Benign Prostatic Hyperplasia (BPH) and Prostate Cancer epidemiology, etiliogy, causes and symptoms, investigations, treatment and management. Handwritten full lecture for USMLE.
ANATOMY of PROSTATE
Central zone of prostate sorrounds ejaculatory duct. The Transitional zone of prostate encompases meddle part of urethra. Peripheral zone is placed outside. Prostate cancer is most common in peripheral zone (60-70%). The Central zone is the second most common site for prostate cancer (25%). The Transition zone only has an occurence rate of 5% for prostate cancer. Benign Prostate Hyperplasia (BPH) is in the transition zone and that is why it presents mostly with urinary symptoms.
BENIGN PROSTATIC HYPERPLASIA (BPH)
Prostate is heavily influenced by DHT and testosterone, however, DHT is ten times more sensitive. Testosterone is converted to DHT by 5alpha reductase. This causes hyperplasia of collagen cells and the smooth muscle. The collagen will cause a physical obstruction while the smooth muscle will cause mechanical obstruction. Eventually there is bladder enlargement which may forma false diverticulum (outpouching of the bladder).
Clinical Signs and Symptoms
Obstructive symptoms – Consists of the patients experiencing hesitancy, difficulty voiding, straining, decrease in the force of stream and dribbling of urine.
Irritation symptoms – increase frequency or urgency as well as nocturia. These symptoms occur as the bladder gets larger and begins to overflow.
These symptoms can produce an International Prostate Symptoms Score (IPSS) which determines severity of Benign prostatic Hyperplasia through symptoms.
Diagnosis of Benign Prostatic Hyperplasia
Digital Rectum Exam is done initially, however it doesn't correlate well with symptoms and it is very difficult to palpate. Urinalysis is also done to rule out prostatitis. PSA is organ specific but can be elevated in cancer and prostatitis. Ultrasound or CT to look for complications such as bladder distention. Transrectal ultrasound is used before surgery.
Treatment for Benign Prostatic Hyperplasia (BPH)
If the degree of benign prostatic hyperplasia (BPH) is minimal such as 0-7 on the IPSS score than watchful waiting because most spontaneously. So for these patients continue monitoring PSA and Digital Rectums Exams. If getting worse continue to medical treatment. Alpha 1 blocker allows relaxation of the smooth muscle that may be constricting the urethra. Finasteride is a 5 alpha reductase inhibitor to prevent formation of DHT from testosterone and help debulk the prostate. Commonly used drugs are terazosin and doxazosin but this can lead to hypotension. More specific is an Alpha A1 blocker such as tamsolusin which is more specific for the prostate and therefore hypotension is not present but can lead to retrograde ejaculation.
Surgery – If medical therapy doesn't work for the Benign Prostatic Hyperplasia (BPH). Two procedures transurethral and prostatectomy.
CLINICAL SIGNS AND SYMPTOMS of PROSTATE CANCER
Can range from asymptomatic to completely fatal.
Screening – Digital Rectal Exam is not helpful and PSA is the only method being used.
Local Disease causes symptoms similar to Benign Prostatic Hyperplasia symptoms, but this suggests involvement of the transition zone.
Metastasis disease include symtpoms related to osteoblastic bone growth, primarily the spine leading to neurological symptoms and back pain. Prostatic Cancer patients may also have patients related to lower extremities due to lymphatic obstruction
INVESTIGATION for PROSTATE CANCER
Digital Rectal Exam shows a single nodule and correlates well with severity of disease. However, it may be a cyst or a stone. PSA normally should be less than 2.5ng/dL (some say less than 4 ng/dL). May also be helpful to measure as PSA Velocity and Free PSA versus Bound PSA. This helps distinguish Benign Prostatic Hyperplasia from Prostate Cancer.
Transrectal Ultrasound may also be used.
Biopsy uses the Gleasson Score which looks at the tissue of prostate under microscope and given a score out of 5.
Staging of prostate cancer utilizes the TNM score.
TREATMENT AND MANAGEMENT of PROSTATE CANCER
Start with active surveillance by monitoring PSA/DRE/Biopsies.
Radiation – Has a lot of GIT complications and may lead to erectile Dysfunction. Brachytherapy is the new treatment.
Radical Prostatectomy – May lead to neruovascular damage causing Erectile Dysfunction and damage to urethra my lead to incontinence.
After treatment continue to monitor PSA to look for Metastasis or resurgency of cancer.
TREATMENT OF METASTASIS OF PROSTATE CANCER
Castration – Orchiectomy (Gold Standard), Leuprolide/Ghrelin (GnRH) but these have a temporary increase in androgens, and Anti-Androgens (Flutamide).
Castration Resistant Prostate Cancer (CRPC) are tumors that are still growing despite castration. Then use chemotherapy (Doxitexal, Mitoxantrone, Dosatinib)
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