Long-term toxicity of an intraoperative radiotherapy boost using low energy X-rays during breast-conserving surgery

Int J Radiat Oncol Biol Phys. 2006 Oct 1;66(2):377-81. doi: 10.1016/j.ijrobp.2006.05.042. Epub 2006 Aug 2.

Abstract

Purpose: Intraoperative radiotherapy (IORT) as a boost for breast cancer delivers a high single dose of radiation to a late-reacting tissue; therefore late toxicity is of particular interest, and long-term follow-up is warranted. To date there are only limited data available on breast cancer patients treated with IORT using low energy X-rays. We analyzed toxicity and cosmesis after IORT as a boost with a minimum follow-up of 18 months.

Methods and materials: A total of 73 patients treated with IORT (20 Gy/50 kV X-rays; INTRABEAM [Carl Zeiss Surgical, Oberkochen, Germany]) to the tumor bed during breast-conserving surgery as a boost followed by whole-breast radiotherapy (WBRT, 46 Gy) underwent a prospective, predefined follow-up (median, 25 months; range 18-44 months), including clinical examination and breast ultrasound at 6-months and mammographies at 1-year intervals. Toxicities were documented using the common toxicity criteria (CTC)/European Organization for Research and Treatment of Cancer and the LENT-SOMA score. Cosmesis was evaluated with a score from 1 to 4.

Results: The IORT in combination with WBRT was well tolerated, with no Grade 3 or 4 skin toxicities and no telangiectasias. Fibrosis of the entire breast was observed in 5% of the patients. A circumscribed fibrosis around the tumor bed was palpable in up to 27% with a peak around 18 months after therapy and a decline thereafter. The observed toxicitiy rates were not influenced by age, tumor stage, or systemic therapy. The cosmetic outcome was good to excellent in>or=90% of cases.

Conclusions: After IORT of the breast using low-energy X-rays, no unexpected toxicity rates were observed during long-term-follow-up.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Breast / pathology
  • Breast / radiation effects*
  • Breast Neoplasms / radiotherapy*
  • Breast Neoplasms / surgery*
  • Chemotherapy, Adjuvant
  • Female
  • Fibrosis
  • Humans
  • Intraoperative Period
  • Mastectomy, Segmental*
  • Middle Aged
  • Radiation Injuries / etiology*
  • Radiotherapy Dosage
  • Radiotherapy, Adjuvant / adverse effects