PENILE CANCER DEFINITION
Penile cancer is uncommon, but, when it is diagnosed, it is psychologically devastating to the patient and often presents a challenge to the urologist. Benign, premalignant, and malignant conditions must be differentiated. Penile squamous cell carcinoma (see image below), the most common penile malignancy, behaves similarly to squamous cell carcinoma in other parts of the skin. Metastasis, which occurs with this type of carcinoma when the diagnosis or treatment is delayed, is usually lethal. This is a slow-growing cancer in its early stages, and because it seldom interferes with voiding or erectile function, patients do not complain until pain or a discharge from the cancer occurs. By this time, the cancer has usually progressed from being superficial to invasive.
PENILE CANCER CAUSES
Human papilloma virus (HPV)
HPV is a common infection and is passed from one person to another by sexual contact. Around 8 out of 10 people (80%) in the UK will be infected with the HPV virus at some time during their lifetime. For most people the virus causes no harm and goes away without treatment. But men with human papilloma virus have an increased risk of developing cancer of the penis. A number of research studies have tried to establish the link between penile cancer and HPV. These studies show that the number of men with penile cancer who have evidence of HPV infection is around 5 out of 10 (47%). HPV also increases the risk of cervical, anal, vulval and vaginal cancers.
HPV is commonly called the ‘wart virus’ because some types cause genital warts. There are over 100 types of HPV and each one has a number. The main types of HPV found in men with penile cancer are HPV 16 and 18, although other types may also be related too. HPV 16 and 18 do not usually cause genital warts but there is evidence that men with a history of genital warts have an increased risk of penile cancer.
In a Danish study, men who had never used condoms had more than double the risk of penile cancer compared to men who had used condoms. This may be because condoms reduce the risk of HPV infection. Men who have two or more sexual partners before the age of 20 have a 4 to 5 increased risk of penile cancer. This may also be due to HPV infection.
PENILE CANCER PATHOPHYSIOLOGY
Penile cancers usually begin as small lesions on the glans or prepuce. They range from white-grey, irregular exophytic to reddish flat and ulcerated endophytic masses. They gradually grow laterally along the surface and can cover the entire glans and prepuce before invading the corpora and shaft of the penis. The more extensive the lesion, the greater the possibility of local invasion and nodal metastasis. Penile cancers may be papillary and exophytic or flat and ulcerative. Untreated, penile autoamputation can occur.
The growth rates of the papillary and ulcerative lesions are similar, but the flat ulcerative lesions tend to metastasize to the lymph nodes earlier and are therefore associated with a lower 5-year survival rate. Cancers larger than 5 cm and those involving more than 75% of the shaft are associated with a high prevalence of nodal metastases and a lower survival rate, but a consistent relationship among the size of the cancer, the presence of inguinal node metastases, and survival has not been identified.
The Buck fascia, which surrounds the corpora, acts as a temporary barrier. Eventually, the cancer penetrates the Buck fascia and the tunica albuginea, where the cancer has access to the vasculature and from which systemic spread is possible.
Metastasis to the femoral and inguinal lymph nodes is the earliest path for tumor dissemination. The lymphatics of the prepuce join with those from the shaft. These drain into the superficial inguinal nodes. Because of lymphatic crossover, cancer cells have access to lymph nodes in both inguinal areas.
The lymphatics of the glans follow a different path and join those draining the corpora. A circular band of lymphatics that drains to the superficial nodes is located at the base of the penis and can extend to both the superficial and deep pelvic lymph nodes.
The superficial inguinal nodes drain to the deep inguinal nodes, which are beneath the fascia lata. From here, drainage is to the pelvic nodes. Multiple cross connections exist at all levels, permitting bilateral penile lymphatic drainage.
Untreated metastatic enlargement of the regional nodes leads to skin necrosis, chronic infection, and, eventually, death from sepsis or hemorrhage secondary to erosion into the femoral vessels. Clinically apparent distant metastases to the lung, liver, bone, or brain are unusual until late in the disease course, often after the primary disease has been treated. Distant metastases are usually associated with regional node involvement.
Microscopically, the tumors vary from well-differentiated keratinizing tumors to solid anaplastic carcinomas with scant keratinization. Most tumors are highly keratinized and are of moderate differentiation. Poorly differentiated carcinomas have variable amounts of spindle cell, giant cell, solid, acantholytic, clear cell, small cell, warty, basaloid, or glandular components.
Penile carcinoma follows a relentless and progressive course that proves to be fatal in most untreated patients within 2 years. The typical SCC has a recurrence rate of 28% and lymph node metastases are found in 28-39% depending upon the extent and grade of the tumor. The mortality rate is 20-38% with a 10-year survival rate of 78%. Spontaneous remission has not been reported.
PENILE CANCER 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.
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 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.
PENILE CANCER DIAGNOSIS
Visiting your GP
If you suspect you might have cancer of the penis, the first doctor you’re likely to see is your GP. Your GP will ask you
What symptoms you are having
When you get your symptoms
Whether anything you do makes your symptoms better or worse
Your doctor will also examine you and ask questions about your general health. After your examination, your doctor may refer you to hospital for tests and X-rays, or may ask you to see a specialist. This is usually a urologist, who is a doctor specialising in diseases that affect the urinary system and genital organs.
At the hospital
The specialist will ask you about your medical history and any symptoms that you have. They will also check you over, including examining the lymph nodes (glands) in your groin to see if there are signs of any cancer spread. If your lymph nodes contain cancer cells, they may be larger than normal.
Your specialist might also arrange some tests. These can include blood tests and a biopsy.
You might have a full blood count to check the number of cells in your blood. It also gives an idea about your general health too. You will also have blood tests to check if your liver and kidneys are working normally.
Having a biopsy
Your doctor may want you to have a biopsy of the abnormal area on your penis. You usually have an incisional or excisional biopsy.
An incisional biopsy means using a surgical knife (scalpel) to remove a small piece of the abnormal area. An excisional biopsy is the same, but the doctor removes the whole of the abnormal area. The sample is sent to a laboratory and a specialist doctor called a pathologist, examines it under a microscope. The pathologist can see if the sample contains areas of cancer.
You will usually have your biopsy under anaesthetic, which might be a local or general anaesthetic. If you have a general anaesthetic, you may need to stay in hospital overnight. After these types of biopsies, you will need to have some stitches put in where the skin has been cut. The stitches will stay in for about a week. You may have to go back to the hospital to have them removed. Or they may be dissolvable stitches.
If the lymph nodes in your groin are larger than normal, your doctor may take a sample of fluid to send to the lab. This is to check if there are any cancer cells. It is called a fine needle aspiration(FNA). There is more about this on the page about further tests for penile cancer.
PENILE CANCER TREATMENT
There are different types of treatment for patients with penilecancer.
Different types of treatments are available for patients with penilecancer. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patientswithcancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Three types of standard treatment are used:
Surgery is the most common treatment for all stages of penile cancer. A doctor may remove the cancer using one of the following operations:
Mohs surgery.A surgical procedure to remove a visible lesion on the skin in several steps. First, a thin layer of cancerous tissue is removed. Then, a second thin layer of tissue is removed and viewed under a microscope to check for cancer cells. More layers are removed one at a time until the tissue viewed under a microscope shows no remaining cancer. This type of surgery is used to remove as little normal tissue as possible.
Laser surgery: A surgical procedure that uses a laser beam (a narrow beam of intense light) as a knife to make bloodless cuts in tissue or to remove a surface lesion such as a tumor.
Cryosurgery: A treatment that uses an instrument to freeze and destroy abnormal tissue. This type of treatment is also called cryotherapy.
Circumcision: Surgery to remove part or all of the foreskin of thepenis.
Wide local excision: Surgery to remove only the cancer and some normal tissue around it.
Amputation of the penis: Surgery to remove part or all of the penis. If part of the penis is removed, it is a partial penectomy. If all of the penis is removed, it is a total penectomy.