The urethra is the structure that carries urine, and in men, semen from
the body. It is located within the penis (organ for reproduction and
urination) in men and in front of the vagina (passageway to the uterus,
birth canal) in women. Urethral cancer is rare and is often associated with
invasive bladder cancer. It tends to metastasize (spread) to adjacent soft
tissue and is often locally advanced when diagnosed.
Different types of urethral cancer develop within different types of cells
and in different portions of the urethra. In women, the urethra is lined
with transitional cells near the urethral opening and squamous cells near
the bladder. In men, transitional cells line the upper portion and squamous
cells line the urethra at the base of and within the penis.
Squamous cell carcinoma develops in flat, scaly surface cells and
is the most common type of urethral cancer. Other types include the
- Transitional cell carcinoma (surface cells of the urethra)
- Adenocarcinoma (develops in glands located near the urethra)
- Melanoma (extremely rare; develops in pigment-producing skin cells)
- Sarcoma (extremely rare; develops in blood vessels, smooth muscle, and
Urethral cancer that is superficial and located in the anterior portion
of the structure (i.e., toward the urethral opening) often can be treated
successfully. Cancer that develops in the posterior portion of the urethra
(i.e., near the bladder) is usually invasive and rarely curable.
In women, urethral cancer often spreads to the labia, vagina, and bladder
neck. In men, the condition may spread to the tissues of the penis and
perineum, the prostate gland, the ligament that surrounds the urethra (urogenital
diaphragm), the regional lymph nodes, and the penile and scrotal skin.
Incidence and Prevalence
Urethral cancer is more common in women. It can occur at any age, but the
incidence is highest in patients in their 60s.
In men, 80% of cases are squamous cell carcinomas, most of which occur in
the urethra at the base of the penis. In women, 60% of cases are squamous