Prostate cancer

The prostate is a gland in the male reproductive system that surrounds the opening of the bladder and creates the fluid component of semen. Prostate cancer occurs when abnormal cells grow uncontrollably in the prostate tissue. These abnormal cells can grow to form a cancer, which can then spread to other parts of the body.

In Australia, prostate cancer is the second-most common cancer in men, after skin cancer. It mainly affects men over 65 years of age.

Causes

The cause of prostate cancer, as with other cancers, is due to damage to cellular DNA. This damage results in uncontrolled cell growth, which leads to a cancer forming that can invade nearby tissue, or break off and spread through the bloodstream or lymphatic system to other areas of the body. The exact cause of the cellular damage is unknown.

Contrary to common belief, benign prostatic hyperplasia is not a risk factor for prostate cancer.

Types

Prostate cancer is categorised according to the type of cell they arise from.

Adenocarcinoma

Adenocarcinoma originates in glandular cells, which help produce the seminal fluid that forms part of the male ejaculate (semen). This is the most common form of prostate cancer.

Transitional cell carcinoma

Transitional cell carcinoma is the most common non-adenocarcinoma. It starts in the cells lining the urethra, the tube that carries urine from the bladder to outside the body.

Small cell carcinoma

Small cell carcinoma is a rare and aggressive form of prostate cancer that originates in small round neuroendocrine cells of the prostate. It is difficult to detect because it usually does not result in increased levels of prostate-specific antigen in the blood.

Sarcoma

Sarcoma is a rare cancer that originates in muscle cells near the prostate. It is usually a side effect of radiotherapy used to treat prostate cancer.

Stages

Treatment outcomes can vary greatly, depending on the stage of cancer. Cancer is staged according to its size and location, and whether it has spread to lymph nodes or organs throughout the body.

Stages of a prostate cancer. 

Signs and symptoms

In the early stages, prostate cancer often has no symptoms. When they do occur, signs and symptoms of prostate cancer are usually non-specific and can also occur with other conditions. They include:

• Frequent and painful urination;
• A weak urine stream;
• Blood in the urine;
• Weight loss;
• Fatigue, and;
• Pain, which can occur during ejaculation.

Methods for diagnosis

Digital rectal exam

A digital rectal exam (DRE) involves a doctor inserting a lubricated, gloved finger into the anus to feel for physical signs such as a hard lump in the prostate. This examination is limited by the fact that only the back of the prostate gland can be checked.

A digital rectal exam. 

Prostate specific antigen

The prostate specific antigen (PSA) is a blood test that measures a protein released by the prostate gland. Generally, the higher the level of PSA, the greater the risk of prostate cancer, but other conditions can also cause increased PSA levels. In some cases, PSA is not elevated even though a cancer is present. Therefore, PSA is not a reliable test on its own to diagnose prostate cancer. It forms a part of the overall information used to diagnose prostate cancer.

PSA can also be used to monitor the success or failure of a treatment.

Transrectal ultrasound

A transrectal ultrasound (TRUS) of the prostate is performed by inserting a small probe into the rectum. It can also be used during a biopsy to guide the needle to the right place.

Types of treatment

Surgery

Radical prostatectomy

Radical prostatectomy is the surgical removal of the prostate and some of the tissues that surround it. This is done in cases where the cancer has not spread beyond the prostate. There is a range of surgical procedures for this operation, and your doctor will advise you of the most suitable one for you.

Pelvic lymphadenectomy

Pelvic lymphadenectomy involves the removal of the lymph nodes in the pelvis. A pathologist will investigate these under a microscope to determine the spread of cancer.

Transurethral resection

A transurethral resection is performed on men who cannot have a radical prostatectomy, to relieve symptoms of prostate cancer. It involves removing a portion of the prostate with a resectoscope, a thin tube with a cutting tool, which is inserted through the urethra.

Orchidectomy

In the past, surgery to remove the testes, known as orchidectomy, was a common treatment for prostate cancer because the testes produce testosterone, which enhances cancer growth. However, hormone therapy has largely replaced this method of treatment.

Additional therapies

Other therapies can be used in addition to surgical treatments, to further improve treatment outcomes. They may be given before surgery (neoadjuvant therapy) and/or after surgery (adjuvant therapy). When given before surgery, they aim to reduce the size, and therefore stage, of the cancer. When given after surgery, they aim to help prevent the cancer returning. These non-surgical treatments include chemotherapy, radiotherapy, hormone therapy or a combination of these.

Occasionally, these therapies may be used if individuals are not suitable for surgical treatment. Often, in these situations, the aim of treatment is to control symptoms, and are not necessarily for cure. The treatment options and aims can differ, based upon the individual, the stage and type of cancer. Your doctor can help explain this information in more detail.

Radiotherapy

Radiotherapy can be applied to the area where the cancer is located, by using focused X-rays. Another form of radiotherapy is brachytherapy. This involves implanting radioactive seeds in the cancer or the nearby area, which deliver cell-destroying radiation directly into the cancer. Radiotherapy can be used alone, or in addition to surgery and/or chemotherapy.

Hormone therapy

Testosterone promotes cancer growth, so hormone therapy is used to reduce this effect. The hormone therapy medications can block testosterone from interacting with cells, or from being produced.

Alternative therapies

Some people diagnosed with cancer seek out complementary and alternative therapies. None of these alternative therapies are proven to cure cancer, but some can help people feel better when used together with conventional medical treatment. It is important to discuss any treatments with your doctor before starting them as they can affect other parts of your treatment.

Potential complications

Treatment side effects

• Nausea, vomiting and fatigue from chemotherapy and radiotherapy;
• Altered bowel habits - constipation or diarrhoea;
• Joint and muscle pain - this may occur after a treatment session and can last a few days;
• Temporary hair loss from the head and body can be caused by some types of chemotherapy. It may grow back after treatment has ended, and;
• Tingling in the hands and feet - some chemotherapy medications can affect the nerves. It is important to tell your doctor if you develop these symptoms.

Erectile dysfunction

Erectile dysfunction can be associated with the surgical removal of the prostate. Treatments are available to help manage this condition.

Urinary problems

An inability to control when one urinates, also known as urinary incontinence, may result from surgery to remove the prostate. However, this side effect is less common in recent years due to new surgical techniques.

Sarcoma

As previously mentioned, in some cases radiotherapy can result in cancer of the muscles in the pelvis, known as sarcoma.

Advanced prostate cancer

Metastasis is when the cancer spreads to other parts of the body through the bloodstream and lymphatic system. The growth of cancer in the organs and other body parts results in a destructive effect on their function. Prostate cancer is particularly known to spread to the bones and this can result in fractures, as cancer growth can weaken bone structure.

Prognosis

The prognosis for prostate cancer varies, depending on the type and stage of cancer. In Australia, the overall five-year survival rate is greater than 92%.

It is important to remember survival rates are only an indication, and are based upon the averages of previously treated patients. It is not an absolute prognosis for an individual. It is often difficult to accurately predict an individual's cure or survival rate. Constant advances in treatment are continually improving these statistics.

Prevention

Due to the fact the exact causes of prostate cancer are unknown, it is difficult to prevent the condition.

Testing for prostate cancer in men without any symptoms is a complex issue. Unlike other cancers, there is insufficient evidence to support the routine screening of men using the PSA test. The benefits of screening are currently outweighed by the risks. However, men who are concerned about prostate cancer, especially those with a family history of the condition, should discuss it with their doctor.