Regression of taxane-related cystoid macular edema after topical dorzolamide treatment: two case reports

BACKGROUND: Cystoid macular edema is a rare, vision-threatening side effect of the taxane family of anticancer agents. There is no established treatment or standard treatment protocol for taxane-related cystoid macular edema. Here, we report two cases of taxane-related cystoid macular edema that were treated with topical dorzolamide. CASE PRESENTATION: In case 1, a 72-year-old Japanese woman with bilateral geographic choroiditis reported for a follow-up visit with a complaint of blurred vision in both eyes for 2 months after starting nanoparticle albumin-bound paclitaxel chemotherapy for multiple metastases of her breast cancer. Her best-corrected visual acuity had dropped from 1.2 to 0.9 in the right eye and from 1.0 to 0.4 in the left eye. Fundus examination showed no newly active geographic choroiditis lesion, but optical coherence tomography exhibited cystoid macular edema. We suspected taxane-related cystoid macular edema and terminated nanoparticle albumin-bound paclitaxel, and started topical dorzolamide treatment. Cystoid macular edema nearly resolved within 6 weeks in the right eye and within 10 weeks in the left eye after starting topical dorzolamide treatment. The resolution of cystoid macular edema without leaving a chorioretinal scar after discontinuation of paclitaxel confirmed our initial diagnosis of taxane-related cystoid macular edema. A few inconspicuous cystoid spaces persisted at the parafovea for a year after dorzolamide treatment ended, but regressed after restarting dorzolamide treatment without any side effects. Best-corrected visual acuity improved to 1.2 in the right eye and 1.0 in the left eye. In case 2, a 70-year-old Japanese man, who received nanoparticle albumin-bound paclitaxel for pancreatic cancer with multiple metastases, developed bilateral cystoid macular edema. Best-corrected visual acuity was 0.3 bilaterally. Cystoid macular edema resolved within 5 weeks after stopping nanoparticle albumin-bound paclitaxel and starting topical dorzolamide treatment confirming the diagnosis of taxane-related cystoid macular edema. Nine weeks later, best-corrected visual acuity improved to 0.8 in the right eye and 1.0 in the left eye. CONCLUSIONS: Cystoid macular edema in each case resolved within a few months without any side effects using topical dorzolamide and terminating taxane-based chemotherapy. Topical dorzolamide appears to be a safe and effective treatment option for patients with taxane-related cystoid macular edema whose quality of life is threatened by visual disturbances.