title: A Single Institution Consensus on the Use of Sequential or Concurrent Hormonal Therapy for Breast Cancer Patients Receiving Radiation Therapy.
abstract: OBJECTIVE
  For hormone-sensitive breast cancers, treatment with breast-conserving surgery, tamoxifen, or aromatase inhibitors, along with adjuvant radiation, is the mainstay of therapy. The ideal timing of hormonal and radiation treatment is not well defined, and there is a significant degree of practice variability between concurrent and sequential treatment regimes. This variability can cause confusion amongst the clinical team resulting in contradictory recommendations, loss of patient trust, and the potential for missed initiation of hormonal therapy.
  
  
  METHODS
  To address this question, a systematic review of the literature was conducted and presented to the breast cancer multidisciplinary team at the London Regional Cancer Center. A three-round modified Delphi method was used to obtain a consensus on a series of a priori determined statements.
  
  
  RESULTS
  With the currently available evidence, the consensus was that hormonal therapy should be given sequentially after radiation. This will limit potential overlapping adverse effects between hormonal therapy and radiation that may decrease completion of treatment. The sequential approach has not been associated with any harm in clinical outcomes, and there is some suggestion of increased toxicity with concurrent use. However, in patients at high risk of distant recurrence, they felt it would be reasonable to consider concurrent treatment to avoid any delay in therapy.
  
  
  CONCLUSIONS
  The consensus of our institution to utilize a sequential approach will standardize the treatment decisions and reduce the risk of failing to initiate hormonal therapy. Despite the lack of level 1 evidence, the Delphi methodology did provide a high level of confidence for our group to choose the sequential approach. The consensus was developed after a review of the literature revealed that there was no clear superiority of one schedule over the other and evidence that concurrent treatment may increase adverse events.
authors.affiliation: Department of Pathology, Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Cecchini
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, CA; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Edward
authors.initials: E
authors.lastname: Yu
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, CA ; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Yaremko
authors.affiliation: London Health Sciences Centre.
authors.forename: R Gabriel
authors.initials: RG
authors.lastname: Boldt
authors.affiliation: Department of Medical Oncology, London Regional Cancer Program, London, Ontario, CA; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Kylea
authors.initials: K
authors.lastname: Potvin
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, CA; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Tracy
authors.initials: T
authors.lastname: Sexton
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, CA ; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: David
authors.initials: D
authors.lastname: D'Souza
authors.affiliation: Department of Surgical Oncology, London Regional Cancer Program, London, Ontario, CA; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Muriel
authors.initials: M
authors.lastname: Brackstone
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, CA; Schulich School of Medicine & Dentistry, Western University, London, Ontario, CA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lock
keywords: aromatase inhibitors; breast cancer; concurrent; hormone therapy; sequential; tamoxifen