External Beam Radiotherapy for Prostate Cancer Chomporn Sitathanee, Radiation Oncology Unit Ramathibodi Hospital, Mahidol University
Roles of RT in prostate cancer Definitive RT; intact prostate Post radical prostatectomy Adjuvant RT: no measurable disease Salvage RT: local recurrence (PSA or gross) Palliative RT: local symptom
Radiotherapy Techniques External beam radiation/ Teletherapy Brachytherapy
Brachytherapy interstitial implant Permanent implant: LDR I-125, Pd-103 Temporary implant: HDR Ir-192
Brachytherapy Definitive treatment - monotherapy in low-intermediate risk risk - combine with EBRT as a boost in high Salvage treatment after EBRT failure
External beam RT Definitive treatment in any stage Adjuvant treatment Salvage treatment after RP failure Palliative treatment
EBRT technique 2D RT 3D conformal radiotherapy (3D-CRT) Intensity modulated radiotherapy (IMRT) Stereotactic body radiotherapy (SBRT) 4D Image-guided radiotherapy (IGRT)
Immobilization CT/MRI simulation RT planning & QA RT delivery
Definitive treatment/ Intact prostate RT dose escalation improves BCF free survival High dose EBRT EBRT + brachy boost Biological dose escalation
RT dose/fraction for definitive tx Conventional fraction: EBRT, LDR brachy Moderate hypofraction: EBRT Ultra (extreme) hypofraction: SBRT, HDR brachy
Low risk disease EBRT conventional f EBRT moderate hypof SBRT Brachy monotherapy: LDR, HDR Treat prostate only (± prox SV) No ADT
Tech d/f (Gy) TTD (Gy) #f TTT (wk) EBRT conv f 1.8-2 76-86.4 38-48 8-10 EBRT mod 2.5-4 57-70 19-30 4-6 hypof 2.5 3 70 60 28 20 6 4 SBRT (ext 7.25-9 36.25-45 5 1-2 hypof) ~to 8 ~to 40 LDR mono 145 I-125 125 Pd-103 1 2d HDR mono 8.5-9.5 34-38 4 2d (ext hypof) 10.5 13 31.5 26 3 2 2d 2d 19 19 1 1d
Intermediate risk disease EBRT conventional f EBRT moderate hypof SBRT Brachy monotherapy: LDR, HDR EBRT 45-50 Gy + brachy boost Treat prostate only (±prox SV) ± short-term ADT 4-6mo (neoadjconcurrent)
High risk disease EBRT conventional f EBRT 45-50Gy + brachy boost (HDR 12-15Gy/1f or LDR 90-100Gy) Treat prostate/sv + pelvic LN or prostate/sv only Long-term ADT 2-3yr (neoadj-concurrentadjuvant)
High risk disease RCTs showed survival benefit of RT+ADT over ADT alone pt with good condition/reasonable life expectancy should receive definitive local treatment
Rational of using hypof in PC PC needs high dose radiation for better LC 8-9 wk of conventional F (38-45f) PC biology: slow growing, low α/β ratio more sensitive to higher daily RT dose More convenient for pt, reduce cost/waiting time, increase pt access to RT
Extreme hypof Stereotactic Body Radiotherapy (SBRT) Stereotactic Ablative Radiotherapy (SABR) A method of EBRT that accurately delivers a high radiation dose to a small welldefined extracranial target in one or few fractions
SBRT Needs rapid dose fall off to spare normal tissues by using multiple small beam entries IGRT, tumor motion management is mandatory Lung, liver, spine, prostate, recur after RT Can be done by conventional LINAC with small field IMRT/IGRT, CyberKnife, Particle beam
172 LR, 137 IR med fu 61 mo ASTRO 2016
Patient work flow Pt selection: - Patho - PSA, lab - MRI Treatment delivery (1-2 wk) Fiducial implant (Gold markers) Treatment planning (~1 wk) At least 1 wk Immobilization CT/MRI simulation
Postoperative RT Adjuvant/Salvage RT
Adjuvant RT RT to prostate bed in men with undetectable PSA (<0.2ng/ml) Risk factors for LR: T3, +margin 3-6 mo post surgery when incontinence has resolved or stabilized Dose 64-68Gy/32-38f
Adjuvant RT vs. Observation Pt# PSA mfu (y) %10y BCFFS %FFDM p No RT RT No RT RT SWOG 8794 EORTC 22911 ARO 96-02 425 33%>0.2 12 28 58 61 71 <0.002 1005 pt3 and/or +margin 30%>0.2 10 41 60 89 90 NS 385 Undetect 9.3 35 56 97 98 NS 20%>0.1
Salvage RT RT to prostate bed/gross tumor in men with LR detectable & rising PSA with or without gross tumor, no distant metas ASTRO/AUA guideline for biochemical recurrence as a detectable or rising PSA after surgery 0.2ng/ml with a second confirmatory level 0.2ng/ml Dose: 68-70Gy (no gross), >70Gy (gross)
Factors predicting outcome of SRT prert PSA** >1 associate with high risk of failure after SRT SRT dose: dose response relationship as in definitive RT, SRT dose should be 70Gy Uncertain benefit: pelvic LN RT (vary by extent of PN removed), ADT (ongoing trial)
Post-op RCT Adjuvant RT vs. observe: SWOG, EORTC, ARO 60-64Gy Adjuvant RT vs. early salvage RT: RAVES, RADICALS, GETUG17 64-66Gy RTOG 9601 salvage RT± ADT 64.8Gy RTOG 0534 salvage RT to PB vs. WPRT ± ADT 64.8-70.2Gy
Entry PSA 0.2-4 SRT± 2y casodex, mfu 7y: RT+ casodex >> better BCFFS & less DM
SRT± STADT: RT to prostate bed vs. pelvic N (3 arms)
Radiation Complications Urinary tract Bowel/rectum Acute - Cystitis/urethritis (frequency, urgency, burning, discomfort) - Urinary retention/ blockage (brachy, SBRT) - Prostatitis (fiducial implant) Diarrhea/acute proctitis Late - Cystitis: frequency, urgency, bleeding - Urethral stricture (postop SRT, brachy) Proctitis: bleeding, increase bowel movement Erectile dysfunction 2 nd cancer
Full bladder, empty rectum
Thank you