Long-Term Outcomes with 3-Dimensional Conformal External Beam Accelerated Partial Breast Irradiation

Area of Science:

• Radiation Oncology
• Breast Cancer Treatment
• Oncologic Outcomes

Background:

• Limitations in long-term tumor control and cosmetic results with current accelerated partial breast radiation (APBI) techniques.
• Need for extended follow-up data on 3-dimensional conformal external beam radiation (3D-CRT) APBI.
• Investigating the efficacy and safety of 3D-CRT APBI in a real-world clinical setting.

Purpose of the Study:

• To evaluate long-term tumor control and cosmetic outcomes of 3D-CRT APBI.
• To analyze factors influencing disease recurrence and survival.
• To assess cosmetic results and pain associated with this treatment modality.

Main Methods:

• Retrospective analysis of patients treated with 3D-CRT APBI from 2006-2012.
• Analysis of ipsilateral breast tumor recurrence (IBTR), progression-free survival (PFS), cosmesis, and pain.
• Outcomes stratified by margin status, radiation dose, disease type, and ASTRO consensus groupings.

Main Results:

• Seven-year IBTR and PFS rates were 1.8% and 95.2% in 266 patients with >1 year follow-up.
• Cosmetic outcomes were good to excellent in 75.2% of patients.
• No significant impact of margin status, disease type, or ASTRO grouping on IBTR or PFS.

Conclusions:

• 3D-CRT APBI provides excellent long-term disease control and favorable cosmetic results.
• Higher radiation dose and larger irradiated breast volume correlated with adverse cosmetic outcomes.
• Patients in 'cautionary' and 'unsuitable' ASTRO groups may still achieve good outcomes with 3D-CRT APBI.