Radiation Therapy for
Localized Prostate
Cancer
Berna DeMalignon, M.D
Goals
• Overview of treatment options for localized prostate CA.
• Review current risk stratification of patients.
• Discuss patient factors that can affect treatment decisions.
• Gain understanding of various radiotherapeutic modalities used for
prostate cancer including advantages and disadvantages.
• Understand implications of fractionation and current options.
• Discuss treatment intensification in high risk patients.
• Review toxicities associated with radiotherapy for prostate cancer.
Treatment options for localized prostate CA
• Active surveillance/observation
• Radical prostatectomy +/- PLND
• EBRT (3D conformal/dose escalated IMRT/IGRTconventional vs hypofractionation including
SBRT)
• Brachytherapy- low dose vs HDR
• EBRT+ brachytherapy+/- ADT; EBRT+ADT
Tools of the Trade
NCCN risk stratification groups
Patient factors to consider in addition to risk
stratification
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Co-morbidities and life expectancy
Degree of anxiety regarding diagnosis/treatment
Level of compliance
Previous TURP
Voiding symptoms/ AUA IPSS score
Gland size
Baseline sexual function and goals for preservation
Distance from radiotherapy facility
Active surveillance
ProtecT trial
Conventional Radiation therapy
• Small daily doses of radiation (1.8-2Gy) per
day to total of 76-81Gy.
• Techniques includes 3D conformal RT, and
more modern IMRT and IGRT
• Today MRI fusion aids in delineation of
prostate
Image-guided radiation therapy (IGRT)
• Important in prostate radiotherapy because changes in bladder
filling and rectal distention can cause prostate displacement.
Moderate hypofractionation (>2.2Gy/fx)
• Should be offered to men with low risk and intermediate risk
disease (100% consensus), 94% agree ok for high risk (No XRT to
LN’s).
• 94% agree that it should be offered regardless of age, comorbidity,
anatomy or urinary function. May prefer to limit to AUA score of
</=15 and gland size <100cc. *RCT’s limited f/u beyond 5 years
• Small increased risk of acute GI toxicity.
• Regimens of 6000cGy in 20 fractions (3Gy each) or 7000cGy in 28
fractions (2.5Gy each) recommended.
Extreme Hypofraction(>5Gy/fx)
AKA “SBRT”
• 7Gy-7.25Gy x 5 = 35Gy-36.25Gy (88% consensus)- offer to low and
intermediate risk with gland size <100cc3.
• Consecutive treatment not suggested
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LINAC based vs Robotic
Intrafraction image guidance used
FASTER AND CHEAPER
ASTRO model policy includes support for SBRT since 2013
IGRT-Intrafraction imaging
Brachytherapy
Brachytherapy
• Advantage over EBRT is that it overcomes organ motion and spares
adjacent normal tissue.
• HDR may have theoretical advantage due to high dose per fraction
(>6Gy/fx).
• Has consistently been found to be the most cost effective
treatment .
• Does not provide adequate perioprostatic disease in certain
intermediate and high risk patients
• Requires technical experience
Treatment intensification with long term ADT
Multiple randomized trials have shown that in high risk patients the addition of long term ADT
improves OS and maximizes disease control compared to single modality therapy.
Treatment intensification with
EBRT+brachytherapy+ long-term ADT
Treatment options by risk stratification
Low Risk
Intermediate risk
High risk/Very High
AS
Favorable IR
RP
RP
Consider AS
EBRT (conventional, may consider
hypofractionation) + long term ADT
(1.5-3yrs)
EBRT (conventional or mod
hypofractionation)
Brachytherapy (LDR or HDR)
SBRT
RP
EBRT (conventional or mod
hypofractionation)
Brachytherapy
-Consider SBRT
NRG clinical trial (5 fxs vs 28)
Unfavorable IR
RP
EBRT (conventional or moderate
hypofractionation)+/- ADT 4 months
Brachy+EBRT+/-ADT
EBRT (45-50Gy/5 weeks+
brachytherapy boost)+ADT (1-3 yrs)
Side effects
Short term:
- Fatigue
- GU changes: increased frequency, decreased flow, obstructionurethritis, cystitis.
- perineal/rectal irritation, mucositis, perineal discomfort or diarrhea.
Long term:
-urethral strictures
- incontinence
- erectile dysfunction
- rectal bleeding