Cost-effective ¹⁸⁸Re-microspheres for selective intra-arterial radionuclide therapy of liver cancer: initial results

The selective intra-arterial radionuclide therapy (SIRT) delivers the radiation to the liver cancer via hepatic artery. This therapy minimizes the radiation to normal liver parenchyma and other organs. The treatment is also given prior to surgery and liver transplantation and also postsurgery to reduce the risk of recurrence. The commercially available Y-90 SIRSpheres/TheraSpheres are beyond the reach of most of the patients. In this study, cost-effective, indigenous Re-188 microspheres were formulated for SIRT. Re-188 microspheres were formulated in house. A clearance from institutional ethics committee and informed written consent from the patients were obtained. The feasibility studies were performed using 74-185 MBq Re-188 microspheres in lipiodol and was delivered via hepatic artery (n = 15). Gamma camera whole-body images were acquired at 1, 6, 12-15, and 24-30 h and single-photon emission computed tomography/computed tomography was acquired 12 h postadministration. For dosimetry studies, urine and blood samples were also collected (n = 3) at various time points. Based on the results of feasibility study, three patients with large tumor and portal vein tumor thrombus were recruited for therapy and dosimetry was performed as described above. Radiolabeling yield and radiochemical purity of Re-188 microspheres was >90% and >98%. Patients showed good and sustained localization of Re-188 microspheres in tumor during the study period. Minimal dose was received by normal liver. However, spleen received ~6% of the ID. Blood and urine showed ~2% ID till 48 h. Significant clinical improvement was observed with no adverse/toxic effects. In two patients >50% reduction in tumor size and in one patient necrosis was noted. The indigenous prepared Re-188 microspheres are easy to formulate in hospital radiopharmacy and are very cost-effective as compared to commercially available Y-90 SIRSpheres/TheraSpheres. Initial treatment data showed very promising results. (author)