There is some data pointing in the direction of a rather high rate of rib fractures.
A prospective trial of proton therapy for breast cancer revealed an increased rib fracture rate of 7%, which is higher than the expected rate based on the literature on photon therapies. We aim to evaluate the hypothesis that the increased relative ...
www.ncbi.nlm.nih.gov
Thirteen of 203 patients in the cohorts exhibited a total of 25 fractures.
Now, I am poor person and don't have protons for breast cancer. I have some proton experience, but I am certainly not an expert.
However, 13/203 =
6.4% of patients experiencing a rib fracture after proton radiotherapy for breast cancer is more than I see in my patients treated with photons.
Beware: This is a study utilizing older proton therapy techniques (passive scattering). It does however highlight a potential issue when using protons for breast cancer.