Breast WBI Fractionation discussion

[BobbyHeenan]

Can someone compare their oncoplastic plus WBRT versus regular lumpectomy with APBI cosmesis?

Livi trial showed better cosmesis congruent with my personal experience with 30/5. If you have an oncoplastic surgery then get breast shrinkage from WBRT, is that better than a “regular” lump with APBI?

I suspect it’s all a foregone conclusion though, if the breast surgeon wants to do it and gets paid more for it what are you as the rad onc gonna do?

---

Members don't see this ad.

 

[scarbrtj]

Not WBI, but... 5 fraction breast now the new standard in the UK for low risk early stage patients.

“At a recent consensus meeting organized by the Royal College of Radiologists, the U.K. adopted the 26-Gy schedule as a new standard, also integrating this with partial breast irradiation, in close collaboration with the U.K. IMPORT Low trial... 'This is very important work. I think this is one of the most important trials in the past few years. It has really changed practice,' commented session co-chair Ben Slotman, MD, PhD, of Vrije Universiteit Medical Center, Amsterdam, and AMC Amsterdam, who was not involved the trial."

One-week radiotherapy course should be standard for early invasive breast cancer, experts say

 

[BobbyHeenan]

Not WBI, but... 5 fraction breast now the new standard in the UK for low risk early stage patients.

“At a recent consensus meeting organized by the Royal College of Radiologists, the U.K. adopted the 26-Gy schedule as a new standard, also integrating this with partial breast irradiation, in close collaboration with the U.K. IMPORT Low trial... 'This is very important work. I think this is one of the most important trials in the past few years. It has really changed practice,' commented session co-chair Ben Slotman, MD, PhD, of Vrije Universiteit Medical Center, Amsterdam, and AMC Amsterdam, who was not involved the trial."

One-week radiotherapy course should be standard for early invasive breast cancer, experts say

So 27 Gy has worse cosmesis, but 26 Gy is A-OK?

I've used 26 Gy on some elderly patients, but I'm not ready to give one week of radiation to a 50 year old stage I patient. Am I entering boomer rad onc territory or is it OK to drag my feet here?

I'm fully on board for 40-42.56/15-16 and use a lot of 30/5 APBI. But 26/5 WBI I've been carefully selecting like older lobular patients.

 

[drewdog1973]

So 27 Gy has worse cosmesis, but 26 Gy is A-OK?

I've used 26 Gy on some elderly patients, but I'm not ready to give one week of radiation to a 50 year old stage I patient. Am I entering boomer rad onc territory or is it OK to drag my feet here?

I'm fully on board for 40-42.56/15-16 and use a lot of 30/5 APBI. But 26/5 WBI I've been carefully selecting like older lobular patients.

I would say it's reasonable to do 15-16 fx, as this is the American standard of care and we are practicing in America.

That being said, I think you're on the edge of Boomerism Why ?

1) 5 years is plenty for cosmesis for breast. No study has had a change from the 5 year to the 10 year follow up for cosmesis.
2) 5 years is plenty for efficacy in terms of local control. Yes, there will be more failures between 5-10, and 10-15, but there is no rational reason for the rate of change to be different. This may be the first ever trial to show a difference, but I doubt it.
3) 26 vs 27 Gy seems insignificant, but there are threshold effects like this - there is a hypoFX prostate study showing 1 less fraction was either less effective or less toxic, I forget which. Shoulders, and what not.
4) In pandemic times, it has been a "no brainer" to suggest this fractionation or 30 Gy / 5 fx to partial breast.
5) Post-pandemic, I think it is very reasonable to suggest this for the CALGB/Prime II subset - instead of saying no RT, we can say 5 days of RT (vs 5 years of a pill). I have made this argument with our breast team and surgeons/medoncs agree.
6) Chirag / Sushil offering it routinely. They are rarely in error about things like this.

It stinks, though. 1 week for our most common cancer puts us truly into technician mode. If you are out that week, you'll have never seen this patient except at sim and consult.

 

[RadOncDoc21]

So 27 Gy has worse cosmesis, but 26 Gy is A-OK?

I've used 26 Gy on some elderly patients, but I'm not ready to give one week of radiation to a 50 year old stage I patient. Am I entering boomer rad onc territory or is it OK to drag my feet here?

I'm fully on board for 40-42.56/15-16 and use a lot of 30/5 APBI. But 26/5 WBI I've been carefully selecting like older lobular patients.

I’m with you boomer! Don’t worry these young kids are all still living with their parents and eating kale. Five fractions will put them all in the bread lines. I think my competitors and I have an agreement to not go below 3 weeks.

 

[evilbooyaa]

So 27 Gy has worse cosmesis, but 26 Gy is A-OK?

I've used 26 Gy on some elderly patients, but I'm not ready to give one week of radiation to a 50 year old stage I patient. Am I entering boomer rad onc territory or is it OK to drag my feet here?

I'm fully on board for 40-42.56/15-16 and use a lot of 30/5 APBI. But 26/5 WBI I've been carefully selecting like older lobular patients.

I'm in the same boat as you.

FAST-FORWARD is powered for LC differences, not for differences in toxicity. the HR for cosmetic issues comparing 26Gy to regular hypofx is 1.19 with a P-value of 0.17. I would argue that this study is underpowered to identify any differences, as numerically, 10% < 12% < 15%.

I will offer it to the elderly that are CALGB/PRIME eligible or otherwise ineligible but super old (like 80-85 yrs old)

"Women in both the 27-Gy and 26-Gy groups were more likely to report moderate or marked breast swelling (5%; P = .007 and 4%; P = .02, respectively, vs. 2%)."

5Fx in 1 week is not the slam dunk that moderate hypofx for WBI was. One is trading unknown differences in late toxicity (due to being underpowered) and higher acute toxicity for a shorter treatment course. Of course I'm not surprised that the UK, with a crumbling NHS system that is looking to cut costs above all, including potential patient preference, has chosen this as their 'preferred' option.

Perhaps, once 10-year data is out, this will turn into a discussion similar to conventional vs moderately hypofx prostate cancer is currently (we have a shorter option that gives you a higher risk of acute side effects, but with likely similar long-term toxicity, with equal oncologic efficacy)

Maybe once APM hits the US and doctors are incentivized for shortest treatment schedules possible (the way docs in the UK are), the US will follow suit. But not until then.

 

[drewdog1973]

I'm in the same boat as you.

FAST-FORWARD is powered for LC differences, not for differences in toxicity. the HR for cosmetic issues comparing 26Gy to regular hypofx is 1.19 with a P-value of 0.17. I would argue that this study is underpowered to identify any differences, as numerically, 10% < 12% < 15%.

I will offer it to the elderly that are CALGB/PRIME eligible or otherwise ineligible but super old (like 80-85 yrs old)

"Women in both the 27-Gy and 26-Gy groups were more likely to report moderate or marked breast swelling (5%; P = .007 and 4%; P = .02, respectively, vs. 2%)."

5Fx in 1 week is not the slam dunk that moderate hypofx for WBI was. One is trading unknown differences in late toxicity (due to being underpowered) and higher acute toxicity for a shorter treatment course. Of course I'm not surprised that the UK, with a crumbling NHS system that is looking to cut costs above all, including potential patient preference, has chosen this as their 'preferred' option.

Perhaps, once 10-year data is out, this will turn into a discussion similar to conventional vs moderately hypofx prostate cancer is currently (we have a shorter option that gives you a higher risk of acute side effects, but with likely similar long-term toxicity, with equal oncologic efficacy)

Maybe once APM hits the US and doctors are incentivized for shortest treatment schedules possible (the way docs in the UK are), the US will follow suit. But not until then.

5% vs 2%... for swelling... acutely.
you’re hanging your hat on that for the longer course?

offer it this way to them - “mrs Johnson, there is a 2% chance of more swelling in the breast if we do it in 1 week vs 3 weeks. Is that something that distresses you? If so, we can do longer course.”

i think our worries about acute toxicity may be less than their worries about resuming their everyday life.

 

[evilbooyaa]

5% vs 2%... for swelling... acutely.
you’re hanging your hat on that for the longer course?

offer it this way to them - “mrs Johnson, there is a 2% chance of more swelling in the breast if we do it in 1 week vs 3 weeks. Is that something that distresses you? If so, we can do longer course.”

i think our worries about acute toxicity may be less than their worries about resuming their everyday life.

When the 10-year data comes out then that line is quite similar to what I will be offering. To patients of most ages.

 

[Burt Radnolds]

5% vs 2%... for swelling... acutely.
you’re hanging your hat on that for the longer course?

offer it this way to them - “mrs Johnson, there is a 2% chance of more swelling in the breast if we do it in 1 week vs 3 weeks. Is that something that distresses you? If so, we can do longer course.”

i think our worries about acute toxicity may be less than their worries about resuming their everyday life.

40/15 wins in every single toxicity endpoint. Unless I was traveling great distances or had other reasons where I could not make the trips, I'd take the long course, even for that small toxicity benefit. 10 more trips to avoid a small chance of a lifetime of toxicity is worth it to me, but the calculus is different for everyone. However, I also would not be overly angry at an insurer or national health care system adopting 26/5 as their standard, given how small the differences are. I also wonder about difference in toxicity that were not classified as "moderate or marked", as that is all that is relayed in the table.

 

[drewdog1973]

40/15 wins in every single toxicity endpoint. Unless I was traveling great distances or had other reasons where I could not make the trips, I'd take the long course, even for that small toxicity benefit. 10 more trips to avoid a small chance of a lifetime of toxicity is worth it to me, but the calculus is different for everyone. However, I also would not be overly angry at an insurer or national health care system adopting 26/5 as their standard, given how small the differences are. I also wonder about difference in toxicity that were not classified as "moderate or marked", as that is all that is relayed in the table.

View attachment 327451

If purist, only the induration was statistically significantly worse, from 0.8% to 1.6%. Can believe trends if you want, but at this size 'n', I tend to stick to p<0.05.

Our preferences may not align with patients' preferences ... re: the desire to do 10 more visits for 0.8% less chance of breast induration. I 100% would not. That calculation is easy to make for me, but it's worthless, b/c I'm not the patient.

 

[communitydoc13]

40/15 wins in every single toxicity endpoint.

If purist, only the induration was statistically significantly worse, from 0.8% to 1.6%.

I'm skeptical of this toxicity data. They report at least one clinician assessment in 98% of patients. In their population between 4-6% with moderate or more breast shrinkage, induration or distortion!! Really? Does this correspond with anybody's clinical experience?

I use a very similar dose format to the 40Gy arm. This is not my experience. (Not even close.) I suspect that the sensitivity of their toxicity assessment was very low. This explains the p values.

The supplemental material has a ton of toxicity data. The rare bad toxicity is preferential in the hypo arms. No way to demonstrate statistical significance here. (But may be clinically significant).

Also note the photographic assessment data in appendix. (Here, 3 clinicians assess and are blinded to patient identity). Some pretty notable differences here.

Hard to believe 27 vs 26 Gy differences outside of bias affecting assessment. This is a 3.7% difference in dose. I've almost seen that dose difference in what Mobius gives me relative to my dose engine. Factor in the inherent uncertainty even in machine QA and it is baffling. Really fascinating data in this regard.

That being said, differences are small. Their non-inferiority breast recurrence goals were sure to be a winner (could probably give 20 Gy in 5 fxns with this cohort and duration of f/u). I can totally see UK saying that the extra 2 weeks aren't worth it.

 

[scarbrtj]

One week breast. The Beatles. The British Invasion. It’s coming. Or I might just be The Fool on the Hill.