Clinical outcome of patients with early stage breast cancer treated with accelerated partial breast irradiation using stereotactic body radiotherapy with Cyberknife – the CK-APBI cohort

Rationale: Erasmus MC Cancer Institute introduced accelerated partial breast irradiation (APBI) using Cyberknife (CK). Short term results regarding patient satisfaction and oncological outcomes are promising, but there is limited knowledge on the long term toxicity and recurrence rate of this treatment.
Objective: To assess acute and late toxicity after CK-APBI in terms of dermatitis, pain, fibrosis, cosmetic results and the rate of recurrence up to 5 years after CK-APBI.
Study design: Prospective, single center, observational cohort study.
Study population: Female patients with early stage low-risk breast cancer
Intervention: none
Main study parameters/endpoints: Primary outcome is toxicity, scored several moments during follow-up according to the CTCAE v5.0 (dermatitis, breast pain and fibrosis). Secondary outcomes are cosmetic results, rated by the patient and physician. Futhermore, recurrence rate will be assessed.
Nature and extent of the burden and risks associated with participation, benefit and group relatedness: This is an observational study without any burden to the patient. There is no benefit nor risk for the participants. The results will be used to improve the treatment for future early-stage breast cancer patients.

The long term outcome of CK-APBI is good

2 weeks, 3, 6, 12 and 36 months