Screening of oral tamoxifen ocular toxicity in patients with breast cancer

Background Carcinoma of the breast is considered as one of the main cancer types among women. Its prevalence is reported to be the second most common type. Several treatment lines have been used in breast cancer besides surgical and radiological interventions. Tamoxifen is one of the medical treatments used in postsurgical prophylaxis of breast cancer. Various visual problems were reported with tamoxifen therapy. These include posterior subcapsular cataracts, color vision affection, intraretinal crystals, and optic neuritis. Aim The aim of this work was to screen for ocular toxicity of tamoxifen used for breast cancer treatment in patients having no ophthalmic complaints and treated with tamoxifen for at least 2 years with a dose of 20 mg per day. Patients and methods We included 50 women with breast carcinoma on tamoxifen therapy for at least 2 years, and then we divided them into two groups regarding duration of tamoxifen intake from 2 to 4 years (group 1) and from 5 to 8 years (group 2). All participants underwent complete careful history taking and full ophthalmological examination. Best-corrected visual acuity was measured using Snellen chart with conversion to logMAR notation for statistical analysis. We assessed the retinal structural changes by optical coherence tomography (OCT) and correlated these changes with the function affection (color vision testing and electrophysiological studies). Results There was a statistically significant correlation between duration of tamoxifen intake and Retinal Pigment Epithelium (RPE) mottling. No other significant correlations were detected. There was no significant difference between the two groups in mean best-corrected visual acuity; intraocular pressure; cup values; disc parameters; ganglion cell complex thickness; retinal nerve fiber layer zones, except for in the inferior quadrant; and macular thickness, except for in the superior quadrant. OCT layer thinning shows retinal nerve fiber layer affection in 34% of cases, ganglion cell complex affection in 48% of cases, and macula affection in 64% of cases. Color vision defects were found in 12%, and electrophysiological test changes were found in a few cases. Conclusion Tamoxifen therapy causes minimal affection on the ocular structure and function. OCT layer thinning (34-64% of cases) precedes the clinical changes. This highlights the importance of OCT examination in those patients to evaluate tamoxifen toxicity, and further studies will be needed to evaluate the reversibility of these changes after stoppage of therapy. The main ocular complications associated with tamoxifen therapy were correlated with duration of treatment.