title: Thermoresponsive polymeric radionuclide delivery system--an injectable brachytherapy.
abstract: Brachytherapy is of increasing popularity in clinical oncology for the local therapy of solid tumors due to high radiation doses delivered to malignant tissue while keeping the whole-body radiation burden low. Pronounced dose-dependent tumor growth reduction was achieved by single dose of injectable intratumoral brachytherapy with iodine-131-labeled thermoresponsive polymer [poly(N-isopropyl acrylamide)] in murine xenograft model (PC3 human prostate adenocarcinoma). The two doses of radionuclide were used, 2 MBq/mouse and 25 MBq/mouse. The higher dose caused gradual tumor volume reduction and 2 of 6 mice from this group were cured. The lower dose caused tumor growth retardation only. In both cases there were no signs of inflammation. The effects of both doses were statistically significant compared to untreated controls. Such injectable system should keep advantages of brachytherapy while making system administration easier and less invasive (injection instead of implantation), patient-tailored (splitting of doses into several depoes) and bioerodable.
authors.affiliation: Institute of Macromolecular Chemistry AS CR, v.v.i., Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic. mhruby@centrum.cz
authors.forename: Martin
authors.initials: M
authors.lastname: Hruby
authors.forename: Pavla
authors.initials: P
authors.lastname: Pouckova
authors.forename: Marie
authors.initials: M
authors.lastname: Zadinova
authors.forename: Jan
authors.initials: J
authors.lastname: Kucka
authors.forename: Ondrej
authors.initials: O
authors.lastname: Lebeda
mesh_terms: D000178:Acrylamides / Q000138:chemical synthesis / Q000737:chemistry*; D000180:Acrylic Resins; D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D045744:Cell Line, Tumor; D004307:Dose-Response Relationship, Radiation; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D015552:Injections, Intralesional; D007457:Iodine Radioisotopes / Q000008:administration & dosage* / Q000737:chemistry / Q000627:therapeutic use; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000737:chemistry / Q000627:therapeutic use; D012995:Solubility; D013696:Temperature; D023041:Xenograft Model Antitumor Assays
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D004337:Drug Carriers; D007457:Iodine Radioisotopes; D011108:Polymers; D019275:Radiopharmaceuticals; C052970:poly-N-isopropylacrylamide