3 cases) and seminomas 25% (1 case) of the male reproductive tract tumours, which constituted 8% of all tumours (excluding TVT) (Fig. 5) (Table 3).
|Fig.4: HP of Mammary myoepithelioma showing neoplastic proliferation of the myoepithelial cells forming nodular masses with abundant fibrous tissue proliferation. H&EX400.||Fig.5: Testicular tumour: Sertoli cell tumour showing neoplastic sertoli cell arranged in a palisade pattern within pseudotubular structure resembling seminiferous tubules. H&EX 100.|
Table 3: Incidence among male reproductive system (N=12)
|Tumor||n= No. of Cases||Incidence (%)|
|Sertoli cell tumours formed||3||75%|
The female reproductive tract tumours formed 14% (7 cases) of all tumours. All the tumours of female reproductive system, excluding TVT, were leiomyoma (100%) (Fig. 6). The skin tumours also comprised 20% (10 cases) of all tumours. Out of ten cases, perianal adenoma formed 30% (3 cases), the fibrosarcoma, anaplastic histiocytoma, and mastocytoma constituted 20% each (each 2 cases), whereas squamous cell carcinoma (SCC) formed 10% (1 case) of the skin tumours.
Fig.6: Vaginal leiomyoma showing interlacing bundles of smooth muscle fibres.
Out of 4 cases of tumours of oral cavity which comprised 8% of overall tumours, 75% (3 cases) were malignant melanoma and 25% (1 case) peripheral odontogenic fibroma. The tumours of appendicular skeleton formed 6% (3 cases) of all tumours and all the tumours were osteosarcoma, forming 100% of bone tumours. Only two tumours of visceral organs were recorded, one of the spleen and the other of the liver, 2% of total tumours respectively. The TVT formed 16% of the total tumour cases. Jani et al.(1992), Rostami et al.(1994) and Rungsipipat et al.(2003) reported neoplasms of the mammary glands were most common followed by skin tumours. The present study prevalence of mammary tumour was highest (24%) followed by skin tumour (20%), transmissible venereal tumour, TVT (16%), female reproductive tract excluding TVT (14%), male reproductive tract and tumours of oral cavity (8% each), appendicular skeleton (6%) and tumours of visceral organs (4%). Vachhani et al.(2004) and Nair et al.(2007) reported that the mammary glands, reproductive organs and skin were the most common sites for the neoplasms in dogs, and Khimta et al.(2010) also in a study recorded highest occurrence of canine TVT followed by tumours of mammary gland and skin. Low incidence of visceral tumours in the present study, due to the fact that the pet owners reported in the hospital for treatment of tumours when they noticed a visible lump on the body and that too when it interfered with normal functions of the animals, whereas the visceral tumours were not observed by the owners and when the animals brought for some other complaints were suspected for some lesions on the liver, spleen or some other visceral organ based on haemato-biochemical alterations, radiography or ultrasonography (USG), the owners declined exploratory celiotomy or ultrasound guided biopsy in most of the cases. Merlo et al.(2008) who recorded 3303 canine cancers out of 6743 biopsy specimens also made a similar observation that because a biopsy specimen was required to make a cancer diagnosis, cancer rates for internal organs cancers, such as respiratory and digestive tract cancers might have been underestimated in the study population.
Highest incidence was among 6-10 year age group (60%, 30 cases), followed by 0-5 year age group (24%, 12 cases), and was least in 10-15 year old dogs (16%, 8 cases) (Table 4).
Table 4: Age wise incidence of canine tumours
|Age in Years||n= no. of cases||Incidence|
The mean age of animals suffering from mammary tumours was 9.1±0.64 years (5-13). Mammary adenocarcinoma were seen in animals aged 9.8±1.28 years (8-13), mammary fibroadenoma in 8.5±1.19 years (5-10), and mammary myoepithelioma in 9±0.57 years (8-10). Tumours of male reproductive tract were seen in animals aged 9.5±1.04 years (7-12). Sertoli cell tumours were recorded in dogs of 8.66±0.88 years age (7-10) and seminoma in a 12 year old dog. Female reproductive tract tumours, leiomyoma, were seen at mean age of 8.85±0.59 years (7-12). The mean age of dogs having skin tumours was 7.9±0.58 years (5-11). The SCC was recorded in a 7 year old dog, whereas the mean age of dogs having fibrosarcoma was 8±1 years (7-9), anaplastic histiocytoma 7.5±0.5 years (7-8), and mastocytoma 5.5±0.5 years (5-6). Perianal adenomas were seen at a mean age of 10±0.58 years (9-11). The mean age of dogs having oral cavity tumours was 7.75±1.88 years (5-13). The tumours of appendicular skeleton, osteosarcoma, were recorded in the dogs aged 7.33±2.78 years (2-11). Splenoma was seen in an 8 year old animal, whereas the age of the animal suffering from hepatocellular carcinoma was 10 years. TVT were recorded in the animals aged 3.37±1.2 years (1-12). The finding were in agreement with Das and Parhi (2003) who observed that the 7-9 year age group had the highest incidence of tumours, particularly at 8 years of age. As the age increased, the incidence declined sharply. Kujur et al. (2009) reported highest incidence of skin tumours in dogs aged 5-10 years and Reddy et al. (2009) observed that the age group at which mammary tumours occurred most frequently was 8-10 years followed by 6-8 years.
Highest incidence of tumours was observed in Labrador breed (34%, 17 cases) followed by non-descript (ND) dogs (30%, 15 cases), Spitz (14%, 7 cases), German shepherd (10%, 5 cases), Neapolitan Mastiff (4%, 2 cases), Rottweiler, Dalmitian, Cocker Spaniel and Pointer (2% each, 1 case each) (Table 5).
Table 5: Breed wise incidence of canine tumours
|Breeds||n= no. of cases||Incidence|
Vachhani et al.(2004) reported that the prevalence of tumours was more in Pomeranian breed (24%) followed by German Shepherd (21.6%), Doberman (10.4%) and Labrador (7.2%). Similarly, Kashyap et al.(2013) also recorded highest tumour cases in Spitz and Pomeranian breeds (60%) followed by German Shepherd (20%), Mongrel (8%), Doberman, Boxer and Lhasa Apso (4% each). However, Malicka et al. (1996) reported that prevalence of neoplasms in mixed breed dogs was highest (27.2%) followed by German Shepherd (12.7%), Poodles (10%), Boxers (7.2%), Dachshunds (6.4%) and Cocker Spaniel (4.7%). Srivastava et al.(2009) also reported highest incidence of canine neoplasms in ND dogs (24.57%) followed by breeds such as Spitz, German Shepherd, Labrador, Doberman, Boxer and Great Dane.
The variation in the incidence of neoplasms in various breeds of dogs reported by different authors might be due to the fact that particular breeds might have been more popular than the other breeds in the areas under study and the number of cases recorded in a breed might correspond to its population in the area. The incidence of tumours in males (48%) and females (52%) in the present study in accordance with the observations of Rungsipipat et al.(2003) and Sostaric- Zuckermann et al.(2013) who did not observe any marked difference between sex related incidence of tumours. Rao and Rao (2009) study reported tumour in canine males (56.09%) and females (43.91%). Das and Parhi (2003), Majie and Majie (2013) and Khimta et al.(2010) observed that canine neoplasm were more in females than in males.
In this study the overall prevalence of canine tumours is 2%. Prevalence of tumours is higher in females (52%), intact animals of both sexes, and age group of 6-10 years. Highest prevalence of tumours was observed in Labrador breed followed by non descript dogs, Spitz, German Shepherd, Neapolitan Mastiff, Rottweiler, Dalmation, Cocker Spaniel, and Pointer. Mammary tumours has highest prevalence followed by skin tumours, transmissible venereal tumours, tumours of female reproductive tract, tumours of male reproductive tract, tumours of oral cavity, tumours of appendicular skeleton and tumours of visceral organs.
Authors are thankful to the DRI, Veterinary Surgery Department, SKUAST-J, for providing necessary facilities to carry out this work