Primary urethral tumors are relatively rare in clinical practice, with malignant types including carcinoma, fleshy tumors, melanoma, etc. Early symptoms may include urethral bleeding, frequent urination, urgency, and dysuria. As the tumor grows, it can also cause difficulty in urination. Treatment is challenging, and the prognosis is generally poor.

bubble_chart Pathological Changes

The histological types of primary urethral cancer vary according to the site of origin, with squamous cell carcinoma being the most common, followed by transitional cell carcinoma, while adenocarcinoma is relatively rare. The navicular fossa of the male urethra is lined with squamous epithelium, the penile and bulbar urethra are covered by pseudostratified or columnar epithelium, and the posterior urethra is lined with transitional epithelium. Tumors of the penile urethra arise from the bulbar region in 50–70% of cases, with approximately 50% secondary to distal urethral strictures accompanied by squamous metaplasia of the mucous membrane, leading to a predominance of squamous cell carcinoma. Adenocarcinoma originates from the bulbourethral glands or Littre glands. Tumors of the bulbar and membranous urethra often invade deep perineal structures, including the skin of the penis and scrotum, the urogenital diaphragm, and the prostate. Tumors of the navicular fossa may invade the glans penis, which is rich in blood vessels and lymphatic channels. Anterior urethral tumors typically metastasize to the superficial and deep inguinal lymph nodes. Posterior urethral tumors metastasize to the obturator and internal/external iliac lymph nodes, but when the tumor invades the penis or perineal skin, it may spread to the inguinal lymph nodes. Urethral cancer (especially anterior urethral cancer) rarely exhibits hematogenous metastasis. The most common sites of distant metastasis are the lungs, followed by the liver and stomach, with occasional metastasis to the pleura and bones.

The age of onset of this disease ranges from 13 to 91 years, with the vast majority being over 50 years old. Patients typically seek medical attention due to symptoms such as urethral obstruction, masses, perineal abscess, urinary extravasation, urethral fistula, and urethral discharge. Some patients experience pain, hematuria, or hemospermia. Tumors in the navicular fossa may present as ulcers or papillary lesions. Bimanual rectal examination can determine whether the tumor has extended to the prostate, anus, or urogenital diaphragm.

Clinical staging is based on clinical and pathological biopsy results, and is further reviewed based on pathological findings from surgical specimens.

Stage O: Limited to the mucosa (carcinoma in situ); Stage A: Lesions extend to the submucosal layer; Stage B: Lesions invade the corpus spongiosum; Stage C: Direct extension to tissues outside the corpus spongiosum or beyond the prostatic capsule; D₁Stage: Regional metastasis including inguinal/pelvic lymph nodes (original follicular tumor can be at any stage); D₂Stage: Distant metastasis (original follicular tumor can be at any stage).

bubble_chart Diagnosis

For elderly men with no previous history of urethral disease or trauma who present with urethral bleeding or obstructive symptoms, worsening symptoms of urethral stricture during treatment, or the development of perineal abscess or urethral fistula, urethral cancer should be suspected. Urethrography, cystourethroscopy, biopsy, and cytological examination of urethral secretions or irrigation fluid should be performed.

Urethral cancer should be differentiated from condyloma acuminatum, urethral stricture, perineal abscess, subcutaneous nodules, and penile cavernous body induration. A biopsy should be performed if necessary.

1. For stage O and A tumors in the penile urethra, transurethral resection of the tumor is advocated. Since clinical staging is often inaccurate, it is more reasonable to perform urethral resection 1–2 cm proximal to the tumor, along with penile or perineal urethrostomy.

2. For stage B and C tumors, partial penectomy should be performed 1–2 cm away from the tumor. If a satisfactory tumor-free margin cannot be achieved, penectomy and perineal urethrostomy should be performed. After resection of the primary tumor, if enlarged inguinal lymph nodes do not shrink and biopsy confirms metastatic carcinoma, deep and superficial inguinal lymph node dissection as well as pelvic lymphadenectomy should be performed.

3. For stage O and A tumors in the membranous or prostatic urethra, transurethral resection may be performed. However, since tumor resection is often incomplete and tumors near the sphincter carry a high risk of urinary incontinence, radical cystoprostatectomy and total urethrectomy are more reasonable. Concurrent pelvic lymphadenectomy should also be performed. If biopsy confirms inguinal lymph node metastasis, lymph node dissection should also be performed.

Generally, tumors of the bulbar urethra are often widely advanced at diagnosis, and even radical surgery may not achieve a cure. The high postoperative recurrence rate is due to the adjacent structures—the inferior pubic ramus, pubic symphysis, and pelvic floor muscles—hindering wide local excision of bulbar urethral tumors. En bloc resection of the tumor, lower urinary tract, reproductive system, and the aforementioned structures may improve cure rates. Preoperative radiotherapy may be beneficial, though experience is limited. Radiotherapy alone can also achieve tumor control in some patients.

Most reported cases in China are at an advanced stage with poor prognosis. Foreign studies indicate that survival rates vary depending on tumor location and stage. Penile urethral cancer has a better prognosis, with a 5-year survival rate of 43%, while bulbous and prostatic urethral cancers have a rate of 14%. The survival rates by stage are: Stage A 100%, Stage B 80%, Stage C 17%, and Stage D 20%. The extended radical surgical approach mentioned above may improve treatment outcomes.