Locoregional Ablative Radiation Therapy for Patients With Breast Cancer Unsuitable for Surgical Resection

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Patients with breast cancer unsuitable for surgery often receive only palliative systemic therapy.
• Ablative radiation therapy presents an alternative treatment modality for this patient group.

Purpose of the Study:

• To evaluate the outcomes of a 5-fraction ablative radiation therapy regimen for nonresected breast cancers.
• To assess local failure rates and severe toxicities associated with this treatment approach.

Main Methods:

• Retrospective analysis of 57 patients with nonresectable breast cancer treated between 2014 and 2021.
• Patients received 35-40 Gy in 5 fractions to the primary tumor or regional lymph nodes.
• Outcomes included local failure incidence and grade ≥3 toxicity (Common Terminology Criteria for Adverse Events, version 5.0).

Main Results:

• The 2-year cumulative incidence of local failure was 11.4%.
• The 2-year cumulative incidence of grade ≥3 toxicity was 15.1%, primarily radiation dermatitis.
• Highly conformal techniques (IMRT, partial breast irradiation) were associated with reduced toxicity compared to whole breast irradiation.

Conclusions:

• A 35-40 Gy in 5 fractions regimen is a safe and effective stereotactic body radiation therapy (SBRT) option for patients with nonresectable breast cancer.
• Conformal techniques such as IMRT and partial breast irradiation are recommended to minimize toxicity.