title: Toxicity risk of non-target organs at risk receiving low-dose radiation: case report.
abstract: The spine is the most common site for bone metastases. Radiation therapy is a common treatment for palliation of pain and for prevention or treatment of spinal cord compression. Helical tomotherapy (HT), a new image-guided intensity modulated radiotherapy (IMRT), delivers highly conformal dose distributions and provides an impressive ability to spare adjacent organs at risk, thus increasing the local control of spinal column metastases and decreasing the potential risk of critical organs under treatment. However, there are a lot of non-target organs at risk (OARs) occupied by low dose with underestimate in this modern rotational IMRT treatment. Herein, we report a case of a pathologic compression fracture of the T9 vertebra in a 55-year-old patient with cholangiocarcinoma. The patient underwent HT at a dose of 30 Gy/10 fractions delivered to T8-T10 for symptom relief. Two weeks after the radiotherapy had been completed, the first course of chemotherapy comprising gemcitabine, fluorouracil, and leucovorin was administered. After two weeks of chemotherapy, however, the patient developed progressive dyspnea. A computed tomography scan of the chest revealed an interstitial pattern with traction bronchiectasis, diffuse ground-glass opacities, and cystic change with fibrosis. Acute radiation pneumonitis was diagnosed. Oncologists should be alert to the potential risk of radiation toxicities caused by low dose off-targets and abscopal effects even with highly conformal radiotherapy.
authors.affiliation: Department of Radiation Oncology, Far Eastern Memorial Hospital, Taipei, Taiwan. shueng@hotmail.com
authors.forename: Pei-Wei
authors.initials: PW
authors.lastname: Shueng
authors.forename: Shih-Chiang
authors.initials: SC
authors.lastname: Lin
authors.forename: Hou-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Ngot-Swan
authors.initials: NS
authors.lastname: Chong
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Chen
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Wang
authors.forename: Yen-Ping
authors.initials: YP
authors.lastname: Hsieh
authors.forename: Chen-Hsi
authors.initials: CH
authors.lastname: Hsieh
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D000975:Antioxidants / Q000627:therapeutic use; D001650:Bile Duct Neoplasms / Q000556:secondary; D001653:Bile Ducts, Intrahepatic / Q000473:pathology; D002574:Cervical Vertebrae / Q000293:injuries; D018281:Cholangiocarcinoma / Q000473:pathology; D003131:Combined Modality Therapy; D006801:Humans; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000209:etiology* / Q000473:pathology / Q000628:therapy; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D016103:Spinal Fractures / Q000209:etiology; D013125:Spinal Neoplasms / Q000150:complications / Q000532:radiotherapy* / Q000556:secondary; D013131:Spine; D036542:Tomography, Spiral Computed
chemical_list: D000305:Adrenal Cortex Hormones; D000975:Antioxidants