Partial Breast Stereotactic Radiation May Lead to Less Toxicity in Breast Cancer Treatment

David D’Ambrosio, MD, radiation oncologist at RWJBarnabas Health, joins Pharmacy Times to discuss CyberKnife, a new type of stereotactic body radiation that precisely targets tumors in stage 0 and stage 1 breast cancer patients. He is contributing author for a poster presented at the San Antonio Breast Cancer Symposium (SABCS) on December 6, 2022, which discussed the new radiation program and its treatment potential.

PT Staff: Please discuss the main takeaways from your research of accelerated partial breast irradiation (APBI) for early-stage breast cancer?

David D’Ambrosio, MD: Doing the standard-of-care for treatment of breast cancer with radiation therapy is typically somewhere in the neighborhood of 3 to 6 weeks of radiation every day, Monday through Friday. So, there has been—not recently but for many, many years— a movement to try to simplify this. To go away from treating the entire breast to just treating the lumpectomy cavity, therefore treating less of the breasts, and decrease the number of treatments. What this study was looking to do (which was sponsored by Georgetown and which we have been a part of, pretty much since they opened it) was looked to deliver this specific type of radiation— partial breast stereotactic radiation (PBSI) using CyberKnife. The goal of this wasn't a randomized study. This was looking at the feasibility and the safety of PBSI. That's what the goal was, and that's what we looked at in this initial presentation of it.

PT Staff: How does this therapy impact short- and long-term toxicity compared to standard whole-breast radiation therapy?

David D’Ambrosio, MD: Right. Because it's a smaller area, the thought process is that it will lead to less toxicity because there's less skin irritation and less long-term potential for fibrosis and scarring. Utilizing CyberKnife for the delivery of this versus other ways of delivering something similar is that as opposed to doing something like, let's say, brachytherapy. This is less invasive, as opposed to using external radiation that's not CyberKnife. We can treat a smaller area because CyberKnife is more precise in its delivery of the treatment. All these things taken together— smaller volumes, smaller treatment times, smaller amount of radiation to normal tissue—both theoretically and intuitively lead to less toxicity.

PT Staff: How do adverse events differ between APBI and standard radiation for early-stage breast cancer patients?

David D’Ambrosio, MD: The biggest [adverse event] that women typically get from standard radiation is some level of skin irritation. That can be anywhere from a little bit of pinkness, or it can be like a bad sunburn to the point of where there's even can be skin peeling. And there can, you know, you can either use medications to help with burns like something like that.

This pretty much takes that off the table because you don't you won't get that level of burning with anybody. That's not to say that there aren't women that would be okay even doing it the standard way. But the thought is that there's less of that acute toxicity and then also less long-term toxicity. Not inconsequential to this either is, given that it's less treatment, it's more convenient. You can treat more patients in a shorter amount of time. And in the long run, it's probably more cost effective as well.