- Design
- Prospective longitudinal observational study
- Population
- 21 patients with HER2-positive breast cancer receiving HER2-targeted ADCs
- Primary outcome
- Ocular surface toxicity and corneal morphology
- Effect
- Toxicity in 18/21 (85.7%); mean onset 28 days; partly reversible
A prospective longitudinal study in the British Journal of Ophthalmology, published on 22 September, followed 21 patients with HER2-positive breast cancer through treatment with HER2-targeted antibody-drug conjugates, with detailed ocular surface testing, in vivo confocal microscopy and, in some, electron microscopy.
Eighteen of 21 (86%) developed ocular surface toxicity, at a mean of 28 days. The typical sequence was inferior subepithelial microcysts progressing to linear deposits and a vortex keratopathy, with dry eye, reduced corneal sensation and marked loss and fragmentation of corneal nerves. Changes were dose- and time-dependent and partly reversible; corneal structure tended to recover after 12 cycles.
These drugs are increasingly used, and the eye is not always on the oncology checklist. The study is small and from one centre, but the high frequency suggests baseline and early ocular review are worthwhile.
- Ask patients on HER2 antibody-drug conjugates about blurred vision, grittiness and dryness from the first month.
- Look for inferior microcysts and vortex keratopathy on slit lamp, and test corneal sensation.
- Treat dry eye actively with lubricants and liaise with oncology about dose if vision falls.
- Consider a baseline ocular surface examination before treatment starts.
- Reassure patients that changes were partly reversible in this study.
Why it matters
Most patients developed toxicity, so routine ocular review belongs in these treatment pathways.
Don't overread it
Twenty-one patients from one centre; the frequency and reversibility may differ elsewhere.
The statistics, in plain English
86% is 18 of 21 patients. With so few, the true proportion could be considerably lower or higher, but toxicity was clearly common.
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