Introduction/purpose Evaluate the baseline radiation dose and fluoroscopic time as well as the factors affecting these parameters during intra-arterial chemotherapy (IAC) of retinoblastoma.

Materials and methods Retrospective review of a prospective database of all patients with SIAC for retinoblastoma over a 5-year period (September 2009-January 2015) was performed. Institutional review board approval as well as informed consent from all the patients was obtained for the study. IAC were performed under general anesthesia with endotracheal intubation via femoral arterial access. Selective catheterization was achieved via ophthalmic artery (OA) or middle meningeal artery (MMA) with microcatheter, or by infusion below balloon occlusion of the ICA (balloon assistance). Innova 3131, biplane vascular radiographic imaging system with flat panel (GE Healthcare), with a low-dose pediatric protocol that included higher level of spectral filtration and low fluoroscopic frame rate was used. Our standard protocol included: 78 KV, 0.5 mAs and 15 frames/sec for fluoroscopy and 75 KV, 121 mA and 1 frame/sec for subtraction angiograms.

Patient demographics, weight, tumor grade, side of treatment, number of chemotherapy cycles, arterial approach, access device and number of drugs administered as well as radiation parameters including the Fluoroscopic time, Dose area product (DAP) and radiation dose were obtained from the database.

Statistical analysis was performed using SPSS for Mac, version 21.0. Generalized linear model regression was used for the univariate and multivariate analysis of the outcome variables such as total fluoroscopic time, DAPS and total dose. The significance level for the statistical analysis was taken as 0.05.

Results 218 patients (M: F= 94:124) had 272 eyes treated by 833 IAC infusions during 792 procedures. Mean age was 19-months, mean weight was 11.4 Kg. Mean cycles of SIAC per patient were 2.72±1.6 (range: 1-9). Mean of 2.48±0.8 medications were administered per procedure. Mean fluoroscopic time, DAP and doses were: 10.2±8.4 minutes, 218.7±240.8 cGy.cm² and 42.3±41.4 mGy, respectively. 18% (n=141) of the procedures were bilateral infusions. Three drugs were administered in 43% (n=340) of procedures. The arterial access was predominantly via OA (71%; n=564), followed by balloon assistance (16.5%; n=130) and MMA (10%; n=77). The radiation parameters (fluoroscopic time, DAP and Dose) of first SIAC cycle (10.8±9.7; 218±239; 43.4±41.6 respectively) were significantly higher (p<0.05) than subsequent 2^nd (10±8; 203±218; 41.6±44) and 3^rd cycles (8.9±6.5; 193±227; 30±35.9). Radiation parameters for bilateral IAC (16.8±11.6; 320.7±268.7; 60.8±45.6) were significantly higher (p<0.001) than for unilateral IAC (8.9±6.6; 212.7±247; 42±41). Similarly, the radiations parameters were significantly lower (p<0.001) for OA approach (7.5±5.4; 147.7±138.4; 28.5±29.4), compared to MMA (13.4±5.6; 242±138; 51.4±27) and balloon assistance (17.8±11.5; 449.8±361; 81.8±63.3). Significant increase in radiation parameters was noted for administration of “>3 medications” (10.1±6.5; 209±185; 37.8±33.2) against “≤3 medications” (19.8±11; 371.4±194; 65.5±38.6) (p<0.001). Finally, the radiation parameters were significantly lower for microcatheter (OA or MMA) (8.6±7.1; 193.4±181.3; 42.3±37) compared to balloon assisted IAC (17.8±11.5; 449.8±361; 81.8±63.3) (P<0.001).

Conclusion In IAC for retinoblastoma, ophthalmic artery access, microcatheter approach, unilateral treatment, and infusion of ≤ 3 medications were associated with significantly lower fluoroscopic time and radiation dose.

Disclosures S. Boddu: None. D. Abramson: None. B. Marr: None. J. Francis: None. P. Gobin: None.