Penile Cancer: Epidemiology, Differential Diagnosis, and Treatment
Penile cancer is a rare malignancy with an incidence of approximately 0.94 per 100,000 males in Europe and 0.5 per 100,000 in the USA, though rates are significantly higher in developing regions (up to 8.3 per 100,000 in Brazil), and treatment centers on organ-preserving surgery when feasible with aggressive lymph node management determining survival outcomes. 1
Epidemiology
Incidence and Prevalence
- Industrialized countries: 0.5-0.94 per 100,000 males 1
- High-incidence regions:
- Brazil: 8.3 per 100,000
- India: 0.7-3.0 per 100,000
- Parts of Africa (Uganda): even higher rates 1
- Age distribution: Peak incidence in the sixth decade, though younger patients are affected 1
- Trend: Slight increase in Western countries, likely due to rising HPV infection rates 1
Recent data from England shows a 30.9% increase in diagnoses from 485 cases in 2013 to 635 in 2019, confirming this upward trend 2.
Differential Diagnosis
Primary Histological Types
More than 95% of penile cancers are squamous cell carcinoma (SCC) 1. The differential diagnosis must distinguish between:
HPV-Independent SCC Subtypes:
- Usual type (45-75% of cases, 20-38% mortality) - most common presentation
- Verrucous (3-8%, 0% mortality) - extremely well-differentiated, no metastasis reported
- Papillary (2-15%, 0-6% mortality)
- Sarcomatoid (1-7%, 45-90% mortality) - most aggressive subtype 1
HPV-Associated Carcinomas:
- Basaloid (4-10%, 21-67% mortality)
- Warty (5-10%, 0-10% mortality)
- Warty-basaloid mixed (4-10%, 30-50% mortality) 1
Precursor Lesions to Exclude:
- Penile intraepithelial neoplasia (PeIN) - precursor to invasive SCC
- Clinical variants: erythroplasia of Queyrat, carcinoma in situ, Bowen's disease 1
- Lichen sclerosus - chronic inflammatory condition requiring monitoring 3
Rare Non-SCC Malignancies:
- Melanocytic lesions
- Mesenchymal tumors
- Lymphomas
- Metastases from other sites 1
Critical pitfall: Flat penile lesions with high HPV content require careful evaluation as their malignant potential remains incompletely characterized 3.
Treatment Approach
Primary Tumor Management
For superficial and glans-confined tumors, penile-preserving strategies are strongly recommended 4. The historical requirement for 2cm margins has been abandoned - margins of 5mm or less are adequate for most tumors with local recurrence rates under 5% 4.
Surgical Options by Tumor Extent:
Small volume/superficial lesions:
- Circumcision
- Wide local excision
- Epithelial ablative techniques
- Caveat: Glanular and preputial mucosa often show field changes; local recurrences may occur requiring retreatment 4
Glanular and distal penile tumors:
- Glansectomy/wide local excision (most common procedures in US data) 5
- Organ-preserving techniques now offer superior cosmetic and functional results compared to partial penectomy 4
Advanced tumors:
- Partial or total penectomy when organ preservation not feasible
- Phalloplasty reconstruction being explored for extensive disease 4
Lymph Node Management
Lymphadenectomy is the standard treatment for inguinal lymph node metastases 4. This is the most critical determinant of survival.
Risk-Stratified Approach:
Clinically node-negative (cN0) patients:
- Routine ultrasound-guided nodal assessment now recommended 6
- Dynamic sentinel node biopsy or modified inguinal lymph node dissection (ILND)
- Video-endoscopic inguinal lymphadenectomy (VEIL) and robot-assisted VEIL (RA-VEIL) are well-established options 7
Clinically node-positive (cN+) patients:
High-risk nodal disease (>1 metastatic node or extranodal extension):
- Consider adjuvant radiation to inguinal region (reduces recurrence from 60% to 11% in limited data) 4
- Important limitation: Larger confirmatory series lacking 4
cN3 disease or pelvic node involvement:
- Multimodal strategy required: chemotherapy + surgery + radiotherapy 7
Complication alert: Approximately 40% of patients experience ILND-related complications, predominantly chronic lymphedema 5.
Radiotherapy
For distal stage T1-T2 tumors, radiotherapy offers organ preservation as an alternative to surgery 4.
Modalities:
- External beam: 66-70 Gy over 6-7 weeks (2 Gy fractions, 5 days/week) 4
- Brachytherapy: 55-60 Gy over 4-6 days using low-dose rate or pulse-dose rate techniques 4
Outcomes: Long-term local control rates of 60-90%, more related to tumor characteristics than treatment parameters 4
Complications:
- Urethral stenosis: 8-45%
- Persistent ulceration/necrosis: 0-23%
- Penectomy for radiation complications: 0-5% 4
Functional advantage: In irradiated patients, global sexual function scores are preserved or only slightly reduced compared to moderate-to-severe reduction after local surgery 4.
Systemic Therapy
Cisplatin-based combination chemotherapy is the cornerstone for advanced disease 4.
Neoadjuvant Setting (Bulky Regional Disease - N2/N3):
- Paclitaxel + cisplatin + ifosfamide: 50% overall response rate, allows consolidation surgery in majority 4
- Four cycles standard before surgery 4
Metastatic Disease:
- Cisplatin + 5-FU: 32% partial response rate, median OS 8 months 4
- Cisplatin + gemcitabine: Sustained palliative responses observed 4
- Paclitaxel monotherapy: 20% response rate in cisplatin-pretreated patients (salvage setting) 4
- Paclitaxel + carboplatin: Alternative for cisplatin-ineligible patients 4
Critical limitation: All evidence is level III (phase II or retrospective studies only); no randomized trials exist 4.
Avoid bleomycin: High incidence of fatal pulmonary toxicity in older patients and smokers 4.
Chemoradiotherapy
Concurrent cisplatin-based chemoradiation shows benefit in locally advanced unresectable disease based on retrospective data, though prospective studies are lacking 4.
Staging Considerations
At presentation in England (2013-2020):
- Stage I-II: 50.8%
- Stage III-IV: 19.3%
- Unknown stage: 29.9% 2
Route to diagnosis matters: Emergency presentations (8.4% of cases) are more common in patients ≥70 years and stage III-IV disease, associated with worse outcomes 2.
Survival Outcomes
Overall survival (England data, all stages):
- 12 months: 86.3%
- 24 months: 77.6%
- 60 months: 63.8% 2
Poor prognostic factors:
- Age ≥70 years
- Stage III-IV disease
- Smoking (49% increased risk of metastatic disease) 5
Protective factor: HPV infection associated with 35% decreased risk of metastatic disease 5
Quality of Life and Centralization
Psychosexual impact is profound - patients suffer not only from cancer diagnosis but stigma of genital malignancy 1. Early holistic multidisciplinary discussion of emotional, social, and physical needs is strongly recommended 1.
Centralization of care to specialist centers is crucial given disease rarity and complexity 1, 8. This allows evaluation of organ-preserving techniques and standardization of lymph node management 4, 7.
Emerging focus: Selective genomic testing, survivorship care, and rationalized follow-up protocols are being incorporated into updated guidelines 6.