Evaluation of Choroidal Melanoma Vascularization by Color Doppler Flow Imaging: An Option for Follow-Up Tumor Control Assessment after CyberKnife^®?

Background and Objectives: Thus far, tumor control for choroidal melanoma after teletherapeutic radiation is clinically difficult. In contrast to brachytherapy, the tumor height does not necessarily have to shrink as a result of teletherapy. Therefore, the objective of this study was to evaluate tumor vascularization determined by color Doppler flow imaging (CDFI) as a possible approach for monitoring the therapy response after teletherapy of choroidal melanoma. Materials and Methods: A single-center retrospective pilot study of 24 patients was conducted, all of whom had been diagnosed with choroidal neoplasm, treated and followed up. Besides tumor vascularization, the following parameters were collected: age, gender, tumor entity, location, radiation dose, knowledge of relapse, tumor height, radiation-related complications, occurrence of metastases, visual acuity in logMAR. Results: The level of choroidal melanoma vascularization markedly decreased in all included subjects after treatment with the CyberKnife^® technology. Initially, the level of vascularization was 2.1 (SD: 0.76 for n = 10); post-therapeutically, it averaged 0.14 (SD: 0.4). Regarding the tumor apex, CDFI sonography also demonstrated a significant tumor regression (mean value pre-therapeutically: 8.35 mm-SD: 3.92 for n = 10; mean value post-therapeutically: 4.86 mm-SD: 3.21). The level of choroidal melanoma vascularization declined in the patient collective treated with ruthenium-106 brachytherapy. The pre-therapeutic level of vascularization of 2 (SD: 0 for n = 2) decreased significantly to a level of 0 (mean: 0-SD: 0). The tumor height determined by CDFI did not allow any valid statement regarding local tumor control. In contrast to these findings, the patient population of the control group without any radiation therapy did not show any alterations in vascularization. Conclusions: Our data suggest that the determination of the tumor vascularization level using CDFI might be a useful and supplementary course parameter in the follow-up care of choroidal melanoma to monitor the success of treatment. This especially applies to robot-assisted radiotherapy using CyberKnife^®. Further studies are necessary to validate the first results of this assessment.