# Make skipping radiotherapy the default for very low-risk breast cancer

Source: https://onco.cc/ideas/idea-prev-omit-radiotherapy-low-risk-breast-default/  
OnCo record `idea-prev-omit-radiotherapy-low-risk-breast-default` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Trials show older women with the lowest-risk breast cancers gain almost nothing from radiotherapy after lumpectomy. Yet most still get it. Track and reward omission.

## Summary

LUMINA, PRIME II and IDEA show low local recurrence without radiotherapy in luminal A breast tumours in older women, yet most still receive it, so this idea makes omission the default pathway, with PAM50 genomic confirmation where needed, and tracks it as a quality metric. The evidence exists; the barrier is inertia and fee-for-service incentives, so payers would measure omission rate and five-year local recurrence. The test is a stepped-wedge implementation across cancer centres with registry follow-up. Being tested at scale, it addresses the bottlenecks Overdiagnosis and false alarms, Toxicity and quality of life are undervalued and Incentives reward me-too drugs and marginal gains.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A default-omission pathway raises radiotherapy omission from about 20% to at least 60% of eligible patients with five-year local recurrence of 3% or less.
- Rationale: The evidence exists; the barrier is inertia and fee-for-service incentives.
- Proposed test: Stepped-wedge implementation across cancer centres with registry follow-up.
- Maturity: being-tested-at-scale
- Actor: payer

## Sources

- Bottleneck evidence (Overdiagnosis and false alarms): Welch & Black, Overdiagnosis in cancer (JNCI 2010): https://doi.org/10.1093/jnci/djq099

## Connected records

- cancers: [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/)
- fronts: [Radiation Therapy](https://onco.cc/fronts/radiation/)
- terms: [PAM50 / intrinsic subtypes](https://onco.cc/terms/pam50/)
- bottlenecks: [Incentives reward me-too drugs and marginal gains](https://onco.cc/bottlenecks/b-incentive-misalignment/), [Overdiagnosis and false alarms](https://onco.cc/bottlenecks/b-overdiagnosis/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/)
- key papers: [Overdiagnosis in cancer](https://onco.cc/key-papers/paper-welch-j-natl-cancer-inst/)

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