Understanding the prostate and spotting signs of cancer!

Written by Bukola/ Published 20/10/22

Today’s article is dedicated to my dad whose birthday is today. l lost my dad two years ago to prostate cancer. He was asymptomatic till he got diagnosed with metastatic prostate cancer. May he continue to rest on.

Prostate cancer is curable, and the prognosis depends on the initial stage at diagnosis. Prostate cancer has a 5 year survival rate of over 95% when diagnosed at stage 1–3, compared with other cancers. However, for the 1 in 5 people diagnosed with stage 4 prostate cancer (metastatic), the 5 year survival rate is just 49% .

[Cancer Research UK, 2020; NICE, 2020; NICE, 2021b]

THE PROSTATE GLAND

 The prostate gland is divided into three zones - peripheral, transition and central.

 The prostate contains two main types of tissue, exocrine glandular tissue and fibromuscular tissue. Prostatic exocrine glandular tissue is epithelial tissue specialised for the secretion of the components of semen and makes up the majority of the prostate.

 Fibromuscular tissue is a mixture of smooth muscle tissue and dense irregular connective tissue containing a number of collagen fibres. The collagen fibres provide strength to the tissue while the smooth muscle permits the tissue to contract in order to expel fluids.

 Fibromuscular tissue forms the outermost layer of the gland and the tissue surrounding the urethra.

 Figure 1 outlines the anatomical location of the various zones.

The prostate is oval shaped approximately 3cm thick. The actual size of the prostate varies from man to man. It can range from the size of a walnut to a small apple. As the gland grows, it can interfere with a man's ability to micturate as the urethra becomes compressed.

 The prostate surrounds the base (or neck) of the bladder, two of its lobes surround the urethra. The prostate gland is covered in a layer of connective tissue called the prostatic capsule and is made up of a variety of cell types:

Gland cells that produce the fluid portion of semen.

Muscle cells controlling urine flow and ejaculation.

Fibrous cells that provide the supportive structure of the gland.

STRUCTURES AROUND THE PROSTATE INCLUDE:

 Seminal vesicles - these produce semen and are located on both sides of the prostate.

Vas deferens - the vas deferens transports sperm from the testicles to the seminal vesicles.

Nerve bundles - these control bladder and erectile function and are on both sides of the prostate.

Muscles - these muscles control urination.

The main function of the prostate is to produce the fluid portion of semen. The gland cells within the prostate produce a fluid that is rich in proteins and minerals. This fluid maintains and nourishes sperm and is a mixture of simple sugars (fructose and glucose), enzymes and alkaline chemicals. It is made continuously and excess fluid is passed in the urine.

 The enzymes work to break down proteins in semen after ejaculation to free sperm cells from the viscous semen.

 When sexually aroused, the man's prostate produces larger amounts of this fluid. This then combines with the sperm and is ejaculated as semen. The pH of the fluid is alkaline, helping to neutralise the acidity within the vagina promoting the survival of the sperm when inside the female.

 The prostate also plays a role in controlling urine flow as the urethra runs from the bladder, through the prostate and out through the penis. The muscle fibres of the prostate wrap around the urethra and are under involuntary nervous system control. These fibres contract to slow and stop the flow of urine.

 WHAT IS PROSTATE CANCER?

 Prostate cancer is a malignant tumour of the prostate.

Almost all cancers of the prostate (95%) are adenocarcinomas (cancers of glandular cells).

Prostate cancer is multifocal — the different foci may be caused by different genetic mutations, which can differ greatly in growth rate and ability to metastasize. Most prostate cancers are indolent and grow slowly; a minority are aggressive in their tendency to invade local structures or to metastasize to remote tissues.

Localized prostate cancer is confined within the capsule and seldom causes symptoms.

Locally advanced prostate cancer extends beyond the capsule of the prostate and is often asymptomatic when diagnosed.

Metastatic prostate cancer most frequently affects the bones, where it causes pain and fragility fractures

 [National Collaborating Centre for Cancer, 2019; BMJ, 2021].

HOW COMMON IS IT?

 Prostate cancer is the most common type of cancer in men in the UK, and the second most common cause of cancer death in males in the UK (after lung cancer).

Each year in the UK about 47,600 people are diagnosed with prostate cancer and about 11,600 die from the disease.

It is estimated that 1 in 6–8 men in the UK will get prostate cancer at some point in their lives.

Prostate cancer is predominantly a disease of older men.

The most common age of diagnosis is 65–69 years.

More than 50% of new cases of prostate cancer diagnosed in the UK are in men aged 70 years and older (2012 data).

The incidence of the disease is highest in people aged 90 years and over (2012–2014 data).

The number of men diagnosed with prostate cancer has been increasing over the last 10 years. This may be due to the increased uptake of PSA testing and an ageing population.

Prostate cancer can also affect trans women, as the prostate is usually conserved after gender-confirming surgery, but it is not clear how common it is in this population.

[NICE, 2020; PHE, 2020; NICE, 2021b; Cancer Research UK, 2019; National Collaborating Centre for Cancer, 2019; PHE, 2020; UK NSC, 2021]. 

CAUSES

 The aetiology of prostate cancer is unknown. However, a number of risk factors have been associated with the development of the disease (BMJ, 2021).

 RISK FACTORS FOR DEVELOPING PROSTATE CANCER INCLUDE:

a). Black ethnicity

There is a higher incidence of, and mortality from, prostate cancer in men of black ethnicity than in white men. The reason for this is unknown.

The lifetime risk of being diagnosed with prostate cancer is 1 in 4 for black men, compared with 1 in 8 for white men.

The lowest incidence rates of prostate cancer are seen in Asian people, particularly in India, China, and Japan. South Asian people living in England have a lower incidence of prostate cancer than their white counterparts (relative risk of 0.8).

(PHE, 2020; NICE, 2021b; National Collaborating Centre for Cancer, 2019; Cancer Research UK, 2020]).

b). Family history of prostate cancer and genetics

People are at higher risk if they have a close relative, for example a brother or father, who has had prostate cancer’

The genetic basis for the hereditary cause is still unclear, but prostate-cancer specific germline mutations (such as HOXB13) have been implicated. Germline mutations associated with other cancers (such as BRCA1/2) have also been associated with an increased risk of prostate cancer. 

[National Collaborating Centre for Cancer, 2019; PHE, 2020].

c). Increasing age

Age is one of the strongest risk factors for prostate cancer.

People are at higher risk if they are aged 50 years or older. The estimated incidence is 0.1% in men younger than 50 years.

 [PHE, 2020; National Collaborating Centre for Cancer, 2019].

 SPOTTING THE SYMPTOMS:

PROSTATE CANCER IS SUSPECTED IN MEN WHO HAVE ANY OF THE FOLLOWING SYMPTOMS THAT ARE UNEXPLAINED:

 Lower back or bone pain.

Lethargy.

Erectile dysfunction.

Visible haematuria.

Anorexia/weight loss.

Lower urinary tract symptoms (LUTS), such as nocturia (Having to urinate more often at night time), urinary frequency, urgency (A sudden, strong need to urinate), hesitancy, urinary retention, terminal dribbling, and/or overactive bladder — these symptoms are common in older men and early prostate cancer will not usually produce these symptoms. However, locally advanced prostate cancer may cause obstructive Lower Urinary Tract Symptoms.

Lower back pain, bone pain, weight loss (are possible symptoms of advanced prostate cancer).

THE COMPLICATIONS OF PROSTATE CANCER INCLUDE:

• Local invasion
• Prostate cancer can be locally invasive and spread to the seminal vesicles, base of the bladder, urethral sphincter, or side wall of the pelvis.
• Distant metastases
• Metastasizing prostate cancer most commonly spreads to the bones, where it can cause pain, pathological fractures, or spinal cord compression.
• Lower urinary tract symptoms (LUTS)
• Early prostate cancer does not usually cause LUTS.
• By the time prostate cancer causes LUTS, it may be advanced and incurable

TREATMENT OPTIONS FOR PROSTATE CANCER INCLUDES:

1). Watchful waiting is part of a strategy for 'controlling' rather than 'curing' prostate cancer and is aimed at people with localized prostate cancer who are either not suitable for, or do not ever wish to receive, curative treatment, and instead involves the deferred use of hormone therapy.

Watchful waiting avoids the use of surgery or radiation, but implies that curative treatment will not be available; people on watchful waiting who require treatment would receive long-term hormone therapy to control their cancer. A significant number of people on watchful waiting follow up need no treatment at all during the rest of their lives.

Watchful waiting is often suitable for older men, men with significant comorbidities, or those with slowly progressing tumours who are likely to die of other causes and not suffer significant morbidity from their prostate cancer. It is an option for men in any prognostic risk group.

2). Active surveillance is part of a 'curative' strategy and is aimed at people with localized prostate cancer for whom radical treatments are suitable, keeping them within a 'window of curability' whereby only those whose tumours are showing signs of progressing, or those with a preference for intervention are considered for radical treatment.

Active surveillance may avoid or delay the need for radiotherapy or surgery.

The difference from watchful waiting is that repeating the prostate biopsy at intervals depending on age and prostate-specific antigen (PSA) levels allows the man's prognostic risk category to reassessed. The aim of active surveillance is to safely reduce the risk of over treatment, as treatment is offered only when the risk increases.

3). Radical treatments include radical prostatectomy, external beam radiotherapy, and brachytherapy.

 Radical prostatectomy is the surgical removal of the entire prostate gland and lymph nodes. This can be done by an open approach or by keyhole technique (laparoscopic or robotically assisted laparoscopic prostatectomy).

 External beam radiotherapy (EBRT) is radiotherapy given by using ionizing radiation (for example, high-energy X-rays) produced in a machine and directed at the tumour from outside the person.

Brachytherapy is a type of radiotherapy in which the radiation is given using either permanently implanted radioactive seeds (low dose rate) or temporarily inserted radioactive sources (high dose rate) directly into the prostate.

4). Adjunctive and palliative treatments include hormone therapy, chemotherapy, and bisphosphonates.

Hormonal treatments are the treatment of cancer by removing and/or blocking the effects of hormones which stimulate the growth of prostate cancer cells. Hormonal treatments used for prostate cancer include:

Androgen deprivation — a treatment that lowers testosterone levels, such as surgery (bilateral orchidectomy) or treatment with luteinizing hormone-releasing hormone (LHRH) agonists (such as goserelin, leuprorelin, triptorelin), or antagonists (such as degarelix).

Androgen blockade — the use of drugs that bind to and block the hormone receptors of cancer cells (for example, cyproterone acetate), thus preventing androgens from stimulating cancer growth.

 Chemotherapy is an option for men with hormone-relapsed metastatic disease.

Bisphosphonates are calcium-regulated drugs which inhibit bone resorption, used in the treatment of hypercalcemia, osteoporosis, and bone pain.

[National Collaborating Centre for Cancer, 2019; NICE, 2021b]

 Local and national cancer information services, and cancer support groups, includes: 

• Cancer Research UK (www.cancerresearchuk.org).
• Prostate Cancer UK (www.prostatecanceruk.org).  
• Macmillan Cancer Support (www.macmillan.org.uk).
• Movember UK (www.movember.com).
• Orchid - Fighting Male Cancer (www.orchid-cancer.org.uk).
• Tackle Prostate Cancer (www.tackleprostate.org).

PLEASE REFER TO YOUR PRIMARY CARE PROVIDER FOR ADVICE, DIAGNOSIS AND TREATMENT.

REFERENCES

• BMJ (2021) Prostate cancer. BMJ Best Practice.
• Cancer 
• Cancer Research UK (2020) Prostate cancer - Risks and causes. Cancer Research UK. 
• National Collaborating Centre for Cancer (2019) Prostate cancer: diagnosis and treatment (full NICE guideline). National Institute for Health and Care Excellence. 
• NICE (2017) Quality Standard: Suspected cancer (QS124). National Institute for Health and Care Excellence.
• NICE (2020) NICE impact prostate cancer. National Institute for Health and Care Excellence.
• NICE (2021a) Quality Standard: Prostate cancer (QS91). National Institute for Health and Care Excellence. 
• NICE (2021b) Prostate cancer: diagnosis and management. National Institute for Health and Care Excellence. 
• NICE (2021c) Suspected cancer: recognition and referral. National Institute for Health and Care Excellence.
• PHE (2016) Prostate cancer risk management programme: overview. Public Health England.
• PHE (2020) Advising well men about the PSA test for prostate cancer: information for GPs. Public Health England. 
• UK NSC (2021) Screening for prostate cancer: external review. UK National Screening Committee.