I am not aware of any patients, who cavities were too big to boost. Usually the cavity is quite small and in the case of large primary tumors many of our patients get neoadjuvant chemo.
There are a couple of surgeons that tend to perform some kind of crazy rotational plastic surgeries in the breast, where once every now and then (1-2 times/year) we can't figure out exactly where the tumor cavity actually is.
In these cases we may choose to deliver a homogenous dose of 56 Gy in 2 Gy fractions to the entire breast and skip the boost. But, like I said, that's a seldom case.
Other than that I boost everybody who's younger than 60 and may skip the boost in over 60 year olds if they have pT1
and pN0
and non-G3
and non-L1
and R0 with at least 5mm margin
and ER/PR positive. If they don't meet all these criteria, they get the boost.
I boost 10 Gy for most patients and reserve 16 Gy for R0 with <3 mm margin or high-risk young women (35 year old with a pT2 G3 triple negative-disease).
One interesting side-effect of 3D-planning for boost with photons is that the size of the boost tends to get bigger for some patients and smaller for others in comparison to the older standard electron boosts. Furthermore the boost may sometimes not be centered on the scar.
I was taught in my early-resident days to use a 6 cm round electron tubus for every T1 and reserve the 8 cm (or seldom 10 cm tubus) for T2s. I didn't plan the boost in 3D, I just looked at the planning CT-slide for the whole irradiation to estimate electron energy and often marked the field on the skin according to the scar / mammography.
I am starting to ask myself, how many of these boosts were actually done on the right place.
