Association of Crystalline Retinopathy With Anastrozole

Tamoxifen retinopathy: A comprehensive review

Tamoxifen is a selective estrogen receptor modulator used mainly for the treatment of breast cancer. Based on the case reports and studies performed to date on the retinal toxicity of tamoxifen, retinopathy appears to occur in as many as 12% of patients taking 20 mg tamoxifen a day for over 2 years. Of this 12%, as many as half develop symptomatic changes in visual acuity. Retinal changes consist primarily of crystalline deposits, cystoid macular edema, hyperreflective deposits in the inner retinal layers, and telangiectasia. Tamoxifen retinopathy is currently managed by discontinuing tamoxifen therapy as the cancer prognosis permits; however, discontinuing therapy demonstrates little to no improvement in visual acuity once visual changes have taken place. Intravitreal injections of steroids or antivascular endothelial growth factor therapy have been performed, but require further studying before conclusions can be made. Until then, optical coherence tomography screening for retinal changes should be performed every 6 months for patients who have been on tamoxifen therapy for 2 years or more. This way, patients can become aware of retinal changes, and their physicians can consider adjusting tamoxifen therapy before they risk developing changes in visual acuity.

Risk of ocular adverse events with aromatase inhibitors

PURPOSE

Aromatase inhibitors (AIs) are a class of medications used for adjuvant treatment of breast cancer. Recent case reports suggest that AIs may be associated with various ocular adverse events (AEs). This study evaluates the risk of ocular AEs in patients who take AIs.

METHOD

Disproportionality analysis was performed using data from the U.S. Food and Drug Administration's Adverse Events Reporting System database from 2004 to 2022. All cases of vitreomacular traction, macular edema, retinal deposits, retinal artery occlusion, macular hole, retinal hemorrhage, uveitis, retinal tear, retinal detachment, dry eye disease, blepharitis, and optic neuropathy were searched for the 3 AIs anastrozole, letrozole, and exemestane. A search also was performed on trastuzumab as a control. Reported odds ratios (RORs) and corresponding 95% CIs were computed.

RESULTS

We identified 322 ocular AEs of interest for the 3 AIs and 55 for trastuzumab. Anastrozole had the most AEs (n = 163) and was found to have strong associations with vitreomacular traction (ROR = 665; 95% CI, 352-1255), macular edema (ROR = 37; 95% CI, 25-54), retinal deposits (ROR = 11; 95% CI, 2-77), and uveitis (ROR = 6; 95% CI, 4-9). Letrozole had strong associations with retinal deposits (ROR = 8, 95% CI, 1-57) and retinal artery occlusion (ROR = 6; 95% CI, 3-11). Exemestane had a strong association with macular holes (ROR = 10; 95% CI, 3-30).

CONCLUSION

Disproportionality analysis revealed an increased risk of ocular AEs with each of the AIs. This study calls for clinicians, especially oncologists and ophthalmologists, to be vigilant in patients who are on AI therapy, allowing them to provide prompt interventions to mitigate further ocular morbidities.

Review of the Literature on Ocular Complications Associated With Aromatase Inhibitor Use

Aromatase inhibitors (AIs), such as anastrozole, letrozole, and exemestane, are commonly used as adjuvant endocrine therapy in hormone-receptive breast cancer in postmenopausal women. Their adverse effects are well documented, except for visual disturbances. The purpose of this study was to review the current literature on ocular disease linked to AI use. Due to the scarcity of published data, any suggested ophthalmic adverse events were included to increase awareness of these drugs. The ocular side effects of tamoxifen use are well documented and were not included. Cases of rare side effects such as papilloedema, macular oedema, and uveitis associated with anastrozole and letrozole have been reported. Studies demonstrating retinopathy, in the form of crystalline retinopathy, hemicentral retinal artery occlusion, and retinal haemorrhages, are also noted. All three third-generation AIs can also lead to ocular surface diseases such as corneal epithelial changes, blepharitis, and keratitis. There is slightly more literature available regarding anastrozole-related ocular diseases. Although these are likely rare side effects, we recommend a high level of clinical suspicion when assessing patients with visual symptoms and on AIs. Larger prospective studies are necessary to further investigate these complications.

Ocular Toxicity of Targeted Anticancer Agents

The proliferation of targeted anticancer agents over the last two decades has revolutionized cancer treatment and improved survival in many previously refractory malignancies. However, many agents are associated with characteristic ophthalmic adverse effects. It is important that ophthalmologists recognize and maintain a high index of suspicion for these side effects in patients on targeted therapy. Most ophthalmic adverse effects can be treated with specific ocular therapy without discontinuation of cancer treatment, although it is important to be aware of the life-threatening and vision-threatening circumstances that would require therapy cessation in conjunction with the patient's oncologist. This review aims to summarize the ophthalmic adverse effects of targeted and hormonal anticancer agents and briefly describe their management.