Fifteen Year Experience with Accelerated Partial Breast Irradiation at a Community Cancer Center

Purpose: Breast cancer is the leading cause of cancer in women in the United States. Many women elect breast conservation versus mastectomy for surgical treatment. Adjuvant radiation has been shown to significantly reduce the risk of local recurrence in women who undergo breast conservation. Accelerated partial breast irradiation (APBI) is an option for post-lumpectomy therapy in appropriate stage 0 and stage 1 breast cancer patients and listed as a treatment option in the NCCN guidelines. This study was performed to review our experience with APBI over the past fifteen years.

Methodology: We evaluated 150 consecutive patients treated with APBI from June 2006 until September 2021. All patients’ electronic medical records were reviewed to obtain pertinent patient statistics and treatment details. This included all pathology, receptor status and specifics of radiation treatment plans.

Results: All patients were treated on a gamma med HDR unit (Ir-192). Prescription was to 1 cm for a total dose of 34 Gy in 10 fractions given twice daily with 6 hours between fractions. The majority of patients were treated over 5 consecutive days (Monday thru Friday) but all treatments were completed within 8 calendar days. One-hundred forty-five patients were treated using Mammosite single lumen and 5 patients were treated using SAVI. One-hundred thirty-three patients (88.7%) were deemed suitable per current ASTRO guidelines and 27 patients were deemed cautionary.

All patients underwent a lumpectomy as the initial part of their treatment with negative margins. The median age of patients was 68 years and median follow-up was 96.5 months (2-180). One-hundred seven patients had invasive ductal carcinoma and 43 patients had ductal carcinoma in-situ (DCIS). All patients with invasive ductal carcinoma were stage 1. One-hundred thirty-six patients (91%) were estrogen receptor positive and 24 patients were estrogen receptor negative. One hundred thirty-one patients (87%) were living at the time of review. One patient (0.7%) was found to have had a local recurrence. This occurred in a DCIS patient who recurred at 5 years with another DCIS in the previously treated region. This patient subsequently underwent a mastectomy.

Conclusions: This review reveals a very low recurrence rate for early stage breast cancer patients treated with accelerated partial breast irradiation after breast conservation surgery at a community cancer center.

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