Incidence and Mortality
Urethral cancer is rare. The annual incidence rates in the Surveillance, Epidemiology, and End Results database over the period from 1973 to 2002 in the United States for men and for women were 4.3 and 1.5 per million, respectively, with downward trends over the three decades. The incidence was twice as high in African Americans as in whites (5 million vs. 2.5 per million). Urethral cancers appear to be associated with infection with human papillomavirus (HPV), particularly HPV16, a strain of HPV known to be causative for cervical cancer.[2,3]
Because of its rarity, nearly all information about the treatment of urethral cancer and the outcomes of therapy is derived from retrospective, single-center case series and, therefore, represents a very low level of evidence of 3iiiDiv. The majority of information comes from cases accumulated over many decades at major academic centers.
The female urethra is largely contained within the anterior vaginal wall. In adults, it is about 4 cm in length.
The male urethra, which averages about 20 cm in length, is divided into distal and proximal portions. The distal urethra, which extends distally to proximally from the tip of the penis to just before the prostate, includes the meatus, the fossa navicularis, the penile or pendulous urethra, and the bulbar urethra. The proximal urethra, which extends from the bulbar urethra to the bladder neck, includes distally to proximally the membranous urethra and the prostatic urethra.
Table 1. Anatomy of the Male Urinary System and the Female Urinary System
|Anatomy of the male urinary system (left) and female urinary system (right) showing the kidneys, ureters, bladder, and urethra. Urine is made in the renal tubules and collects in the renal pelvis of each kidney. The urine flows from the kidneys through the ureters to the bladder. The urine is stored in the bladder until it leaves the body through the urethra.|
The prognosis of urethral cancer depends on the following factors:[4,5,6]
- Anatomical location.
- Depth of invasion.
Superficial tumors located in the distal urethra of both the female and male are generally curable. However, deeply invasive lesions are rarely curable by any combination of therapies. In men, the prognosis of tumors in the distal (pendulous) urethra is better than for tumors of the proximal (bulbomembranous) and prostatic urethra, which tend to present at more advanced stages.[7,8] Likewise, distal urethral tumors tend to occur at earlier stages in women, and they appear to have a better prognosis than proximal tumors.
- Swartz MA, Porter MP, Lin DW, et al.: Incidence of primary urethral carcinoma in the United States. Urology 68 (6): 1164-8, 2006.
- Wiener JS, Liu ET, Walther PJ: Oncogenic human papillomavirus type 16 is associated with squamous cell cancer of the male urethra. Cancer Res 52 (18): 5018-23, 1992.
- Wiener JS, Walther PJ: A high association of oncogenic human papillomaviruses with carcinomas of the female urethra: polymerase chain reaction-based analysis of multiple histological types. J Urol 151 (1): 49-53, 1994.
- Urethra. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 508-9.
- Rabbani F: Prognostic factors in male urethral cancer. Cancer : , 2010.
- Dalbagni G, Zhang ZF, Lacombe L, et al.: Female urethral carcinoma: an analysis of treatment outcome and a plea for a standardized management strategy. Br J Urol 82 (6): 835-41, 1998.
- Dinney CP, Johnson DE, Swanson DA, et al.: Therapy and prognosis for male anterior urethral carcinoma: an update. Urology 43 (4): 506-14, 1994.
- Dalbagni G, Zhang ZF, Lacombe L, et al.: Male urethral carcinoma: analysis of treatment outcome. Urology 53 (6): 1126-32, 1999.
- Gheiler EL, Tefilli MV, Tiguert R, et al.: Management of primary urethral cancer. Urology 52 (3): 487-93, 1998.