Radiotherapy Trends and Variations in Invasive Non-metastatic Breast Cancer Treatment in the Netherlands: A...

Area of Science:

• Oncology
• Radiotherapy
• Breast Cancer Treatment

Background:

• Radiotherapy is a key component of multimodal breast cancer treatment.
• Trends in radiotherapy use and its de-escalation have been observed in recent years.

Purpose of the Study:

• To analyze nationwide trends in radiotherapy use for invasive non-metastatic breast cancer in the Netherlands (2008-2019).
• To identify factors associated with boost irradiation after breast-conserving therapy and regional radiotherapy instead of axillary lymph node dissection (ALND).

Main Methods:

• Population-based data from the Netherlands Cancer Registry (2008-2019).
• Multilevel logistic regression analyses to identify factors associated with specific radiotherapy decisions.
• Analysis of trends in overall radiotherapy use, boost irradiation, and regional radiotherapy.

Main Results:

• Overall radiotherapy use increased from 61% (2008) to 70% (2016), then decreased to 67% by 2019 due to post-BCS omission.
• Boost irradiation in breast-conserving therapy decreased significantly (66% to 37%), associated with lower-risk features.
• Regional radiotherapy use increased substantially (32% to 61%) as an alternative to ALND in node-positive (N+) disease.
• Significant regional variations in boost irradiation and regional radiotherapy use were observed.

Conclusions:

• Radiotherapy use in breast cancer showed an initial increase followed by a decrease post-2016, driven by de-escalation strategies.
• Omission of boost irradiation in low-risk patients and increased regional radiotherapy for N+ disease represent de-escalation in breast cancer treatment.
• Geographical variations in radiotherapy practices highlight potential areas for standardization.