Treatment of Renal Impairment Secondary to Locally Advanced Prostate Cancer

Introduction
Prostate cancer can cause urinary tract obstruction in several ways. Local disease may result in bladder outflow obstruction with subsequent highpressure chronic retention. Ureteric obstruction can occur either via direct disease extension through the trigone or more proximal extrinsic compression secondary to lymph node metastases. Regardless of its mechanism, urinary tract obstruction and renal failure due to prostate cancer present the patient and clinician with a difficult dilemma regarding treatment.

In this chapter, the incidence, presentation and initial management of both upper and lower urinary tract obstruction resulting from prostate cancer are described. The moral and ethical principles guiding the clinician in their decision making are also explained. In discussing the relative merits, weakness and financial implication of the subsequent treatment options, we hope this chapter will provide the clinician with a management framework to allow the development of appropriate treatment plans for each individual patient in their care.

INITIAL MEDICAL TREATMENT
If renal impairment is significant, the standard treatment for renal failure is required. Hyperkalaemia, fluid overload and metabolic acidosis are potentially life threatening and require urgent medical intervention. Insertion of a urethral catheter allows accurate assessment of urine output in the oliguric patient. Hyperkalaemia should be treated with insulin/ dextrose infusions, calcium resonium or salbutamol infusions. Patients failing to respond can be treated with temporary dialysis.

Once a patient is medically stable, the clinician needs to identify those patients who would benefit from relief of obstruction and justify this action. The main objective is to gain as much information about the obstructing process as possible. A thorough physical examination including pelvic and rectal examination are paramount. Appropriate radiology is required in the initial assessment. Accurate diagnosis and staging is reliant on modern imaging techniques of ultrasonography, computerised tomography (CT), magnetic resonance (MR) and isotope bone scanning. When previous tissue diagnosis is not available, then finger or trans-rectal ultrasound-guided prostate biopsies are useful in confirming the diagnosis.