Safety of combining radiation therapy and antibody-drug conjugates in patients with breast cancer: a systematic review and meta-analysis.
Luca Visani, Carlotta Becherini, Marcin Kubeczko et al.
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In 30 seconds
This systematic review and meta-analysis assessed the safety of concurrent radiation therapy (RT) and antibody-drug conjugates (ADCs) in early or metastatic breast cancer. It included 29 studies published between 2014 and 2026, representing 3,817 patients who received at least one RT course during ADC treatment. Across studies reporting the outcome, pooled grade ≥ 3 radiation necrosis was 5% (95% CI: 1-12%; I 2 = 85.9%). Severe pneumonitis and skin effects were rare. The authors concluded that RT can generally be combined with ADCs, while intracranial stereotactic RT warrants particular caution with T-DM1.
Key findings
- Pooled grade ≥ 3 radiation necrosis was 5% (95% CI: 1-12%; I 2 = 85.9%) across studies reporting this endpoint.
- For intracranial RT, pooled grade ≥ 3 treatment-related adverse events were 8% (95% CI: 3-15%; I 2 = 81.7%); the T-DM1 subtotal estimate was 13% (95% CI: 1-34%).
- Grade ≥ 3 pneumonitis was pooled at 0% (95% CI: 0-1%; 12 studies), and grade ≥ 3 skin effects at 0% (95% CI: 0-1%; 13 studies).
Why it matters
As ADC use expands in breast cancer, clinicians need to weigh potential toxicity when coordinating RT with systemic treatment. These pooled findings suggest severe complications are uncommon overall, but intracranial stereotactic treatment—especially alongside T-DM1—may carry a distinct radiation-necrosis concern. Recognising this difference can inform multidisciplinary treatment planning and safety monitoring.
What to keep in mind
The evidence came from 29 studies with substantial heterogeneity for pooled radiation necrosis and intracranial adverse events (I 2 = 85.9% and 81.7%, respectively).