- ARTIC, a new clinicogenomic classifier combining age with a 27-gene expression-based tumor assay, identifies patients who need higher intensity of radiotherapy (RT) after breast-conserving surgery (BCS) for early breast cancer (eBCa).
Why this matters
- ARTIC is the first successful RT classifier for individualized tailoring of postoperative RT.
- Patients with high ARTIC scores are more likely to benefit from more intensive RT, such as tumor-bed boost.
- ARTIC was developed from 3 publicly available cohorts and validated on a randomized controlled trial (SweBCG91-RT; n=748) in which patients with node-negative eBCa (stage I-IIA) were randomly assigned to whole-breast RT or no RT after BCS.
- Primary outcome: cumulative incidence of locoregional recurrence (LRR).
- Funding: PFS Genomics; Swedish Breast Cancer Association; others.
- Median follow-up, 15.0 years.
- In patients treated with RT vs no RT, ARTIC was highly prognostic of LRR (HR, 3.4; 95% CI, 2.0-5.9; P<.001 and predictive of rt benefit>interaction=.005).
- Low ARTIC scores had the greatest benefit from RT (HR, 0.33; P<.001 cumulative incidence of lrr with rt vs without a absolute reduction.>
- High ARTIC scores had a lower benefit from RT (HR, 0.73; P=.23); 10-year cumulative incidence of LRR, 25% vs 32%, a 7% absolute reduction.
- Actual ARTIC scores not given.