Abstract 214P
Background
We aimed to evaluate the effect of chemotherapy (CT) and hormonal therapy (HT) on the acute toxicity of a hypofractionated radiotherapy (RT) schedule after breast conserving surgery.
Methods
We retrospectively analyzed 141 breast cancer patients treated with 3D-CRT from December 2017 to February 2020 with an hypofractionnated regimen (40.05 Gy in 15 fractions to the whole breast followed by 13.35 Gy in 5 fractions to tumor bed). The median age was 53, range [25-82]. Molecular profile was: luminal A (28.4%), luminal B (58.9%), HER2-enriched (2.1%) and triple negative (10.6%). CT was given in 79,4 % of patients (n=112) and HT in 86.5% (n= 122). All patients were monitored for acute skin toxicity during RT according to CTCAE 4.0 (common toxicity criteria for adverse events) scale. The correlation of the incidence of toxicity grading with either the administration of CT or HT was performed with the χ2 test.
Results
Overall, there was no erythema in 6.4 % (n=9), grade 1 erythema in 64.5% (n=91), grade 2 in 26.2% (n=37) and grade 3 in 2.8% (n= 3). No grade 4 erythema was seen. No significant correlation was found between toxicity grading and CT [P= 0.34]. Skin toxicity Grade 2-3 in patient undergone CT or not was 76.2% versus 23.8% respectively. In the subset of patient receiving adjuvant CT (n=99), a significantly higher acute skin toxicity grade 2-3 was observed when the delay between CT and RT was less than 20 days (78.6 % versus 21.4% [P < 0.05]). There was no significant difference between grade 2-3 skin toxicity in patients taking or not hormonal therapy [P=0.7]. Grade 2-3 erythema was significantly higher in subgroup patients taking Letrozole compared to Anastrozole, 42.5% vs 12.5 % respectively [P=0.01].
Conclusions
Our results confirmed that hypofractionated breast radiation was a well-tolerated treatment (3% of grade 3 erythema). Neither CT nor HT have an impact on acute skin toxicity. CT to RT delay shorter than 20 days was significantly associated with higher graded (≥ Grade 2) skin toxicity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Lotfi Kochbati.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.