Key Role of Personalized Dosimetry in Dose Adjustment for Selective Internal Radiotherapy: Retrospective Study of Patients Treated With 90Y Resin Microspheres. (December 2021) - Subreville, Celine
Abstract : Purpose: Selective internal radiotherapy with 90 Y microspheres is widely used for the treatment of patients with liver cancer. A dosimetric analysis using the dosimetry software Simplicit90y (Boston Scientific, Natick, MA) was conducted to define doses to the tumor and healthy liver, and to determine a threshold tumor dose that could predict progression-free survival. Methods: Patients experiencing hepatocellular carcinoma and treated with 90 Y-labeled resin microspheres were included in a retrospective study. The time-to-progression of the target lesions (TTPLs) and overall survival (OS) were evaluated using Kaplan-Meier tests, and this comparison was based on a log-rank test. Results: Twenty-four procedures for patients with portal vein thrombosis were realized. Median follow-up was 16 months. A threshold tumor dose of 125 Gy was determined with a sensitivity of 89% and a specificity of 100%. For patients with a tumor dose of less than 125 Gy, the median OS was 7.5 months (95% confidence interval [CI], 5–14 months) and the TTPL was 3 months (95% CI, 2–6 months) versus 33 months (95% CI, 22–39 months) and 23 months (95% CI, 7–38 months), respectively, for those with a tumor dose of 125 Gy or more ( P = 0.002 and P = 0.0004). Conclusions: Personalized dosimetry based on 99m Tc-MAA SPECT/CT is predictive of TTPL and OS in patients with hepatocellular carcinoma. Customized dosimetry software is essential to optimize treatment planning.