45 Use of Preoperative Ultra-Hypofractionated Radiotherapy in Patients With Locally Advanced Breast Cancer: Clinical and Pathological Outcomes

A Chilean oncology center reports that a preoperative 5-fraction radiotherapy regimen may be a feasible treatment for locally advanced breast cancer. According to a retrospective review conducted from May 2022 to May 2025, this ultra-hypofractionated approach resulted in clinical downstaging for 92.9% of patients who had surgical pathology reports available.

The study analyzed 45 patients who received a total dose of 26 Gy delivered in five fractions to the breast and regional lymph nodes. These patients were part of a larger group of 987 individuals treated at the center during the specified period.

Of the 45 patients, 88.9% were classified as cT4 and 11.1% as cT2. Nodal status varied, with 46.7% classified as cN1, 20% as cN2, 15.6% as cN3, and 17.8% as cN0. Four patients in the group had stage IV metastatic disease.

Did You Know? Out of 987 total patients treated at the Chilean oncology center between May 2022 and May 2025, only 45 received the specific preoperative 5-fraction radiotherapy regimen studied.

What were the clinical results of the radiotherapy regimen?

Favorable clinical responses, including partial or complete responses, occurred in 46.6% of patients. The study found that 15.5% of patients showed disease progression, while 4.4% showed no clinical response. Evaluation was not possible for 33.3% of the group due to loss to follow-up.

At the time of analysis, 68.9% of the study population remained alive. The median follow-up period for the 66.7% of patients who attended one or more follow-up visits was 11.5 months.

Regarding biological subtypes, 80% of the patients were hormone receptor-positive. Triple-negative cases accounted for 13.3%, and 4.4% were HER2-positive. Additionally, 71.1% of the patients were administered neoadjuvant chemotherapy.

Expert Insight: Samantha Carter notes that treating locally advanced breast cancer is a significant therapeutic challenge, particularly when patients have extensive disease or limited initial surgical options. The use of ultra-hypofractionated regimens could potentially offer a more streamlined path to surgical eligibility for those initially deemed unsuitable for operation.

How did the treatment impact surgical outcomes?

Forty-two percent of the patients, or 19 individuals, underwent surgery consisting of a total mastectomy with axillary lymph node dissection. Surgical pathology reports were available for 14 of those patients.

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In 92.9% of those 14 cases, the reports showed a reduction in tumor size and nodal involvement. The oncology center reported that these results were consistent with clinical downstaging.

The radiotherapy was delivered with curative intent in 88.9% of cases, while 11.1% received the treatment with palliative intent.

What may happen next for this treatment approach?

The findings suggest that 5-fraction preoperative radiotherapy may represent an effective option for patients in both curative and palliative settings. This is particularly likely for patients with tumors that are initially unsuitable for surgical management.

Because current evidence for ultra-hypofractionated regimens remains scarce, further data may be required to confirm these preliminary benefits. Future clinical applications could expand based on the feasibility demonstrated in this Chilean cohort.

Frequently Asked Questions

What specific dose of radiation was used in the study?
Patients received a total dose of 26 Gy delivered in five fractions to the breast and regional lymph nodes.

What percentage of patients experienced tumor reduction?
Among the 14 patients with available surgical pathology reports, 92.9% showed a reduction in tumor size and nodal involvement.

What was the survival rate at the time of analysis?
According to the report, 68.9% of the study population remained alive.

How do you feel about the shift toward shorter, more intensive radiotherapy schedules in cancer care?