"The Bladder Tumor Antigen Test" TUMOR TIDBITS, A WEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 105; August 22, 2003. ======================================================================= THIS WEEK'S ANNOUNCEMENTS FROM GULF COAST VETERINARY ONCOLOGY *Free patient care (4 month anemia study) for dogs with cancer. *Free chemotherapy (4 week bleomycin study) for dogs with cancer. *Foundation Golf Tournament November 11th. *Visit www.gcvs.com for more information. ======================================================================= THIS WEEK'S TUMOR TIDBIT: The Bladder Tumor Antigen Test ======================================================================= This Tidbit reviews briefly (yes, it is a Tidbit) the value of the urinary bladder tumor antigen test. Although lower urinary tract tumors comprise less than 1% of all canine neoplasms, the most frequent urinary neoplasm is transitional cell carcinoma. In one study of 115 dogs, transitional cell carcinoma accounted for 87% of all bladder and urethral tumors. The mean age for development of transitional cell carcinoma in dogs is approximately 9 years. The most common site of tumor development is the trigone area of the bladder. Less commonly, these neoplasms originate in the urethra and may involve the prostate gland of males or the vaginal vault of females. The pattern of neoplastic cell growth may be papillary, non-papillary, or invasive. Metastasis occurs approximately 50% of the time. The most common sites for metastasis include regional lymph nodes, surrounding soft tissues, bones of the hindquarters, and lung. In one study, 37% of dogs had metastasis by the time of initial clinical diagnosis. Normal urine may contain a few transitional epithelial cells, crystals (including amorphous crystal), hyaline casts, and fat droplets (especially in cats). Other contaminants may be observed in voided urine specimens. These contaminants may include squamous epithelial cells from the distal urethra, vagina, or prepuce and bacteria. Transitional cell carcinomas usually exfoliate large numbers of neoplastic cells. The cells may be scattered individually or arranged in variably-sized aggregates. Frequently, the cells are markedly pleomorphic with pronounced anisocytosis and anisokaryosis. Overall, the cells are reported to have a high nuclear to cytoplasm ratio, but this cannot be appreciated in all cytology preparations. Also, the cytoplasm may contain small to large pale vacuoles which may compress the nucleus. Cytologic features alone may not distinguish transitional cell carcinoma from transitional cell hyperplasia in all fine-needle aspirates or urine sediments. In dogs, the diagnosis of transitional cell carcinoma may be improved with the use of a commercially available bladder tumor antigen detection test (V-BTA test, POLYMEDCO Inc., 510 Furnace Dock Rd., Cortlandt Manor, NY 10567; www.vetbta.com). This test uses a latex agglutination system to detect a unique tumor-associated glycoprotein in urine. The test works reliably in most instances; however, false positive tests may be associated with marked glucosuria (4+), heavy proteinuria (4+), and pyuria or hematuria (>30-40 WBC or RBC per microscopic hpf of view). In one study of the V-BTA test, groups of dogs were evaluated that included the following: 1) dogs with TCC of the lower urinary tract, 2) healthy control dogs, 3) unhealthy control dogs with non-TCC urinary tract disease, and 4) unhealthy control dogs without urinary tract disease. A total of 229 urine samples were analyzed, including 48 from dogs with suspected (n = 3) or confirmed (45) TCC. Test sensitivities were 88, 87, and 85% for all dogs with (suspected and confirmed) TCC, dogs with confirmed TCC at any site, and dogs with confirmed TCC of the urinary bladder, respectively. Test specificities were 84, 41, and 86% for healthy control dogs, unhealthy control dogs with non-TCC urinary tract disease, and unhealthy control dogs without urinary tract disease, respectively. The test performed slightly better on centrifuged urine samples than on uncentrifuged urine samples. These results indicate that the V-BTA test is useful in screening for urinary tract TCC in dogs. The high sensitivity of the test (and significant negative predictive value) suggest it to be a practical screening test to rule out TCC in geriatric patients or patients with clinical signs related to the lower urinary tract, particularly before pyuria and hematuria develop. The test requires 0.5 ml of urine and is best performed on a freshly collected sample. To date, no studies have found the V-BTA test to be of prognostic importance in the survival of dgos with TCC or have utility in the prediction of response to treatment. ======================================================================= As always, we hope this info helps and don't hesitate to call or email us Gulf Coast Veterinary Oncology! Kevin A. Hahn, DVM, PhD, Diplomate ACVIM (Oncology), drhahn@gcvs.com Janet K. Carreras, VMD, Diplomate ACVIM (Oncology), drcarreras@gcvs.com Glen K. King, DVM, MS, Diplomate ACVR (Radiology & Radiation Therapy), drking@gcvs.com Gulf Coast Veterinary Diagnostic Imaging & Oncology 1111 West Loop South, Suite 150, Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 W: www.gcvs.com ======================================================================= Copyright © 2003, Gulf Coast Veterinary Oncology