Eribulin combined with radiation therapy in a young patient re-irradiated for a new lesion of breast cancer.

Eribulin is widely used in the treatment of metastatic breast cancer, with a manageable toxicity profile. This aggressive disease often requires systemic and local treatments, comprising surgery or radiotherapy. However, eribulin is usually discontinued during radiation therapy due to the lack of data concerning the safety of this combination, especially in the setting of repeat locoregional radiation therapy. Our patient was diagnosed with ER positive invasive ductal carcinoma of the left breast initially treated by surgery, radiation therapy, chemotherapy, and hormone therapy. She then received various lines of chemotherapy for multiple triple-negative relapses in the left axillary region. Since October 2020, she has been treated by eribulin. In order to improve local control, it was decided to add local radiation therapy to the region of recurrence in addition to systemic therapy. She underwent radiation therapy concomitantly with eribulin from February to March 2021. Treatment was very well tolerated, and no acute toxicity was reported. This is the first published case of repeat locoregional radiation therapy in combination with eribulin.

Assessment of a conventional volumetric-modulated arc therapy knowledge-based planning model applied to the new Halcyon© O-ring linac in locoregional breast cancer radiotherapy.

INTRODUCTION: The aim of this study was to evaluate the performance of a knowledge-based planning (KBP) model for breast cancer trained on plans performed on a conventional linac with 6 MV FF (flattening filter) beams and volumetric-modulated arc therapy (VMAT) for plans performed on the new jawless Halcyon© system with 6 MV FFF (flattening filter-free) beams. MATERIALS AND METHODS: Based on the RapidPlan© (RP) KBP optimization engine, a DVH Estimation Model was first trained using 56 VMAT left-sided breast cancer treatment plans performed on a conventional linac, and validated on another 20 similar cases (without manual intervention). To determine the capacity of the model for Halcyon©, an additional cohort of 20 left-sided breast cancer plans was generated with RP and analyzed for both TrueBeam© and Halcyon© machines. Plan qualities between manual vs RP (followed by manual intervention) Halcyon© plans set were compared qualitatively by blinded review by radiation oncologists for 10 new independent plans. RESULTS: Halcyon© plans generated with the VMAT model trained with conventional linac plans showed comparable target dose distribution compared to TrueBeam© plans. Organ sparingwas comparable between the 2 devices with a slight decrease in heart dose for Halcyon© plans. Nine out of ten automatically generated Halcyon© plans were preferentially chosen by the radiation oncologists over the manually generated Halcyon© plans. CONCLUSION: A VMAT KBP model driven by plans performed on a conventional linac with 6 MV FF beams provides high quality plans performed with 6 MV FFF beams on the new Halcyon© linac.

Whole breast radiotherapy in the lateral isocentric lateral decubitus position: Long-term efficacy and toxicity results.

PURPOSE: To evaluate previously published whole breast radiotherapy (WBRT) using ILD (isocentring lateral decubitus) technique in terms of toxicity and efficacy. MATERIALS AND METHODS: From 2006 to 2010, 832 female patients with early-stage breast cancer (BC) treated by conservative surgery underwent 3D-conformal WBRT-ILD at Institut Curie. The acute toxicity of treatment was evaluated weekly and the late toxicity (6months and later after the treatment) was evaluated every 6months till the 5th year after the end of the radiotherapy using NCI CTC v3.0 scale. Dosimetric study was performed to analyse the mean cardiac dose and the mean homolateral and contralateral lung doses. RESULTS: The median follow up was 6.4years. The median age was 61.5years (range, 29-90), and median body mass index (BMI) was 26.3. Fifty one percent of the patients presented left sided BC and 49% right sided. Different type of fractions were used: 46.5% of pts.: 50 (breast)+16Gy (boost) in 33fractions (fr), in 17.9%-50Gy/25fr, in 26.1%-40/15fr or 41.6Gy/13fr and in 9.5%: 30Gy/5fr. Acute dermatitis was present in 93% with a median of apparition of 4weeks, and only 2,8% grade 3. In multivariate analysis, the cup size had significant influence (p=0.0004) and the fractionation had a significative influence (p=0.0001). In the all patients' population, 94.1% of cases had no skin toxicity at 1year. No cardiac or pulmonary toxicity was reported. The median overall survival had not been reached at the end of follow-up. We observed 36 (3.6%) recurrences, as following: 30 local (breast) recurrences, 4 lymph node (LN), and 2pts experiencing both. CONCLUSION: Whole breast radiotherapy in the lateral decubitus position provides excellent results in terms of local control and survival. ILD is well tolerated with very good acute toxicity profile. No cardiac or pulmonary toxicity were observed in this study. Longer follow-up is needed to confirm these results.