Page 1370 - Clinical Small Animal Internal Medicine

1308 Section 11 Oncologic Disease

reveals malignant cells in only 30% of cases. In cases with lent in 10/12 cases. Urinary incontinence is the most
VetBooks.ir high index of suspicion for a bladder mass, cystocentesis common complication.
The use of radiation therapy for the treatment of TCC
should be avoided to decrease the chance of tumor
transplantation or bladder rupture. Concurrent urinary
survival rates following intraoperative radiation therapy
tract infection is prevalent in TCC cases, therefore urine of the bladder is limited. The reported one‐ and two‐year
culture is recommended. were 69% and 23%, respectively. Therapy‐related compli-
Diagnostic imaging is essential for documentation of cations include urinary incontinence, pollakiuria, and
a bladder mass. Abdominal radiographs are usually stranguria, all of which affect the patient’s quality of life.
unrewarding unless the lesion is mineralized. However, A report of weekly course fractional external beam radi-
radiographs may show sublumbar lymphadenopathy, ation therapy in combination with mitoxantrone and
prostatomegaly, a caudal abdominal mass or bony metas- piroxicam was well tolerated but results were no better
tases. Thoracic radiographs demonstrate pulmonary when compared to medical therapy alone. However,
metastasis in 17% of cases at the time of diagnosis. 90% of the dogs had amelioration of their clinical signs.
Pulmonary changes may include nodular interstitial or The mainstay treatment of TCC in dogs is systemic
lobar interstitial opacities and alveolar infiltrates. medical therapy with cyclooxygenase (COX) inhibitors
Ultrasonography is a sensitive diagnostic tool to evalu- alone or in combination with chemotherapy. Cure rates
ate the urinary tract and has largely replaced the use of are relatively low but several different drugs can lead to
double‐contrast cystography. Ultrasonography can also remission or stable disease. In dogs, single‐agent therapy
confirm ureteral obstruction when there is dilation of the with piroxicam or cisplatin has shown a response rate of
renal pelvis alone or accompanied by hydronephrosis. 20% with a median survival time of approximately six
Histopathology is the gold standard for the diagnosis months. Although the concurrent use of cisplatin and
of TCC. However, cytology can also be utilized. There piroxicam combination therapy has shown a response
are multiple methods for obtaining bladder tissue sam- rate of 70%, the high incidences of renal failure lead to
ples such as cystotomy, cystoscopy, and traumatic cath- early termination of the protocol.
eterization. Due to sampling size, multiple tissue samples The most commonly used chemotherapy combina-
2
should be submitted to increase the diagnostic yield. tion in dogs is mitoxantrone (5 mg/m IV q3 weeks) and
Most recently, A DNA based assay to detect genetic piroxicam (0.3 mg/kg once a day). This combination
mutations specifically in the BRAF gene has proven to be has a documented response rate of 35% and median
highly sensitive and specific for the diagnosis of TCC survival of 291 days. Indications to continue therapy

(CADET® BRAF, Sentinel Biomedical). The test evaluates include positive response such as complete or partial
malignant cells naturally shed and is therefore performed remission. Stable disease is considered a positive
on voided urine samples. However, the assay is limited response as long as the patient has no detrimental
TCC and experimentally it has been found that up to effects associated with chemotherapy administration
15% do not have the mutation. and a good quality of life.
Deracoxib (Dermaxx®, Novartis), a COX‐2 inhibitor, at
a dose of 3 mg/kg/day, has shown positive responses,
Therapy
with 17% of dogs having a partial response and 71% of
Because the trigone and urethra are most commonly dogs having stable disease.
involved in dogs, complete removal of the tumor is
usually not possible. In addition, many dogs develop Prognosis
multifocal bladder lesions. As a result, most dogs with
bladder tumors are managed medically, with chemother- The prognosis for TCC in dogs will largely depend on
apy, radiation and/or photodynamic therapy. tumor size, location, and metastasis at the time of diag-
If a patient is suffering from urinary obstruction, sur- nosis. Multiple different treatments have been identified
gery may be considered to reestablish urine flow or place that result in remission and stable disease for several
a cystostomy tube. The most common disadvantages of months. Most of these patients will have an excellent
tube cystostomy are recurrent urinary tract infections quality of life while on treatment. Prognostic factors
and premature removal of the tube by the patient. for survival are tumor stage at the time of diagnosis
Urethral stents are gaining favor over cystostomy tubes. (Box 146.1), younger age (increased risk of distant metas-
Stents are placed surgically and nonsurgically using tasis), prostate involvement (increased risk of distant
fluoroscopy. The most common indication for urethral metastasis), and higher T stage (increased risk of nodal
stenting is luminal obstruction secondary to tumor infil- and distant metastasis). Information regarding prognos-
tration. In a series of 12 cases, urethral stents relieved tic factors in other bladder tumors is limited. Prognostic
obstruction in all cases. The outcome was fair to excel- factors for bladder tumor in cats have not been well