What's the best approach for managing asymptomatic hydronephrosis in a patient with a history of stage four prostate cancer?

Management of Asymptomatic Hydronephrosis in Advanced Prostate Cancer

The best management for this patient with asymptomatic left hydronephrosis is CT urography (CTU) without and with IV contrast as the initial diagnostic step, followed by urological intervention with ureteral stenting if obstruction is confirmed.

Clinical Assessment and Diagnostic Approach

This 78-year-old man presents with:

• Stage IV prostate adenocarcinoma treated with bilateral orchiectomy 3 years ago
• Marked left hydronephrosis discovered incidentally during ultrasound
• Currently asymptomatic
• Elevated creatinine (1.4 mg/dL) suggesting renal impairment
• Elevated PSA (31 ng/mL) suggesting disease progression

Initial Diagnostic Workup

1. CT Urography (CTU) without and with IV contrast

   • First-line imaging for asymptomatic unilateral hydronephrosis of unknown cause 1
   • Provides comprehensive evaluation of the genitourinary tract with both morphological and functional information
   • Can identify the exact location and cause of obstruction (likely metastatic disease in this case)

2. Alternative diagnostic options:

   • MAG3 renal scan - useful to determine functional status of the affected kidney
   • MR urography - if contrast is contraindicated

Management Algorithm

Step 1: Confirm Obstruction and Assess Renal Function

• CTU will determine if true obstruction exists and identify the cause
• Assess differential renal function of the left kidney

Step 2: Intervention Decision Based on Findings

• If obstruction confirmed with compromised renal function:

  • Proceed with decompression of the collecting system
  • Internal ureteral stenting (double-J stent) is preferred for patients with reasonable performance status 2
  • Percutaneous nephrostomy if stenting fails or is contraindicated

• If no significant obstruction or minimal renal function:

  • Consider conservative management with close monitoring

Step 3: Follow-up and Monitoring

• Regular renal function tests (creatinine, BUN)
• Follow-up imaging to assess hydronephrosis resolution
• PSA monitoring to track disease response to treatment

Rationale for Intervention

Despite being asymptomatic, this patient has several concerning features:

• Elevated creatinine indicating renal impairment
• Unilateral hydronephrosis in the context of metastatic prostate cancer
• Elevated PSA suggesting disease progression

In patients with advanced prostate cancer, hydronephrosis often indicates ureteral obstruction from metastatic disease 3. Even when asymptomatic, intervention is typically warranted to preserve renal function and prevent further deterioration.

Important Considerations and Pitfalls

• Do not delay intervention despite lack of symptoms - Asymptomatic hydronephrosis in this context can rapidly progress to irreversible renal damage
• Consider the patient's overall prognosis - With a PSA of 31 ng/mL despite orchiectomy, this indicates hormone-refractory disease
• Avoid nephrostomy tubes as first-line approach - Internal stents are better tolerated and associated with fewer complications in patients with reasonable life expectancy 2
• Monitor for infection - Obstructed systems are prone to infection, which can rapidly become life-threatening

The evidence strongly supports early intervention for hydronephrosis in the setting of metastatic malignancy, even when asymptomatic, to preserve renal function and prevent complications that would significantly impact morbidity and mortality.