Prostate Cancer

Prostate cancer is the development of cancer in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, some grow relatively quickly. The cancer cells may spread from the prostate to other areas of the body, particularly the bones and lymph nodes. It may initially cause no symptoms. In later stages, it can lead to difficulty urinating, blood in the urine or pain in the pelvis, back or when urinating. A disease known as benign prostatic hyperplasia may produce similar symptoms. Other late symptoms may include feeling tired due to low levels of red blood cells.

 

BRIEF ANATOMY OF THE PROSTATE:

The prostate gland is located. It is a compressed inverted cone with 4 zones (peripheral, central, peri-urethral/ transitional +anterior fibro-muscular stroma).

The prostate gland has 2 capsules. The periurethral/transitional zone is the area affected by Benign Prostate Hyperplasia while the peripheral zone is the area affected mostly by Prostate Cancer. The function of the prostate gland is unknown. It produces fluid that contains calcium, citrate acid phosphatase, Zinc, spermine, fibrinolysin, fibrinogenase and electrolytes.

Arterial Supply includes inferior vesical and middle rectal arteries.

EPIDEMIOLOGY:

Prostate Cancer is the commonest malignant tumour seen in men beyond the middle age. Prostate Cancer is usually rare before 50 years of age. Incidence increases with age. In Nigeria, the incidence is about 127/100,000 cases seen in Lagos.  

The incidence of Prostate Cancer and mortality in the US; Blacks-(149/100,000), White-(139/100,000), Orientals-(107/100,000), Chinese-(28/100,000). This shows that the race and diet both have roles to play in the incidence of Prostate Ca. In the western world, 30% of men have a risk of developing Prostate Cancer with about 10% progressing into the clinical disease and 3% at risk of dying from the disease.

RISK FACTORS:

The exact cause of Prostate Cancer is unknown but there are risk factors associated with the development of Prostate Cancer.

Definite Risk Factors

  • Age >50 years
  • Presence of testes
  • DHT and E2/ Testosterone imbalance
  • Family and genetic factors
  • Race (black)

Probable Risk Factors

  • Increased intake of dietary fat
  • Hormones (Testosterone)

Potential Risk Factors

  • Vasectomy before 35years
  • Cadmium
  • Increased intake of Vitamin A
  • Vitamin D deficiency

PATHOLOGY:

  • Histological types
  • Modes of spread
  • Grading System

Histological Types include;

  • Adenocarcinoma
  • Transitional Cell Carcinoma
  • Pure Primary Squamous Cell Carcinoma
  • Sarcomas
  • Lymphomas
  • Secondaries

Modes of Spread include;

  1. Local Spread:
  • Urethra
  • Ureter, bladder, seminal vesicles
  • Distal sphincter
  • Rectum
  • Pelvic cellular tissues
  1. Haematogenous Spread/ Bloodstream:
  • Bones (vertebrae, pelvis, femur, ribs, skull, sternum)
  • Spinal Cord
  • Liver, Lungs and Brain
  • Skin
  • Palate
  • Others
  1. Lymphatic Spread:
  • Internal/ External iliac
  • Para-aortic, mediastinal
  • Inguinal (rarely)
  • Peri-neural lymphatics- pain, lower limb oedema

Grading System include;

The most commonly used grading system is the Gleason grade and score. It uses the glandular pattern and degree of deviation from the normal gland.

CLINICAL FEATURES:

There are various modes in which a patient can present and these include;

  • Asymptomatic presentation
  • Incidental finding of Cancer of Prostate
  • Local Disease
  • Locally advanced disease
  • Metastatic disease
  1. The asymptomatic presentation usually occurs with Routine Screening comprising of
  • Digital Rectal Examination
  • Prostate Specific Antigen
  • Transrectal ultrasound scan
  1. Incidental finding of Cancer of Prostate
  • 10% following Transurethral resection of the prostate(TURP) or Enucleation for Benign Prostate Hyperplasia.
  1. Presentation of Local Disease
  • Lower Urinary Tract System (LUTS)
  1. Irritative
  • Obstructive
  • Others
– Frequency

– Urgency

– Nocturia

– Urge Incontinence

– Pain on Micturition

– Hesitancy

– Straining

– poor stream

– dribbling

– the sense of incomplete voiding

– intermittency

– Haematuria

– Urinary tract Infection

  1. Presentation of Locally Advanced Disease
  • LUTS (Irritative and Obstructive)
  • Haematuria, acute or chronic retention with overflow incontinence, hematospermia
  • Sphincter (urinary incontinence)
  • Nerves (Suprapubic/ perineal pain, impotence)
  • Rectum (Rectal bleeding. Constipation, tenesmus, obstruction)
  1. Metastatic disease
  • Lumbar spine (low back pain, sciatica)
  • Femoral Neck (pathological fracture)
  • Vertebra/ Spinal cord (paraplegia)
  • Lymph nodes (Lymphoedema of the lower limbs, anuria, masses)
  1. Widespread metastases
  • Cerebral (a headache, nausea, vomiting, drowsiness, epilepsy, paresis)
  • Marrow (anaemia, pancytopenia)
  • Uraemia from chronic retention and ureteric obstruction
  • General (lethargy, weight loss and cachexia)

EXAMINATION:

  • General Physical Examination
  • Systemic Examination
  • Digital Rectal Exam

Findings from a digital rectal examination (DRE) suggestive of Prostate Cancer include;

  • Asymmetry of gland
  • Hard or woody inconsistency
  • Nodule, Induration
  • Immobile or fixed rectal mucosa
  • Obliterated median sulcus
  • Palpable seminal vesicle
  • Winging

INVESTIGATIONS:

  1. Prostate Specific Antigen (PSA)     
  • Normal = 0 – 4ng/ml
  • Intermediate = 4 – 10ng/ml
  • Elevated = >10ng/ml

Other causes of elevated PSA are BPH, Prostatitis, Prostatic Calculi, Prostatic infarction, Prostatic trauma

  1. Transrectal Ultrasound Scan (TRUS) of the Prostate
  • Prostate Size
  • Echogenicity (Iso-echoic lesions)
  • Capsule (Irregular, bridged)
  • Calcification
  • Seminal vesicle – invasion
  • Other adjacent structures

Ultrasound Equipment

  1. Prostatic Biopsy. Confirms diagnosis

Indications:  

(a) Elevated PSA

(b) Abnormal DRE findings

(c) Abnormal TRUSS findings

Routes: Transrectal (TruCut) or Transperineal (TruCut)

Guides: Transurethral Ultrasound guided (TRUS) or Digitally guided

Protocols: Directed or Sextant or Extended

Complications:

  1. Haematuria
  2. Rectal Bleeding
  3. Prostatitis
  4. Urinary Tract Infection
  5. Septicaemia
  6. Syncopal attack
  7. Deep perineal pain

Other Investigations include:

  • Urine Microscopy, Culture and Sensitivity
  • Urea, Electrolytes and Creatinine
  • Abdomino-pelvic Ultrasound
  • Urethrocystoscopy
  • Intravenous Urogram (IVU)
  • Uroflometry (peak urine flow = ≥ 20ml/s)
  • Liver Function Test
  • Lymphangiography
  • Radiology for Metastasis (Chest, Lumbosacral, Pelvic and Skull X-ray)
  • Bone radioisotope scan: Tc99 labelled radioisotope, Hotspots
  • Computed Tomography and Magnetic Resonance Imaging for Staging

STAGING OF PROSTATE CANCER

  1. TNM Staging
  2. Whitmore-Jewett Clinical Setting

 

TREATMENT: Depends on the stage

  1. Localized disease (Stages I and II)
  • Watchful waiting
  • Radical Prostatectomy
  • Radiotherapy (External Beam Radiotherapy or Brachytherapy)
  • Others (Cryosurgery, Laser, HIFU)
  1. Advanced disease(Stages III and IV)
  • Aim is palliative
  • Mainly hormonal manipulations
  • Androgen Deprivation Therapy
  • Ablation of Androgen – Orchidectomy, BTO, Subscapular
  • Inhibition of LHRH: LHRH agonists (Goserelin, Buserelin), LHRH antagonists(Abarelix, cervix)
  • Anti-androgens: Nonsteroidal (Flutamide, bicalutamide), Steroidal (Cyproterone acetate)

Management of complications:

  • AUR- catheterize (Urethral/ SPC), Channel TURP
  • Anaemia- Haematinics, BT
  • UTI- Antibiotics
  • Renal Failure- Continous dialysis, Dialysis
  • Backpain- Analgesics, Bisphosphonates, Strontium 89, Localized radiotherapy
  • Haematuria- conservative

PREVENTION:

  • Screening
  • Avoid known risk factors
  • Chemoprophylaxis

CONCLUSION:

The incidence of Prostate cancer is rising, aggressively in blacks. Early detection (DRE, PSA, Screening and Education) is essential. TruCut biopsy is used to confirm diagnosis. Most affected individuals usually present late and have to undergo Orchidectomy. There is still need for public awareness campaign.