Tamoxifen retinopathy may be more of an issue than previously recognized, researchers in South Korea have found—and optical coherence tomography (OCT) may be needed to diagnose the earliest signs of the condition.1
Previous studies have found a prevalence rate of 1.5% to 11.8% in patients being treated for breast cancer. But in this study, the researchers found a prevalence rate of 12%.
TAMOXIFEN IMPACT. This 50-year-old patient with breast cancer had noticed a gradual decrease in vision. She was diagnosed with pseudocystic foveal cavitation; OCT of her left eye shows cystic cavitary alterations and a large outer hole. This image was originally published in the ASRS Retina Image Bank. John S. King, MD, and Paul Hruby, MD. OCT OD Tamoxifen Retinopathy With Pseudocystic Foveal Cavitation. Retina Image Bank. 2019; Image Number 40424. © The American Society of Retina Specialists.
Findings. For this retrospective study, the researchers evaluated the medical records of 251 female breast cancer patients who had undergone both fundus photography and OCT scanning after taking tamoxifen for at least two years. Of these, 19 patients had bilateral tamoxifen retinopathy, and 11 had unilateral disease. Twelve patients had foveal cavitations only, four had refractive crystalline deposits, and 14 had both. Eight of the 30 patients had decreased visual acuity or metamorphopsia.
Breast cancer stage, type of chemotherapeutic agent, history of hormone replacement therapy, and menopausal status were not associated with tamoxifen retinopathy. All patients were on low-dose tamoxifen (20 mg per day).
Surprises. “My institute is the biggest hospital in Korea, and so it has a huge cancer unit,” said Young Hee Yoon, MD, at the University of Ulsan College of Medicine’s Asan Medical Center in Seoul. Even with this case load, she said, the researchers were surprised that the incidence of retinal toxicity was higher than previously reported. They were also surprised that the patients were never advised of the potential ocular risk of tamoxifen by their breast surgeons or oncologists.
OCT the key? In an earlier study, Dr. Yoon and her colleagues evaluated OCT angiography findings of tamoxifen retinopathy.2 In that study, they realized that “some patients no longer had crystalline deposits even if they had typical OCT findings of pseudocystic cavitation or photoreceptor depletion,” Dr. Yoon said.
In addition, she said, because most previous studies of tamoxifen retinopathy used fundus findings alone, “we decided to conduct this study to find out the real incidence of tamoxifen retinopathy” based on both fundus photography and OCT scanning.
And indeed, evaluating OCT scans may have been the key to the results of the current study, Dr. Yoon said. She explained that they might have missed the early retinal changes if they had not checked the OCT scans.
Looking ahead. The ophthalmology and breast cancer teams are currently conducting a prospective study to evaluate the incidence of tamoxifen retinopathy, Dr. Yoon said. She added, “Both patients and doctors should be aware of this toxicity—and, in order to diagnose the retinopathy and manage it properly, teamwork is necessary between breast cancer and retina specialists.”
1 Kim HA et al. Ophthalmology. Published online Nov. 7, 2019.
2 Lee S et al. Ophthalmol Retina. 2019;3(8):681-689.
Relevant financial disclosures—Dr. Yoon: None.
For full disclosures and the disclosure key, see below.
Full Financial Disclosures
Dr. Bharti None.
Dr. Binenbaum Luminopia: C,O; NEI: S; Natus Medical: L; X Biomedical: O,P.
Dr. Digre None.
Dr. Ozudogru None.
Dr. Yoon Alcon: C,L; Allergan: C,L,S; Bayer Pharmaceuticals: C,L,S; Boehringer Ingelheim: C.
||Consultant fee, paid advisory boards, or fees for attending a meeting.
||Employed by a commercial company.
||Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company.
||Equity ownership/stock options in publicly or privately traded firms, excluding mutual funds.
||Patents and/or royalties for intellectual property.
||Grant support or other financial support to the investigator from all sources, including research support from government agencies (e.g., NIH), foundations, device manufacturers, and/or pharmaceutical companies.
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