Topics:
Radiation Oncology • Gastrointestinal Cancers
When treating rectal cancer with conventional neoadjuvant chemoradiation (45 Gy to pelvis with boost to 50.4 Gy), what volume do you use for the boost?
There is no RTOG consensus on boost volume, except to say that it should include the entire mesorectum/presacral region at involved levels + 2 cm in cc directions. According to RTOG 0822, it is recommended that the CTV extends 1 cm into bladder, vagina or prostate. Do you use this parameter for the boost volume? If so, what dose constraint do you use for bladder (as protocol states any volume of bladder > 50 Gy is unacceptable).
Answer from: Radiation Oncologist at Academic Institution
Great question. There does seem to be some variation in boost volume, particularly between 3D and IMRT treatments.
At MDACC, we typically use a prone 3 field belly board technique for most rectal cancer patients receiving standard neoadjuvant long-course chemoradiation. The pelvis goes to 45G...
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Answer from: Radiation Oncologist at Academic Institution
We approach this in much the same way as Emma has described. For 3D treatment, you can simply copy the fields and pull MLCs anteriorly in the lateral fields for more small bowel/bladder sparing. Many times they are quite similar to the original fields especially posteriorly on the lateral fields. Th...
Comments
Radiation Oncologist at Memorial Sloan-Kettering Cancer Center
I agree, the biggest point of emphasis is that the...
I agree, the biggest point of emphasis is that the...
Radiation Oncologist at Washington University School of Medicine
For many cases, the proposed boost fields would pr...
For many cases, the proposed boost fields would pr...