Dosimetry Based on ^99mTc-Macroaggregated Albumin SPECT/CT Accurately Predicts Tumor Response and Survival in Hepatocellular Carcinoma Patients Treated with ⁹⁰Y-Loaded Glass Microspheres: Preliminary Results

Abstract

Radioembolization of liver cancers using 90 Y-loaded microspheres is experiencing more widespread use. However, few data are available concerning the doses delivered to the tumors and the healthy liver. This retrospective study was conducted to calculate the tumor dosimetry (planned tumor dose [T plan D]) and nontumor dosimetry in patients treated by 90 Y-loaded glass microspheres and determine whether tumor dosimetry could predict response and survival. Methods: Thirty-six patients with hepatocellular carcinoma (HCC), including 16 with portal vein thrombosis (PVT), were treated with 90 Y-loaded glass microspheres. The T plan D and the dose delivered to the injected healthy liver were calculated using a quantitative analysis of the 99m Tc-macroaggregated albumin ( 99m Tc-MAA) SPECT/CT exam. Responses were assessed after 3 mo, using the criteria of the European Association for the Study of the Liver. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan-Meier tests. Results: The response rate was 69% for the overall population and 75% for the PVT patients. The dose delivered to the tumor was the only parameter associated with response with multivariate analysis (P 5 0.019). A threshold T plan D value of 205 Gy was predictive of response, with a sensitivity of 100% and an accuracy of 91%. Quantitative 99m Tc-MAA SPECT/CT allowed us to increase the injected activity for 4 patients with large lesions. PFS was only 5.2 mo and OS 9 mo when using a T plan D of less than 205 Gy versus 14 mo (P 5 0.0003) and 18 mo (P 5 0.0322), respectively, with a T plan D of 205 Gy or more. Conclusion: Quantitative 99m Tc-MAA SPECT/ CT is predictive of response, PFS, and OS. Dosimetry based on 99m Tc-MAA SPECT/CT can be used for the selection of patients and for an adaptation of treatment planning, especially in selected patients (particularly in the case of large tumors). These results also confirm the efficacy and safety of 90 Y-loaded microspheres in treating HCC, even in the presence of PVT (and especially when 99m Tc-MAA uptake is seen inside the PVT).

Radioembolisation of hepatocellular carcinoma patients using 90Y-labelled microspheres: towards a diffusion of the technique?

“…The toxicity profile of glass microspheres was shown to be acceptable in the Lambert et al study, in line with previously published reports [2][3][4]. The risk of pulmonary toxicity is effectively detected by MAA scintigraphy, and patients presenting pulmonary risks are systematically excluded from therapy.…”

“…Several cases of portal vein thromboses associated with partial or complete regression were reported after using glass microspheres, which was never observed following 131 I-Lipiodol therapy [4]. Furthermore, 131 I-Lipiodol therapy did not exhibit any efficacy in liver metastasis patients, whereas both glass and resin microspheres [5] were shown to be efficacious in this indication.…”

“…In fact, two studies published in 2011 showed that by using a quantitative analysis of MAA single photon emission computed tomography (SPECT)/ CT, dosimetric evaluation of both tumour and non-tumour volumes, and not just the hepatic volume to be treated as currently done, was feasible [4,7]. These two studies demonstrated that the doses absorbed by the tumour strongly correlated with response rates, with a dose threshold being required in order to achieve an objective response.…”

Semi-Quantitative Analysis of Post-Transarterial Radioembolization 90Y Microsphere Positron Emission Tomography Combined with Computed Tomography (PET/CT) Images in Advanced Liver Malignancy: Comparison With 99mTc Macroaggregated Albumin (MAA) Single Photon Emission Computed Tomography (SPECT)

“…Furthermore, it can predict treatment response. Garin et al [24] reported that 99m Tc MAA SPECT/CT is useful for predicting the prognosis after 90 Y microsphere treatment. When a higher TNR is observed in 99m Tc MAA SPECT/CT, the patient would show a better response, progression-free survival, and overall survival than those of the patients that have a lower TNR.…”

“…We followed the method of Garin et al [24] to obtain the TNR in the tumor and normal parenchyma. To overcome the subjectivity of measuring the normal parenchymal count, we applied two or three VOIs in the normal liver parenchyma at the proximity of each tumor and compared weighted kappa values derived from two independent researchers.…”