Combination of radiotherapy and double blockade HER2 with pertuzumab and trastuzumab for HER2-positive metastatic or locally recurrent unresectable and/or metastatic breast cancer: Assessment of early toxicity

Background and purposes

We evaluate the early toxicity of concurrent use of radiotherapy, pertuzumab and trastuzumab in patients with HER2-positive metastatic or locally recurrent unresectable breast cancer.

Patients and methods

A retrospective study was performed in a population of 23 consecutive patients between 2013 and 2015. Radiotherapy was performed on the chest area or metastatic sites during maintenance with pertuzumab and trastuzumab after six cycles of pertuzumab, trastuzumab and docetaxel. Toxicity was assessed according to the National Cancer Institute Common Toxicity Criteria version 4.

Results

Irradiation volumes were whole breast (8 patients) and chest wall (9 patients) at 50 Gy in 25 fractions, the supraclavicular nodes (16 patients), the axillary area (nine patients) and the internal mammary nodes (9 patients) at 46 Gy in 23 fractions. For five patients, radiotherapy was palliative: bone irradiation (4 patients), whole brain radiotherapy (one patient). Median follow-up was 12.6 months (range: 6.1–21.6 months) since the start of pertuzumab and trastuzumab. One patient presented an asymptomatic decrease of left ventricular ejection fraction below 50%. No symptomatic cardiac events were reported. Two patients presented asymptomatic grade I radiation pneumonitis. Acute skin toxicity was grade III (one patient), grade II (6 patients), and grade I (5 patients). There were two grade II esophagitis.

Conclusion

Combination of pertuzumab, trastuzumab and radiotherapy was well tolerated, which should be confirmed by the results of larger studies.