A MAA-based dosimetric study in patients with intrahepatic cholangiocarcinoma treated with a combination of chemotherapy and 90Y-loaded glass microsphere selective internal radiation therapy.

PURPOSE: Selective internal radiation therapy (SIRT) appears to be an interesting treatment possibility for locally-advanced intrahepatic cholangiocarcinoma (ICC), yet the appropriate dosimetry has never been evaluated in this context. METHODS: We retrospectively studied data from 40 patients treated at our institution with 90Y-loaded glass microsphere SIRT combined with chemotherapy for inoperable ICC as first-line treatment. Macroaggregated albumin (MAA)-based single-photon emission computed tomography (SPECT)/computed tomography (CT) quantitative analysis was used to calculate the tumor dose (TD), healthy-injected liver dose (HILD), and injected liver dose (ILD). Response was evaluated at 3 months using the European Association for the Study of the Liver criteria. Factors associated with response and toxicity were analyzed using univariate analysis. RESULTS: We assessed a total of 35 patients (five excluded) receiving 55 injections. Mean TD was 322 ± 165Gy and mean HILD was 74 ± 24Gy for a mean ILD of 128 ± 28Gy. All but two lesions responded, with a minimal TD for responding lesions of 158Gy. Six Grade 3-4 permanent liver toxicities were observed. Mean HILD was not associated with liver toxicity (73.2 ± 25.8Gy for patients with liver toxicity and 77.8 ± 16.9Gy for patients without, ns). Only underlying Child-Pugh status (p = 0.0014) and underlying cirrhosis (p = 0.0021) were associated with liver toxicity. Median progression-free survival was 12.7 months and median overall survival (OS) was 28.6 months. Median OS was 52.7 months for patients with Child-Pugh A5 status. CONCLUSIONS: When combined with chemotherapy, SIRT is highly effective, with a TD > 158Gy. Tolerance was good except for the few patients with cirrhosis or Child-Pugh status ≥A6, who exhibited some liver toxicity. Prospective studies are warranted to confirm.

Dosimetric parameters predicting contralateral liver hypertrophy after unilobar radioembolization of hepatocellular carcinoma.

PURPOSE: This study aimed at identifying prior therapy dosimetric parameters using 99mTc-labeled macro-aggregates of albumin (MAA) that are associated with contralateral hepatic hypertrophy occurring after unilobar radioembolization of hepatocellular carcinoma (HCC) performed with 90Y-loaded glass microspheres. METHODS: The dosimetry data of 73 HCC patients were collected prior to the treatment with 90Y-loaded microspheres for unilateral disease. The injected liver dose (ILD), the tumor dose (TD) and healthy injected liver dose (HILD) were calculated based on MAA quantification. Following treatment, the maximal hypertrophy (MHT) of an untreated lobe was calculated. RESULTS: Mean MHT was 35.4 ± 40.4%. When using continuous variables, the MHT was not correlated with any tested variable, i.e., injected activity, ILD, HILD or TD except with a percentage of future remnant liver (FRL) following the 90Y-microspheres injection  (r = -0.56). MHT ≥ 10% was significantly more frequent for patients with HILD ≥ 88 Gy, (52% of the cases), i.e., in 92.2% versus 65.7% for HILD < 88 Gy (p = 0.032). MHT ≥ 10% was also significantly more frequent for patients with a TD ≥ 205 Gy and a tumor volume (VT) ≥ 100 cm3 in patients with initial FRL < 50%. MHT ≥10% was seen in 83.9% for patients with either an HILD ≥ 88 Gy or a TD ≥ 205 Gy for tumors larger than 100cm3 (85% of the cases), versus only 54.5% (p = 0.0265) for patients with none of those parameters. MHT ≥10% was also associated with FRL and the Child-Pugh score. Using multivariate analysis, the Child-Pugh score (p < 0.0001), FRL (p = 0.0023) and HILD (p = 0.0029) were still significantly associated with MHT ≥10%. CONCLUSION: This study demonstrates for the first time that HILD is significantly associated with liver hypertrophy. There is also an impact of high tumor doses in large lesions in one subgroup of patients. Larger prospective studies evaluating the MAA dosimetric parameters have to be conducted to confirm these promising results.

Incidental colorectal focal 18 F-FDG uptake: a novel indication for colonoscopy.

BACKGROUND AND STUDY AIMS: The relevance of incidental colorectal focal 18 F-FDG PET/CT uptake is debatable. All patients who were referred for colonoscopy because of incidental colonic focal FDG uptake were included in this retrospective study. PATIENTS AND METHODS: PET/CT imaging characteristics were reviewed by a nuclear physician who was blinded to endoscopic and histopathological findings to determine the location of FDG uptake sites and to measure the maximum standardized uptake values (SUVmax) and metabolic volume (MV). Endoscopic findings were categorized as malignant lesions (ML), high-risk polyps (HRP), low-risk polyps (LRP) or other non-neoplastic lesions (NNL). RESULTS: Seventy patients with 84 foci of FDG uptake were included. The proportions of true-positive (lesions found at colonoscopy at the same location) and false-positive (no lesion at colonoscopy) PET/CT findings were 65.5 % (n = 55) and 34.5 % (n = 29). Median SUVmax values did not differ between true-positive and false-positive findings ( P  = 0.27). Median MV30 values differed significantly between true-positive (5.5 cm 3 , [3.3 - 10.9 cm 3 ]) and false-positive (9.7 cm 3 , [5.2 - 40.8 cm 3 ]) findings ( P  = 0.015). Among the 55 true-positive FDG uptake sites, there were 14 (25.5 %) malignant lesions, 30 (54.5 %) HRP, 4 (7.3 %) LRP, and 7 (12.7 %) NNL. Median MV30 values differed significantly between advanced neoplasia (5.0 cm 3 , [2.9 - 9.7 cm 3 ]) and other endoscopic findings (9.4 cm 3 , [5.2 - 39.8 cm 3 ]) ( P  = 0.001); the AUROC was 0.71. By per-colonic segment analysis, the distribution of true-positive, false-negative, false-positive, and true-negative FDG PET/CT findings was as follows: 21.5 %, 14.2 %, 11.5 %, and 52.8 %, respectively. CONCLUSION: Our study demonstrates that follow-up complete colonoscopy is mandatory in all patients with incidental colorectal focal 18 F-FDG PET/CT uptake.

High impact of macroaggregated albumin-based tumour dose on response and overall survival in hepatocellular carcinoma patients treated with 90 Y-loaded glass microsphere radioembolization.

BACKGROUND & AIMS: Efficacy of radioembolization is derived from radioinduced damage, whereas tumour dosimetry is not considered as yet in prospective clinical trials. OBJECTIVES: This study evaluates the impact of tumour dose (TD), based on 99m Tc macroaggregated albumin (MAA) quantification, on response and overall survival (OS). MATERIALS AND METHODS: We consecutively included 85 patients with hepatocellular carcinoma treated with 90 Y-loaded glass microspheres. TD was calculated using a quantitative analysis of the MAA SPECT/CT. Responses were assessed after 3 months using the European Association for the Study of the Liver criteria. OS was assessed using Kaplan-Meier tests. RESULTS: Response rate was 80.3% on lesion-based analysis (n=132), and 77.5% on patient-based analysis. The response rate was only 9.1% for patients with TD <205 Gy against 89.7% for those with TD ≥205 Gy (P<10-7 ). Non-portal vein thrombosis (PVT) patients exhibited a median OS of 11.75 m (95% CI: 3-30.7 m) for TD <205 Gy, and 25 m (95% CI: 15-34.7 m) for TD ≥205 Gy (P=.0391). PVT patients exhibited a 4.35 m median OS (95% CI: 2-8 m) for TD<205 Gy, and 15.7 m (95% CI: 9.5-25.5 m) for TD ≥205 Gy, (P=.0004), with HR of 6.99. PVT patients exhibited a median OS of 3.6 m (95% CI: 2-8 m) when PVT MAA targeting was poor or with TD <205 Gy (poor candidate), vs 17.5 m (95% CI: 11-26.5 m) for the others identified as good candidates (P<.0001), with HR of 12.85. CONCLUSION: This study confirms the highly predictive value of MAA-based TD evaluation for response and OS. TD evaluation and PVT MAA targeting should be further evaluated in ongoing trials, whereas personalized dosimetry should be implemented in new trial designs.

Selective internal radiation therapy compared with sorafenib for hepatocellular carcinoma with portal vein thrombosis.

PURPOSE: Tumoural portal vein thrombosis (PVT) is a major prognostic factor in hepatocellular carcinoma (HCC). The efficacy of sorafenib, the only treatment approved at an advanced stage, is limited. Based on previous data, selective internal radiation therapy (SIRT), or (90)Y radioembolization, seems an interesting option. We aimed to compare both treatments in this population. METHODS: We retrospectively compared patients treated in two centres for HCC with tumoural PVT. We compared overall survival (OS) between patients treated with SIRT and patients treated with sorafenib. Analyses were performed before and after 1:1 matching with a propensity score for controlling indication bias, using a Cox proportional hazards model. RESULTS: A total of 151 patients were analysed, 34 patients treated with SIRT and 117 patients treated with sorafenib only. In the whole population, SIRT was associated with a higher median OS as compared with sorafenib: 18.8 vs 6.5 months (log-rank p < 0.001). There was an imbalance of baseline characteristics between patients treated by SIRT and sorafenib, which justified patient matching with use of a propensity score: 24 patients treated with SIRT could be matched with 24 patients treated with sorafenib. OS was estimated with a median of 26.2 vs 8.7 months in patients treated with SIRT vs sorafenib, respectively (log-rank p = 0.054). Before and after patient matching, the adjusted hazard ratio related to treatment by SIRT was estimated at 0.62 [95 % confidence interval (CI) 0.39-0.97] (p = 0.037) and 0.40 (95 % CI 0.19-0.82) (p = 0.013), respectively. CONCLUSION: SIRT seems more effective than sorafenib in patients presenting with HCC and tumoural PVT. This hypothesis is being tested in prospective randomized trials.

Occupational radiation exposure of medical staff performing 9°Y-loaded microsphere radioembolization.

PURPOSE: Radioembolization of liver cancer with (90)Y-loaded microspheres is increasingly used but data regarding hospital staff exposure are scarce. We evaluated the radiation exposure of medical staff while preparing and injecting (90)Y-loaded glass and resin microspheres especially in view of the increasing use of these products. METHODS: Exposure of the chest and finger of the radiopharmacist, nuclear medicine physician and interventional radiologist during preparation and injection of 78 glass microsphere preparations and 16 resin microsphere preparations was monitored. Electronic dosimeters were used to measure chest exposure and ring dosimeters were used to measure finger exposure. RESULTS: Chest exposure was very low for both products used (<10 µSv from preparation and injection). In our experience, finger exposure was significantly lower than the annual limit of 500 mSv for both products. With glass microspheres, the mean finger exposure was 13.7 ± 5.2 µSv/GBq for the radiopharmacist, and initially 17.9 ± 5.4 µSv/GBq for the nuclear medicine physician reducing to 13.97 ± 7.9 µSv/GBq with increasing experience. With resin microspheres, finger exposure was more significant: mean finger exposure for the radiopharmacist was 295.1 ± 271.9 µSv/GBq but with a reduction with increasing experience to 97.5 ± 35.2 µSv/GBq for the six most recent dose preparations. For administration of resin microspheres, the greatest mean finger exposure for the nuclear medicine physician (the most exposed operator) was 235.5 ± 156 µSv/GBq. CONCLUSION: Medical staff performing (90)Y-loaded microsphere radioembolization procedures are exposed to safe levels of radiation. Exposure is lower than that from treatments using (131)I-lipiodol. The lowest finger exposure is from glass microspheres. With resin microspheres finger exposure is acceptable but could be optimized in accordance with the ALARA principle, and especially in view of the increasing use of radioembolization.

Personalized dosimetry with intensification using 90Y-loaded glass microsphere radioembolization induces prolonged overall survival in hepatocellular carcinoma patients with portal vein thrombosis.

UNLABELLED: The objective of this study was to evaluate the response rate and survival of hepatocellular carcinoma portal vein thrombosis (PVT) patients treated with (90)Y-loaded glass microspheres using a personalized dosimetry and intensification concept. METHODS: The microspheres were administered to 41 hepatocellular carcinoma PVT patients (main = 12; lobar/segmental = 29). (99m)Tc-macroaggregated albumin SPECT/CT quantitative analysis was used to calculate the tumor dose (TD), healthy injected liver dose (HILD), and injected liver dose (ILD). Response was evaluated at 3 mo using the criteria of the European Association for the Study of the Liver, with CT follow-up lasting until disease progression or death. Survival was assessed using the Kaplan-Meier method. RESULTS: The mean injected activity was 3.1 ± 1.5 GBq, and mean ILD was 143 ± 49 Gy. When a TD threshold of 205 Gy was applied, (99m)Tc-macroaggregated albumin SPECT/CT achieved a 100% sensitivity and 90% overall accuracy (0 false-negatives; 4 false-positives) in response prediction. On the basis of TD and HILD values, 37% of patients received an intensification of the treatment (increased injected activity with the aim of achieving a TD ≥ 205 Gy and HILD < 120 Gy, applying an ILD > 150 Gy). This intensification resulted in a high response rate (85%) without increased liver toxicity of grade 3 or higher (6% vs. 12% in the patients who did not receive treatment intensification; not statistically significant). For the total 41 patients, median overall survival (OS) was 18 mo (95% confidence interval, 11-25 mo). For patients with a TD of less than 205 Gy, median OS was 4.3 mo (3.7-5 mo), versus 18.2 mo (8.5-28.7 mo) for those with a TD of 205 Gy or more (P = 0.005). Median OS was 20.9 mo for patients with a TD of 205 Gy or more and good PVT targeting (n = 36). OS was 12 mo (3 mo to ∞) for patients with main PVT, versus 21.5 mo (12-28.7 mo) for those with segmental or lobar PVT (not statistically significant). For the 5 patients with complete portal vein revascularization who underwent lobar hepatectomy, median OS was not reached yet exceeded 24.5 mo and was significantly higher than that of other patients (P = 0.0493). CONCLUSION: Using a (99m)Tc-macroaggregated albumin SPECT/CT personalized dosimetry and intensification concept with (90)Y-loaded glass microspheres induced prolonged OS for PVT patients as compared with the standard of care (sorafenib), without increasing liver toxicity. Prospective randomized studies are therefore warranted.

In vitro demonstration of synergy/additivity between (188)rhenium and sorafenib on hepatoma lines: preliminary results.

BACKGROUND: Hepatocellular carcinoma is generally diagnosed at advanced stages, for which only palliative treatments are possible by intra-arterial route or by targeted therapies. Among these treatments, metabolic radiotherapy using (90)-yttrium or (188)Re and sorafenib are two options adopted in monotherapy. MATERIALS AND METHODS: We address the question of a possible synergy arising from the combination of these two treatments. Two primary malignant hepatoma cell lines, N1S1 (murine HCC) and HepG2 (human hepatoblastoma) were treated in media containing increasing concentrations of sorafenib with/without (188)Re to assess the cellular toxicities of each treatment alone and in combination. The combination index method was used to look for synergy or additivity. RESULTS: A synergistic advantage of a treatment combining (188)Re and sorafenib is shown in vitro on hepatoma cell lines. CONCLUSION: This combined approach is promising and now needs to be confirmed by more complex in vitro models integrating the tumoral stroma, as well as by in vivo studies.

Volumetric changes after (90)y radioembolization for hepatocellular carcinoma in cirrhosis: an option to portal vein embolization in a preoperative setting?

BACKGROUND: Contralateral hypertrophy after (90)Y radioembolization has been described in case reports, but the incidence and quantitative extent of liver volume modifications after this therapy are unknown. METHODS: This retrospective study examined patients with hepatocellular carcinoma and underlying cirrhosis treated by (90)Y radioembolization. The main inclusion criteria were unilateral treatment, no prior liver surgery, and computed tomographic scans allowing for volumetric assessments. Treated, tumor, and contralateral liver volumes were measured. Whole liver volume and the ratio of contralateral to total functional liver volume after a virtual hepatectomy were calculated. RESULTS: Data of 34 patients were analyzed. Response rates were 26 % according to Response Evaluation Criteria in Solid Tumors (RECIST) and 63 % according to modified RECIST. Median overall survival was 13.5 months. Median treated volume decreased from 938 mL (interquartile range [IQR] = 719) to 702 mL (IQR = 656) (p < 0.001), while median contralateral volume increased from 724 mL (IQR = 541) to 920 mL (IQR = 530) (p < 0.001). The whole liver volume remained stable, with a median volume of 1,702 mL (IQR = 568) versus 1,577 mL (IQR 670), respectively (p = 0.55). The mean maximal increase in contralateral volume was 42 % (95 % confidence interval 16-67). Overall, 13 patients (38.2 %) exhibited increases greater than 30 %, while 13 patients (38.2 %) showed no increase or showed increases less than 10 %. The median ratio of contralateral to total functional liver volume increased from 48.5 to 64.9 % (p < 0.001), with the proportion of patients with a ratio of ≥50 % increasing from 47.1 to 67.6 % (p = 0.013). CONCLUSIONS: (90)Y radioembolization induced frequent and similar increases in functional liver remnant volume compared with portal vein embolization. This technique should be tested in a prospective study phase 2 study before liver resection.

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.

UNLABELLED: 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 = 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 = 0.0003) and 18 mo (P = 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).

Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization.

PURPOSE: Identifying gastroduodenal uptake of (99m)Tc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls. METHODS: Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements. RESULTS: Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver. CONCLUSION: SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind.

Effectiveness of quantitative MAA SPECT/CT for the definition of vascularized hepatic volume and dosimetric approach: phantom validation and clinical preliminary results in patients with complex hepatic vascularization treated with yttrium-90-labeled microspheres.

The goal of this study was to assess the use of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) analysis for vascularized volume measurements in the use of the yttrium-90-radiolabeled microspheres (TheraSphere). A phantom study was conducted for the validation of SPECT/CT volume measurement. SPECT/CT quantitative analysis was used for the measurement of the volume of distribution of the albumin macroaggregates (MAA; i.e., the vascularized volume) in the liver and the tumor, and the total activity contained in the liver and the tumor in four consecutive patients presenting with a complex liver vascularization referred for a treatment with TheraSphere. SPECT/CT volume measurement proved to be accurate (mean error <7%) and reproducible (interobserver concordance 0.99). For eight treatments, in cases of complex hepatic vascularization, the hepatic volumes based on angiography and CT led to a relative overestimation or underestimation of the vascularized hepatic volume by 43.2 ± 32.7% (5-87%) compared with SPECT/CT analyses. The vascularized liver volume taken into account calculated from SPECT/CT data, instead of angiography and CT data, results in modifying the activity injected for three treatments of eight. Moreover, quantitative analysis of SPECT/CT allows us to calculate the absorbed dose in the tumor and in the healthy liver, leading to doubling of the injected activity for one treatment of eight. MAA SPECT/CT is accurate for volume measurements. It provides a valuable contribution to the therapeutic planning of patients presenting with complex hepatic vascularization, in particular for calculating the vascularized liver volume, the activity to be injected and the absorbed doses. Studies should be conducted to assess the role of quantitative MAA/SPECT CT in therapeutic planning.

Utility of Quantitative Tc-MAA SPECT/CT for yttrium-Labelled Microsphere Treatment Planning: Calculating Vascularized Hepatic Volume and Dosimetric Approach.

Objectives. The aim of this study was to assess the effectiveness of SPECT/CT for volume measurements and to report a case illustrating the major impact of SPECT/CT in calculating the vascularized liver volume and dosimetry prior to injecting radiolabelled yttrium-90 microspheres (Therasphere). Materials and Methods. This was a phantom study, involving volume measurements carried out by two operators using SPECT and SPECT/CT images. The percentage of error for each method was calculated, and interobserver reproducibility was evaluated. A treatment using Therasphere was planned in a patient with three hepatic arteries, and the quantitative analysis of SPECT/CT for this patient is provided. Results. SPECT/CT volume measurements proved to be accurate (mean error <6% for volumes ≥16 cm(3)) and reproductive (interobserver agreement = 0.9). In the case report, (99m)Tc-MAA SPECT/CT identified a large liver volume, not previously identified with angiography, which was shown to be vascularized after selective MAA injection into an arterial branch, resulting in a large modification in the activity of Therasphere used. Conclusions. MAA SPECT/CT is accurate for vascularized liver volume measurements, providing a valuable contribution to the therapeutic planning of patients with complex hepatic vascularization.