Three-year Clinical Experience Utilizing 3D-Conformal Radiation Therapy to Deliver Accelerated Partial Breast Irradiation (APBI)

Article Outline

• Purpose/Objective
• Materials/Methods
• Results
• Conclusions
• Copyright

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Purpose/Objective 

We present our 3-year clinical experience utilizing 3D-conformal radiation therapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI) in patients with early-stage breast cancer treated with breast conserving therapy.

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Materials/Methods 

Ninety-six consecutive patients were treated between August 2000 to June 2007 with APBI using our previously reported 3D-CRT technique. Eligibility criteria included patient age >45, tumor size <3 cm, invasive ductal and lobular histologies as well as ductal carcinoma in situ, lumpectomy with negative surgical margins (recommended at least 2mm), ≤3 positive axillary nodes with a minimum 6 nodes sampled, absence of an extensive intraductal component (EIC), no skin involvement, and no Paget's disease of the nipple. The clinical target volume consisted of the lumpectomy cavity plus a 10–15-mm margin; the planning target volume (PTV) was calculated from the CTV using uniform 3-D expansions. The prescribed dose was 34 or 38.5 Gy in 10 fractions given over 5 consecutive days.

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Results 

Median follow-up was 36 months (range, 2-84); 62 years was the median age (range, 41-93). The following are salient patient and tumor characteristics: tumor size <2.0 cm in 89% of cases, margins of >2mm in 93% of patients, and 99% node negative. One local recurrence (LR) developed at 18 months for a 3 and 5-year actuarial rate of 1%. Cosmetic results were rated as good/excellent in 90% of evaluable patients at 3 years (n = 10). Grade I and II rates of erythema, hyperpigmentation, breast edema, breast pain, telangiectasia, fibrosis and fat necrosis with a minimum follow-up of 3 years were 0%, 7%, 0%, 0%, 7%, 21% and 7%, respectively. Only 2 patients (3%) developed grade III toxicity (breast pain) which resolved with time.

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Conclusions 

3D-CRT to deliver APBI resulted in minimal chronic (36 months) toxicity to date with good/excellent cosmetic results. Additional follow-up will be needed to assess the long-term efficacy of this form of APBI.