RT-Technique for mediastinal Hodgkin's Disease

[Palex80]

Heya!

I know this may be a dumb question, but: What RT-technique do you use for mediastinal Hodgkin's Disease?

Young lady in her late 20s with a Stage IIA Hodgkin's disease. Bilateral supraclavicular involvement, large mediastinal mass, right lung hilar involvement. Good response to chemo.

Standard of care was up until recently IFRT, NCCN and some other groups now advise to use ISRT (without much evidence of non-inferiority, but anyway...), some people do INRT.

Now, I've been taught to spare young patients from large-volume low-dose irradiation. Which means I should design simple fields, mostly ap/pa. No matter if you do IFRT or ISRT or even INRT, if you use simple field arrangements, you are often going to get a rather high V20 & V30 at the lungs and the heart. On the other hand you are going to spare a lot of breast tissue from low dose irradiation, which you would had to treat if you were to use more complex 3D arrangements or IMRT/RapidArc/VMAT.

I understand that the risk for secondary malignancies is growing, the more breast tissue you irradiate, but: What about the competing risks of late reactions to lungs & heart?
Why is everyone obsessed with theoretically lowering the risk of secondary malignancies (noone has ever actually shown that more complex techniques increase the risk of secondary malignancies within the context of a trial), rather than playing it safe as far as lungs & heart are concerned (where we actually have quite some data on risks for late reactions with increasing doses of RT)?
Do we really know which is the rather less evil?

Another point to be made is acute toxicity, which is also generally lower with more conformal techniques. Last year I had to take a young patient with early HD and mediocre response to ABVD up to 30 Gy total dose and produced a 10 day lasting Grade 3 esophagitis. I used rather standard field arrangements to spare as much breast tissue as possible from receiving dose. Yet it cost me getting a large portion of the esophagus within the 100% isodose and a rather high V20 for the lungs and the heart. Afterwards I pondered if it would have been better to treat her with a more conformal techique.

So, what do you guys think?

---

Members don't see this ad.

 

[Irradi8or]

Hi,

Great question, and I'm sure the answers vary. Some of the plans I've seen come out of Harvard had massive V5 and 10 lung doses. MDACC presented their experience with the butterfly technique at ASTRO this past year, which caught my eye.

http://www.redjournal.org/article/S0360-3016(13)01092-4/abstract

 

[ramsesthenice]

For a young woman we would either do AP/PA or nothing. Remember secondary cancers are stochastic. Its not yet clear reducing the dose to breasts with modified fields will really result in less breast cancers (though it might). That being said there is little data showing a survival advantage for path CR in stage 1-2 patients. Wouldn't be wrong to not treat a girl though at our institution we wouldn't not treat a male in that position.

PS: next time a med onc drops the secondary cancer stat on you ask them what percent of secondary AMLs are alive in 2 years.

 

[Palex80]

That being said there is little data showing a survival advantage for path CR in stage 1-2 patients. Wouldn't be wrong to not treat a girl though at our institution we wouldn't not treat a male in that position.

I am sorry, I am not sure I understand what you mean by that.

Path CR in stage 1-2? What do you mean?
And why wouldn't you treat a male hodgkins patient with RT?

 

[medgator]

I am sorry, I am not sure I understand what you mean by that.

Path CR in stage 1-2? What do you mean?
And why wouldn't you treat a male hodgkins patient with RT?

The NCCN guidelines in the US allow for chemo alone in the favorable Stage I/II population. I am surprised to hear it from a rad onc though.... usually it's the med oncs that try to omit XRT in early-favorable HD. There may not be an OS difference, but there is data to show a difference in relapses.

 

[Gfunk6]

And why wouldn't you treat a male hodgkins patient with RT?

"Wouldn't not" = double negative = they would treat males

Personally, I do IMRT (with INRT) to hit post-chemo disease extent with margin. I try to minimize dose to esophagus/lungs/heart. Never had a problem with short-term > Grade 2 toxicity.

I understand that there is a risk of secondary malignancy, but there is also a risk of local failure. Yin and yang.

 

[ramsesthenice]

The NCCN guidelines in the US allow for chemo alone in the favorable Stage I/II population. I am surprised to hear it from a rad onc though.... usually it's the med oncs that try to omit XRT in early-favorable HD. There may not be an OS difference, but there is data to show a difference in relapses.

Don't get me wrong, Im a believer in adjuvant radiation for path CR. Basically every trial done has shown decreased recurrence. Several have come close to a survival advantage (though the Mumbi data was driven by stage 3 and 4 pts). Salvage chemo is no joke and as I eluded to above the risk of secondary AML after multiple rounds of chemo is unknown but the prognosis is terrible in those that get it. I have yet to see it but our lymphoma guy has said he would consider no RT for young female patients because of breast concerns.

 

[medgator]

I have yet to see it but our lymphoma guy has said he would consider no RT for young female patients because of breast concerns.

You probably won't. That decision is likely being made by the med onc before your attending even gets the referral

 

[brendav]

Can anyone point me to clear definitions of IFRT vs. ISRT vs. INRT? I've been going through articles, but can't quite seem to nail this down. Thanks.

 

[CyberKnife19]

Can anyone point me to clear definitions of IFRT vs. ISRT vs. INRT? I've been going through articles, but can't quite seem to nail this down. Thanks.

The ILROG Guidelines for Hodgkin lymphoma were published in Red Journal in June of 2013 and offers a nice explanation...

http://www.ncbi.nlm.nih.gov/pubmed/23790512

The ILROG then published another set of guidelines in Red Journal last year for Non-Hodgkin lymphoma...

http://www.ncbi.nlm.nih.gov/pubmed/24725689

 

[BobbyHeenan]

This is not a dumb question at all. Back in residency even attendings within our own department disagreed about the best technique for mediastinal HL or NHL.

All agreed on the importance of XRT and using the new ISRT guidelines for creating a PTV, but they seemed split about simple AP/PA or 3-D conformal vs. VMAT.

My approach:

I use ISRT, based on pre-chemo volumes per the guidelines. I use pre-chemo GTV plus ~1.5 cm margin = CTV . However, I do pull the CTV in off the lung/uninvolved organs (bone, lung, etc) when the node shrinks down after chemo (probably what Gfunk is referring to). I try simple 3-D approach first, especially if it's a high (level 2, for example) mediastinal node. If lung or heart dosimetry looks poor to me, I switch to VMAT/IMRT. I like that MD Anderson approach, I had not seen that before, so thanks for posting. It looks like a good compromise between limiting V20/V30 while only slightly increasing V5.