Review Note
Last Update: 02/18/2024 05:30 AM
Current Deck: Part 2::6. High Yield Questions::Genitourinary
PublishedCurrently Published Content
Front
A
65-year-old man presents with a PSA of 0.3 mcg/L 12 months after a radical
prostatectomy.
His initial pathology showed adenocarcinoma (Gleason 4+5) with
extracapsular
extension and a positive margin.
Describe
a suitable radiation therapy technique and dose fractionation schedule for this
patient. Back
Presim:
o Review
pathology, PSAs, imaging, MRI
o pelvic
floor training
o Commence
short term ADT
Simulation
o Position
– supine, arms on chest
o Immobilization:
neck support, knee supports, ankle stocks
o Bladder
full, rectum empty- protocol (rescan if rectum >4cm diam)
o CT
scan – 3DCT from L3/4 (ASIS) 1.5cm below ischial tuberosities
Dose: 68Gy/34# to the prostate bed, 56Gy/34# to the pelvic nodes in a SIB technique
o 9 fractions per fortnight
o VMAT 6/10 MV photons
Target volumes
CTV: Surgical
bed
- Inf border of CTV is 5mm below anastomosis
- Ant= posterior aspect of pubic symphisis for inferior 3cm of volume, then posterior 1.5cm of bladder wall
- Post= Space delineated by levator ani + anterior rectal wall.
- Lat= medial border of levator ani/obturator internus
- Sup= superior vascular clip, or inferior portion of vas deferens.
PTV= CTV+ 7mm
CTV nodes = obturator nodes, external, internal iliac, presacral lymphnodes.
PTV = CTV+5mm
OAR constraints
- Rectum
- V40<60%
- V50<50%
- V60<40%
- V66<30%
- Bladder
- V40<50%
- V65<25%
- Femoral
heads
- V50<5%
- V60<30%
- V45Gy<60%
- Penile bulb: Mean <52.5Gy
- Small bowel:
- 2cc <60Gy, 100cc <45Gy (cavity)
Further information, not for memorising (no card)
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