Thirty-Year Single Institution Experience of Accelerated Partial Breast Irradiation for Early-Stage Breast Cancer

Document Type

Conference Proceeding

Publication Date

11-1-2021

Publication Title

International Journal of Radiation Oncology, Biology, Physics

Abstract

Purpose/Objective(s)

Accelerated partial breast irradiation (APBI) can reduce treatment time and spare normal breast tissue. Techniques for APBI include applicator-based, external beam radiotherapy (EBRT), intra-operative radiotherapy (IORT), and interstitial implant-based. Data comparing these various APBI modalities and associated outcomes are lacking in the literature. We conducted a single-institution retrospective analysis of patients treated with APBI to compare treatment techniques and report outcomes.

Materials/Methods

Patients treated with APBI between 1990 and 2019 were included. Baseline patient characteristics, clinical and pathological features, treatment details, and clinical outcomes were retrospectively reviewed using a single-institution database. Outcomes were updated through August 2020. Statistical methods included Kruskal-Wallis test, Fisher's exact test, chi-square test of independence, and Kaplan-Meier analysis.

Results

A total of 926 APBI cases were analyzed, a majority of which were invasive ductal carcinoma (50.6%). Comparing applicator-based to EBRT, IORT, and implant-based, there was no difference in overall survival, freedom from local recurrence, or freedom from mastectomy (Table 1). 5-, 10-, and 25-year cumulative incidence of ipsilateral breast tumor recurrence (IBTR) was 1.5% (0.87-2.5%), 3.3% (2.3-4.7%), and 5.2% (3.9-6.7%), with no difference between treatment techniques. The median follow-up time was 121.6 months (66-165.7 months). Cosmesis was good/excellent in 91%, 84%, and 93%, for applicator, EBRT, and interstitial techniques, respectively. Late toxicities assessed included pigmentary changes, telangiectasias, induration/fibrosis, and fat necrosis. The majority of late toxicities were none or Grade 1, with less than 10% of patients experiencing Grade 2 or greater toxicity.

Conclusion

With our 30-year single-institution APBI experience using various treatment techniques, long term outcomes of both disease control and local morbidity demonstrate that the various APBI techniques are equally effective for suitable early-stage breast cancer patients. As evolving radiotherapy paradigms incorporate more shortened time-course treatments, these results affirm that APBI remains a viable alternative for such favorable patients.

Volume

111

Issue

3 Suppl.

First Page

S36

DOI

https://doi.org/10.1016/j.ijrobp.2021.07.107

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