treating IM nodes

[deleted1116990]

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When you use inverse planning for intact breast, how far do you all crop the PTV from skin? I was taught to crop 5mm for 3D tangent planning in intact breast; however, the FLORENCE trial crops to 3mm and they use IMRT.

I am doing a 5 fraction whole breast plan with VMAT. Fast-Forward cropped to 5mm. However, doing this with VMAT seems wrong.

 

[jondunn]

3 mm or 5 mm, same diff. pick one and breathe easy. I do 3 mm from skin always. some people do 5.

 

[TheWallnerus]

When you use inverse planning for intact breast, how far do you all crop the PTV from skin? I was taught to crop 5mm for 3D tangent planning in intact breast; however, the FLORENCE trial crops to 3mm and they use IMRT.

I am doing a 5 fraction whole breast plan with VMAT. Fast-Forward cropped to 5mm. However, doing this with VMAT seems wrong.

The cropping is mostly so the fluence doesn't get choppy/ugly at the skin. I agree, "tangent VMATs" won't be as simple/pragmatic as tangent static 2-beam IMRT. Even though you crop, you should still "flash" IMHO.

What I do:
1) I put on traditional tangents that would match what we have done historically; these beams de facto define the PTV and there is no need to contour anything outside (or under-contour for that matter) traditional tangents. Of course feel free to contour lungs, heart (you need those to put on to make good tangents anyways).
2) This best-tangent field arrangement is open calc'd... in Eclipse, this will give a plan of Dmax about 200% of Rx dose, and the ~170% (which would be ~85% if plan were normalized at this point but there is no need to) to 180% isovolume is chosen for Eclipse to convert this to a structure. Again, this is the PTV and essentially is the area treated inside the fields of traditional tangents.
3) This structure is "pre-cropped"... you don't need to edit it, the calc algorithm already handled it.
4) Using the same tangents, go into inverse optimization. Click "fixed field sizes." Optimize to the PTV. E.g. if the Rx is 40 Gy, 100% of the PTV will receive 40 Gy or more. I set BODY max at 42 Gy with high priority; this makes the plan very homogenous (max dose in plan of 105% in other words). X&Y smooth of 40/30 usually (the default).
5) Now use the fluence editing tool(s) to extend the fluence ~1.5cm out past the skin surface for flash.
6) Calc.

From start to finish, usually 20min or less. Other centers have different "programs" and automated ways of doing more or less the same thing. Many different ways can work.

EDIT: It is my understanding that in the UK 26/5 partial breast is the new standard and the most common treatment now for low risk breast. They see no need to give the whole breast either 26 Gy (or 40 Gy or whatever) or Livi-level 30 Gy to partial breast. They have combined the idea of 26 Gy whole breast with IMPORT-LOW. To me, it makes good sense. I must admit I do whole breast not that commonly these days and essentially never in Stage I.

 

[Burt Radnolds]

The cropping is mostly so the fluence doesn't get choppy/ugly at the skin. I agree, "tangent VMATs" won't be as simple/pragmatic as tangent static 2-beam IMRT. Even though you crop, you should still "flash" IMHO.

What I do:
1) I put on traditional tangents that would match what we have done historically; these beams de facto define the PTV and there is no need to contour anything outside (or under-contour for that matter) traditional tangents. Of course feel free to contour lungs, heart (you need those to put on to make good tangents anyways).
2) This best-tangent field arrangement is open calc'd... in Eclipse, this will give a plan of Dmax about 200% of Rx dose, and the ~170% (which would be ~85% if plan were normalized at this point but there is no need to) to 180% isovolume is chosen for Eclipse to convert this to a structure. Again, this is the PTV and essentially is the area treated inside the fields of traditional tangents.
3) This structure is "pre-cropped"... you don't need to edit it, the calc algorithm already handled it.
4) Using the same tangents, go into inverse optimization. Click "fixed field sizes." Optimize to the PTV. E.g. if the Rx is 40 Gy, 100% of the PTV will receive 40 Gy or more. I set BODY max at 42 Gy with high priority; this makes the plan very homogenous (max dose in plan of 105% in other words). X&Y smooth of 40/30 usually (the default).
5) Now use the fluence editing tool(s) to extend the fluence ~1.5cm out past the skin surface for flash.
6) Calc.

From start to finish, usually 20min or less. Other centers have different "programs" and automated ways of doing more or less the same thing. Many different ways can work.

EDIT: It is my understanding that in the UK 26/5 partial breast is the new standard and the most common treatment now for low risk breast. They see no need to give the whole breast either 26 Gy (or 40 Gy or whatever) or Livi-level 30 Gy to partial breast. They have combined the idea of 26 Gy whole breast with IMPORT-LOW. To me, it makes good sense. I must admit I do whole breast not that commonly these days and essentially never in Stage I.

Guess the NHS reads SDN

 

[TheWallnerus]

Guess the NHS reads SDN

When I started putting fiducials in for prostate around 2004, my prostate mentor said “You should really think about that… you’re braver than I.” Several years later I heard he started using fiducials. I asked him “So you’re using fiducials now?” His reply: “You must!”

 

[medgator]

When I started putting fiducials in for prostate around 2004, my prostate mentor said “You should really think about that… you’re braver than I.” Several years later I heard he started using fiducials. I asked him “So you’re using fiducials now?” His reply: “You must!”

Apparently you, me and Matthew Katz are old school.

Millennials live and die by CBCT

DEFINE_ME

Evaluation of kV cone-beam ct performance for prostate IGRT: a comparison of automatic grey-value alignment to implanted fiducial-marker alignment - PubMed

CBCT with soft-tissue-based automatic corrections is not an accurate alignment compared with manual alignment to fiducial markers for prostate IGRT. We have concluded that a daily manual alignment to fiducials is one of the most reliable methods to maintain accuracy in prostate IGRT.

pubmed.ncbi.nlm.nih.gov

 

[TheWallnerus]

Apparently you, me and Matthew Katz are old school.

Millennials live and die by CBCT

DEFINE_ME

Evaluation of kV cone-beam ct performance for prostate IGRT: a comparison of automatic grey-value alignment to implanted fiducial-marker alignment - PubMed

CBCT with soft-tissue-based automatic corrections is not an accurate alignment compared with manual alignment to fiducial markers for prostate IGRT. We have concluded that a daily manual alignment to fiducials is one of the most reliable methods to maintain accuracy in prostate IGRT.

pubmed.ncbi.nlm.nih.gov

Anyone who ever cares to do their own in-house measurement comparisons (if they don't do fiducials, and want to try) will always find the same thing. What should have been done after all this at an academic center somewhere, but hasn't afaik, is measure the clinical outcomes both for toxicity and PSA after fiducial based vs CBCT in a randomized fashion with totally equal doses and PTV margin choices in either arm. Even then, it would be easy to muddy a trial like this up unless you have the right boffins. 'Til then we can have nice debates.

 

[deleted1111261]

Anyone who ever cares to do their own in-house measurement comparisons (if they don't do fiducials, and want to try) will always find the same thing. What should have been done after all this at an academic center somewhere, but hasn't afaik, is measure the clinical outcomes both for toxicity and PSA after fiducial based vs CBCT in a randomized fashion with totally equal doses and PTV margin choices in either arm. Even then, it would be easy to muddy a trial like this up unless you have the right boffins. 'Til then we can have nice debates.

All the studies we do, and this hasn’t been done ??

 

[Palex80]

We are doing fiducials AND cbct. Daily.

We contour the fiducials on the planning CT, then match them on the CBCT.

The argument is that we want to have both things: match fiducials and still have a view on bladder/rectum filling to be confident that the DVH that was calculated for risk organs actually resembles daily practice.

 

[TheWallnerus]

All the studies we do, and this hasn’t been done ??

No enthusiasm for it evidently. Well done phIII clinical outcomes of no-IGRT vs IGRT, or IGRT-type1 vs IGRT-type2, in any dz site, studies are... non-existent???

 

[Palex80]

All the studies we do, and this hasn’t been done ??

The French tested daily vs. weekly IGRT, but that's not exactly the question the Wallnerus asked.

I am very confident that we have over 30 randomized trials on RT +/- ADT in the primary setting, I now feel a lot more confident than if we had only ... 20 trials.

 

[medgator]

All the studies we do, and this hasn’t been done ??

Unfortunately fractions don't get cut in one of the arms, so the pps exempt folks are not interested

 

[evilbooyaa]

Apparently you, me and Matthew Katz are old school.

Millennials live and die by CBCT

DEFINE_ME

Evaluation of kV cone-beam ct performance for prostate IGRT: a comparison of automatic grey-value alignment to implanted fiducial-marker alignment - PubMed

CBCT with soft-tissue-based automatic corrections is not an accurate alignment compared with manual alignment to fiducial markers for prostate IGRT. We have concluded that a daily manual alignment to fiducials is one of the most reliable methods to maintain accuracy in prostate IGRT.

pubmed.ncbi.nlm.nih.gov

I don't knock fiducials because of prostate alignment. It does a great job at it. I knock it because you don't know if bladder/rectum are same day to day, and this is something that all folks who use CBCT can see wild variations in on a day to day basis that can affect not only bladder and rectum dosimetry, but also small bowel based on extent of your field.

Relegating CBCT on that study to 'automatic matching' only without discussing that CBCT is also manually matchable to the prostate... seems silly to me. Or perhaps wanted to compare to an 'inferior' arm to prove what they do is better. But what do I know, I'm just a silly millenial.

No problems with fiducial at all, but (especially) if you poo-poo SpaceOAR because it's a procedure, then I ask the same question about the necessity of fiducials when we have a non-invasive modality in the absence of data that actually shows fiducials helps. It's like saying you only do old-school fixed frame GK-SRS even though rigid frame screwed into the skull isn't necessary anymore for high quality SRS...

 

[medgator]

I don't knock fiducials because of prostate alignment. It does a great job at it. I knock it because you don't know if bladder/rectum are same day to day, and this is something that all folks who use CBCT can see wild variations in on a day to day basis that can affect not only bladder and rectum dosimetry, but also small bowel based on extent of your field.

Relegating CBCT on that study to 'automatic matching' only without discussing that CBCT is also manually matchable to the prostate... seems silly to me. Or perhaps wanted to compare to an 'inferior' arm to prove what they do is better. But what do I know, I'm just a silly millenial.

No problems with fiducial at all, but (especially) if you poo-poo SpaceOAR because it's a procedure, then I ask the same question about the necessity of fiducials when we have a non-invasive modality in the absence of data that actually shows fiducials helps. It's like saying you only do old-school fixed frame GK-SRS even though rigid frame screwed into the skull isn't necessary anymore for high quality SRS...

The question is the morbidity of the procedure vs benefit.... Many of us had great gi toxicity rates before spaceOAR ever hit the market, and i never saw a patient need a long term temporary colostomy with abx until spaceOAR hit the scene. The most I've ever seen with fiducials is a uti, usually treated outpt, maybe 1-2 pts I've seen end up admitted, usually because they were noncompliant with the prophylactic peri-procedure abx

Equating fiducials to spaceOAR just makes no sense to me in that regard.

Best answer probably CBCT with fiducials @Palex80 daily.... But that is something very few of us are probably doing i imagine outside of SBRT. Given the compromise of physician supervision guidelines with cbct in our practice matched with the desire to maintain good treatment accuracy, weekly cbct on otv day with daily kv/fiducials has become my standard practice.

Unfortunately some of us do not have the luxury of camping out a Linac to check CBCT all day, 5 days a week, and the data clearly shows, maybe that's what is needed to get better accuracy (since i doubt you or anyone else is doing that either)

 

[deleted1111261]

The question is the morbidity of the procedure vs benefit.... Many of us had great gi toxicity rates before spaceOAR ever hit the market, and i never saw a patient need a long term temporary colostomy with abx until spaceOAR hit the scene. The most I've ever seen with fiducials is a uti, usually treated outpt, maybe 1-2 pts I've seen end up admitted, usually because they were noncompliant with the prophylactic peri-procedure abx

Equating fiducials to spaceOAR just makes no sense to me in that regard.

Best answer probably CBCT with fiducials @Palex80 daily.... But that is something very few of us are probably doing i imagine outside of SBRT. Given the compromise of physician supervision guidelines with cbct in our practice matched with the desire to maintain good treatment accuracy, weekly cbct on otv day with daily kv/fiducials has become my standard practice.

Unfortunately some of us do not have the luxury of camping out a Linac to check CBCT all day, 5 days a week, and the data clearly shows, maybe that's what is needed to get better accuracy (since i doubt you or anyone else is doing that either)

YOU .. DON’T .. HAVE .. TO .. CAMP .. OUT .. AT .. LINAC .. THIS .. IS .. NOT .. 2002

 

[TheWallnerus]

YOU .. DON’T .. HAVE .. TO .. CAMP .. OUT .. AT .. LINAC .. THIS .. IS .. NOT .. 2002

of historical interest only...

MDs were never required to have stand-by-the-machine personal supervision for 77014 CBCT, only kV X-ray 77421 IGRT. This was fake news that propagated and spread far and wide across rad onc, presumably because CBCT would seem to logically require more supervision than plain kV X-rays. But whoever said CMS was logical? And, this was only changed in July of 2009, made retroactive to Jan 2009. For the historical record, one can find one and only mention of this in the Old Internet, and it is here:

 

[medgator]

YOU .. DON’T .. HAVE .. TO .. CAMP .. OUT .. AT .. LINAC .. THIS .. IS .. NOT .. 2002

Clearly the data suggests cbct alone isn't working.... You think that's therapist error or MD error?

 

[deleted1111261]

What data?

Teach your RTTs anatomy, train your RTTs to know what looks good, have a low threshold to call you. It’s really not rocket science and if you’re RTTs can’t handle it, it’s on you for not training them and if not trainable than for hiring them.

 

[medgator]

What data?

Teach your RTTs anatomy, train your RTTs to know what looks good, have a low threshold to call you. It’s really not rocket science and if you’re RTTs can’t handle it, it’s on you for not training them and if not trainable than for hiring them.

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