Long-term toxicity of an intraoperative radiotherapy boost using low energy X-rays during breast-conserving surgery.
OBJECTIVE
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
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.
Kraus-Tiefenbacher
Uta
U
Department of Radiation Oncology, Mannheim Medical Center, University of Heidelberg, Mannheim, Germany. uta.kraus-tiefenbacher@radonk.ma.uni-heidelberg.de
Bauer
Lelia
L
Scheda
Antonella
A
Fleckenstein
Katharina
K
Keller
Anke
A
Herskind
Carsten
C
Steil
Volker
V
Melchert
Frank
F
Wenz
Frederik
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology / Q000528:radiation effects*; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D017024:Chemotherapy, Adjuvant; D005260:Female; D005355:Fibrosis; D006801:Humans; D007432:Intraoperative Period; D015412:Mastectomy, Segmental; D008875:Middle Aged; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects