Penis cancer is a type of cancer that affects the penile tissues. The American Cancer Society estimates that cancer of the penis (penile cancer) will be diagnosed in 1,570 men in the United States in 2013, and that about 310 men will die of the disease. Although cancer of the penis is uncommon in North America and Europe (accounting for less than 1% of cancers in men in the United States), it makes up 10% of cancer in men in some parts of Asia, Africa, and South America.
What is penis cancer?
The penis consists of several different types of cells, and each type is capable of becoming cancerous. However, about 95% of penis cancer develops in the flat skin cells called squamous cells. The squamous cells are found mainly on the foreskin (in uncircumcised men) or on the glans (tip of the penis). Because these tumors typically grow slowly, they can be identified at an early stage and usually can be cured.
Squamous cell cancer of the penis can be further classified as:
- Verrucous carcinoma, in which the cancer resembles a large benign genital wart. This type of cancer of the penis grows slowly but can become very large and invade the surrounding tissue.
- Carcinoma in situ, which is the earliest stage of squamous cell cancer of the penis. At this stage, the cancer cells are located in the top layers of the skin only.
Melanoma is a type of skin cancer that originates in cells called melanocytes. This type of penis cancer tends to grow and spread rapidly and is rare. In fact, less than 2% of penile cancers are melanomas.
Basal cell cancer of the penis also is rare (less than 2% of penis cancers). This type of penile cancer grows slowly and rarely spreads to other parts of the body. Yet an even rarer type of penis cancer is adenocarcinoma, and it can develop from sweat glands in the skin of the penis.
Causes and risk factors for penis cancer
Experts do not know the exact cause of penis cancer. However, they have identified some risk factors for the disease.
- Not being circumcised. Circumcision is the partial or complete removal of the foreskin of the penis, and the procedure appears to protect against penile cancer if it is performed shortly after birth. One reason is that men who are circumcised cannot develop phimosis and cannot accumulate smegma (see below). In addition, circumcised men are less likely to get and remain infected with human papilloma virus (HPV), another risk factor for cancer of the penis.
- Phimosis. Men who are not circumcised may develop phimosis, in which the foreskin becomes tight and difficult to retract. Penile cancer is more common in men with phimosis. To help prevent phimosis, uncircumcised men should retract the foreskin when washing the penis.
- Smegma. This is a cheese-like, odorous substance that accumulates under the foreskin of an uncircumcised penis and may increase the risk of penis cancer.
- Poor hygiene. Good genital hygiene is important in preventing penile cancer. Uncircumcised men need to retract the foreskin and clean the entire penis. If the foreskin is difficult to retract, a cream can be prescribed for application to the penis. If this does not work, a physician can do a procedure called a dorsal slit to make retraction easier.
- History of genital warts or HPV. Men can have HPV for years without symptoms (e.g., genital warts).
- Having numerous sexual partners
- Age older than 60
Penis cancer symptoms
Cancer of the penis is associated with only a few signs and symptoms. They include sores, redness, irritation, or a lump on the penis, and/or bleeding or discharge from the penis. You should consult your healthcare provider if you notice any of these penis cancer symptoms or signs.
Penis cancer diagnosis
Cancer of the penis is usually diagnosed using a physical exam, including checking for penis cancer symptoms and signs of disease such as lumps and lesions, and taking a history of the patient’s habits and illnesses. A biopsy can be ordered to identify signs of cancer.
Once penis cancer has been diagnosed, tests are done to discover if the cancer has spread within the penis or to other parts of the body. This process is called staging, and knowing the stage of penile cancer is important so the doctor can determine the best treatment. To stage cancer of the penis, a doctor may order one or more of the following tests:
- CT (computed tomography) scan. A CT scan uses x-rays to get detailed images of inside the body. The doctor may order a dye be injected or swallowed to help visualize the area more clearly.
- Magnetic resonance imaging (MRI). This procedure uses radio waves, a magnet, and a computer to make a series of images. A substance called gadolinium is injected into a vein, and it gathers around cancer cells, which helps clinicians better visualize the affected area.
- Ultrasound. The use of sound waves, which bounce off internal tissues and organs, make echoes that form an image of body tissues.
Staging penis cancer
The following stages are used to categorize cancer of the penis. The treatments associated with each stage are those recommended by the National Cancer Institute, and the treatments are explained in the section below, “Penis Cancer Treatment.”
- Stage 0: Also known as carcinoma in situ, this stage involves abnormal cells located on the surface of the skin of the penis. These abnormal cells may become cancerous. Treatments may include topical chemotherapy, Mohs surgery, cryosurgery, and laser surgery.
- Stage 1: The cancer has developed and spread to the connective tissue just beneath the skin of the penis. Treatments may include wide local excision or circumcision (if the cancer affects the foreskin only), partial or total penectomy, radiation therapy (external or brachytherapy), Mohs microsurgery, or laser therapy.
- Stage 2: At this stage, the cancer has spread to both the connective tissue under the skin and to one lymph node in the groin; or to the spongy tissue in the penis (the erectile tissue) as well as to one lymph node in the groin. Treatment may include penectomy (partial or total), radiation therapy (external or brachytherapy) followed by surgery, sentinel lymph node biopsy followed by surgery, or laser therapy.
- Stage 3: This stage is characterized by cancer that has affected the connective tissue or erectile tissue and more than one lymph node; or by cancer that has affected the urethra or prostate, and may have spread to one or more lymph nodes. Treatment may include penectomy with or without radiation therapy, radiation therapy, sentinel lymph node biopsy followed by surgery, or chemotherapy before or after surgery.
- Stage 4: This is the most serious stage of cancer of the penis and is characterized by cancer that has spread to tissues near the penis as well as to lymph nodes in the groin or pelvis; or cancer that is anywhere in or near the penis and has spread to one or more lymph nodes deep in the groin or pelvis; or cancer that has spread to other parts of the body. Treatment options include wide local excision and removal of lymph nodes in the groin, radiation therapy, and chemotherapy before or after surgery.
Penis cancer treatment
Currently available treatment for penis cancer falls into three categories: radiation therapy, chemotherapy, and surgery. The most common treatment for any stage of penile cancer is surgery, which may include any one of the following techniques:
- Mohs microsurgery. In this procedure, the tumor is sliced from the skin in thin layers. During the procedure, each layer of tumor that is removed is examined under a microscope to check for cancer cells. Once no more cancer cells are seen in a tissue sample, the surgeon stops removing additional tissue.
- Laser surgery. This procedure involves using a narrow beam of light (laser) to make bloodless cuts in the penile tissue or to remove a surface tumor.
- Cryosurgery (cryotherapy). The surgeon uses an instrument that delivers extreme cold to the tumor to freeze and destroy it.
- Circumcision. This removes all or part of the foreskin of the penis.
- Wide local excision. This surgical procedure removes the tumor and some of the healthy tissue that surrounds it.
- Penectomy. A penectomy is removal of either part or all of the penis. When a partial penectomy is performed, typically only the tip or glans of the penis is removed. A total (radical) penectomy involves removal of parts of the penis that extend into the pelvic area. The surgeon must also create a new opening for the urethra for urination.
- Sentinal node biopsy followed by surgery. The sentinel node is the first lymph node a cancer is likely to spread to from a tumor. To determine if the cancer has spread, a radioactive substance and/or dye is injected near the tumor, and the first lymph node to receive the substance or dye is removed. A pathologist examines the lymph node and if no cancer cells are present, no more lymph nodes need to be removed, and the surgeon can then proceed with surgery to remove the cancer. If cancer cells are present, more lymph nodes can be removed.
Some men also undergo chemotherapy or radiation therapy after surgery for cancer of the penis to help ensure all the cancer cells are eliminated. Radiation therapy or chemotherapy may also be used instead of surgery depending on the cancer stage.
- Radiation therapy involves the use of high-energy x-rays or other types of radiation to kill cancer cells or prevent them from growing and spreading. Two types of radiation therapy can be used: external radiation therapy, which delivers radiation from a machine outside the body; and brachytherapy, which uses implanted radioactive seeds or needles in or near the cancer to deliver radiation.
- Chemotherapy is the use of oral, topical, or injected drugs to stop the growth or spread of cancer. Stage 0 cancer of the penis can be treated with topical chemotherapy while other stages involve oral or injected medications.
Cancer of the penis that comes back after treatment (recurrent penile cancer) can be treated with penectomy, chemotherapy, or radiation therapy. Men with recurrent cancer of the penis may also discuss with their physician the possibility of enrolling in a clinical trial. New treatments that are being tested in clinical trials include biologic therapy (also known as immunotherapy), in which patients are given substances to enhance, direct, or restore the body’s natural defenses against cancer; or radiosensitizers, which are drugs that make tumor cells more sensitive to radiation treatment.