Penile cancer develops in or on the penis. Cancer starts when cells begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas in the body.
Cancers of the penis
Each type of tissue in the penis contains several types of cells. Different types of penile cancer can develop from these cells. The differences are important because they determine the seriousness of the cancer and the type of treatment needed.
Almost all penile cancers start in skin cells of the penis.
Squamous cell carcinoma
About 95% of penile cancers develop from flat skin cells called squamous cells. Squamous cell carcinoma (also known as squamous cell cancer) can develop anywhere on the penis. Most of these cancers occur on the foreskin (in men who have not been circumcised) or on the glans. These tumors tend to grow slowly. If they are found at an early stage, they can usually be cured.
Verrucous carcinoma:This is an uncommon form of squamous cell cancer that can occur in the skin in many areas. A verrucous carcinoma growing on the penis is also known as Buschke-Lowenstein tumor. This cancer looks a lot like a large genital wart. Verrucous carcinomas tend to grow slowly but can sometimes get very large. They can grow deep into surrounding tissue, but they rarely spread to other parts of the body.
Carcinoma in situ (CIS):This is the earliest stage of squamous cell cancer of the penis. In this stage the cancer cells are found only in the top layers of skin. They have not yet grown into the deeper tissues of the penis. Depending on the location of a CIS of the penis, doctors may use other names for the disease. CIS of the glans is sometimes called erythroplasia of Queyrat. CIS on the shaft of the penis (or other parts of the genitals) is called Bowen disease.
Melanoma
Melanoma is a type of skin cancer that starts in melanocytes, the cells that make the brownish color in the skin that helps protect it from the sun. These cancers tend to grow and spread quickly and are more dangerous than the more common types of skin cancer. Melanomas are most often found in sun-exposed skin, but rarely they occur in other areas like the penis. Only a very small portion of penile cancers are melanomas. For more information about melanoma and its treatment, see Melanoma Skin Cancer.
Basal cell carcinoma
Basal cell carcinoma (also known as basal cell cancer) is another type of skin cancer that can develop on the penis. It makes up only a small portion of penile cancers. This type of cancer is slow-growing and rarely spreads to other parts of the body.
Adenocarcinoma (Paget disease of the penis)
This very rare type of penile cancer can develop from sweat glands in the skin of the penis. It can be very hard to tell apart from carcinoma in situ (CIS) of the penis.
Sarcoma
A small number of penile cancers are sarcomas. These cancers develop from blood vessels, smooth muscle, or other connective tissue cells of the penis. For more about this type of cancer
Risk Factors
A risk factor is anything that affects your chance of getting a disease such as cancer. Different cancers have different risk factors. Some cancer risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.
But having a risk factor, or even several, does not mean that you will get the disease. On the other hand, some men who develop penile cancer have no known risk factors.
Scientists have found certain risk factors that make a man more likely to develop penile cancer.
Human papilloma virus (HPV) infection
Human papilloma virus (HPV) is a group of more than 150 related viruses. They are called papilloma viruses because some of them cause growths called papillomas, which are more commonly called warts. Different HPV types cause different types of warts in various parts of the body. Certain HPV types can infect the genital organs and the anal area, causing raised, bumpy warts called condyloma acuminata (or just condylomas).
Other HPV types have been linked with certain cancers. For example, infection with some types of HPV appears to be an important risk factor for penile cancer. HPV is found in about half of all penile cancers.
HPV is passed from one person to another during skin-to-skin contact with an infected area of the body. HPV can be spread during sex – including vaginal, anal, and oral – but sex doesn’t have to occur for the infection to spread. All that is needed is skin-to-skin contact with an area of the body infected with HPV. Infection with HPV can also spread from one part of the body to another. For example, infection may start in the penis and then spread to the anus.
HPV infection is common. Some research has suggested that about half of all men have a genital HPV infection at any point in time. In most men, the body clears the infection on its own. In some, however, the infection does not go away and becomes chronic. Chronic infection, especially with certain HPV types, can eventually cause some types of cancer, including penile cancer. Men who are not circumcised are more likely to get and stay infected with HPV.
Not being circumcised
Circumcision removes all (or part) of the foreskin. This procedure is most often done in infants but it can be done later in life. Men who were circumcised as children have a lower chance of getting penile cancer than those who were not, but the same protective effect is not seen if the foreskin is removed as an adult. Some studies even suggested a higher risk of penile cancer in men who were circumcised as adults.
The reason for the lower risk in circumcised men is not entirely clear, but it may be related to other known risk factors. For example, men who are circumcised can’t develop the condition called phimosis, and don’t accumulate material known as smegma (see next section). Men with smegma or phimosis have an increased risk of penile cancer. The later a man is circumcised, the more likely it is that one of these conditions will occur first. Also, circumcised men are less likely to get and stay infected with the human papilloma virus (HPV), even after accounting for differences in sexual behavior. Again, the later a man is circumcised, the more likely it is that he will be infected with HPV before the procedure.
In weighing the risks and benefits of circumcision, doctors consider the fact that penile cancer is very uncommon in the United States, even among uncircumcised men. Although the American Academy of Pediatrics has stated that the health benefits of circumcision in newborn males outweigh the risks, it also states these benefits are not great enough to recommend that all newborns be routinely circumcised.
In the end, decisions about circumcision are highly personal and often depend more on social and religious factors than on medical evidence.
Phimosis and smegma
Uncircumcised men with certain conditions are at higher risk for penile cancer.
Phimosis
In men who are not circumcised, the foreskin can sometimes become tight and difficult to retract. This condition is known as phimosis. Penile cancer is more common in men with phimosis. The reason for this is not clear, but it might be related to the buildup of smegma.
Smegma
Sometimes secretions can build up underneath an intact foreskin. If the area under the foreskin isn’t cleaned well, these secretions build up enough to become a thick, sometimes smelly substance called smegma. Smegma is more common in men with phimosis, but can occur in anyone with a foreskin, if the foreskin is not retracted regularly to clean the head of the penis.
In the past some experts were concerned that smegma might contain compounds that can cause cancer. Most experts now believe that smegma itself probably doesn’t cause penile cancer, but it can irritate and inflame the penis, which can increase the risk of cancer. It may also make it harder to see very early cancers.
Smoking
Men who smoke are more likely to develop penile cancer. Smokers who have HPV infections have an even higher risk. Smoking exposes your body to many cancer-causing chemicals. These harmful substances are inhaled into the lungs, where they are absorbed into the blood. They can travel in the bloodstream throughout the body to cause cancer in many different areas. Researchers believe that these substances damage genes in cells of the penis, which can lead to penile cancer. Smoking also increases the risk of HPV infection, probably due to its effects on immune function.
UV light treatment of psoriasis
Men who have a skin disease called psoriasis are sometimes treated with drugs called psoralens, followed by exposing the body to an ultraviolet A (UVA) light source. This is known as PUVA therapy. Men who have had this treatment have been found to have a higher rate of penile cancer. Because of this risk, men being treated with PUVA now have their genitals covered during treatment.
Age
The risk of penile cancer goes up with age. The average age of a man when diagnosed is 68, and about 4 out of 5 penile cancers are diagnosed in men over age 55.
AIDS
Men with AIDS have a higher risk of penile cancer. This higher risk seems to be related to their weakened immune system, which is a result of this disease. But it might also be linked to other risk factors that men with HIV (the virus that causes AIDS) are more likely to have. For example, men with HIV are more likely to smoke and to be infected with HPV.
Symptoms
The signs and symptoms below don’t always mean a man has penile cancer. In fact, many of them are more likely to be caused by other conditions. Still, if you have any of these signs or symptoms, see your doctor right away so the cause can be found and treated, if needed. The sooner a diagnosis is made, the sooner you can start treatment and the more effective it is likely to be.
Skin changes
Most often, the first sign of penile cancer is a change in the skin of the penis. This is most likely to be on the glans (tip) of the penis or on the foreskin (in uncircumcised men), but it can also be on the shaft. Possible signs of penile cancer include:
- An area of skin becoming thicker and/or changing color
- A lump on the penis
- An ulcer (sore) that might bleed
- A reddish, velvety rash
- Small, crusty bumps
- Flat, bluish-brown growths
- Smelly discharge (fluid) under the foreskin
Sores or lumps from penile cancer are not usually painful, but they can be in some cases. You should see a doctor if you find any kind of new growth or other abnormality on your penis, even if it is not painful.
Swelling
Swelling at the end of the penis, especially when the foreskin is constricted, is another possible sign of penile cancer.
Lumps under the skin in the groin area
If the cancer spreads from the penis, it most often travels first to lymph nodes in the groin. This can make those lymph nodes swell. Lymph nodes are collections of immune system cells. Normally, they are bean-sized and can barely be felt at all. If they are swollen, the lymph nodes may be felt as lumps under the skin.
But swollen lymph nodes don’t always mean that cancer has spread there. More commonly, lymph nodes swell in response to an infection. The skin in and around a penile cancer can often become infected, which might cause the nearby lymph nodes to swell, even if the cancer hasn’t reached them.
Diagnosis
Medical history and physical exam
Your doctor will need to take a complete medical history to get details about your symptoms and any possible risk factors you have.
Your doctor will also look at your genital area carefully for possible signs of penile cancer or other health problems. Penile lesions usually affect the skin on the penis, so a doctor often can find cancers and other abnormalities by looking closely at the penis. The doctor may look at and feel the lymph nodes in the groin area as well to see if they are swollen.
If symptoms and/or the results of the exam suggest you might have penile cancer, you will need other tests. These might include a biopsy and imaging tests.
Biopsy
A biopsy is needed to diagnose penile cancer. In this procedure, a small piece of tissue from the abnormal area is removed and sent to a lab, where it is looked at under a microscope to see if it contains cancer cells. The results are usually available in a few days, but may take longer in some cases.
The type of biopsy used depends on the nature of the abnormality.
Incisional biopsy
For an incisional biopsy only a part of the abnormal area is removed. This type of biopsy is often done for lesions that are larger, are ulcerated (the top layer of skin is missing or the lesion appears as a sore), or that appear to grow deeply into the penis.
These biopsies are usually done with local anesthesia (numbing medicine) in a doctor’s office, clinic, or outpatient surgical center.
Excisional biopsy
In an excisional biopsy, the entire lesion is removed. This type of biopsy is more often used if the abnormal area is small, such as a nodule (lump) or plaque (raised, flat area). If the abnormal area is only on the foreskin, your doctor might recommend circumcision (removal of the foreskin) as a form of excisional biopsy.
These biopsies are usually done in a hospital or outpatient surgical center. Local anesthesia (numbing medicine) or general anesthesia (where you are asleep) may be used.
Lymph node biopsy
If the cancer has invaded deep within the penis, nearby lymph nodes usually will need to be checked for cancer spread. This is done to help determine the stage (extent) of the cancer after the diagnosis. These lymph nodes can be checked either with fine needle aspiration or with surgery to remove them.
Fine needle aspiration (FNA): For this type of biopsy, the doctor places a thin, hollow needle directly into the lymph node and withdraws cells and a few drops of fluid. Local anesthesia may be injected into the skin over the node to numb the area.
If the enlarged lymph node is deep inside your body and the doctor can’t feel it, imaging methods such as ultrasound or CT scans can be used to guide the needle into the node.
This type of biopsy is often done to see if enlarged lymph nodes contain cancer. It is not used to sample lesions on the penis itself. This procedure can be done in a doctor’s office or clinic.
Surgical biopsy: In some cases, the lymph nodes are not checked with FNA, but instead through surgery to remove one or more lymph nodes. These surgical lymph node biopsies, which include sentinel lymph node biopsy and lymphadenectomy,
Imaging tests
Imaging tests use x-rays, magnetic fields, or sound waves to create pictures of the inside of your body. If the doctor thinks the cancer is advanced or has spread, then one or more of these tests may be ordered to help determine the stage of the cancer.
Computed tomography (CT)
The CT scan uses x-rays to make detailed cross-sectional images of your body. Instead of taking one picture, like a standard x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into images of slices of part of your body.
A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You will need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring while the pictures are being taken
Before the test, you may be asked to drink 1 to 2 pints of a liquid called oral contrast and/or get an intravenous (IV) injection of a contrast dye that helps better outline abnormal areas in the body. The injection can cause some flushing (redness and warm feeling). A few people are allergic to the dye and get hives or, rarely, more serious reactions like trouble breathing and low blood pressure. Medicine can be given to help prevent and treat allergic reactions. Be sure to tell the doctor if you have any allergies (especially to iodine or shellfish) or if you have ever had a reaction to any contrast material used for x-rays.
CT-guided needle biopsy: CT scans can be used to guide a biopsy needle into an enlarged lymph node or other area of possible cancer spread. For this procedure, you remain on the CT scanning table while a doctor moves a biopsy needle through the skin and toward the mass. CT scans are repeated until the needle is within the mass. A biopsy sample is then removed and sent to be looked at under a microscope.
Magnetic resonance imaging (MRI)
Like CT scans, MRI scans provide detailed images of soft tissues in the body. But MRI scans use radio waves and strong magnets instead of x-rays to create the images. A contrast material might be injected just as with CT scans, but this is used less often.
When MRI scans are used to look at penile tumors, the pictures are better if the penis is erect. The doctor can inject a substance called prostaglandin into the penis to make it erect.
MRI scans take longer than CT scans – often up to an hour – and are a little more uncomfortable. You may have to lie on a table that slides inside a narrow tube, which can upset people with a fear of enclosed spaces. Special, more open MRI machines can sometimes help with this if needed, but the drawback is that the images may not be as clear. The MRI machine makes buzzing and clicking noises that you may find disturbing. Some places will provide earplugs to help block this noise out. MRIs are not safe for people with pacemakers or certain implants containing metals that are strongly attracted to magnets.
Ultrasound
This test uses sound waves to make pictures of internal organs or masses. It can be useful for determining how deeply the cancer has penetrated into the penis. It can also show enlarged lymph nodes in the groin.
For this test, a small microphone-like instrument called a transducer gives off sound waves and picks up the echoes as they bounce off body tissues. The echoes are converted by a computer into an image on a computer screen.
This test is painless and does not expose you to radiation. For most ultrasound exams, the skin is first lubricated with gel. Then a technician moves the transducer over the skin above the part of your body being examined.