58° Congresso Nazionale SCIVAC: Oncologia veterinaria

58° Congresso Nazionale SCIVAC • Milano, 7-9 Marzo 2008 • Oncologia veterinaria - Alle soglie del III Millennio
diment. There can be over interpretation of the criteria of malignancy in cells
in the urine sediment as inflammation by itself can cause changes that closely
mimic malignancy. Flow cytometry may be more sensitive in the evaluation
of bladder cells in urine. Its use to identify cancer cells may be valuable
in the recognition of malignant cells as well as a sensitive indicator of
response to therapy.
Secondary bacterial infection is also common and there is often reported
an initial response to antibiotic therapy followed by a return of the clinical
signs when antibiotic therapy ceases. A new urine-based diagnostic test is
commercially available in the United States for screening for bladder cancer
in the dog.
This test is referred to as the VBTA test and detects an oncofetal antigen
released by tumors into the urine of affected dogs. While this test is highly
sensitive, it is very non-specific. The test had an overall sensitivity of 90%
and a specificity of 78% in one study of 19 healthy control dogs, 20 dogs
with TCC, and 26 dogs with non-neoplastic urinary disease. Any cause of
hematuria can result in a false positive finding with this assay. For this reason,
we are not commonly using the test and suggest that all positive tests
in a screening setting be validated by careful cytologic, biopsy, and imaging
studies.
Radiography is probably the most valuable tool in the diagnosis of bladder
tumors. Plain radiographs of the abdomen usually do not provide the diagnosis,
however, positive and negative contrast cystograms readily identify mucosal
irregularities, filling defects, and masses.
Radiographs should also be examined for calcification of the bladder
wall, sublumbar lymph node enlargement, prostatomegaly, caudal abdominal
mass, bladder displacement, and periosteal reaction along the lumbar
vertebrae or pelvis.
Ultrasound can be used as a diagnostic tool to look for bladder masses as
well as evaluate the kidneys, ureters, and sublumbar lymph nodes for metastatic
disease. Further, masses within the bladder can be easily measured at
each ultrasound and used to evaluate response to treatment.
Intraveneous urograms are often not necessary to diagnose bladder masses
unless urethral obstruction prevents urinary catheter passage. It is estimated
that 20% of dogs with TCC have metastasis at the time of diagnosis, although
this metastasis may be confined to sublumbar lymph nodes.
Thoracic radiographs to detect evidence of lung metastasis should be performed
at the time of diagnosis. Most typical patterns of pulmonary metastasis
seen with TCC are interstitial nodular and diffuse interstitial patterns.
While much can be gained from performing the above diagnostic tests, the
final diagnostic step should include biopsy. Biopsy can be obtained by cystoscopy,
traumatic catheterization, or cystotomy via laparotomy.
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