Cancer of the penis

When a man sees a sore or a spot on his penis, he often thinks the worst. For some men, it's worry about a sexually acquired disease, but for many, it's concern about cancer of the penis. It's a rare disease in the United States, but since early diagnosis is so important, men should know how to tell whether a spot is worrisome. And it's also useful to understand why penile cancer is so much more common in other parts of the world.

Who gets penile cancer?

Since about 1,500 cases are diagnosed in the United States each year, the disease accounts for less than 1% of all malignancies in American men. But it's much more common in Asia, Africa, and South America, where it constitutes 10%–20% of all male malignancies. There are three explanations for this wide disparity.

Circumcision. Penile cancer is almost unheard of in Jewish males, who are traditionally circumcised on the eighth day of life. It is only slightly more common in Muslims, who often delay circumcision until sometime between the ages of 3 and 13. But circumcision in adulthood is not protective. All in all, circumcision reduces the risk of penile cancer by over 70%, with infant circumcision the most beneficial.

Hygiene. By removing the foreskin, circumcision prevents phimosis, a condition in which the foreskin adheres tightly to the glans, or tip of the penis. If the foreskin cannot be retracted, inflammation and infection can develop and a layer of debris called smegma can build up. Doctors believe that over time, this chronic irritation can lead to cancer. But good hygiene will prevent chronic irritation. In fact, soap and water are nearly as protective as circumcision.

Sexually transmitted infection. In this case, the culprit appears to be the human papilloma virus (HPV), or at least two strains of the critter (HPV-16 and HPV-18). In recent studies, evidence of HPV has been detected in 30%–80% of penile cancers. HPV is the main cause of cancer of the cervix in women, and it has been proposed as a possible factor in some cases of prostate cancer.

Clinical features

The disease typically develops between ages 50 and 70. The vast majority of these cancers occur on the tip of the penis, most often on the glans itself (see figure above). Over 95% are squamous cell cancers, which arise from the skin. At first, it may look like a small area of redness or thickening or sometimes like a small wart. In time, it may burrow into the skin to produce an ulcer that does not heal, or it may pile up to form a warty mass. In advanced cases, a bloody or foul-smelling discharge becomes evident.

Diagnosis

A biopsy is the only way to diagnose cancer of the penis. That doesn't mean you should run to your doctor every time you see a spot near the tip of your penis. It's safe to wait 2–4 weeks to see if the abnormality clears on its own. If not, see a urologist or dermatologist, who may also watch it for a while before performing a biopsy.

If the biopsy shows cancer, the next step is to find out if the disease has spread. In most cases, penile cancer spreads first to the lymph glands in the groin, then the glands in the pelvis. A doctor can feel glands in the groin; but since enlargement is often caused by infection, he may prescribe a trial of antibiotics before recommending a lymph node biopsy. CT scanning is the best way to hunt for cancerous nodes in the pelvis.

Treatment

Cancer therapy is rarely pretty, but the traditional treatment for cancer of the penis is particularly distressing: radical penectomy, or amputation. This drastic operation is still necessary for some advanced or recurrent cases, but early disease can often be cured with far less aggressive procedures. If there ever was a case for early diagnosis, this is it.

Small, superficial cancers confined to the foreskin can be cured with circumcision. Those on the penis itself can be treated with Mohs micrographic surgery, a technique in which tissues are removed in layers that are checked under a microscope to be sure all the cancer is removed. Laser therapy and radiotherapy, using external beams or local implants, have been quite successful for early to moderate cases. Surgery is still necessary for more advanced or relapsed cases, but partial penectomy is preferred to amputation; removal of the groin lymph nodes is often helpful. Chemotherapy is showing promise.

Prevention first

Penile cancer is hard to treat but easy to prevent. Advocates of infant circumcision cite the operation's proven ability to prevent cancer as a strong point in its favor. They have a point, but good hygiene is nearly as protective. But if prevention fails, early diagnosis is the next best — and that starts with a simple look at this often overlooked part of the male anatomy.