Prostate cancer is the third most common form of cancer after skin cancer and lung cancer; it is the most common cancer diagnosed in men. The incidence of prostate cancer in men is approximately equal to the incidence of breast cancer in women. In 2012 there were 241,740 new cases of prostate cancer reported which resulted in 28,170 deaths, according to the American Cancer Society. Prostate cancer generally appears relatively late in life. The median age at diagnosis for cancer of the prostate was 66 years of age, with over 68% of the cases being diagnosed between the ages of 55 and 74.
What is the prostate?
The prostate is a gland that encircles the urethra just below the bladder. Within the prostate, the duct of the seminal vesicles that carry sperm from the testicles merges with the urethra which serves as a common duct to carry urine and semen through the penis. The main function of the prostate is to store and secrete a fluid that comprises approximately one quarter of the volume of semen. The fluid is slightly alkaline and prolongs the lifespan of sperm by neutralizing the acidity of the vaginal tract.
Symptoms of prostate cancer
The early stages of prostate cancer usually have no symptoms, but as the prostate enlarges, more advanced forms of prostate cancer may have symptoms such as:
There is no known strategy for preventing prostate cancer, but the risk may be reduced by adopting habits for healthy living such as avoiding smoking, avoiding obesity, eating a healthy diet and exercising. Increasing the amount of fruits and vegetables in the diet and decreasing high-fat foods are thought to reduce the risk of prostate cancer. These practices are not specific for prostate cancer, but they reduce the overall chance of getting cancer. There is some evidence that the phytonutrients and polyphenols in pomegranate fruit juice and green tea can reduce Prostate-Specific Antigen (PSA) levels and prevent prostate cancer.[3,4]
Screening and Diagnosis of prostate cancer
An enlarged prostate gland may be indicative of cancer. A doctor may perform a Digital Rectal Exam by inserting a gloved finger into the rectum to palpate the prostate gland. Any abnormalities in the size, texture or shape of the gland may indicate that additional tests are needed.
A cancerous prostate gland may produce an increased level of Prostate-Specific Antigen (PSA). This can be detected by analyzing a blood sample. An increased PSA level may indicate an infection or enlargement of the prostate. An ultrasound test can be used to further evaluate the prostate using sound waves to make a picture of the prostate gland. The confirmation of cancer requires taking a tissue sample of the prostate with a needle and then doing a microscopic examination for cancerous cells.
To obtain prostate tissue for cancer testing, between 12 and 24 needles are inserted into different areas of the gland. The probing has been guided by ultrasound since the 1980s, but the ultrasound images are not clear enough to distinguish cancerous from normal prostate tissue. An MRI scan is better than ultrasound for identifying suspicious areas in the prostate gland, but it is not possible to diagnose cancer from an MRI image. Recently, researchers have developed software that merges those detailed MRI scans with live, real-time ultrasound images of the prostate. A patient first undergoes the MRI scan. A radiologist reviews it and marks suspicious areas. Later, in an outpatient setting, an ultrasound probe in the patient's rectum can be used to guide biopsy needles using the fused 3-D ultrasound/MRI view.
Treatments and side effects
Prostate cancer may be treated with surgery, chemotherapy, cryotherapy, hormonal therapy or radiation. The treatment will depend on the aggressiveness of the cancer and whether it has spread to other parts of the body. Surgery has the risk of damaging the nerves in the surrounding tissue and causing impotence, incontinence or reduced penile size. Since many prostate cancers develop very slowly, some doctors have adopted the practice of "watchful waiting", usually without repeated biopsies. The patient is not treated unless the PSA levels indicate an increase in the aggressiveness of the cancer. This protocol was developed after observing that patients with prostate cancer usually died of unrelated causes and that patients who underwent prostate therapy usually regretted the consequences of their surgeries or other treatments.