Cyberneo trial investigating the efficacy of stereotactic radiotherapy combined to neoadjuvant chemotherapy for locally advanced breast cancer: 14-years follow-up results

Abstract

Purpose

The purpose of the phase I trial named “Cyberneo” was to define the efficacy of the stereotactic radiotherapy using CyberKnife® for locally advanced (stage III) breast tumours combined to a neoadjuvant chemotherapy for patients for whom a conservative surgery could not be considered at the onset. Neoadjuvant chemotherapy consisted of six cycles: three cycles of docetaxel and three cycles of the combination of 5-fluorouracil, epirubicin and cyclophosphamide. Stereotactic radiotherapy using CyberKnife® was performed during the second cycle of chemotherapy. Breast surgery was performed 6 to 8 weeks later and conventional breast irradiation without boost, afterwards. The main objective was to define the maximum tolerated dose of hypofractionated radiotherapy concurrent with neoadjuvant chemotherapy. We present an updated survival data for patients included in this trial and we evaluate the late toxicity of this combination.

Patients and methods

We updated the survival data of 25 patients treated for a stage III breast cancer between 2007 and 2009 at the Antoine-Lacassagne centre in Nice and included in the Cyberneo trial by recording late toxicity events and aesthetic results.

Results

With a median follow-up of 12 years (95 % confidence interval [CI]: 10–14 years), 19 patients were in remission (76 %), one patient had a controlled axillary lymph node relapse (4 %) and five patients (20 %) died due to metastatic progression within a median of 5 years after treatment (range: 1–9 years). Nine patients had a complete histological response (36 %). The highest percentage of complete histological response was in the group of patients treated in the fourth stage (28.5 Gy in four fractions). Overall survival rate at 14 years was 71 % (95 % CI: [53–94 %]). Two patients developed chronic radiation toxicity during follow-up with a fibrosis (8 %) of which one was in the fourth stage and one in the fifth stage (31.5 Gy). Three patients (12 %) had a change of prosthesis after treatment, which for one patient was 24 months after the end of support.

Conclusion

The updated results of the Cyberneo trial with 14 years of follow-up confirm the satisfactory results in terms of local control with an excellent long-term safety profile.