Canine perineal tumours and selected tumour markers

Abstract

The most frequent canine perineal tumour is the perianal (gland) adenoma (also known as the circumanal adenoma or the hepatoid adenoma). Tumour markers are substances that are produced by the body in response to cancer, or may be produced by cancer itself. Carcinoembryonic antigen (CEA) and tissue polypeptide specific antigen (TPSA) are tumour antigens that are markers of carcinogenesis, with significantly elevated serum concentrations in the case of some types of tumours. In our study it has been proven that dogs with a perineal tumour (n = 35) had a mean value of CEA 0.69 ng·ml-1 compared to control dogs (n = 150) with 0.67 ng·ml-1 (P > 0.05). In TPSA dogs with perineal tumour, the mean value of TPSA was 15.86 IU·l-1 vs 13.92 IU·l-1 in the control dogs (P < 0.05). The results of the present study show that there is significant differences in TPSA between control dogs and group of dogs with a perineal tumour. Analysis of oncomarkers is a valuable tool for practitioners within small animal oncology, having an advantage over tissue biomarkers as the measurement procedure is non-invasive and shows dynamic changes of physiological and pathological states before clinical signs appear. Therefore, it may be used for an early detection of cancer. CEA, TPSA, statistical analysis, blood, radioimmunoassay The most frequent canine perineal tumour is the perianal (gland) adenoma (also known as the circumanal adenoma or the hepatoid adenoma) which is a common tumour that arises from the sebaceous glands surrounding the anus. It is so common that it accounts for 80% of all canine tumours that occur in the perineal area and that are seen most frequently in intact male dogs, because of the tumour’s testosterone dependence. The malignant version is the perianal adenocarcinoma which is considered far less common than the perianal adenoma (Vos et al. 1989; Bennett et al. 2002). Adenoma of the hepatoid gland occurs in the perineal region. Newly proliferated tumour tissue is encapsulated and the neoplasm is well demarcated from surrounding tissue. In a multilobulated pattern it has a rim of small reserve cells at the peripheral with central differentiation to large hepatoid cells. Adenocarcinoma of the hepatoid gland is usually less well organized into trabecules or distinct lobules. It mostly consists of only one cell type which is poorly differentiated: hyperchromatic nuclei, little cytoplasm, and prominent nucleoli. Under malignancy the hepatoid cells have an abundant eosinophilic cytoplasm and large nuclei with several prominent nucleoli and are mitotically active with small mitotic counts. It has been characterized as a feature of malignancy. Histologically, mitosis of hepatoid cells and/or invasion of neoplastic cells into the surrounding connective tissue or lymphatic vessels are the most important (Goldschmidt and Hendrick 2002). Tumour markers are substances that are produced by the body in response to cancer, or may be produced by cancer itself. Some of them are specific to one cancer, while others ACTA VET. BRNO 2019, 88: 419–424; https://doi.org/10.2754/avb201988040419 Address for correspondence: Ľubica Horňáková Small Animal Clinic Komenského 73 041 81 Košice, Slovakia Phone: +421 917 171 104 E-mail: [email protected] http://actavet.vfu.cz/ may be present in several types of cancer. They are generally used to evaluate the patient’s response to treatment or to monitor for recurrence – the return of cancer after treatment (Vachani 2016). Broadly, it is known that carcinoembryonic antigen (CEA) protein may appear in the blood with certain kinds of cancers, especially cancer of the large intestine (colon and rectal cancer). It may also be present in a subject with cancer of the pancreas, mammary gland, ovary, or lung. Tissue polypeptide specific antigen (TPSA) is one of the most valuable tumour markers, which is a complement to CA 19-9 (carbohydrate antigen 19-9) in the detection of the various epithelial cancers, including breast, colorectal, ovarian, lung and prostate cancer (Young et al. 2002; Fareed et al. 2012; Shao et al. 2012). The rising or declining value of a marker concentration in majority of malignancies predicts a progression or a remission of diseases. The diagnostic efficiency of tumour markers depends on a variety of factors such as sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Sensitivity of these markers means the probability that the test results will be positive when a tumour is present. Their specificity is a screening parameter which indicates whether it may be used for describing the percentage of healthy individuals whose result is negative. The PPV describes the probability that the disease in question is actually present if the test result is positive. The NPV describes the probability that the disease is not actually present when the test result is negative (Malati 2007). In this study, we attempted to examine CEA and TPSA in blood serum in dogs with perineal tumours. The aim of this study was to compare our results with these markers in clinically healthy dogs. Materials and Methods Dogs with a perineal tumour The group of dogs with a perineal tumour (n = 35) came from private breeding in the Kosice Region (Eastern Slovakia). They were of different ages (1–16 years), sexes (5 females and 30 males), intact. The breeds included the Mongrel (n = 14), West Highland White Terrier (n = 5), Cocker Spaniel, Yorkshire Terrier, Jack Russel Terrier, Fox Terrier (n = 2 each), Staffordshire Terrier, Shi-tzu, Labrador Retriever, German Shepherd, Maltese, Bichon, Dalmatian, and Pit Bull Terrier (n = 1 each). The mean age of dogs with the perianal adenoma was 10.7 (from 1 to 16) years and with the perianal adenocarcinoma 11.7 (from 9 to 15) years.