Step 1: Classify the tumour by Gleason score and PSA.
Gleason score 6 indicates a well-to-moderately differentiated (low-grade) adenocarcinoma of the prostate. PSA <8 ng/ml further supports low-risk disease. Using standard risk stratification (D'Amico or NCCN):
- Well-differentiated: Gleason sum 2-4
- Moderately differentiated: Gleason sum 5-6
- Poorly differentiated: Gleason sum 8-10
Step 2: Consider the patient's age and expected survival.
The patient is 85 years old. At this age, multiple comorbidities are expected. Prostate cancer with Gleason 6 and PSA <8 ng/ml is a low-risk, slow-growing tumour. The patient is unlikely to die from this cancer within his remaining life expectancy.
Step 3: Select the appropriate management.
Active surveillance (watchful waiting) is the recommended strategy for elderly patients with low-risk, localised prostate cancer who have a limited life expectancy or significant comorbidities. It avoids the morbidity of surgery or radiation (incontinence, erectile dysfunction, radiation proctitis) in a patient who will not benefit from aggressive treatment.
- TURP addresses urinary obstruction but does not treat cancer definitively.
- Radical prostatectomy and radiation carry significant morbidity in an 85-year-old.
Conclusion: Active surveillance is the most appropriate management for an 85-year-old with low-risk prostate cancer (Gleason 6, PSA <8).