External Beam Accelerated Partial-Breast Irradiation Using 32 Gy in 8 Twice-Daily Fractions: 5-Year Results of a Prospective Study

Journal Article · Thu Nov 01 04:00:00 EDT 2012 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2012.04.019· OSTI ID:22149558

Pashtan, Itai M. ^[1]; Recht, Abram ^[2]; Ancukiewicz, Marek ^[3]; Brachtel, Elena ^[4]; Abi-Raad, Rita F. ^[3]; D'Alessandro, Helen A. ^[5]; Levy, Antonin; Wo, Jennifer Y. ^[3]; Hirsch, Ariel E. ^[6]; Kachnic, Lisa A. ^[7]; Goldberg, Saveli ^[3]; Specht, Michelle; Gadd, Michelle; Smith, Barbara L. ^[7]; Powell, Simon N. ^[3]

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1. Harvard Radiation Oncology Program, Boston, Massachusetts (United States)
2. Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, Massachusetts (United States)
3. Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)
4. Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts (United States)
5. Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts (United States)
6. Department of Radiation Oncology, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts (United States)
7. Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts (United States)

Purpose: External beam accelerated partial breast irradiation (APBI) is an increasingly popular technique for treatment of patients with early stage breast cancer following breast-conserving surgery. Here we present 5-year results of a prospective trial. Methods and Materials: From October 2003 through November 2005, 98 evaluable patients with stage I breast cancer were enrolled in the first dose step (32 Gy delivered in 8 twice-daily fractions) of a prospective, multi-institutional, dose escalation clinical trial of 3-dimensional conformal external beam APBI (3D-APBI). Median age was 61 years; median tumor size was 0.8 cm; 89% of tumors were estrogen receptor positive; 10% had a triple-negative phenotype; and 1% had a HER-2-positive subtype. Median follow-up was 71 months (range, 2-88 months; interquartile range, 64-75 months). Results: Five patients developed ipsilateral breast tumor recurrence (IBTR), for a 5-year actuarial IBTR rate of 5% (95% confidence interval [CI], 1%-10%). Three of these cases occurred in patients with triple-negative disease and 2 in non-triple-negative patients, for 5-year actuarial IBTR rates of 33% (95% CI, 0%-57%) and 2% (95% CI, 0%-6%; P<.0001), respectively. On multivariable analysis, triple-negative phenotype was the only predictor of IBTR, with borderline statistical significance after adjusting for tumor grade (P=.0537). Conclusions: Overall outcomes were excellent, particularly for patients with estrogen receptor-positive disease. Patients in this study with triple-negative breast cancer had a significantly higher IBTR rate than patients with other receptor phenotypes when treated with 3D-APBI. Larger, prospective 3D-APBI clinical trials should continue to evaluate the effect of hormone receptor phenotype on IBTR rates.

• OSTI ID: 22149558
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 84; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CLINICAL TRIALS
ESTROGENS
IRRADIATION
MAMMARY GLANDS
NEOPLASMS
PATIENTS
PHENOTYPE
RADIATION DOSES
RECEPTORS
SURGERY