Anatomy matters
The Diagnosis: Why Location Mattered
This page explains Oscar's diagnosis. It does not tell you how to treat your dog. Every treatment Oscar received was directed by my oncologist.
Oscar's diagnosis was not just bladder cancer. It was a tumor in the bladder/trigone/proximal urethral region.
That location mattered because the trigone is where the urinary system narrows into consequences. It is close to the ureters, where urine comes from the kidneys, and the urethra, where urine leaves the bladder.
What a tumor there can threaten
- Ability to empty the bladder
- Ureters and kidneys upstream
- Urine stream strength
- Infection and inflammation risk
- Bleeding, pain, and urgency
- Surgical options (trigonal tumors are hard to “just cut out”)
The April 2025 diagnostic ultrasound described a solitary heterogeneous irregular mass along the caudal dorsal bladder wall, extending into the trigone and proximal urethra (± distal left ureter). It measured about 3.2 cm long × 1.3 cm thick. There was marked left renal pyelectasia (~1 cm) with a dilated left ureter. The prostate was symmetrically enlarged (~6.27 cm width).
BRAF mutation testing was positive in April 2025, prior to the oncology consult. That result supported the urothelial/TCC picture and shaped early questions for my oncologist.
What I watched at home
Because of the location, I watched urine stream strength, repeated attempts after peeing, blood in urine, cloudy urine, licking, appetite, vomiting, restlessness, kidney values, ureter/kidney dilation, and — late in the journey — stool and pelvic discomfort.
Practical lesson: ask where the tumor is. The location changes the risk.
Questions to ask after a bladder/TCC diagnosis
- Where exactly is the tumor?
- Is it in the trigone, bladder neck, urethra, prostate, or away from the outlet?
- Is there ureter or kidney dilation?
- Is urinary obstruction an immediate risk?
- Should we run BRAF testing?
- Is the tumor sample suitable for molecular profiling?
- What symptoms should trigger an emergency visit?
- How will we monitor urine, kidney values, and blood pressure?
- What is the comfort plan from day one?
- What does success mean: shrinkage, stable disease, comfort, or time?