Confused over Involved Field Irradiation in the Neck

[Palex80]

So, I am kind of confused.
I was reading the excellent article by Yalalom on the Involved Field definitions and I just can't understand this...
http://www.ncbi.nlm.nih.gov/pubmed/12078908

"Unilateral cervical/supraclavicular region
Medial Border
If the supraclavicular nodes are not involved, place the border at the ipsilateral transverse processes, except when medial nodes close to the vertebral bodies are seen on the inital staging neck CT scan."

Isn't that like dangerously close?
Does he actually mean the tip of the transverse processes?

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[Gfunk6]

I believe you are correct. He means the tip of the transverse process.

 

[Palex80]

I believe you are correct. He means the tip of the transverse process.

Thanks Gfunk. This does mean however that parts of the carotid artery and the jugular vein would be blocked out, right?

 

[G'ville Nole]

Thanks Gfunk. This does mean however that parts of the carotid artery and the jugular vein would be blocked out, right?

Especially down around Level 4. Yahalom's field descriptions provide an excellent template, but they're certainly not inviolable. My medial border allows for adequate dosimetric margin on the pre-chemo volume. I try to block the larynx when I can, but I tend to err on the side of overly inclusive. Keep in mind that I don't treat kids, so I have that luxury.

 

[medgator]

Especially down around Level 4. Yahalom's field descriptions provide an excellent template, but they're certainly not inviolable. My medial border allows for adequate dosimetric margin on the pre-chemo volume. I try to block the larynx when I can, but I tend to err on the side of overly inclusive. Keep in mind that I don't treat kids, so I have that luxury.

I've heard that classical field design is still very much alive as an oral boards topic in lymphoma (unlike many other sites). Can't wait to start reviewing all this

 

[deleted4401]

Absolutely ridiculous that we aren't supposed to be using 3D imaging to design our fields on the board exam. Any one who trained in this era should be incensed that people who examine us want to tie one hand back. CT imaging and knowledge of 3D anatomy based treatment planning is integral to modern radiation oncology. Why the heck would I use bony landmarks when I can contour out the actual lymph node region and utilize fields to block out normal structures?

It's like someone examining a cardiologist and asking about treatment of an MI and then saying, "Oh, but wait, the pharmacy has run out of beta blockers. Now what do you do? Nope, they don't have O2 either. They have opium and leeches."

I've heard that classical field design is still very much alive as an oral boards topic in lymphoma (unlike many other sites). Can't wait to start reviewing all this

 

[Palex80]

My clinic is participating in the HD- Hodgkin Trials of the German Hodgkin Study Group and they have pretty specific recommendation for field designs.

Here's what they write on IF-RT of the cervical region:


Cranial border: mastoid

Caudal border: lower end of sternoclavicular joint

Medial border: to include:
a) the ipsilateral submandibular nodes,
b) the spinal cord and
c) the medial end of the M. sternocleidomastoideus

Lateral border: to include 2/3 of the clavicula



They also allow a gantry rotation of 5-10% in order to spare some of the pharynx (although if you have to treat all of the spinal cord, that doesn't help at all).
So in reality you need to include more than half of the vertebral body, so that you have all that in your field. Therefore you may just place you margin on the contralateral edge of the vertebral body.

 

[G'ville Nole]

It's like someone examining a cardiologist and asking about treatment of an MI and then saying, "Oh, but wait, the pharmacy has run out of beta blockers. Now what do you do? Nope, they don't have O2 either. They have opium and leeches."

Hee hee. Love it!

Your examiners aren't immune to reason. The lymphoma section does rely on classical field design to a greater extent than others, but my cases had pre- chemo volumes drawn on a DRR, so as long as you explained that you were deviating from classical design to allow appropriate coverage (as I had to do in one case), there was no problem.

Medgator, you're correct to a point. More than ever, the examiners in all sections are open to 3D-CRT/IMRT as appropriate treatments, but if you advocate it, make sure you know the details of said treatment cold (PTV coverage, DVH eval, etc.). In my view, it pays to be reasonably conversant in both classical and conformal techniques, but certainly go with what you know best.