When is pelvic lymph node dissection performed in patients with prostate cancer?

When is Pelvic Lymph Node Dissection Performed in Prostate Cancer?

Pelvic lymph node dissection (PLND) should be performed in high-risk prostate cancer patients undergoing radical prostatectomy, using an extended bilateral approach, while low-risk patients should not routinely undergo this procedure. 1

Risk Stratification Framework

The decision to perform PLND is based on the patient's risk category, which determines the likelihood of lymph node metastasis:

Low-Risk Patients (Do NOT perform PLND)

• Patients with PSA <10 ng/ml AND Gleason score ≤6 AND clinical stage <T2b should NOT routinely undergo pelvic lymph node dissection. 1
• These patients have less than 10% risk of lymph node metastasis, making the procedure unnecessary. 1
• The cost per metastasis diagnosed in low-risk patients is approximately $43,600, with only 1.3-2.2% having nodal involvement. 2

Intermediate-Risk Patients (Individualized Decision)

• Intermediate-risk patients undergoing prostatectomy should have a discussion about risk/benefit of lymph node dissection informed by nomogram estimates. 1
• Use validated nomograms (such as the Briganti nomogram) to calculate individual risk of lymph node involvement. 1, 3
• Consider PLND when the calculated risk exceeds 5% probability of lymph node invasion. 3
• The decision must weigh the diagnostic benefit against complications including lymphoceles (occurring in approximately 4% of cases) and lymphedema. 1, 4, 5

High-Risk Patients (ALWAYS perform extended PLND)

• High-risk patients having radical prostatectomy should have an extended bilateral lymph node dissection unless prior imaging shows gross multiple lymph node involvement. 1
• High-risk features include: PSA ≥20 ng/ml, Gleason score ≥8, or clinical stage ≥T3. 1
• Extended dissection detects approximately twice as many metastases compared to limited obturator fossa dissection alone. 1
• In high-risk patients, 17-19% will have lymph node metastases detected. 5, 3

Technical Specifications for Extended PLND

When performing PLND, the anatomic boundaries should include: 1, 5

• Superior boundary: Bifurcation of the common iliac artery
• Inferior boundary: Node of Cloquet (circumflex iliac vein)
• Lateral boundary: External iliac vein
• Medial boundary: Bladder wall and hypogastric vessels

The goal is to remove at least 10-20 lymph nodes, with a mean of 14-21 nodes in extended dissections. 5, 3

Important Caveats and Contraindications

• Do NOT perform PLND if imaging demonstrates gross multiple lymph node involvement (nodes >2 cm diameter), as this typically contraindicates curative surgery. 1
• Limited obturator fossa dissection alone is inadequate and misses approximately 50% of metastases. 1
• Frozen section analysis during surgery to decide whether to proceed with prostatectomy should NOT be performed. 1

Patients Receiving Radiation Therapy

• Intermediate and high-risk patients treated with radiotherapy should have pelvic imaging (preferably PSMA PET/CT if available) unless they have had surgical lymph node staging. 1, 6
• PSMA PET/CT has 85% sensitivity and 98% specificity for nodal metastases, compared to 38% sensitivity and 91% specificity for conventional imaging. 6

Therapeutic Value Consideration

While PLND remains the gold standard for staging, recent evidence suggests its therapeutic benefit is unclear. 3, 7 A multi-institutional study found no significant difference in biochemical recurrence-free survival (60.4% vs 65.6%, p=0.07), metastasis-free survival (87.0% vs 90.0%, p=0.06), or cancer-specific mortality (95.2% vs 96.4%, p=0.2) between patients who did or did not undergo PLND at 120 months. 3 However, the staging information remains critical for treatment planning and prognosis, particularly in high-risk disease where management decisions depend on nodal status. 1