Retrospective review: Proton therapy well tolerated in patients undergoing breast conserving surgery

While the assessment of proton therapy in breast cancer treatment continues through clinical trials, data relating to early toxicity and cosmetic outcomes for this population are limited. As members of the only hospital-based proton therapy program in New Jersey affiliated with a National Cancer Institute-designated Comprehensive Cancer Center, investigators at Rutgers Cancer Institute of New Jersey conducted a retrospective review of patients treated with proton therapy following breast-conserving surgery and found acceptable toxicity rates along with good-to-excellent patient-reported cosmetic outcomes.

Results of the work are being shared as part of a poster presentation at the San Antonio Breast Cancer Symposium this week by senior investigator Nisha Ohri, MD, a radiation oncologist who manages the care of patients in the Stacy Goldstein Breast Cancer Center at Rutgers Cancer Institute, as well as the Laurie Proton Therapy Center at Robert Wood Johnson University Hospital, an RWJBarnabas Health facility. Dr. Ohri, who is also an assistant professor of radiation oncology at Rutgers Robert Wood Johnson Medical School, shares more about the work.

Q: Why is this topic important to explore?

A: The dosimetric benefits of reducing radiation exposure to the normal organs with proton-based radiotherapy are well documented. However, there is limited data available on cosmetic outcomes in breast cancer patients after proton therapy, which is of particular importance among those patients undergoing breast-conserving surgery.

Q: Tell us about the work and what you and your colleagues found.

A: We looked at all patients treated with breast-conserving surgery who received radiation treatment at our proton center. We found that our patients tolerated proton radiotherapy well, with the most common short-term side effects being skin irritation and fatigue. Radiation doses to the normal organs (heart, lungs) were very low with proton therapy. We asked our patients to rate their cosmetic outcomes after treatment as either excellent, good, fair, or poor. The majority of patients (79 percent) reported good-to-excellent cosmesis.

Q: Why are these results significant?

A: As the number of proton centers continues to increase nationwide, the use of proton-based radiotherapy in the treatment of malignancies is expanding. While it is clear that proton-based radiotherapy can reduce radiation exposure to the nearby normal organs (heart, lungs) compared to standard photon-based treatment, it is also important to understand the possible side effects of proton-based radiotherapy. We found that proton-based radiotherapy was well tolerated among our patients with a high rate of favorable cosmetic outcomes.