Prostate cancer is a disease which usually only affects men over the age of 45. It is very uncommon before this age. The average age at disease discovery is around 70. Asians are affected the least compared to the rest of the world's population. It must be added, however, that some affected people die of other causes before the diagnosis of prostate cancer is ever made. Thus, it is estimated that the disease actually affects many more people than indicated by current statistics.
Risk factors for prostate cancer development
There are many risk factors for cancer development, the main one being the man's age. In addition, the mentioned racial differences also exist. The next important factor is nutrition; it is believed that men who consume great quantities of animal fat are more likely affected by the disease than those who consume many fruits and vegetables.
A further important factor in cancer development is familial predisposition and genetics. Family history of cancer doubles the risk of cancer appearing also in another family member. Changes in the genes on chromosomes 8 and 17 play an important role in cancer development because their protein products are linked to the prostate in various ways.
Prostate cancer can present itself with different features. It is not unusual for the patient to be entirely symptom-free. If symptoms are present, they are most commonly associated with difficulties in urination including difficulty starting and maintaining a steady stream of urine, frequent or painful urination or even complete urine retention. Other problems are also possible such as erectile difficulties, blood in the urine and seminal fluid, or pain in other body parts such as the lower back, hips or thighs.
However, the mentioned symptoms are most often due to a less dangerous disease called the benign prostatic hyperplasia which is characterised by non-cancerous prostate enlargement.
As usual, a detailed physical exam is a prerequisite for a good diagnosis. The physician performs a rectal exam and draws blood for lab tests. Among the laboratory parameters, the best disease indicator is an increased concentration of the so called prostate specific antigen (PSA) which is a substance secreted by the prostate into the seminal fluid and other bodily fluids such as blood. If PSA is drastically increased, it is most often an indication that prostate cancer is present.
In addition to the physical exam and basic lab tests, imaging studies are also available to confirm the diagnosis of prostate cancer. They include a transrectal ultrasound with a transducer placed in the rectum to make images of the prostate, and cystoscopy which includes inserting a tube into the urethra through the opening at the end of the penis and endoscopically visualising the urethra and urinary bladder. To confirm the diagnosis, a biopsy must be performed. It involves removing a tissue sample to check for the presence of cancer tissue and its spread within the prostate.
Prevention plays a central role in prostate cancer for cancer detection in early stages is the only way to a complete cure. It is recommended that men after the age of 45 undergo annual screening.
Three exams are used in prostate cancer screening:
Determining the serum prostate specific antigen (PSA). Given that PSA may be increased in other situations as well (e.g. inflammation and benign prostate hypertrophy), the increase does not necessarily mean cancer.
Digital rectal exam or palpation of the prostate through the rectum still represents the main exam in prostate cancer screening. It can be used to determine the surface changes of the organ, its size, sensibility, borders, symmetry, etc. This method is very subjective and can miss the non-palpable cancer forms; thus, it must always be employed in conjunction with other exams.
Transrectal ultrasound uses a probe that is inserted into the rectum; it enables the physician to obtain an exact view of the organ as well as to perform a prostate biopsy, where a tissue sample is removed and sent for histological examination.
When the cancer is still limited to the prostate itself, the physician may choose from the following therapy options:
Hormonal therapy – the male sex hormone testosterone stimulates the growth of cancerous prostate cells. Anti-androgens are hormonal drugs that prevent the effect of testosterone. This is not a curative therapy; it only slows down disease progression.
Irradiation represents an important part of therapy. Depending on the therapy's goal (i.e. curative or palliative) and cancer stage, either the radical external beam radiotherapy or the interstitial radiotherapy can be used. In the former, the aim is to "target" the affected structures precisely and cause as little damage to the adjacent healthy tissue as possible, while in the latter a radioactive implant is placed into the prostate itself in order to exert its effect on the malignant tumour for 24 hours. These methods are used in patients with early forms of disease. Radiotherapy may also be used as a co-therapy therapy following surgical procedures in which the entire tumour has not been surgically removed, or for palliative reasons to ease the problems (i.e. difficulties with urination, urine retention, recurrent urinary tract infections, etc.) and improve the patient's quality of life.
Radical prostatectomy is a surgical procedure whereby the entire prostate is surgically removed. Its application is limited to cases where the cancer is limited to the prostate itself. Over the years, the surgical technique has improved a lot. However, disturbing side effects may still appear such as urine incontinence that may remain present for weeks or months following surgery. Most men, however, regain continence with time. Furthermore, a possible consequence of surgery is impotence, although the surgery aims at maintaining the nerves responsible for erection. Lately, the endoscopic prostate resection has gained in popularity.