Prostate Cancer

LEARNING OBJECTIVES

  • Describe the structure and functions of the prostate gland

  • Define the risk factors for prostate cancer.

  • Identify the clinical picture, staging, diagnosis and treatment of prostate cancer.

  • Describe the value of PSA as a screening test for prostate cancer

Prostate Anatomy

  • Retroperitoneal organ, encircling the neck of the bladder and urethra.

  • 20g

  • Devoid of distinct capsule.

  • 4 distinct zones

    • Central zone (CZ)

    • Peripheral zone (PZ) - most tumors here

    • Transitional zone (TZ) - most hyperplasia here

    • Periurethral zone.

Prostate Histology

  • Histologically the prostate is composed of glands lined by two layers of cells.

  • A basal layer of low cuboidal epithelium covered by a layer of columnar secretory cells.

  • In many areas there are small papillary infoldings of the epithelium.

  • These glands are separated by abundant fibromuscular stroma.

  • Testicular androgens control the growth and survival of prostatic cells.

Prostate Functions

  • Accessory sex gland.

  • Function → Secrete prostate fluid

    • Contents: PSA, prostaglandins, fructose, Zinc, Citrate.

  • Muscles of the prostate gland also help propel seminal fluid into the urethra during ejaculation.

  • PSA → Liquefying semen that has thickened after ejaculation. This thinning action allows sperm to swim more freely.

Prostate Cancer

  • Age: men over 50

  • Ethnicity: African Caribbean men

  • Family History (1st degree relative)

  • High dietary fat and obesity

  • Vitamin D or E deficiency.

Pathology

  • Most common form is adenocarcinoma (glandular prostate cancer).

  • Lined by a single uniform layer of cuboidal or low columnar epithelium.

  • The outer basal cell layer typical of benign glands is absent.

  • Cancer glands are more crowded and characteristically lack branching and papillary infoldings.

Prostate Cancer: Presentation

  1. EARLY STAGE USUALLY ASYMPTOMATIC

    • Most cases detected by serum PSA screening.

    • Palpable nodule or firmness on DRA (digital rectal examination).

  2. ADVANCED STAGES

    • Urinary retention/renal failure.

    • Bone pain

    • Anemia

    • Weight loss, fatigue.

    • Spinal cord compression.

Diagnosis of prostate cancer

PSA → prostate specific antigen

DRA → Digital rectal exam

  • Asymmetrical, hard and nodular enlargement with loss of median sulcus.

Transrectal ultrasound alone/CT scan/MRI not sensitive enough to make the diagnosis.

Prostate cancer treatment considerations

  • Patients age

  • Co-morbid health conditions

  • Tumor grade

  • Often a patient choice

Early stage cancer

  • Prostatectomy

  • Radiotherapy

  • Radioactive Seeds (brachytherapy)

Advanced Prostate Cancer

  • Androgen deprivation

  • Antiandrogens

  • Supportive therapies

  • Analgesics

  • Steroids

  • Vitamin D/Calcium

  • Chemotherapy

Brachytherapy

  • Tiny radioactive seeds are put into the prostate.

  • Each seed is the size and shape of a grain of rice.

  • Seeds stay in the prostate forever and give a steady dose of radiation over a few months.

  • Radiation damages prostate cells and stops them multiplying and growing.

  • Cancer cells cannot recover and die.

  • Healthy cells can repair themselves easily.

Prostate Screening

PSA as a test

  • 4.0ng/ml is upper limit of normal

  • More than 10ng/ml → likely cance

  • 4 - 10ng/ml → gray area.

  • Low specificity (false +ve) and sensitivity (false -ve)

  • Limited value for screening - need DRE, transrectal sonography, needle biopsy.

  • Useful to monitor disease - after treatment increasing levels indicate recurrence/metastasis.

What can increase PSA levels?

  • Prostate Cancer

  • BPH - benign prostatic hyperplasia

  • Age - PSA goes up with age.

  • Prostatitis - infection of the prostate gland

  • Ejaculation

    • PSA increased for a short time

    • Men are asked to abstain from ejaculation for 2 days before testing.