CRPC is defined according to the Prostate Cancer Clinical Trials Working Group 2 as progression of prostate cancer despite castrate levels (<1.7 ng/ ml) of testosterone. Progression may be biochemical (three consecutive prostate specific antigen (PSA) rises >2 ng/ ml above nadir, minimum 1 week apart) or radiological or symptomatic.
- 10–20% of prostate cancer patients develop CRPC within approximately 5 years of follow-up
- 84% of patients have metastases present at the time of CRPC diagnosis
- In those without metastases at diagnosis, 33% of patients with CRPC develop metastases within 2 years of their diagnosis
- The median age of men with CRPC is in the seventies
Symptoms
Not everyone experiences symptoms of prostate cancer. Many times, signs of prostate cancer are first detected by a doctor during a routine check-up.
Some men, however, will experience changes in urinary or sexual function that might indicate the presence of prostate cancer. These symptoms include:
- A need to urinate frequently, especially at night
- Difficulty starting urination or holding back urine
- Weak or interrupted flow of urine
- Painful or burning urination
- Difficulty in having an erection
- Painful ejaculation
- Blood in urine or semen
- Frequent pain or stiffness in the lower back, hips, or upper thighs
Other conditions may cause the same symptoms. As men age, the prostate may get bigger and block the urethra or bladder. This may cause trouble urinating or sexual problems. The condition is called benign prostatic hyperplasia (BPH), and although it is not cancer, surgery may be needed. The symptoms of benign prostatic hyperplasia or of other problems in the prostate may be like symptoms of prostate cancer.
Investigations
- Digital Rectal Examination (DRE): The DRE involves the doctor inserting a gloved finger in the anus, where it is possible to feel part of the surface of the prostate. Most prostate cancers are located in the peripheral zone of the prostate and may be detected by DRE when the volume is about 0.2 mL or larger. In about 18% of all patients, PCa is detected by a suspect DRE alone, irrespective of the PSA level.
- PSA blood test (PSA): The PSA blood test looks for the presence of a protein in the blood that is produced specifically by prostate cells. The use of PSA as a serum marker has revolutionized the diagnosis of PCa. Serum levels may be elevated in the presence of benign prostatic hypertrophy (BPH), prostatitis and other non-malignant conditions. The level of PSA as an independent variable is a better predictor of cancer than suspicious findings on DRE or transrectal ultrasound (TRUS) .The level of PSA is a continuous parameter: the higher the value, the more likely the existence of PCa.
- Transrectal ultrasound : A procedure in which a probe that is about the size of a finger is inserted into the rectum to check the prostate. The probe is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. Transrectal ultrasound may be used during a biopsy procedure.
- Transrectal magnetic resonance imaging (MRI): A procedure that uses a strong magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. A probe that gives off radio waves is inserted into the rectum near the prostate. This helps the MRI machine make clearer pictures of the prostate and nearby tissue. A transrectal MRI is done to find out if the cancer has spread outside the prostate into nearby tissues. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist. The pathologist will check the tissue sample to see if there are cancer cells and find out the Gleason score. The Gleason score ranges from 2-10 and describes how likely it is that a tumor will spread. The lower the number, the less likely the tumor is to spread.
- A transrectal biopsy is used to diagnose prostate cancer. A transrectal biopsy is the removal of tissue from the prostate by inserting a thin needle through the rectum and into the prostate. This procedure is usually done using transrectal ultrasound to help guide where samples of tissue are taken from. A pathologist views the tissue under a microscope to look for cancer cells.
