title: Comparison of chronic toxicities between brachytherapy-based accelerated partial breast irradiation and whole breast irradiation using intensity modulated radiotherapy.
abstract: OBJECTIVE
  Brachytherapy-based APBI (bAPBI) shortens treatment duration and limits dose to normal tissue. While studies have demonstrated similar local control when comparing bAPBI and whole breast irradiation using intensity modulated radiotherapy (WBI-IMRT), comparison of late side effects is limited. Here, we report chronic toxicity profiles associated with these two treatment modalities.
  
  
  METHODS
  1034 patients with early stage breast cancer were treated at a single institution; 489 received standard-fractionation WBI-IMRT between 2000 and 2013 and 545 received bAPBI (interstitial 40%, applicator-based 60%) between 1993 and 2013. Chronic toxicity was evaluated ≥6 months utilizing CTCAE version 3.0; cosmesis was evaluated using the Harvard scale.
  
  
  RESULTS
  Median follow-up was 4.6 years (range 0.1-13.4) for WBI-IMRT versus 6.7 years (range 0.1-20.1) for bAPBI (p < 0.001). Compared to WBI-IMRT, bAPBI was associated with higher rates of ≥grade 2 seroma formation (14.4% vs 2.9%, p < 0.001), telangiectasia (12.3% vs 2.1%, p = 0.002) and symptomatic fat necrosis (10.2% vs 3.6%, p < 0.001). Lower rates of hyperpigmentation were observed (5.8% vs 14.5%; p = 0.001). Infection rates were similar (3.3% vs 1.3%, p = 0.07). There was no difference between rates of fair (6.1% vs. 4.1%, p = 0.30) or poor (0.2% vs. 0.5%, p = NS) cosmesis. Mastectomy rates for local recurrence (3.1% for WBI-IMRT and 1.2% for bAPBI, p = 0.06), or for other reasons (0.8% and 0.6%, p = 0.60) were similar between groups.
  
  
  CONCLUSIONS
  With 5-year follow-up, WBI-IMRT and bAPBI are associated with similar, acceptable rates of toxicity. These data further support the utilization of bAPBI as a modality to deliver adjuvant radiation in a safe and efficacious manner.
authors.affiliation: Dept of Radiation Oncology, Arthur G. James Hospital/Ohio State Comprehensive Cancer Center, The Ohio State University Wexner Medical Center, Columbus, OH, USA. Electronic address: jessica.wobb@osumc.edu.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Wobb
authors.affiliation: Cleveland Clinic, Dept of Radiation Oncology, Taussig Cancer Institute, Cleveland, OH, USA.
authors.forename: Chirag
authors.initials: C
authors.lastname: Shah
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Maha S
authors.initials: MS
authors.lastname: Jawad
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Wallace
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Dilworth
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Inga S
authors.initials: IS
authors.lastname: Grills
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Ye
authors.affiliation: Dept of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA.
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D005218:Fat Necrosis / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017495:Hyperpigmentation / Q000209:etiology; D008408:Mastectomy / Q000379:methods; D008875:Middle Aged; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000150:complications*; D018714:Radiotherapy, Adjuvant; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D049291:Seroma / Q000209:etiology; D013684:Telangiectasis / Q000209:etiology; D016896:Treatment Outcome
keywords: APBI; Breast cancer; Chronic toxicity; IMRT