Pelvic Node Boost

[FrostyHammer]

Dear colleagues,

Longtime observer but I have a quick question that I'd like to run by y'all.

In various pelvic cancers - specifically, I am thinking of prostate but I suppose could be extrapolated to others that go to pelvic LNs - if you are using IMRT to treat an involved node within the pelvic nodes, how high do y'all go on that node, and what is the dose constraint you use to the bowel (max, mean, whatever y'all use - or if it's different if it's small vs large bowel)?

Thanks!

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[Palex80]

My constraint for small bowel is generally D2cc<54 Gy. I will accept point doses up to 60 Gy.

 

[Reaganite]

Dear colleagues,

Longtime observer but I have a quick question that I'd like to run by y'all.

In various pelvic cancers - specifically, I am thinking of prostate but I suppose could be extrapolated to others that go to pelvic LNs - if you are using IMRT to treat an involved node within the pelvic nodes, how high do y'all go on that node, and what is the dose constraint you use to the bowel (max, mean, whatever y'all use - or if it's different if it's small vs large bowel)?

Thanks!

I've had the run of all run of these. Really depends on the circumstances for me. I had a very young lady with an unresectable nodal recurrence of endometrial cancer invading the pelvic side wall. Solitary site. No other mets. Did chemo RT and there was piece of bowel adjacent to the mass that got at least 66Gy point dose. She did end up getting a bowel obstruction. I don't know if it was from me or the surgery, but it was pretty easily corrected and for now she's NED.

For paraaortic nodes from say cervical cancer, I will go as high as 60. I watch the cbct day-to-day to see what bowel is doing and if moving around, I don't have a problem with that dose.

If tumor is near duodenum, I have seen a couple of papers suggest V55<10-15ccs and I really try to adhere to that since duodenum is basically fixed and most of the nodes are down by the last part of the duodenum/jejunum which apparently is more difficult to get to with a laser to stop bleeding.

 

[Gfunk6]

How do you distinguish small/large bowel on a cone-beam CT??

 

[medgator]

How do you distinguish small/large bowel on a cone-beam CT??

You probably could if the field of view is long enough.... prob would be hard though given the quality of the images

 

[evilbooyaa]

If you can start at the rectum and work your way up you could follow the sigmoid more proximally. I'm not sure of the value of this, however, and it depends on how good your CBCTs are. With MVCT, I don't think it would be feasible.

 

[Palex80]

If you can start at the rectum and work your way up you could follow the sigmoid more proximally. I'm not sure of the value of this, however, and it depends on how good your CBCTs are. With MVCT, I don't think it would be feasible.

It can be quite difficult some times. I think we all have seen a few cases of small bowel coming into the small pelvis between bladder and sigmoid.
We currently have a prostate patient here with a pT3b tumor in need of salvage RT, with small bowel more or less in the area where the seminal vesicles used to be.
Tough to give 66 Gy, bearing in mind that it's probably immobile small bowel down there.