MODULE 1
1/46
Module 1: BPH – The Disease
Mostafa M. Elhilali MD, PhD, FRCSCProfessor and Chair, Department of SurgeryMcGill UniversityRoyal Victoria HospitalMontréal, Québec
MODULE 1
2/46
To understand the difference between histologic and symptomatic BPH and the prevalence of each.
To learn the meaning of the different acronyms describing the symptoms of BPH and how they manifest in the condition.
To understand the progression of BPH and how it affects the function of the lower urinary tract.
To understand the micro- and macrophysiology of BPH and the role of androgens in the growth of the prostate.
To learn how BPH affects health-related quality of life (HRQoL).
1.1 Learning Objectives
BPH = Benign Prostatic Hyperplasia, HRQoL= Health-Related Quality of Life
MODULE 1
3/46
1.2 Introduction
BPH is a progressive, non-malignant condition that affects men worldwide
All aging males develop BPH Few experience symptoms
Fewer seek treatment
BPH = Benign Prostatic Hyperplasia
MODULE 1
4/46
BPH is associated with:
Bothersome LUTS
Can affect quality of life (e.g. interference with daily activity & sleep)
Histological definition of BPH: Stromal and epithelial cell hyperplasia beginning in the periurethral zone
of the prostate
LUTS = Lower Urinary Tract Symptoms
MODULE 1
5/46
Figure 1.1: Prevalence of BPH
Adapted from Oesterling JE. Arch Fam Med 1992;1(2):257-66
100
15 25 35 45 55 65 75 850
20
40
60
80
Age (years)
% Prevalence MicroscopicBPH Countries Sampled
JapanIndiaAustria
DenmarkEnglandUSA
MODULE 1
6/46
Figure 1.2: Natural History of BPH: Relationship Between Symptoms and Prostate Volume
Adapted from Girman CJ et al. J Urol 1995;153:1510-1515.
40–49 50–59 60–69 70–79
Age (years)
30
20
10
0
Mild symptoms
Moderate/severe symptoms
% o
f m
en w
ith
pro
stat
e vo
lum
e >
50 m
l
(N=2115)
MODULE 1
7/46
As with histologic evidence of BPH, the prevalence of bothersome symptoms also increases with age.
Approximately one half of all men who have a histologic diagnosis have moderate to severe LUTS4
4. McDonald H et al. Can J Urol 2004;11:2327-2340. (p2327, intro)
BPH = Benign Prostatic Hyperplasia; LUTS = Lower Urinary Tract Symptoms
MODULE 1
8/46
About 50% of Canadian men 50 years of age and over display mild to
severe symptoms of BPH, which worsen with age 5
If left untreated, LUTS can progress to AUR: AUR is a distressing condition requiring urgent catheterization and
hospitalization 6
5. McDonald H et al. Can J Urol 2004;11:2327-2340. (p2327, intro)6. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:7-8.BPH = Benign Prostatic Hyperplasia; LUTS = Lower Urinary Tract Symptoms; AUR = Acute Urinary Symptoms
MODULE 1
9/46
The defining characteristic of BPH:
Histological evidence of hyperplastic prostatic tissue
As the condition progresses, it leads to urinary tract symptoms such as:
Urinary hesitancy
Weak urinary stream
Increased urinary frequency and urgency 7
Further discussed in Module 2
7. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:22.BPH = Benign Prostatic Hyperplasia
MODULE 1
10/46
Table 1.1: Definition of Terms
LUTS Lower Urinary Tract Symptoms
BPE Benign Prostatic Enlargement (macroscopic)
BOO Bladder Outlet Obstruction
BPH Benign Prostatic Hyperplasia (microscopic/histologic)
BPO Benign Prostatic Obstruction (BOO caused by BPE)
Clinical BPH LUTS + BPE + BOO
MODULE 1
11/46
1.3 Symptoms
The symptoms that most characterize BPH are lower urinary tract symptoms (LUTS)
These are so typical of BPH that they are often referred to as “prostatism” or “symptoms of benign prostatic hyperplasia” 9
9. Abrams P. BMJ 1994;308:929-930.
MODULE 1
12/46
Table 1.2: Problems and Consequences
Histological BPH (Stromoglandular)
By itself may not cause any problems
LUTSBother, Impact on QoL,
interference with daily living, sexual dysfunction(?)
BPEAcute Urinary Retention (AUR),
Surgical Intervention,
Secondary Changes of bladder anatomy and function, other outcomes (UTI, stones, renal
failure, incontinence, etc.)BOO
LUTS = Lower Urinary Tract Symptoms; BOO = Bladder Outlet Obstruction; BPE = Benign Prostatic Enlargement
MODULE 1
13/46Adapted from Nordling J et al. In: Benign Prostatic Hyperplasia. Plymouth, United Kingdom: Health Publication, 2001:107-166.
Aging
Anoxia
Obstruction
High nocturnaldiuresis
Age-relateddiseases
Neurologicdiseases
Localdisease
Bladder
LUTS
Figure 1.3: Conditions Potentially Leading to LUTS
MODULE 1
14/46
Many experts group LUTS into voiding or obstructive symptoms and storage or irritative symptoms 12,13
However, as the BPH progresses, LUTS becomes increasingly evident and severe
12. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:21. 13. Ramsey EW, McSherry J. A community care program on benign prostatic hyperplasia: a primary-care physician’s guide.
Mississauga, ON: Astra Pharma Inc.; 1996:19.LUTS = Lower Urinary Tract Symptoms; BPH = Benign Prostatic Hyperplasia
MODULE 1
15/46
1.4 Natural History of BPH
A difficult assessment
Biopsy results on large male populations are not readily available, and are impractical to obtain 14
Currently achieved through: 15
Surgical findings
Autopsy studies
Symptom assessments
Measures of urinary flow rates, prostatic volume, bladder wall thickness
Prostate Specific Antigen levels [PSA]
14. Jacobsen SJ et al. Urology 2001;58(Suppl 6A):5-16. p6
15. Jacobsen SJ et al. Urology 2001;58(Suppl 6A):5-16.
MODULE 1
16/46
BPH begins with an asymptomatic preclinical stage and progresses into the clinical stage with signs of voiding dysfunction
Clinical BPH takes years to develop, and only a small portion of men with preclinical BPH develop the clinical disease
BPH = Benign Prostatic Hyperplasia
MODULE 1
17/46
BPE
All Men> 40 yrs
BOOLUTS /Bother
Histologic BPH
Figure 1.4: The Problem
Adapted from Roerhborn CG. AUA 2005.LUTS = Lower Urinary Tract Symptoms; BPE = Benign Prostatic Enlargement; BOO = Benign Outlet Obstruction
MODULE 1
18/46
Figure 1.5: Early BPH - BPH Progression
Bladder
ProstaticUrethra
DetrusorMuscle
Developing benign
hyperplastic tissue in
transition zone
Further enlargement of transition zone
caused by proliferation of
cells
Diminished flow of urine from bladder
Peripheral zone
Transition zone
Central zone
Adapted from Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005.
MODULE 1
19/46
Figure 1.6: Advanced BPH-Complications and the Need for Surgery
Obstructed prostatic urethra
Hypertrophied detrusor muscle
Considerable BPH tissue presence
Progressive impairment of
bladder emptying
Peripheral zone
Transition zone
Central zone
Adapted from Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005.
MODULE 1
20/46
Potential Complications of BPH
Bladder stones
Bladder damage (Trabeculations, Cellules, Diverticula)
Urinary tract infection
Urinary retention
Renal impairment
Gross Hematuria
Overflow incontinence
MODULE 1
21/46
Figure 1.7: Relative Risk of AUR in Relation to Prostate Volume
A cohort of 2115 men, aged 50-79, was randomly selected from an enumeration of the Olmsted County. A 25% random subsample (n=537) were selected for a detailed clinical examination which included PSA determination, digital rectal examination and transrectal sonograpic examination of the prostate (73 men [13%] refused to participate or did not complete all diagnostic tests and 4 men [1.3%] were found to have prostate cancer and were excluded from the analysis). Follow-up was performed through a retrospective review of community medical records to determine the occurrence of AUR in the subsequent 4 years.Adjusted estimates were not calculated due to the small sample size.Reference category
*
*****
Prostate volume (ml)
95% CI*** (1.0 – 9.0)
< 30*** >30
Jacobsen, SJ et al. J Urol 1997;158:481-7
AUR = Acute Urinary Retention; PSA = Prostate-Specific Antigen; CI = Confidence Interval
MODULE 1
22/46
Figure 1.8: MTOPS Subanalysis: Prostate Volume and Risk of BPH Progression
McConnell JD et al. J Urol. 2003;169(suppl):332.
< 31 ng/ml
≥ 31ng/ml
3.43
0.3 0.6
5.6
4.3
1
2
0
1
2
3
4
5
6
7
OverallProgression
SymptomProgression
AUR Invasive Therapy
Rat
e p
er 1
00 P
YR
P=0.0031
P=0.001
P=0.004
P=0.0003
MTOPS = Medical Therapy of Prostatic Symptoms
MODULE 1
23/46
Figure 1.9: MTOPS Subanalysis – PSA and Risk of BPH Progression
< 1.6ng/ml
≥ 1.6ng/ml
3.12.8
0.30.8
5.9
4.5
1
1.8
0
1
2
3
4
5
6
7
OverallProgression
SymptomProgression
AUR Invasive Therapy
Rat
e p
er 1
00 P
YR
Adapted from McConnell JD et al. J Urol. 2003;169(suppl):332 PSA = Prostate Specific Antigen
P=0.0008
P=0.0251
P=0.0029
P=0.018
MODULE 1
Figure 1.10: PLESS Cumulative Incidence of AUR, Surgery and Either One for Placebo Treated Patients by Increasing PSA
0
5
10
15
20
25
30
>0.0
>0.5
>1.0
>1.5
>2.0
>2.5
>3.0
>3.5
>4.0
>4.5
>5.0
>5.5
>6.0
>6.5
>7.0
>7.5
>8.0
Cu
mu
lati
ve I
nci
den
ce (
%) Either
Surgery
AUR
Adapted from Roerhborn CG. AUA 2005.; AUR = Acute Urinary Retention; PSA = Prostate Specific Antigen 24/49
MODULE 1
25/46
The precise causes of BPH are unknown, but the disease is clearly mediated by the androgen testosterone, and its more active metabolite dihydrotestosterone (DHT) 20
Other extrinsic factors (i.e. systemic, genetic, environmental) are also involved 20
20. Lee C, Cockett, A, Cussenot O, et al. Regulation of prostate growth. In: Chatelain C, Denis L, Foo KT, et al. eds. Benign prostatic hyperplasia. Plymouth, UK: Health Publication; 2001:81.
BPH = Benign Prostatic Hyperplasia
1.5 Pathology and Pathogenesis
MODULE 1
26/46
Figure 1.11: Regulation of Prostate Growth: The Role of Androgens
Testosterone Dihydrotestosterone
O
OH
O
OH
H
5α-reductase
Adapted from Bartsch G et al. Eur Urol 2000;37(4):367-380.
MODULE 1
27/46
Figure 1.12: Relative Roles of Type I and Type II 5α-reductase
Tissues in which type I and type II 5α-reductase are predominant
Skin (sebaceous glands)
Type I
Prostate gland
Type II
Liver
Adrenal glands
Internal/external genital tissues
Seminal vesicles
Epidiymis
Hair follicles
Liver
Russell DW et al. Annu Rev Biochem 1994;63:25-61. Norman RW et al. J Urol 1993;150(5, pt 2):1736-9. Rittmaster RS. J Androl 1997;18(6):583-7. Gnanapragasam VJ et al. BJU Int 2000;86:1001-13. Bartsch G et al. Eur Urol 2000;37((4):367-80. Yokoi H et al. Histochem Cell Biol 1998;109(2):127-34. Thigpen AE. J Clin Invest 1993;92(2):903-10.
MODULE 1
28/46
DHT enters the nucleus and stimulates the translation and
transcription of growth factors such as:
EGF – Epidermal Growth Factors
PDGF – Platelet Derived Growth Factors
FGF – Fibroblast Growth Factors
Other intrinsic factors that promote hyperplasia in the stromal and epithelial prostatic compartments
DHT = Dihydrotestosterone
MODULE 1
29/46
Additional mechanisms that promote prostate growth include inhibition of apoptosis by factors such as Transforming Growth Factor (TGF)
Inhibition of apoptosis creates an imbalance between cell proliferation and death
This leads to progressive growth in the prostate’s transition zone 21
21. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:10.
MODULE 1
30/46
Figure 1.13: Dynamic and Static Obstruction in BPH
Dynamic Obstruction: Obstruction due to smooth muscle tone
Static Obstruction: Obstruction due to enlargement of the prostate
BPH = Benign Prostatic HyperplasiaAdapted from Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005.
MODULE 1
31/46
Static Obstruction is caused by enlargement of the prostate as previously described
Dynamic Obstruction is caused by an increase in smooth muscle tone in the prostate and surrounding organs
Up to 60% of hyperplastic tissue is composed of smooth muscle cells and connective tissue
MODULE 1
32/46
Sympathetic nerve stimulation causes the release of norepinephrine,
which binds to α1-andrenoreceptors located on the membrane of the smooth muscle cells
This triggers the influx of calcium and increases prostatic smooth muscle tone
There are several α1-receptor subtypes:
α1A – predominant in the prostate
α1B – involved in peripheral vasoconstriction
α1D – abundant in the liver, spleen, and bladder
MODULE 1
33/46
The two mechanisms described above form the basis for the two major pharmacological approaches to treating BPH:
Inhibition of 5α-reductase to reduce the conversion of testosterone to DHT, resulting in prostate volume reduction
Inhibition of α1-adrenoreceptors to relax the smooth muscle contractions in the bladder neck and the prostatic urethra
BPH = Benign Prostatic Hyperplasia; DHT = Dihydrotestosterone
MODULE 1
34/46
Pathology of BPH
Histologically, the first sign of BPH is the appearance of stromal nodules ranging in size from a few millimeters, to a few centimeters in diameter
The nodules are located in the peripheral area of the transition zone
This is followed by glandular hyperplasia and enlargement of the prostate
BPH = Benign Prostatic Hyperplasia
MODULE 1
35/46
No correlation between prostate size and the degree of outflow obstruction.
This may be due to: 22
Relative proportions of stromal and glandular tissue
Variations in sympathetic nerve stimulation in the smooth muscle
Variable enlargement of the prostate’s middle lobe, resulting in a “ball-valve” obstruction without overall enlargement of the gland
Prostate enlargement is still correlated with risk of progression and complications such as AUR and the need for surgery 23
22. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:11.
23. Kirby RS, McConnell JD. Benign Prostatic Hyperplasia. 5th ed. Oxford: Health Press; 2005:12.
AUR = Acute Urinary Retention
MODULE 1
36/46
1.6 BPH and Quality of Life (QoL)
In most men, BPH is a quality-of-life disease
Histologically, most men are symptom free especially in the early stages
Significant number go on to experience bothersome LUTS
BPH = Benign Prostatic Hyperplasia; LUTS = Lower Urinary Tract Symptoms
MODULE 1
37/46
10
8
6
4
2
0
6.1
9.0
3.6
5.6
2.3
Symptom score
(p<0.0001)
Bother score
(p<0.005)
Activity score
(NS)
Hea
lth
-rel
ated
q
ual
ity-
of-
life
sco
re
3.1
(n=471) Prostate 40 ml
Prostate > 40 ml
Higher Score Worse Status
Adapted from Girman CJ et al. Eur Urol 1999;35:277-284.
Figure 1.14: BPH and Quality of Life
MODULE 1
38/46
HRQoL studies performed in Scotland and the United States in the early 1990’s revealed similar findings 25
Of the 410 men with BPH in the Scottish study, 51% reported interference with at least one of a selected number of daily living activities as a result of urinary dysfunction
This was compared to 28% of men who did not have the condition 26
25. Garraway WM et al. Urology 1994;44:629-36. p629
26. Garraway WM et al. Br J Gen Pract. 1993;43:318-21.
HRQoL=Health-Related Quality of Life; BPH = Benign Prostatic Hyperplasia
MODULE 1
39/46
In 17% of (working-aged) men aged 40-64 with BPH, this interference occurred most or all of the time for at least one activity of daily living, compared with about 3% of men in the same age group who did not have this condition
These men were more likely to be bothered by: Nocturia
Hesitancy
Straining, Intermittency
Weak stream force
Dribbling and Urgency (most bothersome)
BPH = Benign Prostatic Hyperplasia
MODULE 1
40/46
US Study (1993)
In a US study (n=707), men with BPH reported the most bothersome problems to be urgency, frequency and nocturia
Obstructive symptoms, peak urinary flow rates, and post-void urine estimates were unrelated to diminished QoL 27
These men complained of having to limit fluid intake before sleep or travel, and avoid outdoor sports or places without toilets 27
Considering the evidence, it is clear that HRQoL needs to be considered in any treatment plan
27. A comparison of quality of life with patient reported symptoms and objective findings in men with benign prostatic hyperplasia. The Department of Veterans Affairs Cooperative Study of transurethral resection for benign prostatic hyperplasia. J Urol. 1993;150(5 Pt 2):1696-700.
BPH = Benign Prostatic Hyperplasia; QoL = Quality of Life; HRQoL = Health Related Quality of Life
MODULE 1
41/46
1.7 Conclusion
This module helped us differentiate between histologic and symptomatic BPH as well as the prevalence of each.
It clarified the different acronyms used for describing BPH symptoms.
It addressed the progression of BPH and how this affects the function of the lower urinary tract.
We specifically covered the micro- and macro-physiology of BPH with the role of androgens and α1-adrenoreceptors in the prostate as far as growth and dynamic changes.
Considering how BPH affects health-related quality of life (HRQoL) issues, it is very important that we include this component in any treatment plan.
BPH = Benign Prostatic Hyperplasia; HRQoL=Health-Related Quality of Life
MODULE 1
42/46
1.8 Quiz
1. What percentage of men 60 years or older have symptomatic BPH?
a) 20%
b) 30%
c) 40%
d) 50%
e) >50% (correct)
BPH = Benign Prostatic Hyperplasia
MODULE 1
43/46
2. What is the defining characteristic of BPH?
a) An enlarged prostate
b) Symptoms of urinary obstruction (weak flow, hesitancy, and straining )
c) Elevated PSA
d) Symptoms related to storage (frequency,urgency,incontinence)
e) Histological evidence of hyperplastic prostatic tissue, obtained by biopsy (correct)
PSA = Prostate Specific Antigen; BPH = Benign Prostatic Hyperplasia
MODULE 1
44/46
3. Which of the following is NOT a risk factor for acute urinary retention?
a) advanced age
b) large prostate
c) family history (correct)
d) previous history of AUR
e) severe LUTS
AUR = Acute Urinary Retention; LUTS = Lower Urinary Tract Symptoms
MODULE 1
45/46
4. Which type of 5α-reductase is most prominent in the prostate?
a) Type 1
b) Type 2 (correct)
c) Both types
d) It varies from individual to individual
MODULE 1
46/46
5. What does the term “dynamic obstruction” refer to?
a) Symptoms suggestive of acute urinary retention
b) Urinary obstruction due to increased smooth muscle tone in the prostate and surrounding tissues (correct)
c) Enlargement of the prostate resulting in urinary obstruction
d) Progressive LUTS
e) LUTS resistant to medical treatment
LUTS = Lower Urinary Tract Symptoms