Purpose:
To assess the tumor volume and vascularization in retinoblastoma by ecodoppler
Methods:
Retinoblastoma tumors in children with bilateral disease were studied using the "Toshiba Aplio XG,14 MHz and 20 MHz Transducer (Tokio, Japan)". The tumors stage B or higher (larger than 3mm), were assessed before and after three cycles of the operative protocol treatment in the HC-FMUSP. The protocol consists in monthly chemotherapy coupled with focal consolidation. The tumor volume was calculated manually based on three ultrassonographic measurements and the vascularization was indicated merely as present or absent. The data was compared with the ophthalmoscopy findings.
Results:
There were 14 elegible tumors in 5 children (2 males and 3 female). The mean age of presentation was 10 months (3 to 21months). Only two lesions were excluded due to unreliable data. The initial mean volume of the twelve tumors was 0.37cm3 ± 0.68 cm3 (0.004 cm3 to 2.36 cm3). Intrinsic vessels were detected in 9 lesions with mean volume of 0.49 cm3±0.76 cm3 while in three lesions, mean volume of 0.01cm3±0.01cm3, tumor vessels could not be demonstrated by echo doppler. The difference between these groups was statistically significant ( p=0.036 Mann-Whitney).The mean volume at three months was 0.04cm3 ± 0.06cm3 (zero to 0.172 cm3), corresponding to a mean reduction of 86%. The tumor vessels pattern was exuberant showing variable degrees of turbulence before treatment. The vascularization at 3 months, considered only in 6 tumors that were not flat, was still present in 1 (16%) and totally absent in 5. All 6 tumors showed features of viability at fundus examination in the third month, meaning opaque tissue sometimes with visible vessels. The tumor where vascularization was detected by ecodoppler at three months, was resistant to treatment albeit the reduction in the mass volume.
Conclusions:
Echo doppler is able to assess size and vascularization of the tumor in the same session. Intrinsic vessels may be overlooked in very small tumors. Lack of vascularization in the follow-up does not imply total involution of the tumor. This diagnostic tool should be considered in poor collaborative baby patients
Keywords: retinoblastoma • imaging/image analysis: clinical