A 68-year-old man with no prior PSA screening presents with lower urinary tract symptoms and is found to have a PSA of 8.5 ng/mL and a suspicious nodule on digital rectal examination. A transrectal ultrasound-guided biopsy confirms adenocarcinoma of the prostate (Gleason score 7, 3+4). MRI pelvis shows no extraprostatic extension. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has **localized prostate cancer** (Gleason 7, PSA 8.5, no extraprostatic extension on MRI). Before committing to definitive treatment, staging investigations are mandatory to rule out metastatic disease. ## Staging Workup for Intermediate-Risk Prostate Cancer **Key Point:** Intermediate-risk prostate cancer (Gleason 7 or PSA 7–20 or T2b–T2c) requires staging imaging to exclude metastases before treatment planning. **High-Yield:** The risk of occult metastases increases with: - Gleason score ≥7 - PSA >10 ng/mL - Clinical stage T3 or higher This patient meets intermediate-risk criteria (Gleason 7, PSA 8.5). Bone scan and CT chest/abdomen/pelvis are standard to assess for skeletal and visceral metastases. ## Why Staging First? | Investigation | Rationale | | --- | --- | | **Bone scan** | Detects osteoblastic metastases (most common site in prostate cancer) | | **CT chest/abdomen/pelvis** | Assesses for nodal involvement and distant visceral disease | | **MRI pelvis** | Already done; excludes local extraprostatic extension | **Clinical Pearl:** Staging must precede treatment selection. If metastases are found, curative surgery is inappropriate and systemic therapy becomes the focus. ## Treatment Decisions After Staging Once staging is complete and metastases are excluded: - **Intermediate-risk, localized disease** → Radical prostatectomy ± pelvic lymph node dissection, or external-beam radiotherapy ± ADT - **Metastatic disease** → ADT ± chemotherapy (docetaxel) **Mnemonic: PSA-Gleason-Stage (PGS)** — All three must be known before treatment planning. [cite:Harrison 21e Ch 182]