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Prostate anatomy, structure & function – define BPH & BOO, which terminology?. Kieran Jefferson Consultant Urological Surgeon. Biography. 08 -Partner, Warwickshire Urology 06 - Consultant, UHCW 05-06 Fellow in uro -oncology, Bristol 98-05 SpR urology, Southwest deanery - PowerPoint PPT Presentation
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Prostate anatomy, structure & function – define BPH & BOO, which terminology?
Kieran JeffersonConsultant Urological Surgeon
Biography
08 - Partner, Warwickshire Urology
06 - Consultant, UHCW
05-06 Fellow in uro-oncology, Bristol
98-05 SpR urology, Southwest deanery
94-98 Basic surgical training, Bristol
90-93 BM BCh, Oxford
87-90 BA (Nat Sci), Cambridge
• Ipsen (Decapeptyl)Paid consultant; principal trial investigator; book sponsorship; meeting sponsorship
• Wyeth/Takeda (Prostap)Trial co-investigator; meeting sponsorship; paid lecturer; book sponsorship
• Glaxo (Dutasteride)Trial co-investigator, meeting sponsorship, paid lecturer
• Astrazeneca (Zoladex)Principal trial investigator; meeting sponsorhip; paid lecturer
• Novartis (Zoledronate)Trial co-investigator; meeting sponsorship
• Sanofi Synthelabo (Docetaxel)Meeting sponsorship; book sponsorship
Potential conflict of interest
What is a prostate?
• prostate = ‘protector’ gr.
• exocrine gland
• reproductive role
Who needs a prostate?
• Phylogenetic conservation in mammals
• Wide variation in ejaculatory volumes• human 3ml, boar 250ml!
• Ejaculate nourishes sperm & ↑ motility• fructose, citrate, spermine, prostaglandins, Zinc
• Optimises fertility • acid-base buffering, antibacterial
Semen
• Spermatozoa (100 million)+ seminal plasma
• Plasma from SVs and prostate
• PSA – serine protease; ? lyses seminal clot
• Seminogelins – coagulation and capacitation
Embryology
• Wolffian ducts form SV, epididymis, vas• requires testosterone (not DHT)
• Prostate develops from urogenital sinus• requires DHT/5-AR• glands bud from urogenital sinus• reciprocal induction
• Stromal-epithelial interaction• endoderm/mesenchyme
Adult prostate
• Androgen dependent (DHT)
• Differentiation vs proliferation vs apoptosis
• Testicular androgens from Leydig Cells
• Prostatic 5-AR converts to DHT
Gross anatomy
• 20g; 3 x 4 x 2 cm• Ovoid; narrow apex and
broad base• Apex continuous with
rhabdosphincter• Inf vesical, int pudendal
and mid rectal arteries• Lymphatic drainage to
obturator/iliac nodes
Sagittal section
• B = bladder; CS = verumontanum; DVC = dorsal venous complex; PS = pubic symphysis;
• pPF/SVF = Denonvilliers’ fascia; R = rectum; RU = rectourethralis; SS = striated (rhabdo) sphincter; VEF = visceral endopelvic fascia
Axial section mid-prostate
• DVC = dorsal vascular complex; ED = ejaculatory ducts
• NVB = neurovascular bundle; PEF/VEF = parietal/visceral endopelvic fascia; PF = prostatic fascia; pPF/SVF = Denonvilliers’ fascia; R = rectum; U = urethra
Axial section at sphincter
• DVC = dorsal venous complex; MDR = median dorsal raphe; NVB = neurovascular bundle; PB = pubis; PPL = puboprostatic ligament
• SS = striated (rhabdo) sphincter; U = urethra; VEF = visceral endopelvic fascia.
McNeal’s Zones
• Transition Zone (TZ; 5-10%)• BPH & excess cancers (20%)• Surrounding stroma
• Central Zone (CZ; 25%)• ? Wolffian Duct origin• surrounds ejaculatory ducts
• Peripheral zone (PZ; 70%)• Most prostate cancers• Most prostatitis
• Anterior fibromuscular stroma (AFS)
McNeal’s Zones
TZ
PZ
TZ
PZ
CZ
Histology
70% glandular structures; 30% stroma
Thin fibromuscular capsule
Surrounds urethra lined with transitional epithelium
Stromal-epithelial interaction
• Details complex (if at all understood)and constantly changing
• Androgen actions on stromal cells trigger paracrine release of growthfactors, which act on epithelial cells, regulating differentiation, proliferationand apoptosis
Nomenclature
• Benign prostatic hyperplasia (BPH)• histological diagnosis• cellular proliferation (epithelium & stroma)• Transition zone predominantly
• Benign prostatic enlargement (BPE)• clinical/radiological diagnosis
• Lower urinary tract symptoms (LUTS)• does not presume cause cf ‘prostatism’
• Bladder outlet obstruction (BOO)• cystometric finding• low flow despite high detrusor pressure
Benign Prostatic Hyperplasia
• Overgrowth of epithelium and stroma
• SM hypertrophy and increased tone
• Predominantly TZ change of unknown aet
• Imbalance of proliferation/apoptosis
• May cause BOO, LUTS and complications
• Near ubiquitous in old men (90% > 80y/o)
LUTS
• Possible to have any combination of LUTS, BPH and BOO
• Reasonable association between LUTS, prostate volume and PSA
• Storage vs voiding symptoms
• IPSS score increases with age
• Degree of bother important
BOO
• No population level stats for cystometric BOO
• Qmax < 10ml/s – likely to have BOO
• Qmax > 15ml/s – unlikely to have BOO
• Flow rates decline with age
Complications of BPH/BOO
• Incomplete bladder emptying/OAB• Bladder stones
– (0.1% per year)
• UTI – unusual in RCTs
• Obstructive uropathy – rare in RCTs; no case in 3000 MTOPs patients in 4 years
• Acute retention of urine– 2% per year in PLESS study
Conclusions
• Prostate essential for reproduction
• BPH is almost universal in older men
• LUTS and complications are common but most men do not experience them
• Degree of enlargement does not equate to severity of LUTS