title: Targeted intraoperative radiotherapy tumour bed boost during breast-conserving surgery after neoadjuvant chemotherapy.
abstract: BACKGROUND
  The use of targeted intraoperative radiotherapy (TARGIT-IORT) as a tumour bed boost during breast-conserving surgery (BCS) for breast cancer has been reported since 1998. We present its use in patients undergoing breast conservation following neoadjuvant therapy (NACT).
  
  
  METHODS
  In this retrospective study involving 116 patients after NACT we compared outcomes of 61 patients who received a tumour bed boost with IORT during lumpectomy versus 55 patients treated in the previous 13 months with external (EBRT) boost. All patients received whole breast radiotherapy. Local recurrence-free survival (LRFS), disease-free survival (DFS), distant disease-free survival (DDFS), breast cancer mortality (BCM), non-breast cancer mortality (NBCM) and overall mortality (OS) were compared.
  
  
  RESULTS
  Median follow up was 49 months. The differences in LRFS, DFS and BCM were not statistically significant. The 5‑year Kaplan-Meier estimate of OS was significantly better by 15% with IORT: IORT 2 events (96.7%, 95%CI 87.5-99.2), EBRT 9 events (81.7%, 95%CI 67.6-90.1), hazard ratio (HR) 0.19 (0.04-0.87), log rank p = 0.016, mainly due to a reduction of 10.1% in NBCM: IORT 100%, EBRT 89.9% (77.3-95.7), HR (not calculable), log rank p = 0.015. The DDFS was as follows: IORT 3 events (95.1%, 85.5-98.4), EBRT 12 events (69.0%, 49.1-82.4), HR 0.23 (0.06-0.80), log rank p = 0.012.
  
  
  CONCLUSIONS
  IORT during lumpectomy after neoadjuvant chemotherapy as a tumour bed boost appears to give results that are not worse than external beam radiotherapy boost. These data give further support to the inclusion of such patients in the TARGIT-B (boost) randomised trial that is testing whether IORT boost is superior to EBRT boost.
authors.affiliation: Department of Gynecology and Obstetrics, Marienhospital Bottrop gGmbH, Josef-Albers-Str. 70, 46236, Bottrop, Germany. hans-christian.kolberg@mhb-bottrop.de.
authors.forename: Hans-Christian
authors.identifier: http://orcid.org/0000-0003-0221-3272
authors.initials: HC
authors.lastname: Kolberg
authors.affiliation: BORAD, Bottrop, Germany.
authors.forename: Gyoergy
authors.initials: G
authors.lastname: Loevey
authors.affiliation: Department of Gynecology and Obstetrics, Marienhospital Bottrop gGmbH, Josef-Albers-Str. 70, 46236, Bottrop, Germany.
authors.forename: Leyla
authors.initials: L
authors.lastname: Akpolat-Basci
authors.affiliation: Department of Gynecology and Obstetrics, Marienhospital Bottrop gGmbH, Josef-Albers-Str. 70, 46236, Bottrop, Germany.
authors.forename: Miltiades
authors.initials: M
authors.lastname: Stephanou
authors.affiliation: University of Erlangen, Erlangen, Germany.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Fasching
authors.affiliation: Helios Klinikum Berlin-Buch, Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Untch
authors.affiliation: University Hospital Schleswig-Holstein/Campus Lübeck, Lübeck, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Liedtke
authors.affiliation: University of Notre Dame, Fremantle, Australia.|University College, London, UK.
authors.forename: Max
authors.initials: M
authors.lastname: Bulsara
authors.affiliation: University College, London, UK.
authors.forename: Jayant S
authors.initials: JS
authors.lastname: Vaidya
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality* / Q000628:therapy*; D059186:Chemoradiotherapy, Adjuvant / Q000401:mortality* / Q000706:statistics & numerical data; D018572:Disease-Free Survival; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008137:Longitudinal Studies; D015412:Mastectomy, Segmental / Q000401:mortality* / Q000706:statistics & numerical data; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000401:mortality / Q000706:statistics & numerical data; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control; D015995:Prevalence; D000069473:Radiation Dose Hypofractionation; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Breast cancer; External boost; Intraoperative radiotherapy; Neoadjuvant therapy; Tumor bed boost