PROSTATE CANCER SCREENING – THE KNOTTY ISSUES.


I am a male retiree. I have noticed that there is public screening against breast cancer and cervical cancer by many health facilities and organizations in the country. But I do not see the same action being taken against prostate cancer. Why? In responding to this enquiry I have used materials from the National Cancer Document and National Guideline for Cancer Management.

After hepatocellular cancer, prostate cancer is the second leading cause of male cancer deaths. Evidence of early prostate cancer can be found at any adult age but it is more common in men over 60 years of age. When it progresses and becomes more advanced, prostate cancer can kill men of any age.

Blacks have a 60% higher chance of getting prostate cancer than whites due to an unexplained genetic factor. In Africa some of the epidemiological studies have revealed the following incidences of the disease: Ghana about 200 per100, 000 men, Nigeria 127 per100, 000men and Cameroun 130 per 100,000 men.

More than 70% of Ghanaians presenting with prostate cancer do so very late with locally invasive and metastatic disease. The natural history of prostate cancer indicates that most men will die with their prostate cancer than from their prostate cancer because some early prostate cancers may not progress. Prostate cancer, unlike most other cancers, often can have a very long natural history, taking many years to grow and progress.

The controversy in testing large groups of men is that many men with prostate cancer will be identified who may never really need to undergo treatment. Since there currently is no way to determine which early cancers will progress, curative treatment (in the form of surgery or radiation) may be used on patients who might actually never need this intervention. The problem is that any form of curative treatment can have significant long-term side effects, impairing quality of life. In addition to the high cost involved for the patient, his family and the health care system.

Even though the Prostate Lung Colorectal and Ovarian (PLCO) trial failed to demonstrate any benefit for screening, the European Randomized Study of Screening for Prostate Cancer (ERSPC) study showed a 31% reduction in the risk of dying of prostate cancer in men actually screened. Screening could lead to over diagnoses and consequent over treatment of majority of prostate cancer that is inactive. It is also true that screening in the fashion reported by ERSPC showed that using PSA range of 3-3.9ng/ml harboured aggressive prostate cancer. These cancers will be missed with the traditional cut off of 4.0ng/ml. Such aggressive prostate cancer tends to be more common in African and African American men.

The reasons for screening in cancers, among others, are to prevent deaths from cancer by reaching diagnosis at an early stage, improve the quality of life, and reduce cost of treatment. In light of the findings of PLCO and ERSPC trials, the National Guideline For Cancer Management (2017) does not recommendpopulation-based PSA screening for prostate cancer because reduction in prostate cancer mortality will be at the expense of over diagnosis and over-treatment.

Individualized screening is therefore suggested taking into account family history, PSA density and velocity.

Risk factors for prostate cancer include age (relatively rare in men below 50 years, incidence increases in men above 60 years), race (high in Africans and men of African descent), family history (men with a first-degree relative affected by prostate cancer have a 2-fold risk, men with a second-degree relative affected by prostate cancer have a 1.7 times risk, men with both first and second degree relatives affected by prostate cancer have an increased relative risk of 8.8). There is evidence to show a link between an increased risk of prostate cancer where there is a family history of breast, ovarian, bladder or kidney cancer.

The tests for detecting prostate cancer are Digital Rectal Exam (DRE), Prostate Specific Antigen (PSA), Transrectal ultrasound (TRUS) and Biopsy.

Digital rectal examination is a simple and easy procedure that can be used to detect prostate cancer. An abnormal DRE needs further evaluation to determine if cancer is present. A normal DRE does not rule out cancer.

Prostate-specific antigen is a protein that is made by both normal prostate gland tissue and prostate cancer cells. PSA testing is encouraged for all men above the age of 40 years. The PSA is a kalliktein-like serine protease produced almost exclusively by the epithelial cells of the prostate. PSA is organ specific but not cancer-specific. Therefore serum concentrations of PSA can be elevated in the presence of benign prostatic hyperplasia (BPH), prostatis, and other non-malignant conditions. There is no optimal PSA threshold value that most effectively avoids the detection of insignificant cancers that are unlikely to be life threatening.

Neither the PSA test nor DRE, alone or together, is a truly accurate test for prostate cancer.

If abnormalities are detected by a PSA test or DRE, tissue specimens will be needed for diagnosis, usually with transrectal ultrasound (TRUS) imaging to permit spatial positioning of biopsy needles.

To help decide whether to have a prostate biopsy, healthcare professional should discuss with the person the PSA level, DRE findings (including an estimate of prostate size), co-morbidities, risk factors (age, family history) and any history of a previous negative prostate biopsy. Where biopsy is indicated, it can be either digitally guided or by transrectal ultrasound guided (gold standard).

The indications for a repeat biopsy if the first biopsy is negative include increasing and/or persistently elevatedPSA, suspicious DRE, atypical small acinar proliferation (ASAP), and extensive (multiple biopsy sites) prostatic intraepithelial neoplasia.

Symptoms and signs of prostate cancer include urinary symptoms such as straing at micturition, poor urinary stream, hesitancy and feeling of incomplete bladder emptying. There could be nocturia, urgency and urge incontinence. Some persons present with acute or chronic retention of urine. Others present with low back pain, haematuria, erectile dysfunction, haemospermia (blood in semen), and weight loss.  There could also be anaemia, easy fatigability, palpitation and pallor. In metastatic disease, the patient may present with paraparesis or paraplegia as well as pathological fractures (e.g. vertebrae, neck of the femur). Some men will not present symptoms at all.

The National Cancer Document strategies among others are to increase awareness on the signs and symptoms of prostate cancer and encourage men with these sign to see their health care provider. There should be voluntary screening among men who are 45 years and above and are at risk such as those with family history. It advises practitioners to monitor the rate of change of PSA level (velocity).

EDWARD O. AMPORFUL

CHIEF PHARMACIST

COCOA CLINIC

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