Radiation dose to the low axilla in patients treated for early-stage breast cancer by locoregional intensity-modulated radiotherapy (IMRT).

PURPOSE: To determine the dose received by the low axilla during locoregional radiotherapy (RT) for early-stage breast cancer and to assess the impact of the treatment technique (three-dimensional conformal radiotherapy (3D-CRT) or rotational IMRT (VMAT) or helical tomotherapy (HT). MATERIALS AND METHODS: The dosimetric study was performed on patients receiving normofractionated (NFRT - 50Gy in 25 fractions) or hypofractionated (HFRT - 40Gy in 15 fractions) locoregional radiotherapy (breast or chest wall and internal mammary, supraclavicular and infraclavicular nodes±axillary nodes) by 3D-CRT or VMAT or HT at the Institut Curie Paris. Patients treated by breast-conserving surgery received a boost dose of 16Gy and 10Gy to the tumour bed, respectively. RESULTS: Sixty-eight patients treated by RT from February 2017 to January 2019 were studied. The mean dose received by the low axilla when it was not part of the target volume was 30.8Gy, 41.0Gy and 44.4Gy by 3D-CRT, VMAT and HT, respectively for NFRT and 24.2Gy, 33.0Gy and 34.9Gy, respectively, for HFRT. With NFRT, 4.1% of the axilla received 95% (V95) of the prescribed dose by 3D-CRT compared to 24.5% and 33.6% by VMAT and HT, respectively; with HFRT, V95 was 3.9%, 19.5% and 24.1%, respectively. CONCLUSION: The axilla receives a non-negligible dose during locoregional radiotherapy; this dose is greater when VMAT or HT are used. Prospective studies must be conducted to assess the impact of this axillary dose in terms of morbidity, which currently remains unknown.

[Dosimetric impact of hydrogel spacer use for stereotactic body radiotherapy of localised prostate cancer]. / Impact dosimétrique de la pose d'un espaceur rectal dans le traitement de cancer de la prostate localisé par irradiation en conditions stéréotaxiques.

PURPOSE: Stereotactic body radiotherapy (SBRT) of prostate cancer is associated with rectal toxicities, which can be reduced by using a hydrogel spacer. The object of this retrospective study was to show the feasibility of spacer placement under local anesthesia and utility of hydrogel spacer to reduce the dose to the rectal wall. MATERIAL AND METHODS: We collected data from all patients with localised prostate cancer treated with SBRT (40Gy in 5 fractions) between 2018 and 2020. A hydrogel spacer (SpaceOAR®) was placed depending on the availability of the product. We collected dosimetric data for target volumes and organs at risk. We calculated mean values, which were compared using non-parametric tests. RESULTS: Among 35 patients, mean age was 75 years. Seventeen had a spacer placed, with a mean space created of 10mm. No complication was reported during the intervention. High doses to the rectal wall were significantly lower in spacer group (V38: 0.39 cm3 vs. 0.72 cm3; P=0.02). PTV were better covered in spacer group (P=0.07). Doses to the bladder wall were similar in both groups. CONCLUSION: Spacer procedure under local anesthesia was well tolerated. Hydrogel spacer allowed to reduce doses to the rectum while improving PTV coverage.

[Immunotherapy and radiotherapy for management of breast cancer: Rational and overview on clinical practice]. / Immunothérapie et radiothérapie dans la prise en charge du cancer du sein : rationnel et synthèse de la littérature sur les applications cliniques actuelles.

The discovery of immunotherapy led to understand the major role of immune system during the tumor process. Conventional treatments, such as chemotherapy, are directly tumoricidal. New drugs are developed to target specifically the immune system to make it regain its ability to recognize and eliminate cancer cells. Radiotherapy is used for a long time for its local action, but its systemic role, based on its impact on immunity, is now better known. Breast cancer was wrongly considered poorly immunogenic and put aside the amazing progress in this new area of treatment. In this article, we would like to present the pre-clinical and clinical rationales to associate immunotherapy to radiotherapy in the management of breast cancer.

Protontherapy versus best photon for mediastinal Hodgkin lymphoma: Dosimetry comparison and treatment using ILROG guidelines.

The purpose of this work was reducing treatment-related toxicity for Hodgkin lymphomas using practical procedure inspired by the ILROG guidelines. Reporting the first case of localized Hodgkin lymphoma treated with protontherapy in France. A 24-year-old female with mediastinal, bulky, localized, mixed-cellularity, classic Hodgkin lymphoma required an involved-site radiation therapy after complete response following polychemotherapy. Three-dimensional conformal radiation therapy was not acceptable due to high doses to breasts, heart and lungs. We realized a four-dimensional computed tomography (CT) to evaluate target movements and another CT with gating and breath-hold technique. Delineation was performed on both CT using the initial fluorodeoxyglucose positron-emission tomography/CT. One dosimetric plan with rotational intensity-modulated radiation therapy with a helical Tomotherapy© was realized and compared to another one with conformational protontherapy. Ninety-five percent of the planning target volume was covered by 98 and 99% of the prescribed dose with protontherapy and helical Tomotherapy©. Protontherapy provided the best organ at risk protection. Lung and heart protections were better with protontherapy: lung mean dose (3.7Gy vs. 8.4Gy) and median dose (0.002Gy vs. 6.9Gy), heart mean dose (2.6Gy vs. 3.7Gy). Breast sparing was better for both breasts using protontherapy: right breast mean dose (2.4Gy vs. 4.4Gy) and left (1.9Gy vs. 4.6Gy). The biggest difference was seen with low doses, which were better with protontherapy: volume of lung receiving 5Gy was 17.5% vs. 54.2% with Helical Tomotherapy©. In view of these results, we decided to treat our patient with protontherapy using respiratory assessment. We delivered 30Gy (15 fractions) using protontherapy with one direct anterior field using pencil beam scanning and deep inspiration breath-hold technique. We observed only grade 1 skin erythema during treatment and no toxicity during early follow-up.

[Stereotactic body radiotherapy: Prospective study to evaluate asthenia and quality of life]. / Radiothérapie en conditions stéréotaxiques : étude prospective évaluant la fatigue et la qualité de vie.

PURPOSE: To evaluate prospectively asthenia and the quality of life in patients treated by stereotactic body irradiation and to determine their predictive factors. METHODS AND MATERIALS: Quality of life was assessed by the EORTC QLQ-C30 and asthenia was evaluated with the Brief Fatigue Inventory (BFI), on the first day (T1), last day (T2) and 1-3 weeks after the end of treatment (T3). RESULTS: Sixty-three patients were treated with stereotactic body irradiation from February 2017 to May 2017 and 41 were included in the analysis (22 patients excluded for lack of understanding, organization, psychologic disorders or refusal). The mean number of fractions was 5 (±2). The compliance to quality of life assessment was 98%, 95% was 81% at T1, T2 and T3, respectively. An increase of asthenia and a worsened quality of life were found in 12 (29%) and 14 (34%) patients between T1 and T2. Univariate analysis demonstrated a correlation between asthenia and quality of life were correlated with performans status (P=0.03 and 0.05 respectively), hemoglobin level (p=0.01 and 0.004), albumin level (P=0.01 and 0.06), distance between home and radiotherapy department (P=0.05 and 0.02). Multivariate analysis demonstrated a correlation between female gender (P=0.012), albumin level (P<0.001), distance over 25km (P<0.001) with asthenia, and albumin level (P=0.003), hemoglobin level (P=0.004) and previous chemotherapy (P=0.003) with quality of life. No influence of stereotactic body ratiotherapy parameters was seen. CONCLUSION: Despite hypofractionation, stereotactic body radiotherapy induced asthenia and deterioration of quality of life.