title: Proton beam therapy for malignancy in Bloom syndrome.
abstract: OBJECTIVE
  Bloom syndrome is a DNA repair disorder that is hypersensitive to radiotherapy. We describe the first case in which proton beam therapy (PBT) was used in a patient with Bloom syndrome to treat oropharyngeal cancer.
  
  
  METHODS
  The patient was a 32-year-old woman with Bloom syndrome who was diagnosed with oropharyngeal cancer staged as T2N2bM0 poorly differentiated squamous cell carcinoma. The primary tumor was located on the right tongue base and extended to the right lateral pharyngeal wall. Several right upper region lymph nodes were positive for metastases.
  
  
  RESULTS
  We selected PBT in anticipation of dose reduction to normal tissue. The clinical target volume was defined as the area of the primary tumor and lymph node metastases plus an 8-mm margin. After treatment with 36 GyE (Gray equivalent) in 20 fractions (4-5 fractions per week), dietary intake was decreased by mucositis and intravenous hyperalimentation was started. Termination of treatment for 2.5 weeks was required to relieve mucositis. Administration of 59.4 GyE in 33 fractions markedly reduced the size of the primary tumor, but also caused moderate mucositis that required termination of PBT. One month later, lung metastases and breast cancer developed and the patient died 9 months after PBT. At this time the reduction in size of the primary tumor was maintained without severe late toxicity.
  
  
  CONCLUSIONS
  We obtained almost complete response for a radiosensitive patient with a deficiency of DNA repair, indicating the excellent dose concentration of proton beam therapy.
authors: Department of Radiation Oncology, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, Japan. mizumoto@pmrc.tsukuba.ac.jp
authors: M
authors: M
authors: Mizumoto
authors: H
authors: H
authors: Hashii
authors: M
authors: M
authors: Senarita
authors: S
authors: S
authors: Sakai
authors: T
authors: T
authors: Wada
authors: T
authors: T
authors: Okumura
authors: K
authors: K
authors: Tsuboi
authors: H
authors: H
authors: Sakurai
mesh_terms: D000328:Adult; D001816:Bloom Syndrome / Q000532:radiotherapy*; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology / Q000532:radiotherapy; D008279:Magnetic Resonance Imaging; D009061:Mouth Mucosa / Q000528:radiation effects; D052016:Mucositis / Q000209:etiology; D009367:Neoplasm Staging; D009959:Oropharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D061766:Proton Therapy / Q000009:adverse effects / Q000379:methods*; D011832:Radiation Injuries / Q000209:etiology; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*