Clinical outcome analysis in "high-risk" versus "low-risk" patients eligible for national surgical adjuvant breast and bowel B-39/radiation therapy oncology group 0413 trial: five-year results.
OBJECTIVE
To report the local control and overall survival outcomes after lumpectomy followed by accelerated partial breast irradiation in high-risk patients as defined by the current inclusion criteria for the National Surgical Adjuvant Breast and Bowel B-39/Radiation Therapy Oncology Group 0413 Intergroup trial.


METHODS
Between 2000 and 2005, 273 women with early-stage breast cancer were treated using either multicatheter interstitial brachytherapy (n=247) or MammoSite (n=26). Patients received 32-34 Gy in 8-10 twice-daily fractions using high-dose-rate 192Ir brachytherapy. All patients met the initial inclusion criteria for the Intergroup trial and were separated into two groups: high-risk patients (representing the cohort that remained eligible for the Intergroup trial) who satisfied one or more of the "high-risk" criteria (age<50 years, estrogen receptor negative, and/or positive lymph nodes; n=90), and low-risk patients who comprised the remainder of the cohort (n=183). The outcomes of the two cohorts were analyzed and compared.


RESULTS
The median follow-up of the entire cohort was 48.5 months. No significant difference was found in outcomes at 5 years between the low- and high-risk groups, with a local control rate of 97.8% vs. 93.6%, crude local recurrence rate of 2.2% (n=4) vs. 4.4% (n=4), and overall survival rate of 92.1% vs. 89.5%, respectively.


CONCLUSIONS
At 5 years, no statistically significant difference was found in outcomes for patients deemed to be at greater risk in the current National Surgical Adjuvant Breast and Bowel B-39/Radiation Therapy Oncology Group 0413 Intergroup trial. These clinical data support the inclusion of this "high-risk" population in this important ongoing study.
Patel
Rakesh R
RR
Department of Radiation Oncology, University of Wisconsin Hospital and Clinics, Madison, WI 53792, USA. patel@humonc.wisc.edu
Christensen
Michael E
ME
Hodge
C Wesley
CW
Adkison
Jarrod B
JB
Das
Rupak K
RK
D001918:Brachytherapy / Q000379:methods*; D001943:Breast Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D015412:Mastectomy, Segmental; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012306:Risk; D015996:Survival Rate; D016896:Treatment Outcome
D007496:Iridium Radioisotopes