Abstract
Purpose :
The 8th edition AJCC classification reliably predicts metastasis risk and globe salvage rate in retinoblastoma (Rb), but there are no clinical parameters that predict response to intra-arterial chemotherapy (IAC), which has become the first-line therapy for unilateral Rb and has applications for both primary and salvage treatment. Adjunctive ultrasound doppler imaging has been used in non-ocular tumors, specifically uterine cancers, to predict response to treatment. In this retrospective study, we evaluate the utility of ophthalmic ultrasound with microvascular flow imaging (MFI) to predict Rb response to IAC treatment.
Methods :
Fourteen patients with 20 eyes affected by Rb were included. Records of baseline clinical information and ultrasound assessment, including tumor volume, and resistive index (RI) and pulsatility index (PI) of both the central retinal artery (CRA) and feeding vessel (FV) were retrieved. Tumor volume from repeat assessment 3-6 weeks after initial IAC treatment was recorded. The data was summarized using frequencies and proportions for categorical variables and median, quartiles, and range for continuous variables. Group comparisons were conducted using the Wilcoxon rank-sum test, with p-values <0.05 deemed statistically significant.
Results :
Median baseline tumor volume was 0.40 cm3 (IQR 1.09) measured by ellipsoid volume formula. Median percent change in volume before and after IAC treatment was 71% (IQR 33%). Tumors with baseline volume less than 1 cm3 were associated with increased CRA RI (median 0.73) and PI (median 1.36) compared to larger tumors (median CRA RI 0.60, p-value 0.0353; median CRA PI 1.03, p-value 0.0317), as well as higher FV RI (median 0.72) and PI (1.40) than larger tumors (median FV RI 0.63, p-value 0.0170; median FV PI 1.01, p value 0.0012). None of the included doppler parameters, including RI and PI of the CRA and FV, were significantly associated with absolute or percent change in tumor volume following IAC.
Conclusions :
In this preliminary study, we found that Rb tumor volume is directly correlated with various doppler characteristics of the central retinal artery and feeder artery. No significant association was found between the baseline doppler parameters and the change in tumor volume following IAC. Further studies are required to elucidate potential ocular blood flow patterns that may predict response to IAC therapy.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.