Nodal involvement is the single most important prognostic factor for survival — 5-year survival is lower once nodes are involved (the node-positive figure ranges widely, ~0–86%, depending on the extent of involvement).
Clinically Negative Groins
- ~20% of patients with clinically non-palpable nodes harbour occult metastases.
- CT and MRI cannot reliably detect occult nodal disease and are used mainly to assess pelvic nodes.
- Immediate resection of clinically occult metastases improves survival versus delayed resection at the time of clinical detection.
Surgical Staging
Indicated for high-risk tumours (≥pT1b; optional for T1a G2); surveillance is an alternative for reliably compliant patients. Two options — dynamic sentinel node biopsy (DSNB, preferred) or modified inguinal lymphadenectomy.
DSNB removes the node(s) first affected by spread, relying on orderly stepwise lymphatic progression. Technique: inguinal ultrasound with FNA of suspicious nodes first (positive FNA → proceed straight to lymphadenectomy; negative FNA → lymphoscintigraphy with technetium-99m nanocolloid, patent blue dye, and intraoperative gamma-probe localization to resect the sentinel node).
- Advantages — much less morbid than modified or standard lymphadenectomy; bridges imaging and resection for clinically negative groins.
- Disadvantages — restricted to high-volume centres, requires dedicated experience, and should target a false-negative rate ≤5%.
- Accuracy is improved by preoperative inguinal US with needle biopsy of suspicious nodes, routine inguinal exploration even without radiotracer visualization, intraoperative palpation for abnormal nodes, and extended pathologic analysis of excised nodes.
- DSNB is diagnostic — it lets some men avoid a therapeutic lymphadenectomy; a positive DSNB mandates full therapeutic lymphadenectomy. It applies only to clinically negative nodes, not palpable adenopathy.
Palpable Lymphadenopathy
- Palpable adenopathy reflects metastasis in 43% of cases (inflammation in the rest); FNA can differentiate.
- Treat with bilateral inguinal lymphadenectomy (open or video-endoscopic) — it can be curative given the prolonged locoregional phase before distant spread. The superficial dissection is bilateral even if adenopathy is unilateral; complete ilioinguinal dissection (nodes deep to the fascia lata in the femoral triangle, plus pelvic nodes) follows if superficial nodes are positive on frozen section.
- Exception — verrucous carcinoma: metastasis is very unlikely, so palpable adenopathy is usually reactive and is observed; biopsy only if it persists/grows, and lymphadenectomy only for biopsy-proven metastasis.
Fixed & Pelvic Nodes
- Fixed nodes (cN3) — neoadjuvant chemotherapy followed by radical inguinal lymphadenectomy in responders.
- Favourable pN+ features (better long-term survival after curative resection): unilateral involvement, minimal disease (≤2 nodes, pN1), no extranodal extension, and no pelvic nodal metastasis — i.e. pN1 without pN2/pN3 features.
- There is no direct lymphatic drainage from the penis to the pelvic nodes — pelvic spread does not occur without inguinal involvement first.
- Pelvic lymph node dissection (distal common iliac, external iliac, obturator) is indicated during inguinal lymphadenectomy when ≥2 inguinal nodes are positive or extranodal extension is present; it serves as a staging tool to identify candidates for adjunctive therapy.
Nodal Treatment Summary
| Node status | Management |
|---|---|
| cN0 | Tis, Ta G1, T1 G1 → surveillance. ≥T1b or ≥T2 → invasive nodal staging by bilateral modified inguinal lymphadenectomy or DSNB |
| cN1/cN2 (palpable) | Surgically remove enlarged nodes, assess by frozen section; if positive, radical inguinal lymphadenectomy |
| cN3 (fixed) | Neoadjuvant chemotherapy, then radical inguinal lymphadenectomy in responders |
| Pelvic nodes | Ipsilateral pelvic lymphadenectomy if ≥2 inguinal nodes positive or extracapsular extension (pN3) |
| Adjuvant chemotherapy | For pN2/pN3 after radical lymphadenectomy |
| Radiotherapy | Not recommended for nodal disease except as palliation |
Chemotherapy
A cisplatin-containing regimen should be considered for advanced/metastatic penile cancer and may enable curative resection (the optimal regimen is undetermined). If the tumour progresses through chemotherapy, surgery is not recommended.
Self-Test
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What proportion of clinically negative groins harbour occult metastasis, and what is the implication? ~20% — and immediate resection of occult disease improves survival over delayed resection, so high-risk patients (≥pT1b) undergo invasive nodal staging.
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How does DSNB triage the groin? Suspicious nodes get FNA; positive → lymphadenectomy; negative → lymphoscintigraphy + blue dye + gamma-probe sentinel node resection. A positive DSNB mandates full lymphadenectomy; target false-negative rate ≤5%.
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When is pelvic lymphadenectomy added during inguinal dissection? With ≥2 positive inguinal nodes or extranodal extension — there is no direct penile-to-pelvic drainage, so pelvic disease implies prior inguinal spread.
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How is palpable adenopathy in verrucous carcinoma managed? Observed (usually reactive given the very low metastatic potential); biopsy only if persistent/growing, and lymphadenectomy only for biopsy-proven metastasis.