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Subject: search.filters.subject.MR-guided radiotherapy

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    The utility of 1.5 tesla MR-guided adaptive stereotactic body radiotherapy for recurrent ovarian tumor - Case reports and review of the literature
    (2022) Yavas, Guler; Kuscu, Ulku Esra; Ayhan, Ali; Yavas, Cagdas; Onal, Cem; 36261943
    Introduction: Although epithelioid ovarian cancer (EOC) is a radiosensitive tumor and radiotherapy (RT) played a significant role in adjuvant treatment management in the past, the role of RT has evolved with the advent of platinum-based chemotherapy regimens. Nonetheless, modern RT techniques may be useful in certain patients particularly those with recurrent disease.Presentation of case: After surgery and chemotherapy, two patients, aged 57 and 70, presented with recurrent lesions in the parailiac region. The recurrent lesions were treated with high field 1.5-Tesla MR-Linac treatment in 5 fractions at a dose of 30 Gy. The patients tolerated the treatment well and were disease free after 12 and 20 months of magnetic resonance guided radiotherapy (MRgRT), respectively.Discussion: MRgRT is a novel and rapidly evolving technology that allows for the highly precise treatment of even mobile targets through direct visualization of the tumor. The majority of patients with EOC frequently present with abdominal-pelvic recurrences. It has been demonstrated that EOC requires high radiation doses for curative treatment. MR-Linac enables monitoring of organ motion during treatment, which is necessary for delivering higher doses to target volumes while sparing surrounding organs.Conclusion: To reduce radiation doses to nearby normal tissues, MRgRT allows for the delivery of hypofractio-nated RT with tight safety margins. Regardless of initial resistance or gradual development of intolerance to standard chemotherapy regimens, the role of RT in patients with persistent or recurrent EOC should be reconsidered.
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    The Potential Role Of MR-Guided Adaptive Radiotherapy In Pediatric Oncology: Results From A SIOPE-COG Survey
    (2021) Seravalli, Enrica; Kroon, Petra S.; Buatti, John M.; HalL, Matthew D.; Mandeville, Henry C.; Marcus, Karen J.; Onal, Cem; Ozyar, Enis; Paulino, Arnold C.; Paulsen, Frank; Saunders, Daniel; Tsang, Derek S.; Wolden, Suzanne L.; Janssens, Geert O.; 34159265
    Background and purpose: Magnetic resonance guided radiotherapy (MRgRT) has been successfully implemented for several routine clinical applications in adult patients. The purpose of this study is to map the potential benefit of MRgRT on toxicity reduction and outcome in pediatric patients treated with curative intent for primary and metastatic sites. Materials and methods: Between May and August 2020, a survey was distributed among SIOPE- and COG-affiliated radiotherapy departments, treating at least 25 pediatrics patients annually and being (candidate) users of a MRgRT system. The survey consisted of a table with 45 rows (clinical scenarios for primary (n = 28) and metastatic (n = 17) tumors) and 7 columns (toxicity reduction, outcome improvement, PTV margin reduction, target volume daily adaptation, online re-planning, intrafraction motion compensation and on-board functional imaging) and the option to answer by 'yes/no'. Afterwards, the Dutch national radiotherapy cohort was used to estimate the percentage of pediatric treatments that may benefit from MRgRT. Results: The survey was completed by 12/17 (71% response rate) institutions meeting the survey inclusion criteria. Responders indicated an 'expected benefit' from MRgRT for toxicity/outcome in 7% (for thoracic lymphomas and abdominal rhabdomyosarcomas)/0% and 18% (for mediastinal lymph nodes, lymph nodes located in the liver/splenic hilum, and liver metastases)/0% of the considered scenarios for the primary and metastatic tumor sites, respectively, and a 'possible benefit' was estimated in 64%/46% and 47%/59% of the scenarios. When translating the survey outcome into a clinical perspective a toxicity/outcome benefit, either expected or possible, was anticipated for 55%/24% of primary sites and 62%/38% of the metastatic sites. Conclusion: Although the benefit of MRgRT in pediatric radiation oncology is estimated to be modest, the potential role for reducing toxicity and improving clinical outcomes warrants further investigation. This fits best within the context of prospective studies or registration trials.