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Background To determine the effects of concurrent irradiation and T-DM1 on HER2-positive breast cancer cell lines. Methods Five human breast cancer cell lines (in vitro study) presenting various levels of HER2 expression were used to determine the potential therapeutic effect of T-DM1 combined with radiation. The toxicity of T-DM1 was assessed using viability assay and cell cycle analysis was performed by flow cytometry after BrdU incorporation. HER2 cells were irradiated at different dose levels after exposure to T-DM1. Survival curves were determined by cell survival assays (after 5 population doubling times). Results The results revealed that T-DM1 induced significant lethality due to the intracellular action of DM1 on the cell cycle with significant G2/M phase blocking. Even after a short time incubation, the potency of T-DM1 was maintained and even enhanced over time, with a higher rate of cell death. After irradiation alone, the D10 (dose required to achieve 10% cell survival) was significantly higher for high HER2-expressing cell lines than for low HER2-expressing cells, with a linearly increasing relationship. In combination with irradiation, using conditions that allow cell survival, T-DM1 does not induce a radiosensitivity. Conclusions Although there is a linear correlation between intrinsic HER2 expression and radioresistance, the results indicated that T-DM1 is not a radiation-sensitizer under the experimental conditions of this study that allowed cell survival. However, further investigations are needed, in particular in vivo studies before reaching a final conclusion.

In recent years, magnetic resonance imaging (MRI) has become one of the standard imaging tools to define the macroscopic gross tumor volume in locally advanced cervical cancer patients based on T2-weighted sequence. Recent data suggest that functional MRI could be used to potentially improve the delineation of target volumes based on physiologic features, defining radioresistant subvolumes that may require higher doses to achieve local cure. Functional imaging can be used to predict tumor biology and outcome, as well as for assessment of tumor response during radiotherapy. The concept of adaptive radiotherapy relies on the possibility of monitoring variations in target volumes structures to guide treatment-plan modification during radiotherapy, taking into account not only internal movements but also tumor response. With integrated MRI in radiotherapy linear accelerators, motion monitoring during treatment delivery has become available. MRI can be also used to accurately evaluate cervical tumor residual volume after chemoradiotherapy, and therefore allowing a personalized treatment planning for brachytherapy boost, based on tumor radiosensitivity. In this review, we discuss how MRI tumor response assessment could be included into clinical practice during radiation therapy in locally advanced cervical cancer patients.

Purpose Esophageal cancer is characterized by its propension to local evolution, which conditions prognosis and quality of life. Brachytherapy may be a therapeutic option for all stages of esophageal cancer. Methods and Materials This retrospective unicentric study included all consecutive patients treated for an esophageal high-dose-rate brachytherapy in our institution from 1992 to 2018. Results Ninety patients were included. They were treated in four distinct indications: exclusive (7 patients), boost after external beam radiotherapy (41), reirradiation (36), or palliative aim (6). Most frequently prescribed schemes were 3 × 5 Gy (boost) or 6 × 5 Gy (exclusive treatment and reirradiation) at applicator's surface or at 5 mm. At the end of follow-up, 50% of patients had presented with local recurrence. Seventeen percent of patients had a metastatic relapse. Median overall survival was 15 months in the whole cohort: 22 months in the boost setting, 25 months for exclusive brachytherapy, 15 months for reirradiation, and only 2 months for palliative treatment. Tumor length at brachytherapy, brachytherapy dose, and interfraction response were significantly associated to overall survival. 40% of patients presented with grade 2+ toxicity, mostly esophagitis, including three toxic deaths. Conclusions Although local control outcomes are still poor, one must remember that patients are unfit for any curative therapeutic option and that palliative chemotherapy offers mediocre results. The most promising setting probably is reirradiation because brachytherapy offers a remarkable dose gradient allowing best organ at risk sparing, with an encouraging rate of long survivors (19% at 2 years). Esophageal brachytherapy deserves to be further investigated because some patients, even unfit, may benefit from it, with acceptable toxicity.

Since dose escalation allowed by image-guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer (LACC), local relapses have become a rare event. Only scarce data are available on the outcome of patients experiencing a local relapse after IGABT.Between 2004 and 2016, all consecutive patients treated at Gustave Roussy Institute for LACC and receiving concomitant chemoradiation and IGABT were analysed. Clinical and treatment-related prognostic factors for survival after local relapse were searched, in order to potentially identify patients requiring salvage treatment.Two hundred and fifty-nine patients were treated during this period. With a median follow-up of 4.1 years, 10.8% (n = 28) had a local relapse. Among these patients, 53.6% had synchronous lymph nodes or distant metastatic relapse and only 13 patients (5% of all patients) had isolated local relapse. After local relapse, median survival was 47 months and three patients were alive at last follow-up. Only three patients with local relapse could receive salvage surgery (10.7%). Metastases occurrence and pelvic wall involvement were the main contraindications (67.9%) for salvage surgery. Among the three patients treated with surgery, two are still alive at last follow-up without significant complication. Improved survival was observed among the two patients who could have surgery (p = .02). Local progression led to serious symptoms in 75% of patients. Only the time interval between brachytherapy and relapse (1 year) was prognostic for 2-year overall survival (p = .005).Salvage surgery is feasible in a very low number of highly selected patients with local relapse following IGABT. Local failure is a major cause of severe local symptoms, confirming that every effort should be done to achieve long-term local control through dose escalation.

To investigate the efficacy and long-term side effects of hypofractionated postmastectomy radiation therapy (HFRT-PM) of 26 Gy in 6 fractions over 5 weeks.We retrospectively reviewed characteristics and outcomes of patients with stage I to III breast cancer treated with HFRT-PM between 2000 and 2009. Treatment provided 4 fractions of 4 Gy (days 1, 3, 15, 17) and then 2 fractions of 5 Gy (days 29 and 31) over 5 weeks. The treatment techniques were applied by using 3-dimensional conformal radiation therapy of the chest wall with regional nodal volume if required.We identified 454 patients with a median follow-up of 10.6 years (range, 0.5-22.9). Regional nodal irradiation was done in 84.1% of patients. At 10 years, the cumulative incidence of locoregional relapse was 15.1%. In multivariate analysis, regional lymph node involvement (≥4 nodes) was associated with worse locoregional control (hazard ratio, 1.68; 95% confidence interval, 1.06-2.67; P = .03) and overall survival (hazard ratio, 2.16; 95% confidence interval, 1.59-2.95; P.001). The toxicities were acceptable. The incidence of cardiac disorders (3.3%), and symptomatic lung fibrosis (1.5%) was low during follow-up. At 10 years, the cumulative rate of arm lymphedema was 9.5% and considered severe in 20 patients (4.4%).The long-term results of this study show that HFRT-PM of 26 Gy in 6 fractions over 5 weeks seems safe, but locoregional recurrence seems slightly higher than that observed in the literature, highlighting the need for long-term follow-up and for randomized trials for hypofractionated radiation therapy postmastectomy.

Purpose/Objective(s): To determine the effects of concurrent irradiation and T-DM1 on HER2-positive breast cancer cell lines. Materials/Methods: Five human breast cancer cell lines (in vitro study) presenting various levels of HER2 expression were used to determine the potential therapeutic effect of T-DM1 combined with radiation. The toxicity of T-DM1 was assessed using CellTiter-Glo® assays and cell cycle analysis was performed by flow cytometry after BrdU incorporation. HER2 cells were irradiated at different dose levels after exposure to T-DM1. Survival fractions were determined by cell survival after 5 population doubling times. Results: The results revealed that T-DM1 induced significant lethality due to the intracellular action of DM1 on the cell cycle with significant G2/M phase blocking. Even after a short time incubation, the potency of T-DM1 was maintained and even enhanced over time, with a higher rate of cell death. After irradiation alone, the D10 (dose required to achieve 10% cell survival) was significantly higher for high HER2-expressing cell lines than for low HER2-expressing cells, with a linearly increasing relationship. In combination with irradiation, using conditions that allow cell survival, T-DM1 does not induce a radiosensitivity, both effects are strictly additive. Conclusion: Although intrinsic HER2 expression is a factor of radioresistance, the results indicated that T-DM1 is not a radiation-sensitizer under the experimental conditions of this study. However, further investigations are needed, in particular in vivo studies before reaching a final conclusion. Citation Format: Fabien Mignot, Youlia Kirova, Pierre Verrelle, Marie-Paule Teulade-Fichou, Frédérique Megnin-Chanet. Trastuzumab Emtansine (T-DM1): No radiosensitizing effect in vitro on HER2-positive breast cancer cells (study in vitro) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-24.

Purpose To study the prognostic value of gross tumor volume (GTV) shrinkage and its dosimetric implication in a large cohort of patients with cervical cancer receiving definitive chemoradiotherapy plus image guided adaptive brachytherapy. Methods and Materials Clinical records of consecutive patients treated in our institution between February 2004 and November 2015 by concurrent chemoradiotherapy (45 Gy in 25 fractions ± lymph node boosts) followed by a magnetic resonance imaging-guided adaptive pulse-dose rate brachytherapy were included. The prognostic value of GTV and its evolution after chemoradiotherapy were examined first on initial staging magnetic resonance imaging and then at time of brachytherapy. All measures and measurement cutoffs were selected using time-dependent area under the curve for 3-year progression-free survival (PFS). Results GTV evolution between diagnosis and the time of brachytherapy was assessed in 247 patients. After chemoradiotherapy, complete response was observed in 75 patients (28%). Optimal cutoffs were GTV = 55 cm 3 at diagnosis, GTV = 7.5 cm 3 at brachytherapy, and GTV reduction ≥90%. All patients with volume above or reduction below these cutoffs had significant reduced overall survival, PFS, local control, and distant metastasis control ( P P P Conclusions These results could provide a rationale for dose de-escalation studies in brachytherapy for patients displaying optimal GTV volumetric reduction after chemoradiotherapy and may reinforce the need for dose escalation in poorly responding patients.

International audience; Purpose: The study evaluates the results of the concurrent use of lenalidomide-dexamethasone with intensity modulated radiation therapy (IMRT) for solitary plasmacytoma in terms of toxicity and outcome. Methods and Materials: Forty-six patients were treated for histologically proven solitary plasmacytoma (SP) between June 2007 and June 2018 in our Department (Curie Institute, Paris, France). All patients received IMRT. The median total dose was 40 Gy (range, 40-46). Prescription of concurrent lenalidomide-dexamethasone with radiation therapy was left to the discretion of the referring hematologist-oncologist and started the first day of radiation therapy for 4 cycles. Results: Twenty-seven solitary plasmacytoma were treated with IMRT alone and 19 with lenalidomide-dexamethasone in association with IMRT. At 5 years, the local control, multiple myeloma–free survival (MMFS), and progression-free survival (PFS) rates were 96.3%, 85.4%, and 60%. MMFS and PFS were significantly higher in the IMRT plus lenalidomide-dexamethasone group compared with IMRT alone group (100% vs 77.1%, P = .02 and 81.7% vs 48.4%, P = .047, respectively). No major toxicity was found in either group. Conclusions: Lenalidomide-dexamethasone in association with IMRT in the treatment of solitary plasmacytoma is safe and improves MMFS and PFS. Further prospective and comparative studies are needed to confirm these results.

Purpose Only scarce data are available on the possibility to include radiobiological optimization as part of the dosimetric process in cervical cancer treated with brachytherapy (BT). We compared dosimetric outcomes of pulse-dose-rate (PDR) and high-dose-rate (HDR)-BT, according to linear-quadratic model. Methods and Materials Three-dimensional dosimetric data of 10 consecutive patients with cervical cancer undergoing intracavitary image-guided adaptive PDR-BT after external beam radiation therapy were examined. A new HDR plan was generated for each patient using the same method as for the PDR plan. The procedure was intended to achieve the same D90 high-risk clinical target volume with HDR as with PDR planning after conversion into dose equivalent per 2 Gy fractions (EQD2) following linear-quadratic model. Plans were compared for dosimetric variables. Results As per study's methodology, the D90 high-risk clinical target volume was strictly identical between PDR and HDR plans: 91.0 Gy (interquartile: 86.0–94.6 Gy). The median D98 intermediate-risk clinical target volume was 62.9 GyEQD2 with HDR vs. 65.0 GyEQD2 with PDR (p Conclusion Both BT modalities provided satisfactory target volume coverage with a slightly higher value with the HDR technique for OARs D2cc while intermediate-risk clinical target volume received higher dose in the PDR plan. The radiobiological benefit of PDR over HDR was predominant when BT contribution dose to OARs was >20 Gy.

Purpose Disseminated tumor cells (DTCs) collect in the bone marrow and indicate micrometastatic spread. We previously reported that DTCs could be a predictive factor for the efficacy of regional node irradiation (internal mammary nodes [IMNs]/supra- and infraclavicular nodes [SCNs]). In this article, we report the long-term results (>10 years) on the impact of DTC status in early stage breast cancer. Methods and Materials Patients with localized breast cancer were eligible for inclusion in this prospective cohort. DTCs were obtained from a medullary iliac crest sample performed before any primary therapy. DTC status was prospectively assessed by pathologists. Irradiation volumes were defined per standard of care. Cumulative incidence rates and hazard ratios were obtained using both Cox and Fine-Gray models. Interaction tests were performed to confirm the predictive value of DTC status in a multivariate analysis. Results Six hundred twenty patients with localized breast cancer were included. Overall, 94 patients (15.2%) were DTC-positive. After a median follow-up of 11.7 years, 47 patients (7.6%) experienced locoregional relapse. DTC detection was associated with a higher risk of locoregional relapse in univariate and multivariate analyses (Cox hazard ratio, 3.26; 95% confidence interval, 1.6-5.7; P = .001). In the multivariate subgroup analysis, IMN/SCN irradiation significantly reduced locoregional relapse among DTC-positive patients compared with DTC-negative patients (interaction test: hazard ratio, 0.3; 95% confidence interval, 0.1-0.9; P = .02). IMN/SCN was the only irradiation volume with an impact on locoregional relapse in patients according to DTC status, and the predictive value of DTC status for the benefit of locoregional irradiation was independent of locoregional nodal status. Conclusions This long-term analysis confirms the predictive impact of DTC status on the efficacy of regional radiation therapy for locoregional relapse in early breast cancer. After further studies, DTC status could be used as a decision tool to better tailor adjuvant radiation therapy in patients with early stage breast cancer.

The aim of this study was to evaluate if bone marrow (BM) SUVmax measured on pre-treatment 18F-FDG PET/CT predicts the clinical outcome of locally advanced cervical cancer (LACC). We recruited retrospectively patients with LACC who underwent staging 18F-FDG PET/CT and had baseline blood tests, then treated by chemoradiation therapy (CRT), followed by image-guided adaptive brachytherapy (IGABT). BM SUVmax was calculated and correlated to inflammatory blood markers. Tumor size and pelvic lymph node involvement were evaluated on baseline MRI. Prognostic value of SUV uptake and blood markers regarding overall survival (OS), pelvic and extra-pelvic recurrence-free survival (PRFS and EPRFS respectively) was assessed using Cox models with adjusted p-values. 116 patients with FIGO stage Ib-IVa cervical cancer, treated between 2005 and 2014, were analyzed. The median follow-up was 75.5 months. BM SUVmax was significantly correlated to tumor SUVmax. In multivariate analysis, PRFS was significantly poorer in patients with high BM SUVmax (>2.8) and neutrophilia (p 5 vs ≤5 cm) could predict PRFS, EPRFS and OS (p 12 vs ≤12) were not prognostic for OS or pelvic and extra-pelvic relapses. Patients with LACC and high BM SUVmax on 18F-FDG PET have worse PFRS following CRT plus IGABT. These results can be potentially explained by the pro-inflammatory role of the tumor microenvironment and G-CSF expressed by tumor cells. These data support the role of PET as a potential indicator of disease aggressiveness beyond tumor staging.

Background: Over the past few years, anti-HER2 targeted therapies have proven to be a key treatment in the management of human epidermal growth receptor 2 (HER2)-positive breast cancers, as well as gastrointestinal tract tumors and head and neck tumors. Anti-HER2 therapies administered alone or in combination with chemotherapy have been extensively studied, but only limited robust data are available concerning the safety and efficacy of anti-HER2 molecules in combination with radiotherapy. Methods: We searched on Medline, Embase and Cochrane databases the articles providing data on the concomitant association between the antiHER2 therapies used in clinical practice (trastuzumab, pertuzumab, lapatinib and T-DM1) with radiotherapy. The articles were selected according to their pre-clinical and clinical relevance. Results: The trastuzumab-irradiation combination is the most studied, with a focus on the cardiac toxicity. The combination of lapatinib-irradiation was particularly studied in the context of cerebral metastases of HER2-positive breast cancer. The data on pertuzumab and T-DM1 were poor and are mainly case reports. Conclusion: To date, reliable conclusions about the toxicity and/or efficacy of concomitant irradiation with anti-HER2 therapies are difficult to make due to the heterogeneity of the data in the literature and need to be confirmed on a larger scale and long term follow-up. Nevertheless, no serious adverse events are reported and the toxicity profile seems to be manageable.