Esophagus

[jb2]

Do you exclude the esophagus from CTV and/or PTV for lung cancer?

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[ShirleyT]

Provided there is no direct extension into these structures on imaging or other findings, I always trim the CTV out of the heart and esophagus in lung cancer patients, but I do let the PTV expand into these areas. also if they have mediastinal adenopathy, i trim the CTV out of the lung laterally based on movement of the mediastinum on 4DCT because i figure it is rare for mediastinal adenopathy to directly extend into the lung and it helps with the lung DVH (but i do let the ptv extend laterally into the lung)

 

[Seldon1985]

I exclude esophagus from CTV (think "smart CTV") but allow PTV expansion into it.

 

[BraggPeak]

When doing esophageal cancer, do you guys exclude the heart and lung completely from your ctv?

 

[medgator]

When doing esophageal cancer, do you guys exclude the heart and lung completely from your ctv?

I do, unless they're involved.

 

[TarHeelRadOnc]

Do you exclude the esophagus from CTV and/or PTV for lung cancer?

I think that this is mostly academic. If your CTV has to be edited off of the esophagus, you are not going to effectively spare the esophagus from your nodal prescription dose at that level anyway (even with IMRT). Agree that PTV should not be edited off of anything in the mediastinum.

 

[ShirleyT]

For esophagus, i also exclude heart and lung from CTV unless they are involved. anything to try to help the lung dvh.....

 

[RadRadRad]

If you exclude lung and heart from CTV for your esophagus patients, what radial margin are you putting on your PTV? Some protocols are allowing 5mm PTV margin. I think you'd have a pretty tight PTV if you subtracted all lung/heart and only put 5mm for PTV.

 

[napoleondynamite]

If you exclude lung and heart from CTV for your esophagus patients, what radial margin are you putting on your PTV? Some protocols are allowing 5mm PTV margin. I think you'd have a pretty tight PTV if you subtracted all lung/heart and only put 5mm for PTV.

You are correct - but that's the point. You're giving a large mucosal margin sup/inf and a tight radial margin is appropriate and fitting with pattern of spread of esophageal ca. Unless a normal structure is involved or suspected to be involved, why include it in your CTV?

 

[BraggPeak]

I see the point, but I'm not sure it's safe. There can still be a lot of motion, especially for distal/GE jxn tumor. Many centers are doing a 4D CT and doing some type of motion management. If you're note, I think 0.5 cm margin radially might be a little tight. The classic fields are 2-2.5 to block edge radially, right?

For lung DVH, I can always meet V20; it's the V5 that seems to be an issue. Maybe with the new CROSS data, we can cut the dose to 41.4 with carbo/platinum, provided that surgery is planned?

 

[deleted4401]

So, lets say you did 2.5cm block margin in the past. That's 0.8cm margin for penumbra, 1 - 1.5cm for motion and setup error, in an era of no motion management. Leaves you with approximately 0.5 for CTV.

So, with motion management, I think you can carve out uninvolved critical structures and use 0.5cm of you do daily imaging. I end up doing 3 scans (inspiration, expiration, free-breathing) and contouring GTV/CTV/ITV from here, carving out normal tissue and using 0.5cm PTV. Not perfect, but that's the technology we have.

Marginal misses aren't really the issue.

But, if you're doing 3DCRT/volumetric planning, I agree that is pretty academic, as that few mm that is carved out is going to get dose.

 

[BraggPeak]

Does everyone do 4D-CT for esophagus?

 

[RadRadRad]

I do 4DCT for my esophagus patients (especially if distal/GE jxn). I do frequent cone beam CT scans during treatment. I see the following problems.
1. With a field that is long in the sup-inf direction (ie every esophagus field), there are often rotational errors in the pitch axis that are difficult to fully correct despite respositioning.
2. There is some positional variation day to day of the distal esophagus that is not accounted for in a 4DCT that is acquired over a few minute period (I have not tried Simul's technique of insp, exp, FB which might allow better estimation of this motion)
3. The esophagus sometimes is swollen/distended midway through treatment such that its radial dimensions are larger than on my planning CT.

All of these things make me think that GTV+5mm to PTV is too tight. Given that local control is already 50% at best, I think potentially missing the GTV is significant.

 

[Palex80]

The guys from Heidelberg published this quite interesting case of an gastroesophageal-junction tumor a couple of years ago.

http://www.ncbi.nlm.nih.gov/pubmed/19714309

The GTV was moving up to 4 cm in that case in interfraction CBCT controls!