Abstract 263P
Background
The tolerance of the concurrent use of radiotherapy (RT), pertuzumab (P) and trastuzumab (T) is unknown.
Methods
A retrospective study was performed in our institution for all consecutive pts treated with concurrent RT-P-T. The RT was performed while P and T were administrated as a maintenance treatment at the dose of 420mg (total dose) and 6mg/kg respectively every 3 weeks without chemotherapy. Toxicity was assessed according National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Left ventricular ejection fraction (LVEF) was measured at baseline and then every 3 - 4 months.
Results
We studied 77 pts. treated in between 2013 and 2019 with median follow-up of 38 months (range 0-264 months). Median age was 53 years (33-86). There were 50 pts. (64.9%) with metastatic and 27 pts. (35.1%) with recurrent disease. All pts received Docetaxel followed by P-T as first line treatment and they received 34 cycles (10-85) of P-T. All pts. experienced partial or complete response according to RECIST criteria. Irradiation volumes were whole breast (41 pts., 53.2%) and chest wall (29 pts., 37.7%) at a dose of 50 Gy with a median duration of 39 days. Radiotherapy of lymph nodes (LN) was performed in 53 patients (68.8%) as following: supraclavicular-infra clavicular and axillary LN in 52 pts (67.5%), and internal mammary nodes in 31 pts (40.3%). For 20 pts. (26.0%) RT was palliative: bone irradiation (12 pts., 15.6%), whole-brain RT (2 pts, 2.6%), cerebral metastasis irradiation (6 pts). As early toxicity we observed: radio dermatitis: 36 pts (46.8%) presented grade I, 17 pts (22.1%) presented grade II, and 3 pts (3.9%) presented grade III. One patient (1.3%) presented grade II esophagitis One patient (1.3%) presented asymptomatic decrease of LVEF during RT-P-T and 6 pts (7.7%) presented a decrease of LVEF. There was no radiation induced pneumonitis. As late toxicity we observed 1 (1.3%) case of grade I and 1 (1.3%) with grade II telangiectasia. There was 1 case (1.3%) of grade III cardiac toxicity, 8 months after the concurrent treatment.
Conclusions
The concurrent use of RT-P-T is feasible with good tolerance. Larger prospective data with longer follow-up is needed to confirm these results.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The author.
Funding
Has not received any funding.
Disclosure
The author has declared no conflicts of interest.