- UBC Urology Rounds

10-10-20
Radiation-based Strategies for
Penile Preservation
Juanita Crook MD
FRCPC
Professor of Radiation
Oncology
University of British Columbia
Center for the Southern Interior
Kelowna BC
External Radiotherapy
•  small lesion:
–  kilovoltage or superficial electron (6MeV)
–  direct apposition
–  fractionation typical for skin cancer
ie/ 3500/5, 4250/10
•  larger lesion (>1/3 of circumference)
–  need to treat full thickness with full dose to surface
–  requires more prolonged fractionation scheme
such as 6600 cGy/30 fractions/6 weeks
1
10-10-20
treatment
cone
dorsal view
1
2
transverse view
Wax or
lucite block
technique
• wax provides full bolus
to skin surface
• penile swelling as treatment
progresses may make fitting
wax difficult
• can’t see the target once
the wax is in place
• Lucite transparent for easy
verification of coverage
• Can be available in various
sizes to accommodate change
2
10-10-20
Reaction to treatment
•  moist desquamation in treated area
•  takes 4-6 weeks to heal
•  long-term may see hypo/hyper
pigmentation, telangiectasia
•  effect on potency/erections depends on
proportion of penile shaft treated
Penile
brachytherapy
always need circumcision
first for full exposure
and to avoid foreskin
necrosis/phimosis
3
10-10-20
Implant technique:
Low dose rate
•  Paris system of dosimetry
•  17-19.5 gauge steel needles in 3D array in
predrilled plexiglass template
•  # of needles: 6 (2-9)
•  # planes:
1-3
•  spacing:
12-18 mm
•  dose:
60 Gy
•  dose rate:
50-65 cGy/hr
•  duration:
4-5 days
Technique
• 
• 
• 
• 
performed under local or general anesthesia
takes 30-45 minutes
patient catheterized for duration of implant
penis supported in styrofoam collar to
minimize dose to neighbouring tissue
•  recommend prophylactic LD heparin and
anti-embolic stockings
•  minimal analgesia required
4
10-10-20
Population
• 
• 
• 
• 
• 
• 
Interstitial brachytherapy using Ir-192 wires
or PDR after-loading
74 SCC of the penis Sept 89 - Dec 2007
56% T1 / 33% T2 / 8% T3
cN0:61 cN1:4, cN2:2
35% WD / 46% MD / 2% PD
Size < 2 cm: 18 / 2-3 cm: 19 / > 3cm: 23
(7 + margin post excisional bx)
Paris system of dosimetry:
schematic of 2-plane implant
5
10-10-20
Penile Brachytherapy
17 gauge needles
template
styrofoam collar
Dosimetry
•  since rigid geometry is
maintained throughout
duration of implant,
dosimetry is very accurate
•  after-loading “pulse dose
rate” allows optimization
if desired
6
10-10-20
Asymmetric tumor
7
10-10-20
Pre-implant
post dorsal slit and
gross excision
phimosis and “warty” SCC
Schematic of single-plane vs.
2-plane implant
Isodose
Radioactivity placed
exterior to penis
Isodose
Bolus
Radioactive needles
within penis
8
10-10-20
Exterior plane
Bolus
Deep plane
Acute moist desquamation
9
10-10-20
Late reactions
•  urethral stenosis : 9 %
–  requires periodic dilatation
•  mild to moderate fibrosis, telangiectasia,
pigmentation change
•  some tissue atrophy at the tumor site if
deeply invasive
•  soft tissue necrosis 12%
•  erectile function maintained in majority
0.6
0.4
0.2
# At Risk
49
0.0
Proportion Failure Free
0.8
1.0
5yr actuarial LF free survival = 88%
0
0
31
22
2
5
4
4
6
8
10
10
Local Failure Free Survival (Years)
15
12
10
10-10-20
median follow-up: 4 yrs (0.5-16.2)
8 local failures: 8/67 = 12%
stage
grade
T3
surgery
timing
penectomy
7 mo
T2
WD
partial
12 mo
T1
MD
partial
12 mo
Tx
WD
partial
21 mo
Tx
verrucous
penectomy
21 mo
T1
MD
partial
4.5 yrs
T1
WD
partial
7 yrs
T1
WD
partial
8.5 yrs
0.6
0.4
0.2
# At Risk
57
0.0
Proportion Alive
0.8
1.0
10 year actuarial CSS 83.6 %
0
39
28
5
5
10
15
Disease Specific Survival (Years)
11
10-10-20
Organ sparing
•  2 penectomies for LF
•  6 partial penectomies for LF
•  2 partial penectomies for radiation
necrosis
•  57/67 intact penis @ LFU or death
•  26/32 report satisfactory potency
0.8
0.6
0.4
0.2
# At Risk
55
0.0
Penile Preservation Rate
1.0
Intact penis: 5 yr 88%;10 yrs 67%
0
35
26
5
10
Penile Preservation (Years)
12
10-10-20
Metastatic predictors
•  only 1 WD tumor has failed regionally or
distantly
•  39% of moderately or poorly
differentiated tumors have failed
regionally and/or distantly
•  grade predictor of DFS p=0.005
Reported BT results
Author/
year
n
Dose
F/up (mo)
LC:5y (10 CSS
y)
compn
Penis
presn
Chaudery
1999
23
50
21 (4-117)
70%
2/23 sten
70% (8y)
Crook
2008
67
60
48 (4-194)
87%(5y)
72(10y)
84%
(10 y)
12% nec
9% sten
88% (5y)
67%(10y)
DeCrevoisier
2008
144
65
68 (6-348)
80%(10)
92%
(10y)
26% nec
29% sten
72%
(10 y)
Delannes
1992
51
50-65
65 (12-144)
86% c
85%
Kiltie 2000
31
63.5
61.5
81%
85%
23% nec
75%
45%
sten
Penile conservation
75%
~ 70%8%
@nec
10 years
44% sten
Mazeron
1984
50
60-70
Rozan
1995
184
63
Soria 1996
102
61-70
LC 36-96
@ 5 years
70-87%
139
111
78% c
3 nec
19% sten
74%
86%
88%
21% nec
45% sten
78%
77%
72%
ns
72%(6y)
13
10-10-20
External Beam RT Results
Author
n
Dose
F/up
LC (5 yr) CSS
compn
Penis
presn
Gotzadse
2000
155
40-60
40 yrs
65%
86%
nec: 1
sten: 5
65%
McLean
1993
26
35/10
60/25
116
(84-168)
62%
69%
7/26
66% c
Mistry
2007
18
55/16
62
63%
75%
nec: 2
sten: 1
66% c
Neave
1993
20
50/25
36 mo
70%
58%
10% sten
60%
Sarin
1997
59
66%
nec: 3%
sten:15%
50% c
Ozsahin
2006
33
sten: 10%
52%
LC @ 5 yrs
60/30Wt av
62 61% 55%
(2-264)
52
62
(6-450)
44%
Conclusions
•  Brachytherapy provides excellent LC of T1-T2
penile SCC, (selected T3), ideally < 4 cm with
no extension onto shaft
•  Circumcision pre BT essential
•  penile conservation rate @ 5 yrs: 87% and @
10 years 70% with BT, 60% with external beam
•  Observation of LN appropriate for WD tumors
•  Close follow-up mandatory as local failures &
many regional failures can be salvaged
•  Local recurrence may be late (8-10 yrs+)
•  Meatal stenosis/ soft tissue ulceration higher
with BT (manage conservatively)
14
10-10-20
2010
HDR for penile cancer in BC
VCC
Mira Keyes
clinical associate professor
radiation oncology VCC
LDR and HDR
LDR
HDR
• 
• 
• 
• 
• 
• 
• 
• 
• 
Dose:
6000cGy over 4-5 days
dose rate:
50-65 cGy/hr
PDR –pulse dose rate (after
loading system)
•  Infinite number of small
fractions
Dose??
45Gy
Dose rate 200cGy/min
BID (400cGy/day)
6 days
•  Few large fraction
“Dose Rate” is the rate at which dose is deposited in the tissue
Tissue express different (late) tissue damage pattern
and different tumour control with different dose rate – dose needs to be adjusted
15
10-10-20
LDR vs. HDR
LDR
HDR
•  Known dose response
•  Uncertainty about dose and
dose delivery schedules
•  Outcomes and side effects not
fully known
•  Known outcomes side effects
•  Radiation exposure for patients
and health care providers may •  No radiation exposure to
health care providers
be significant
•  Dose optimization challenging
•  Dose optimization excellent
(technically more forgiving,
less operator dependant)
PDR advantages of LDR - (dose) and
HDR - no exposure to staff and dose optimization
BCCA cases
Dose 42-45 Gy x12# BID
6 days
HDR
16
10-10-20
17
10-10-20
18
10-10-20
10 weeks
6 weeks
14 weeks
9 mo
19
10-10-20
CASE 2 T2No gr3
5weeks June 11
July 21
Aug 18
July 21
20
10-10-20
Aug 16
Sept 7
21