title: Rib fractures after reirradiation plus hyperthermia for recurrent breast cancer: Predictive factors.
abstract: BACKGROUND
  Combining reirradiation (reRT) and hyperthermia (HT) has shown high therapeutic value for patients with locoregional recurrent breast cancer (LR). However, additional toxicity of reirradiation (e.g., rib fractures) may occur. The aim of this study is to determine the impact of potential risk factors on the occurrence of rib fractures.
  
  
  METHODS
  From 1982-2005, 234 patients were treated with adjuvant reRT + HT after surgery for LR. ReRT consisted typically of 8 fractions of  4 Gy twice a week, or 12 fractions of  3 Gy four times a week. A total of 118 patients were irradiated with abutted photon and electron fields. In all, 60 patients were irradiated using either one or alternating combinations of abutted AP electron fields. Hyperthermia was given once or twice a week.
  
  
  RESULTS
  The 5-year infield local control (LC) rate was 70 %. Rib fractures were detected in 16 of 234 patients (actuarial risk: 7 % at 5 years). All rib fractures occurred in patients treated with a combination of photon and abutted electron fields (p = 0.000); in 15 of 16 patients fractures were located in the abutment regions. The other significant predictive factors for rib fractures were a higher fraction dose (p = 0.040), large RT fields, and treatment before the year 2000.
  
  
  CONCLUSIONS
  ReRT + HT results in long-term LC. The majority of rib fractures were located in the photon/electron abutment area, emphasizing the disadvantage of field overlap. Large abutted photon/electron fields combined with 4 Gy fractions increase the number of rib fractures in this study group. However, as these factors were highly correlated no relative importance of the individual factors could be estimated. Increasing the number of HT sessions a week does not increase the risk of rib fractures.
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands. s.oldenborg@amc.uva.nl.
authors: Sabine
authors: S
authors: Oldenborg
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Christel
authors: C
authors: Valk
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Rob
authors: R
authors: van Os
authors: Institute Verbeeten (BVI), Tilburg, The Netherlands.
authors: Bing
authors: B
authors: Oei
authors: Institute Verbeeten (BVI), Tilburg, The Netherlands.
authors: Jack
authors: J
authors: Venselaar
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Paul Zum Vörde Sive
authors: PZ
authors: Vörding
authors: Department of Radiology Academic Medical Center, University of Amsterdam (AMC), Amsterdam, The Netherlands.
authors: Adriënne
authors: A
authors: van Randen
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Hans
authors: H
authors: Crezee
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Geertjan
authors: G
authors: van Tienhoven
authors: Department of Radiation Oncology, Z1-215, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 22660, Amsterdam, The Netherlands.
authors: Coen
authors: C
authors: Rasch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000532:radiotherapy*; D010025:Osteoradionecrosis / Q000209:etiology*; D011832:Radiation Injuries / Q000209:etiology*; D018714:Radiotherapy, Adjuvant; D011882:Radiotherapy, High-Energy / Q000379:methods*; D000069475:Re-Irradiation; D012253:Rib Fractures / Q000209:etiology*; D012272:Ribs / Q000528:radiation effects*; D012307:Risk Factors
keywords: Hyperthermia; Local control; Recurrent breast cancer; Reirradiation; Toxicity