1. Acute Toxicity for
Prostatectomy Patients receiving
y g
Intensity Modulated Radiotherapy
V. Kong, T. Craig, A. Bayley, R. Bristow, C. Catton,
P. Chung, M. Gospodarowicz, M. Milosevic, P. Warde, C. Ménard

2. Introduction
Radical Prostatectomy
y
Effective treatment for patients with favorable
prognostic factors
Intent of Post-Operative Radiotherapy
Reduces local recurrence rate for high risk patients
Used as either adjuvant or salvage therapy
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3. Post-
Post-Operative Radiotherapy
Treatment Volume & Technique
q
Defined using bony landmark
4 Field Box
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4. Side effects from Radiotherapy
Gastrointestinal (GI)
Proctitis
Loose bowel movement
or diarrhea
Genitourinary ( )
y (GU)
Urinary incontinence
Increased frequency
Pain/Burning senation
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5. Advancement of Technology
New consensus guideline for prostate bed
g p
Clinical Target Volume (CTV) definition
Increase volume? -> Increase toxicity?
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6. The need to change
Treatment technique
q
Conformal 4 field box
62.7 Gy
55.0 Gy
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7. Objectives
To describe the development of an Intensity
p y
Modulated Radiotherapy (IMRT) technique for
the Prostate Bed
To
T report th clinical dosimetric characteristics of
t the li i l d i t i h t i ti f
the new technique
To report acute GI and GU toxicity outcomes
To compare results with a historical cohort
treated by 4 field box technique (4FB)
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8. Method
50 patients accrued to prospective trial
p p p
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9. Process Flowchart
Patient Education Sess o
at e t ducat o Session
CT Simulation
Delineation of Regions of Interest (ROI)
Generation of IMRT Distribution
Treatment
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10. Process Flowchart
Patient Education Sess o
at e t ducat o Session
CT Simulation
Delineation of Regions of Interest (ROI)
Generation of IMRT Distribution
Treatment
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11. CT Simulation
Full bladder and empty rectum
py
Pelvic vacuum immobilization device
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12. Process Flowchart
Patient Education Sess o
at e t ducat o Session
CT Simulation
Delineation of Regions of Interest (ROI)
Generation of IMRT Distribution
Treatment
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13. Clinical Target Volume
Inferior CTV (ICTV) Superior CTV (SCTV)
Wiltshire et al. IJROBP 2007 69(4); 1090-1099
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14. Planning Target Volume
Planning Target Volume (PTV) Margin (mm)
g g ( ) g ( )
Online guidance using soft tissue/surgical clip
Chu, 2007
AP SI RL
SCTV 14 13 7
ICTV 10 11 5
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15. Organ at Risk (OAR)
Rectal Wall (RW)
( )
Bladder Wall (BW)
Penile Bulb (PB)
Femur
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16. Process Flowchart
Patient Education Sess o
at e t ducat o Session
CT Simulation
Delineation of Regions of Interest (ROI)
Generation of IMRT Distribution
Treatment
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17. IMRT
7 field step-and-shoot distribution
p
Dose fractionation
66Gy in 33 fractions
y
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18. IMRT
Treatment planning objectives
p g j
1. Avoid irradiating rectum circumferentially to
55 Gy
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19. IMRT
Posterior Rectal Wall (pRW)
(p )
62.7
62 7 Gy
55.0 Gy
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20. IMRT
Treatment planning objectives
p g j
1. Avoid irradiating rectum circumferentially to
55 Gy
2. PTV D99 ≥ 54 Gy
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21. IMRT
Treatment planning objectives
p g j
1. Avoid irradiating rectum circumferentially to
55 Gy
2. PTV D99 ≥ 54 Gy
3. Maximize % of PTV receiving 95% of
prescription dose – V95
i ti d
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22. Dose Constraints
Organs at Risk Metric Dose (Gy)
Rectal Wall 1 cm3 ≤ 66 0
66.0
Bladder Wall 2 cm3 ≤ 67.3
Penile Bulb 0.5 cm3 ≤ 66.0
Femur 1 cm3 ≤ 55.0
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23. Monitoring Side Effect
Acute Toxicity Scoring
y g
Common Terminology Criteria Adverse Events
(CTCAE) v3.0
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24. V. Kong, PMH Conference

25. Monitoring Side Effect
Acute Toxicity Scoring
y g
Common Terminology Criteria Adverse Events
(CTCAE) v3.0
GI GU
Diarrhea Frequency
Proctitis Haematuria
Cystitis
Spasm
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26. Is IMRT better?
Comparison with 4FB technique
p q
23 patients with acute toxicity scored using
CTCAE v3.0
Dose to Rectal Wall and Bladder Wall
Acute GI/GU toxicity
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27. Result
Mean PTV V95 = 95.2% (SD = 2.1)
( )
20
18
16
14
Number 12
of 10
Patients 8
6
4
2
0
90 92 94 96 98 100
PTV V95 (%)
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28. Result
64.0
Patient A
62.0
60.0
PTV D99
58.0
(Gy)
56.0
54.0
2
R = 0.8514
Patient B 52.0
90.0 92.0 94.0 96.0 98.0 100.0
PTV V95 (%)
Mean PTV D99 = 57.8 Gy (
y (Range: 53.4 – 62.9 Gy)
g y)
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29. Result
Patient A Patient B
62.7 Gy
55.0 Gy
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30. Result
Acute GI Toxicity
y
Score Diarrhea Proctitis GI
0 19 (38%) 17 (34%) 10 (20%)
1 25 (50%) 23 (46%) 27 (54%)
2 6 (12%) 13 (20%) 13 (26%)
3 0 0 0
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31. Result
Acute GI Toxicity
y
Score Diarrhea Proctitis GI
0 19 (38%) 17 (34%) 10 (20%)
1 25 (50%) 23 (46%) 27 (54%)
2 6 (12%) 13 (20%) 13 (26%)
3 0 0 0
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32. Result
Acute GU Toxicity
y
Score Frequency Haematuria Cystitis Spasms GU
0 19 (38%) 45 (90%) 39 (78%) 27 (54%) 14 (28%)
1 24 (48%) 5 (10%) 10 (20%) 20 (40%) 28 (56%)
2 5 (10%) 0 1 (2%) 3 (6%) 6 (12%)
3 2 (4%) 0 0 0 2 (4%)
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33. Result
Acute GU Toxicity
y
Score Frequency Haematuria Cystitis Spasms GU
0 19 (38%) 45 (90%) 39 (78%) 27 (54%) 14 (28%)
1 24 (48%) 5 (10%) 10 (20%) 20 (40%) 28 (56%)
2 5 (10%) 0 1 (2%) 3 (6%) 6 (12%)
3 2 (4%) 0 0 0 2 (4%)
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34. Result
Comparison of Dose to Rectal Wall
p
100
4FB
IMRT
80
Normalized 60
Volume
(%) 40
20
0
0 1000 2000 3000 4000 5000 6000 7000
Dose (cGy)
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35. Result
Comparison of Dose to Bladder Wall
p
100
4FB
IMRT
80
Normalized 60
Volume
(%) 40
20
0
0 1000 2000 3000 4000 5000 6000 7000
Dose (Gy)
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36. Result
Comparison of Acute GI/GU Toxicity Score ≥ 2
p y
50 IMRT
4FB
40
Number 30
of
Patient
20
(%)
10
0
GI GU
G and
GI a d GU C Square value = 5
Chi Squa e a ue 5.21 & 9 , d = 1, p < 0 05
9.77, df , 0.05
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37. Conclusion
Avoidance of circumferential irradiation of rectum
to 55Gy with minimal compromise of PTV coverage
is achievable with IMRT
The use of IMRT reduces acute GI/GU toxicity rate
when compared with the 4FB technique
Ongoing investigation to determine if improved
dosimetry to OARs translates to improved late
toxicity and biochemical control
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38. Acknowledgment
Dr. Kirsty Wiltshire
y
Dr. William Chu
Clinical Trial Co ordinators
Co-ordinators
Debbie Tsuji
Bernadeth Lao
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