Do you treat synchronous bilateral breast cancers with RT simultaneously or sequentially?

We see a fair number of synchronous bilateral cases here. I am not aware of any compelling arguments or data for sequential treatment over simultaneous. Simultaneous is more efficient in terms of overall length of time, and allows for better coordination of the fields (but there is more time on the table, of course). For lower-risk cases, it may be helpful to have both plans generated at the same time to best gauge how much you want to scale back on lung/heart dose while adequately covering your...

Although data on this is limited, I have treated a number of patients over the years with bilateral simultaneous treatment and do not feel that sequential treatment with the extended time required on the patient and resources is necessary. I personally simply do bilateral 3 D conformal with bilateral tangential treatment. One could consider VMAT or Tomotherapy if one were treating the internal mammary and nodal regions. Here, I would compare the 3 D conformal vs. IMRT type plans evaluating heart...

I will use strong words here. In almost all cases, sequential is approaching unethical.

I have seen it many times, having worked at multiple centers and seeing follow ups.

It doubles the cost to the patient/system.

And doubles the time. Pre hypo-era, this meant 12-13 weeks - 14 when they did 1.8 for boost, as well.

There may be a handful of cases, but honestly, if a patient can’t make it through two breast treatments, does doubling the number of days make any sense?

There are enough publication...

The earliest series I know of examining this issue in a series of patients was one from the Joint Center for Radiation Therapy in Boston of 24 patients treated from 1977-1989. Outcome and complication rates were the same as for patients with unilateral cancers treated in the same era (Gollamudi et al., PMID 9083159).

Therefore, I agree with the previous comments that there is no reason to routinely do sequential rather than concurrent treatment of both sides. However, one of the worst cases of ra...

I also treat these simultaneously. I think patients tolerate bilateral treatment well and can't really think of when I would intentionally separate the treatments to sequential delivery. I think that might actually be a higher risk for unintentional overlap. As an aside, we recently published our bilateral breast cancer proton experience - this can be a helpful technique for OAR sparing when bilateral comprehensive RNI is indicated. Garda et al., Advances in Radiation Oncology 2022

I treat these cases simultaneously and have had no issues.