Abstract
Abstract: :
Purpose: Tamoxifen, an antiestrogen, has been used as an effective therapeutic agent in the treatment of breast cancer. The drug has been shown to cause ocular toxic effects, mainly at high dosage. The purpose of this study was to determine retinal toxicity by full-field and focal electroretinograms (ERGs) in a cohort of patients treated with low-dosage tamoxifen (20mg/day) for breast cancer. Methods: Full-field and focal ERGs were obtained from 3 different groups. Group I - 14 females (47-72 years,mean 58.3 9.1) with normal fundus, treated with tamoxifen from 3 to 37 months. Group II -10 females (39-65 years,mean 50.1 8.7) with previous breast cancer diagnosis who have not taken tamoxifen until ERG testing. Group III- 15 normal female volunteers (41-81 years, mean 52.7 12.1). Peak-to-peak amplitude (µV) and b-wave implicit time (msec) were measured and statistically analyzed (one-way ANOVA). Pearson correlation was performed between focal ERG amplitude and duration of tamoxifen therapy. Results: Mean peak-to-peak amplitudes and implicit time from full-field and focal ERGs were comparable for the 3 different groups. Mean and standard deviation for the five different standardized ERG responses: scotopic rod, maximal response, oscillatory potentials, single-flash cone response and 30 Hz flicker were respectively: Group I - 186.050.9, 319.271.5, 106.944.2, 83.527.6, 57.218.0; Group II - 195.235.2, 360.878.4, 125.646.4, 100.227.9, 67.916.3 and Group III - 183.943.5, 292.581.4, 113.659.5, 104.457.7, 66.434.4. For focal ERG, mean peak-to-peak amplitudes (mV) were 24740, 30169 and 29650 respectively. There was no asignificant correlation between focal ERG amplitude and tamoxifen therapy duration. Conclusion: Low-dosage tamoxifen therapy caused no retinotoxic effect in this small group of women with breast cancer. However, follow-up investigation, as well as multifocal ERG testing could provide a better understanding of these effects.
Keywords: 395 electroretinography: clinical • 390 drug toxicity/drug effects • 554 retina