title: Thermal dose is related to duration of local control in canine sarcomas treated with thermoradiotherapy.
abstract: OBJECTIVE
  To test that prospective delivery of higher thermal dose is associated with longer tumor control duration.
  
  
  METHODS
  122 dogs with a heatable soft tissue sarcoma were randomized to receive a low (2-5 CEM43 degrees CT90) or high (20-50 CEM43 degrees CT90) thermal dose in combination with radiotherapy. Most dogs (90%) received four to six hyperthermia treatments over 5 weeks.
  
  
  RESULTS
  In the primary analysis, median (95% confidence interval) duration of local control in the low-dose group was 1.2 (0.7-2.1) years versus 1.9 (1.4-3.2) years in the high-dose group (log-rank P = 0.28). The probability (95% confidence interval) of tumor control at 1 year in the low-dose versus high-dose groups was 0.57 (0.43-0.70) versus 0.74 (0.62-0.86), respectively. Using multivariable procedure, thermal dose group (P = 0.023), total duration of heating (P = 0.008), tumor volume (P = 0.041), and tumor grade (P = 0.027) were significantly related to duration of local tumor control. When correcting for volume, grade, and duration of heating, dogs in the low-dose group were 2.3 times as likely to experience local failure.
  
  
  CONCLUSIONS
  Thermal dose is directly related to local control duration in irradiated canine sarcomas. Longer heating being associated with shorter local tumor control was unexpected. However, the effect of thermal dose on tumor control was stronger than for heating duration. The heating duration effect is possibly mediated through deleterious effects on tumor oxygenation. These results are the first to show the value of prospectively controlled thermal dose in achieving local tumor control with thermoradiotherapy, and they establish a paradigm for prescribing thermoradiotherapy and writing a thermal prescription.
authors: Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27606, USA. don_thrall@ncsu.edu
authors: Donald E
authors: DE
authors: Thrall
authors: Susan M
authors: SM
authors: LaRue
authors: Daohai
authors: D
authors: Yu
authors: Thaddeus
authors: T
authors: Samulski
authors: Linda
authors: L
authors: Sanders
authors: Beth
authors: B
authors: Case
authors: Gary
authors: G
authors: Rosner
authors: Chieko
authors: C
authors: Azuma
authors: Jeannie
authors: J
authors: Poulson
authors: Amy F
authors: AF
authors: Pruitt
authors: Wilma
authors: W
authors: Stanley
authors: Marlene L
authors: ML
authors: Hauck
authors: Laurel
authors: L
authors: Williams
authors: Paul
authors: P
authors: Hess
authors: Mark W
authors: MW
authors: Dewhirst
mesh_terms: D000818:Animals; D003131:Combined Modality Therapy; D004195:Disease Models, Animal; D004285:Dogs; D006979:Hyperthermia, Induced; D009374:Neoplasms, Experimental; D011446:Prospective Studies; D011897:Random Allocation; D012509:Sarcoma / Q000532:radiotherapy* / Q000662:veterinary; D016896:Treatment Outcome