Is 1-Week Radiotherapy Safe and Effective for Breast Cancer?

In breast cancer treatment, postoperative adjuvant radiotherapy is an integral part of treatment for reducing local recurrence risk and improving survival. It is used particularly after breast-conserving surgery to eliminate remaining microscopic cancer cells. Adjuvant radiotherapy enables long-term control with a lower recurrence risk.

Treatment sessions traditionally spread over weeks are challenging for patients and place a financial burden on healthcare systems. Developed during the COVID-19 pandemic and rapidly attracting interest, ultrahypofractionated radiotherapy offers a 1-week schedule that promises to address these challenges.

However, its efficacy and safety outcomes require careful assessment. On 4 November 2024, Advances in Radiation Oncology published a study evaluating the effects of this method using real-world data.

Study Background: Why Does It Matter?

During the COVID-19 pandemic, international and national guidelines recommended that patients with node-negative breast cancer receive 1-week ultrahypofractionated radiotherapy. By delivering 26 Gy in 5 fractions, it aimed to produce outcomes similar to conventional hypofractionated regimens. Beyond theoretical results, however, how patients responded and the extent of adverse effects remained important questions.

Types of Radiotherapy and Dosing

Radiotherapy techniques are named according to how doses are divided into daily fractions (sessions) and the total treatment duration. The main difference between standard (conventional) radiotherapy, hypofractionated radiotherapy , and ultrahypofractionated radiotherapy is the daily dose and total treatment duration.

1. Conventional Radiotherapy:

   • Daily Dose: 1.8-2 Gy
   • Total Dose: 45-50 Gy
   • Duration: 5-7 weeks (25-30 sessions)

2. Hypofractionated Radiotherapy:

   • Daily Dose: 2.5-3 Gy
   • Total Dose: 40-42.5 Gy
   • Duration: 3-4 weeks (15-16 sessions)

3. Ultrahypofractionated Radiotherapy:

   • Daily Dose: 5-8 Gy
   • Total Dose: 26-30 Gy
   • Duration: 1 week (5 sessions)

Treatment selection depends on the patient's condition and tumor biology. Short-course approaches are effective and safe in suitable patients.

Study Design

Conducted at 3 centers in Ireland between March and August 2020, the study evaluated 135 consecutive patients . Adverse effects were assessed at 3, 6, and 12 months after treatment. Patient views were measured particularly through pain, swelling, hardness, and hypersensitivity . Satisfaction with telehealth was also examined.

Findings: Adverse Effects and Patient Satisfaction

The study's primary endpoint was the worst toxicity level reported at each assessment.

• First-Year Results:

  • At 3 and 6 months, 76% of patients reported mild or no toxicity.
  • 12. At the monthly assessment, this proportion rose to 82%.
  • 17% of patients experienced moderate toxicity, generally breast pain, while only 2% experienced severe toxicity, such as breast hardness or skin changes.

• Patients Receiving a Boost:
  There was no difference in toxicity between patients receiving a sequential boost (4-8 fractions) and those receiving only 26 Gy.

• Patient Perspectives:

  • 78.6% of patients considered the shorter treatment duration an important advantage.
  • 59% found the approach beneficial for infection control.
  • High satisfaction rates were reported for telehealth communication:
    • 97.3% of patients felt adequately informed about their diagnosis.
    • 88% felt well informed about treatment adverse effects.
    • 94% felt supported by the healthcare team.
  • However, only 27% agreed to a breast examination by video consultation.

Commentary and the Study's Importance

The results suggest that ultrahypofractionated radiotherapy is promising in both efficacy and adverse-effect profile. At 1 year of follow-up, the low rate of serious adverse effects suggests it may be a suitable alternative to conventional regimens.

Telehealth methods also made a notable contribution to patient satisfaction. However, low acceptance of video-based breast examinations indicates a need for more patient education and communication.

Study Limitations

Despite these promising results, several limitations should be considered:

1. Short Follow-Up: 1 year may not be sufficient to assess late toxicities.
2. Patient Reports: Reliance on patient-reported adverse effects may affect the consistency of the results.
3. Variation in Boosts: The effects of different fraction numbers on patient experiences require further study.