Thread by @subatomicdoc

@DrAttai T2. Let’s talk now about radiation specifically for breast cancer. We’ll start w/ breast conserving therapy (BCT) – a term for breast conserving surgery w/radiation as a combined strategy with similar results to a mastectomy. #bcsm #radonc 1/

@DrAttai T2. Vera Peters, whose mother had breast cancer, was a radiation oncologist advocating for smaller surgery w/RT in the 1960s-1970s. Amazing researcher and helped push us toward BCT as an option thefoldingchairhistory.com/2018/03/23/dr-… #bcsm #radonc 2/

@DrAttai T2. The thought initially was that with a smaller breast surgery, we should irradiate the entire breast with whole breast irradiation since we weren’t doing a mastectomy. In a 2D era without molecular medicine it worked great. #radonc #bcsm 3/

@DrAttai T2. Like the trend toward less surgery, we have found radiation can be completed in shorter times, sometimes treating only part of the breast, or leaving out radiation completely in some cases. #bcsm #radonc 4/

@DrAttai T2. Making sure there isn’t cancer at the edge of the surgery (clear margins) is important to ensure adequate surgery has been done before radiation takes place, which is usually ~4-6 weeks after surgery. #bcsm #radonc 5/

@DrAttai T2. Different breast cancer subtypes may have a higher risk of local recurrence even w/ RT - #TNBC & Her2+ - though w/ modern systemic therapy may be less of a difference ascopubs.org/doi/10.1200/JC… #bcsm #radonc 6/

@DrAttai T2. Shorter treatment times: Based upon old planning, we had to give treatment in 1.8-2 Gray doses so it took 5+ weeks, daily Mon-Fri. A ‘boost’ to the surgical area in the breast would add a week #bcsm #radonc 7/

@DrAttai T2. With modern planning and better understanding of radiobiology, we usually treat in 3-4 weeks if doing whole breast RT, not 5-6. The less aggressive appearing the tumor, the ‘boost’ may be left out. Pic via @UCLAradonc #bcsm #radonc * 8/

@DrAttai @UCLAradonc T2. Recently there has been data to shorten breast RT to one week. Only 5 year results so early to broadly implement. Here is the FAST-FORWARD trial thelancet.com/journals/lance… #bcsm #radonc 9/

@DrAttai @UCLAradonc T2. Partial breast irradiation (PBI) has evolved to be a consideration if we’re less worried about other breast tissue having cancer cells. External RT or brachytherapy have both been used. #bcsm #radonc * 10/

@DrAttai @UCLAradonc 2. PBI w/ external beam radiation is likely to be more common now, based upon UK and Italian randomized trials. But brachytherapy still an option for many. #bcsm #radonc 11/
thelancet.com/journals/lance…
ascopubs.org/doi/10.1200/JC…

@DrAttai @UCLAradonc T2. What about leaving radiation out completely? Currently, it’s a reasonable consideration in low risk DCIS and early stage invasive breast cancer in women 70+ years. But it requires good discussion of risks/benefits between patient and doc #bcsm #radonc 12/

@DrAttai @UCLAradonc T2. Just like the decision between mastectomy and BCT, which should be based upon patient’s preferences, the need for radiation in lower risk disease should be an informed choice #bcsm #radonc 13/

@DrAttai @UCLAradonc T2. A decade ago, academic editorials pushed more for leaving out radiation. Recently, there’s a sentiment to include it again. What really matters is that each patient understands his/her risk/benefit to make an informed choice. #bcsm #radonc 14/

@DrAttai @UCLAradonc T2. Part of that informed choice is balancing the risks of recurrence w/ the risk of side effects. Side effects are next as T3 #bcsm #radonc 15/