Prostate Cancer

Description

The prostate is a small organ located below the bladder and in front of the rectum. Its main function is the excretion of a fluid that adds bulk to semen and increases sperm mobility. Most men will die with prostate cancer rather than die from the disease itself. Prostate cancer is the most common cancer in men and the second most common cancerous disease to cause death in men.

Causes

The cause of prostate cancer is not known but can be attributed to the presence of certain risk factors. Age is known to be a risk factor, with 75% of cases occurring in the over 65 year old age group. The common occurrence of prostate cancer in families suggests a genetic link. This is thought to be a combination of genetic susceptibility, common environmental factors in families, and largely chance – as the prevalence of the disease is so high in older males. Ethnicity is another known risk factor. Asia has the lowest incidence of disease; North America and Scandinavia have the highest.

Treatment

The approach to treatment varies depending on the severity of the prostate cancer and patient life expectancy.

Active Monitoring or Watchful Waiting

Disease progression is observed and continuously monitored without any active treatment. Although this may seem an unusual manner to manage a cancerous disease, prostate cancer has a history of being a slow progressing cancer, mainly presenting in elderly patients. The aim is to weigh treatment options by balancing the speed of tumor growth with the person’s age and life expectancy.

Surgery

This is considered for younger men with a longer life expectancy. Surgery is typically used to treat prostate cancer that is confined to one area (localized). The prostate, small tubal glands (seminal vesicles), and a part of the bladder neck are removed. The procedure has high cure rates, although there is the risk of developing post-operative side effects such as impotence and urinary incontinence. Another surgical procedure, cryotherapy, involves inserting rods into the prostate and alternating between freezing and reheating the rods. This change in temperature causes damage to the cancer cells.

Radiation Therapy

Ionizing radiation is delivered to the cancerous prostate causing damage to the DNA make-up of the cancerous cells. Radiation therapy is useful when surgery is unsuitable and when the cancer is confined to the prostate. Radiation can be delivered via an external beam. Associated side effects of external beam radiation are erectile dysfunction, incontinence, fatigue, and damage to the bladder.

Intensity modulated radiation therapy (IMRT) can target the cancerous cells more accurately than standard external beam radiation. Radiation doses can be altered during treatment to change the intensity of the dose being delivered to the cancer cells.

Proton therapy has gained popularity for its ability to deliver precise radiation to the cancerous cells. Its typical use is on localized and isolated tumors, killing the cancerous cells with high intensity proton beams before it has the chance to spread to other tissues in the body.

With brachytherapy, the radioactive source is planted directly into the tumor and emits radiation over a period of time. Brachytherapy has a lower risk of developing erectile dysfunction and incontinence, yet the prevalence of other side effects, such as urinary dysfunction and rectal bleeding, is higher.

Hormone Therapy

This treatment is used in combination with surgery or radiation therapy as a curative procedure or to manage the cancer when it spreads beyond the prostate to the lymph nodes. Because testosterone is crucial for prostate tumor growth, hormone therapy aims to reduce testosterone production and action. A number of different hormonal agents can be used such as estrogens, progesterone, and anti-androgens.