Thought provoking UK breast study

[Burt Radnolds]

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)31145-5/fulltext

Fairly wide entry criteria randomized to 40/15 whole breast, 36/15 whole breast with integrated 40/15 to cavity, or 40/15 partial breast only.

No difference in local control, with improved toxicity profile for de-escalated arms.

Was discussing this with a friend, at least this isn't an anti radiation trial!

A few initial thoughts, need to dive deeper into manuscript.

- reinforces that blocking the crap out of heart and lung at the expense of uninvolved breast is totally kosher

- you can do qday partial breast, which always made theoretical sense anyway, and the toxicity of this appears very favorable

In the end, all the arms got 15 treatments so no one's robbing your retirement. I use 40/15 for all tangential patients anyway. I do find this to be a very clean thought provoking study. I may consider adopting that intermediate dosing scheme as my low risk patient paradigm

Thoughts?

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[Palex80]

We have been offering partial breast irradiation with hypofractionated EBRT to all low-risk breast cancer patients for a few years now.

We have been using the START B regiment in terms of fractionation (39.9/2.66).
The main idea was that if START B was as efficient as standard fractionation for whole breast tumor control, then there shouldn't be any difference in terms of local control at the tumor site either.
So if you were going to treat the patient with intraoperative irradiation using electrons or whatever (but you didn't, because it's not available at your site), you may as well do it postoperatively with hypofractionated EBRT.

In terms of target volume definition, we have been delineating the PBI-volume exactly as we would have delineated the boost. These does lead to a larger volume of the breast being treated than with a single-shot intraoperative procedure.

Toxicity is really good, I also have the impression from the couple dozen of patients I have seen so far, that fatigue is actually less as well.

When we started doing this about 3 years ago, we only did it in patients who would profit in terms of sparing of lung/heart for a special reason. The very first patient I did, had a severe COPD, the second one a pacemaker implanted above the affected breast (she had a tumor in the lower outer quadrant). A year or so later we started offering it to more patients.

Our criteria are:
- age >60
- pT1
- no extensive DCIS
- no L1, no Pn1
- pN0
- ER/PR +
- Her2 -
- R0

These are the patients at the lowest of risk of recurrence, there is still an ongoing debate if they need irradiation at all. I find the hypofractionated EBRT regime a very good compromise.
Still there is room for improvement, cause it's still 3 weeks. Probably delivering something like 5 x 5.5 Gy would also do the trick and you'd be done in one week, but we don't have the data on that yet.
Down the road, I envision that these vastly hypofrationated treatments would also lead to intraoperative techniques losing ground. Their main argument was less toxicity and less treatment appointments. But the trials were designed back when 5-6 week treatments were standard of care. We have already cut that down to 3 weeks and maybe we are going to be able to cut it down to 1 week soon.

 

[medgator]

These are the patients at the lowest of risk of recurrence, there is still an ongoing debate if they need irradiation at all. I find the hypofractionated EBRT regime a very good compromise.
Still there is room for improvement, cause it's still 3 weeks. Probably delivering something like 5 x 5.5 Gy would also do the trick and you'd be done in one week, but we don't have the data on that yet.
Down the road, I envision that these vastly hypofrationated treatments would also lead to intraoperative techniques losing ground. Their main argument was less toxicity and less treatment appointments. But the trials were designed back when 5-6 week treatments were standard of care. We have already cut that down to 3 weeks and maybe we are going to be able to cut it down to 1 week soon.

Agreed. Most women on the edge seem to be fine with 3 weeks of hypo-fx when I talk to them. One of my partners offers SAVI PBI and I don't, and given that you actually need 10 tx with it (5 days BID) plus the need to keep the catheter in starting the week before, I've had several women prefer 3 weeks of hypo-fx over a SAVI device. Of course, the surgeons who do SAVI get a nice fee putting it in, so really it's surgeon dependent in terms of how the pt is biased when they are referred.

 

[gvsudew]

Our institution has been doing Canadian hypofractionated PBI for a good number of years (probably have >150 pts). Have anecdotally experienced good LC, cosmesis, and overall pt satisfaction. There has been talk of putting together and publishing this retrospective experience for a couple years now. Probably would have been good to do before the results of this large randomized phase 3 inferiority trial were published!

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)31145-5/fulltext

Fairly wide entry criteria randomized to 40/15 whole breast, 36/15 whole breast with integrated 40/15 to cavity, or 40/15 partial breast only.

No difference in local control, with improved toxicity profile for de-escalated arms.

Was discussing this with a friend, at least this isn't an anti radiation trial!

A few initial thoughts, need to dive deeper into manuscript.

- reinforces that blocking the crap out of heart and lung at the expense of uninvolved breast is totally kosher

- you can do qday partial breast, which always made theoretical sense anyway, and the toxicity of this appears very favorable

In the end, all the arms got 15 treatments so no one's robbing your retirement. I use 40/15 for all tangential patients anyway. I do find this to be a very clean thought provoking study. I may consider adopting that intermediate dosing scheme as my low risk patient paradigm

Thoughts?

 

[nkmiami]

thanks for posting. As you said block the ... out of the heart, consider mixing in a lot of high energies, and how about not treating the inframm fold for those upper outer quadrants...? Whole breast was not really "whole breast" anyway- many would always skimp on medial or lateral coverage of the breast to angle tangents to best spare heart and lungs as long as tangents covered lumpectomy + margin.

The average 70 year old luminal A breast cancer probably benefits so little today from radiation, that it is going to be hard to show the difference between one type of treatment vs another. The real benefit of savi/mammo is that they serve as kickback to the surgeon to send you patients. kind of like prostate brachy, they cure pts who probably didnt need treatment

 

[Haybrant]

what do you guys do when they fail after PBI either local or in the breast. They get mastectomy and thats that?

 

[seper]

Finally, a safe EBRT PBI regimen, supported by a rock-solid study. Thanks

 

[BobbyHeenan]

I've used this technique (40 in 15 partial breast) on a patient in her early 60's that had small T1 luminal A cancer with a good performance status but a pacemaker that couldn't be moved without risk. Nice to have a full text of this, because my consult note uses only the abstract as justification.

I too use APBI mammosite, as I think the 3-D EBRT BID schemes come with more toxicity/worse cosmesis so I don't offer one-week APBI unless patient consents for the semi-invasiveness of the balloons/SAVI. Agree, the XRT modality is heavily surgeon influenced, as some of them love APBI balloons so patients come to consult really wanting that. If they meet ASTRO consensus guidelines they're OK for that in my eye. Really takes a motivated surgeon though that knows how to place the balloons, because technique and patient pain/discomfort is really surgeon dependent.

Given these results suggesting aggressive heart/lung blocking can be done for a wide array of patients, I question whether left sided whole breast protons seems less appealing. I don't personally do this nor recommend it, but I know it's being done.