Carcinoma of the penis

Penile cancer is a malignant growth found on the skin or in the tissues of the penis, usually originating in the glans and/or foreskin. It is a rare form of cancer with an incidence of 1 in 100,000 per year in developed countries.^[1]

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Risk factors

The American Cancer Society provides the following as risk factors for penile cancer:^[2] human papillomavirus (HPV) infection, smoking, smegma, phimosis, treatment of psoriasis, age, and AIDS. The other etiologic factor most commonly associated with penile carcinoma is poor hygiene. There is some evidence that lichen sclerosus (also known as balanitis xerotica obliterans) may also be a risk factor.^[3]

Risk

The lifetime risk of a man developing invasive penile cancer (IPC) in the United States is 1 in 600 if he is uncircumcised,^[4] and more than 3 times lower if he was circumcised neonatally.^[5][6][7]

This and other evidence suggests that childhood circumcision reduces the incidence of penile cancer.^{[8][5][4][9][10][11]}

Studies have found that circumcision decreases the risk of HPV infection in males and thereby the risk of developing penile cancer.^[12][13][14]

But Wallerstein found that the risk of penile cancer in Finland, Norway, and Denmark (all noncircumcising countries) is about the same (1 in 100,000 per year) as in the US. The American Medical Association and the Royal Australasian College of Physicians say the use of infant circumcision in hope of preventing penile cancer in adulthood is not justified.^[15][16]

The American Cancer Society stated in 1998:

"... penile cancer risk is low in some uncircumcised populations, and circumcision is strongly associated with other socioethnic practices that are associated with lessened risk. The consensus among studies that have taken these other factors into account is that circumcision alone is not the major factor preventing cancer of the penis. It is important that the issue of circumcision not distract the public's attention from avoiding known penile cancer risk factors -- having unprotected sexual relations with multiple partners (increasing the likelihood of human papillomavirus infection) and cigarette smoking."^[2]

Symptoms

A draining sore on the foreskin or glans of the penis may be a sign of penile cancer. Anyone with these symptoms should consult a doctor immediately.

Pathology

• A. Precancerous Dermatologic Lesions
• B. Carcinoma in Situ (Bowen Disease, Erythroplasia of Queyrat)
• C. Invasive Carcinoma of the Penis

Staging

Like many malignancies, penile cancer can spread to other parts of the body. It is usually a primary malignancy, the initial place from which a cancer spreads in the body. Much less often it is a secondary malignancy, one in which the cancer has spread to the penis from elsewhere. Doctors use the extent of metastasis to estimate what stage the disease is in, to aid in treatment decisions and prognosis. The stages are assessed as follows:

• Stage I - Cancer has only affected the glans and/or foreskin.
• Stage II - Cancer has spread to the shaft of the penis.
• Stage III - Cancer has affected the penis and surrounding lymph nodes.
• Stage IV - Cancer has moved beyond the groin area to other parts of the body.
• Recurrent - Cancer that has returned after treatment.

Prognosis can range considerably for patients, depending where on the scale they have been staged. Generally speaking, the earlier the cancer is diagnosed, the better the prognosis. The overall 5-year survival rate for all stages of penile cancer is about 50%.

Treatment

There are several treatment options for penile cancer, depending on staging. They include surgery, radiation therapy, chemotherapy, and biological therapy. The most common treatment is one of four types of surgery:

• Wide local excision - The tumor and some surrounding healthy tissue are removed
• Microsurgery - Surgery performed with a microscope is used to remove the tumor and as little healthy tissue as possible
• Laser surgery - laser light is used to burn or cut away cancerous cells
• Circumcision - cancerous foreskin is removed
• Amputation (penectomy) - a partial or total removal of the penis, and possibly the associated lymph nodes. This is the most common and effective treatment.

Radiation therapy is usually used adjuvantly with surgery to reduce the risk of recurrence. With earlier stages of penile cancer, a combination of topical chemotherapy and less invasive surgery may be used. More advanced stages of penile cancer usually require a combination of surgery, radiation and chemotherapy.

Vaccine

A quadri-valent vaccine to prevent HPV infection, Gardasil, has been developed, successfully tested and approved for women by the US Food and Drug Administration.^[17] Approval for men is expected in 2008. It is licensed and in production, and could substantially reduce the incidence of HPV infection in men, the incidence of genital warts and ano-genital cancers including penile cancer, and mortality.^[18]

References