Although penile cancer is rare, it is real and it happens. The sooner it is detected, the greater the chances of beneficial therapeutic outcomes. Any suspicious discoloration, bump or ulcer on the penis should be called to the attention of a doctor. Because the cancer is so rare, few doctors have seen it and some may not consider it when working up a diagnosis.
The Glickman Urological and Kidney Institute is home to some of the world's leading urologists and cancer specialists. They are always available for primary examinations or consultation with other urologists and primary care physicians.
What is penile cancer?
As with all cancers, penile cancer evolves from a disruption in one or more genes in a cell's DNA. Genes control cell activities including division and growth. When cells die, a normal and common event, they are replaced by new cells as the body needs them. However, when the genes that orchestrate this natural replacement process are disrupted by chemicals, illness, or other unknown factors, control over cell division and growth is lost. The resultant uncontrolled mass of tissue is a tumor.
The majority (48%) of penile cancers begin as a lesion (a noticeable change in tissue) in the glans, the rounded end of the penis or in the prepuce (21%), the loose skin that folds over the base of the glans. About 9% of penile cancers involve both the glans and prepuce; 6% involve the coronal sulcus, the groove beneath the glans, and about 2% occur on the shaft.
Penile cancers usually begin as a small painless discoloration or bump not unlike a wart on the glans or prepuce. Some tumors may appear as a sore that refuses to heal. They gradually expand around the surface until eventually covering the entire glans. As they grow along the surface the also grow into the surface slowly invading the shaft of the penis.
Circumcision at birth vastly reduces the risk of penile cancer. Circumcision in pre-pubertal boys also reduces the risk but circumcision in adults appears to have no effect. Because it is so rare, definitive risk factors are difficult to assess.
Genital warts, having more than 30 sexual partners, and smoking all appear to increase risk. Poor hygiene, especially in uncircumcised men, is believed by many to be a risk but it has yet to be proven. It is possible that herpes simplex virus, a common sexually transmitted disease, may have an effect on the incidence of the cancer.
The primary means of diagnosis is biopsy, a procedure in which a small piece of suspicious tissue is removed and studied by a specialist (pathologist) under a microscope. The entire lesion (suspicious growth or injury) may be removed if it is small.
A number of lab tests such as blood counts and tests to evaluate the status of the liver, kidneys, heart and lungs may be conducted. These are conducted to detect any other problems and to establish base values if therapies are initiated. Magnetic resonance imaging (MRI) and ultrasonography may be used to determine the extent (stage) of the cancer. MRI is particularly good at producing images of the internal structures of the penis.
When the cancer is diagnosed at its earliest stage while it is still confined to the skin surface, it may be treated with a topical anti-cancer agent such as 5-fluorouracil.
Radiation treatment is also reserved for selected patients whose cancers are small and have yet to penetrate deeper than the surface of the skin. Two radiation treatment approaches are available. External beam radiation aims the radiation like a tightly focused flashlight beam on the tumor. Several treatments are usually required. Brachytherapy involves creating a radioactive mold which is placed over the penis and worn for 12 hours a day for a week. These treatments are also applied to men who refuse surgical interventions and as a palliative therapy for those whose cancer has metastasized.
There are a variety of drugs that are administered intravenously in patients whose cancers have metastasized beyond local lymph nodes and the pelvic area. Some chemotherapies are combined with radiation treatments.
The goal of surgery is to remove the cancer and the threat it poses. In the instance of small, well-defined tumors that are confined to the prepuce, only the tumor and a little extra tissue are removed. A technique called microsurgery in which the surgeon uses a microscope to distinguish normal cells from malignant cells at the edge of the incision can minimize the amount of tissue being removed adjacent to the tumor. Laser surgery has also been used in these cases.
More adjacent tissue is removed when the tumors are larger than 1.5 cm, a little over half an inch. Studies have shown that when only the tumors and minimal amounts of adjacent tissue are removed, up to half of the cancers recur. When the cancer involves a substantial portion of the head of the penis and has started down the shaft, a partial amputation is recommended.
Removal of any less substantially raises the risk of recurrence and a second operation. Penectomy (amputation) and radical penectomy (amputation plus removal of lymph nodes in the groin) are the preferred surgeries when the cancer shows evidence of extensive spread.
The sooner penile cancer is detected, the greater the chances of beneficial therapeutic outcomes. Any suspicious discoloration, bump or ulcer on the penis should be called to the attention of a doctor.