Topics:
Radiation Oncology • Genitourinary Cancers
What bowel constraints do you use when treating definitive bladder?
When treating intact bladder case to 63-64.8 Gy with shrinking fields, the max bowel dose is close to the rx dose. Old RTOG trials often just used V45 < 300 but aim for V45 <195cc from QUANTEC. Do you have a max constraint or a V55 constraint? We use V55 < 5-10 cc from GYN cases but has not been typically possible.
Answer from: Radiation Oncologist at Academic Institution
The SWOG S1806 trial approaches this by contouring small bowel loops (excluding large bowel) and constraining this to Max (0.03cc) <55 Gy, V50 Gy <15 Gy, V45 Gy<100cc, V40 Gy<130cc and <30%, and V30 Gy <150cc.
IMRT can help if you are running into trouble with the lower dose...
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