title: Planning combined treatments of external beam radiation therapy and molecular radiotherapy.
abstract: Molecular radiotherapy (MRT) with radiolabeled molecules has being constantly evolving, leading to notable results in cancer treatment. In some cases, the absorbed doses delivered to tumors by MRT are sufficient to obtain complete responses; in other cases, instead, to be effective, MRT needs to be combined with other therapeutic approaches. Recently, several studies proposed the combination of MRT with external beam radiation therapy (EBRT). Some describe the theoretical basis within radiobiological models, others report the results of clinical phase I-II studies aimed to assess the feasibility and tolerability. The latter includes the treatment of various tumors, such as meningiomas, paragangliomas, non-Hodgkin's lymphomas, bone, brain, hepatic, and breast lesions. The underlying principle of combined MRT and EBRT is the possibility of exploiting the full potential of each modality, given the different organs at risk. Target tissues can indeed receive a higher irradiation, while respecting the threshold limits of more than one critical tissue. Nevertheless, clinical trials are empirical and optimization is still a theoretical issue. This article describes the state of the art of combined MRT and EBRT regarding the rationale and the results of clinical studies, with special focus on the possibility of treatment improvement.
authors.affiliation: Department of Medical Imaging and Radiation Sciences, Istituto Europeo di Oncologia , Milan, Italy .
authors.forename: Marta
authors.initials: M
authors.lastname: Cremonesi
authors.forename: Mahila
authors.initials: M
authors.lastname: Ferrari
authors.forename: Francesca
authors.initials: F
authors.lastname: Botta
authors.forename: Francesco
authors.initials: F
authors.lastname: Guerriero
authors.forename: Cristina
authors.initials: C
authors.lastname: Garibaldi
authors.forename: Lisa
authors.initials: L
authors.lastname: Bodei
authors.forename: Concetta
authors.initials: C
authors.lastname: De Cicco
authors.forename: Chiara Maria
authors.initials: CM
authors.lastname: Grana
authors.forename: Guido
authors.initials: G
authors.lastname: Pedroli
authors.forename: Roberto
authors.initials: R
authors.lastname: Orecchia
mesh_terms: D019583:Dose Fractionation, Radiation; D006801:Humans; D009369:Neoplasms / Q000532:radiotherapy*; D011868:Radioisotopes / Q000008:administration & dosage; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*
chemical_list: D011868:Radioisotopes; D019275:Radiopharmaceuticals
keywords: cancer treatments; combined therapies; external beam radiation therapy; molecular radiotherapy