Prostate Cancer Flashcards
How common is prostate cancer?
Prostate cancer is the most common cancer in men in the UK, accounting for 26% of all male cancer diagnoses, and is estimated that 1 in 8 men will be diagnosed with prostate cancer in their lifetime.
Briefly describe the pathophysiology of prostate cancer
Although the exact aetiology of prostate cancer is the subject of ongoing research, it is widely agreed that the growth of prostate cancer is influenced by androgens (testosterone and dihydrotestosterone (DHT)).
The majority of prostate cancers (>95%) are adenocarcinomas. Over 75% of prostate adenocarcinomas arise from the peripheral zone, with 20% in the transitional zone and 5% in the central zone. Prostate cancers are often multifocal.
How can prostate adenocarcinomas be classified?
Prostate adenocarcinomas can be categorised into two types:
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Acinar adenocarcinoma- originates in the glandular cells that line the prostate gland
- This is the most common form of prostate cancer
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Ductal adenocarcinoma- originates in the cells that line the ducts of the prostate gland
- This tends to grow and metastasise faster than acinar adenocarcinoma
What are the risk factors for prostate cancer?
- Age
- Ethnicity
- Men of black African or Caribbean ethnicity are twice as likely to be diagnosed with prostate cancer in their lifetime when compared to white Caucasian men
- Family history of prostate cancer
- Genetic predisposition
- BRCA2 or BRCA1 gene are at greater risk
- Other less significant modifiable risk factors include obesity, diabetes mellitus, smoking (associated with increased risk of prostate cancer death) and degree of exercise (considered protective)
What are the clinical features of prostate cancer?
Patients can present with a wide variety of symptoms, dependent on stage of the disease. Localised disease can present with lower urinary tract symptoms (LUTS) including weak urinary stream, increased urinary frequency and urgency.
More advanced localised disease may also cause haematuria, dysuria, incontinence, haematospermia, suprapubic pain, loin pain, and even rectal tenesmus. Any metastatic disease may cause, amongst others, bone pain, lethargy, anorexia, and unexplained weight loss.
A Digital Rectal Examination (DRE) is essential if a diagnosis of prostate cancer is suspected, as most prostate adenocarcinomas arise from the posterior peripheral zone. The examination should be checking for evidence of asymmetry, nodularity, or a fixed irregular mass.
What is being assessed in the DRE of prostate cancer?
A Digital Rectal Examination (DRE) is essential if a diagnosis of prostate cancer is suspected, as most prostate adenocarcinomas arise from the posterior peripheral zone.
The examination should be checking for evidence of asymmetry, nodularity or a fixed irregular mass.
What is the role of Prostate Specific Antigen (PSA) in diagnosing prostate cancer?
Prostate Specific Antigen (PSA) is a serum protein produced by both malignant and normal healthy cells in the prostate gland. PSA can be elevated secondary to prostate cancer.
Further calculations using PSA, such as free:total PSA ratio, can be used to increase the accuracy of the test for men with PSA from 4-10; a low free:total ratio is associated with an increased chance of diagnosing prostate cancer.
PSA density can also be used, which is the serum PSA level divided by prostate volume determined by imaging (i.e. TRUS, CT, or MRI); higher PSA densities can suggest an increased likelihood of prostate cancer.
Give examples of other causes that can raise PSA
PSA can become artificially raised with several other conditions, including BPH, prostatitis, vigorous exercise, ejaculation, and recent DRE, reducing its specificity.
Describe the guide for normal age-adjusted serum PSA levels
40-49 years <2.5 ng/mL.
50-59 years <3.5 ng/mL.
60-69 years <4.5 ng/mL.
>70 years <6.5 ng/mL.
Is there screening for prostate cancer?
To date, there is no national prostate cancer screening programme in many Western countries.
What is the current method use to diagnose prostate cancer?
The current standard method for diagnosing prostate cancer is through biopsies of prostatic tissue, with two potential methods:
- Transperineal (Template) biopsy
- TransRectal UltraSound-guided (TRUS) biopsy
Briefly describe Transperineal (Template) biopsy
This involves sampling prostatic tissue transperineally in a systematic manner, done as a day case under general anaesthetic. The transperineal approach allows better access to the anterior part of the prostate and also has a lower risk of infection.
Shown as A on the diagram.
Briefly describe TransRectal UltraSound-guided (TRUS) biopsy
This involves sampling the prostate transrectally, usually under local anaesthetic. Generally 12 cores are taken bilaterally in equal distribution from base to apex. Transrectal biopsies are associated with a 1-2% risk of sepsis.
Shown as B on the diagram.
What imaging is used in prostate cancer?
Multi-parametric magnetic resonance imaging (mp-MRI) is increasingly used to aid in the diagnosis of prostate cancer. Mp-MRI can identify abnormal areas of the prostate, which can then be targeted for biopsy by MRI-ultrasound fusion or cognitive-guidance techniques.
Staging of prostate cancer is typically done for men with intermediate and high-risk disease. Staging is accomplished with abdomino-pelvic CT imaging and bone scan.
Why has mp-MRI not replaced biopsy in the diagnosis of prostate cancer?
Mp-MRI has not replaced biopsy in the diagnosis for prostate cancer as a subset of patients with prostate cancer will have a negative MRI.
Briefly describe the Gleason Grading System
The Gleason grading system is a scoring system by which prostate cancers are graded, based upon their histological appearance.
The sample of prostate tissue is assigned a score according to its differentiation and the Gleason Score is then calculated as the sum of the most common growth pattern + the second most common growth pattern seen.
In essence, the lowest score that can be assigned to an individual with prostate cancer is Gleason 3+3. Higher Gleason scores are associated with a poorer prognosis.
In clinical practice, Gleason scores alone are not used to determine prognosis and recurrence risk, instead the score is used in conjunction with PSA levels and TNM staging.
