Accelerated partial breast irradiation: An update on published Level I evidence.

Area of Science:

• Oncology
• Radiation Oncology
• Surgical Oncology

Background:

• Multiple adjuvant radiation therapy options exist for breast-conserving surgery.
• Standard fractionated whole breast irradiation (WBI), accelerated whole breast irradiation (AWBI), and accelerated partial breast irradiation (APBI) are common modalities.
• Recent randomized trials provide Level I evidence comparing APBI to WBI.

Purpose of the Study:

• To review Level I evidence supporting APBI.
• To guide the selection of APBI versus WBI, AWBI, or excision alone.
• To address application-related questions for APBI.

Main Methods:

• Review of four contemporary randomized trials comparing APBI and WBI.
• Analysis of over 2000 patients included in these trials.
• Comparison of APBI outcomes with AWBI and endocrine therapy alone (excision).

Main Results:

• No significant differences in local/regional recurrence or survival between APBI and WBI.
• Reduced acute and chronic toxicity observed with APBI in some trials.
• Improved cosmetic outcomes reported with APBI in specific studies.
• AWBI patient cohorts show comparable characteristics to APBI.
• Endocrine therapy alone cohorts represent lower-risk patients.

Conclusions:

• Level I evidence supports APBI as an alternative to WBI for selected breast-conserving therapy patients.
• Further research is needed to refine patient selection criteria for APBI.
• Optimal APBI techniques and targets require clarification.
• Comparative effectiveness of APBI, AWBI, and excision alone needs further investigation.
• Potential for further fractionation schedule reductions in APBI warrants exploration.