Selective Internal Radiation Therapy (SIRT) for liver metastases secondary to colorectal adenocarcinoma

Role of diffusion-weighted imaging in response prediction and evaluation after high dose rate brachytherapy in patients with colorectal liver metastases

BACKGROUND

The aim of the study was to assess the role of diffusion-weighted imaging (DWI) to evaluate treatment response in patients with liver metastases of colorectal cancer.

PATIENTS AND METHODS

In this retrospective, observational cohort study, we included 19 patients with 18 responding metastases (R-Mets; follow-up at least one year) and 11 non-responding metastases (NR-Mets; local tumor recurrence within one year) who were treated with high-dose-rate brachytherapy (HDR-BT) and underwent pre- and post-interventional MRI. DWI (qualitatively, mean apparent diffusion coefficient [ADCmean], ADCmin, intraindividual change of ADCmean and ADCmin) were evaluated and compared between pre-interventional MRI, first follow-up after 3 months and second follow-up at the time of the local tumor recurrence (in NR-Mets, mean: 284 ± 122 d) or after 12 months (in R-Mets, mean: 387+/-64 d). Sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) for detection of local tumor recurrence were calculated on second follow up, evaluating (1) DWI images only, and (2) DWI with Gd-enhanced T1-weighted images on hepatobiliary phase (contrast-enhanced [CE] T1-weight [T1w] hepatobiliary phase [hb]).

RESULTS

ADCmean significantly increased 3 months after HDR-BT in both groups (R-Mets: 1.48 ± 0.44 and NR-Mets: 1.49 ± 0.19 x 10-3 mm2;/s, p < 0.0001 and p = 0.01), however, intraindividual change of ADCmean (175% vs.127%, p = 0.03) and ADCmin values (0.44 ± 0.24 to 0.82 ± 0.58 x 10-3 mm2/s) significantly increased only in R-Mets (p < 0.0001 and p < 0.001). ADCmin was significant higher in R-Mets compared to NR-Mets on first follow-up (p = 0.04). Sensitivity (1 vs. 0.72), specificity (0.94 vs. 0.72), PPV (0.91 vs. 0.61) and NPV (1 vs. 0.81) could be improved by combining DWI with CE T1w hb compared to DWI only.

CONCLUSIONS

DW-MRI seems to be helpful in the qualitative and quantitative evaluation of treatment response after HDR-BT of colorectal metastases in the liver.

Locoregional Therapies for Primary and Secondary Hepatic Malignancies

Management of hepatic malignancies is a multidisciplinary task with the involvement of hepatologists, medical/surgical/radiation oncologists, transplant surgeons, and interventional radiologists. Patients should be selected for a specific targeted therapy after multidisciplinary consensus. Interventional oncology, with image-guided locoregional cancer therapies, can decrease systemic toxicity without compromising tumoricidal effect.

Analysis of Periprocedural X-ray Exposure in Transarterial Radioembolization with Glass or Resin Microspheres

Background: Transarterial Radioembolization (TARE) is an effective treatment option for both primary and secondary liver malignancies. However, challenging anatomical conditions can lead to prolonged fluoroscopy times (FT), elevated doses of periprocedural X-radiation (DAP), and increased use of contrast agents (CAs). In this study, we examined the influence of our radiologists' experience and the choice of microspheres on X-ray exposure and CA doses in TARE. Material and Methods: Datasets comprising 161 TARE and 164 preprocedural evaluation angiographies (TARE-EVA) were analyzed. Our study focused on assessing DAP, FT, and CA concerning both microsphere types, the radiologist's experience, and whether the same radiologist performed both the TARE-EVA and the actual TARE. Results: In TARE, the use of resin microspheres resulted in significantly higher FT and CA compared to glass microspheres (14.3 ± 1.6 min vs. 10.6 ± 1.1 min and 43 ± 2.2 mL vs. 33.6 ± 2.1 mL, p < 0.05), with no notable differences in DAP (p = 0.13). Experienced radiologists demonstrated reduced FT/DAP, with a 19% decrease in DAP and 53% in FT during the evaluation angiography (p < 0.05) and a 49% reduction in DAP during the actual TARE (p < 0.05), with no statistical differences in FT. Performing TARE and TARE-EVA under the same radiologist led to a 43% reduction in DAP and a 25% decrease in FT (p < 0.05, respectively). Conclusions: To mitigate X-radiation exposure, it is advisable for radiologists to undergo thorough training, and, ideally, the same radiologist should conduct both the TARE and the TARE-EVA. While the use of glass spheres may decrease intraarterial CA, it does not significantly impact periprocedural X-ray exposure.

Radiochemical Feasibility of Mixing of 99mTc-MAA and 90Y-Microspheres with Omnipaque Contrast

Yttrium-90 (90Y) microspheres are widely used for the treatment of liver-dominant malignant tumors. They are infused via catheter into the hepatic artery branches supplying the tumor under fluoroscopic guidance based on pre-therapy angiography and Technetium-99m macroaggregated albumin (99mTc-MAA) planning. However, at present, these microspheres are suspended in radiolucent media such as dextrose 5% (D5) solution. In order to monitor the real-time implantation of the microspheres into the tumor, the 90Y microspheres could be suspended in omnipaque contrast for allowing visualization of the correct distribution of the microspheres into the tumor. The radiochemical purity of mixing 90Y-microspheres in various concentrations of omnipaque was investigated. The radiochemical purity and feasibility of mixing 99mTc-MAA with various concentrations of a standard contrast agent were also investigated. Results showed the radiochemical feasibility of mixing 90Y-microspheres with omnipaque is radiochemically acceptable for allowing real-time visualization of radioembolization under fluoroscopy.

Therapeutic Approaches for Metastases from Colorectal Cancer and Pancreatic Ductal Carcinoma

Metastasis is the process of dissemination of a tumor, whereby cells from the primary site dislodge and find their way to other tissues where secondary tumors establish. Metastasis is the primary cause of death related to cancer. This process warrants changes in original tumoral cells and their microenvironment to establish a metastatic niche. Traditionally, cancer therapy has focused on metastasis prevention by systematic treatments or direct surgical re-sectioning. However, metastasis can still occur. More recently, new therapies direct their attention to targeting cancer stem cells. As they propose, these cells could be the orchestrators of the metastatic niche. In this review, we describe conventional and novel developments in cancer therapeutics for liver and lung metastasis. We further discuss the resistance mechanisms of targeted therapy, the advantages, and disadvantages of diverse treatment approaches, and future novel strategies to enhance cancer prognosis.

[Transarterial radioembolization : Immune effects and immuno-oncology]

BACKGROUND

Transarterial radioembolization (TARE) is a locoregional minimally invasive therapeutic strategy to treat primary and secondary hepatic neoplasia.

AIM

The objective was to assess TARE-induced immuno-oncological effects and its perspective for potential therapy improvement by using a combinatory strategy with immune checkpoint inhibitors (ICI).

RESULTS

Yttrium-90 (⁹⁰Y) TARE is used in patients with persisting liver function as the first- and second-line treatment for cholangiocarcinoma and hepatocellular carcinoma and chemotherapy refractory liver metastasis of different primaries. Combination therapy with ⁹⁰Y TARE and ICI may synergistically improve antitumoral immunity and patient outcome. Currently, there are no clinical studies with published data regarding this combination therapy and the subsequently induced immunological effects. Clinical data on other isotopes, e.g., holmium-166 (¹⁶⁶Ho), are also lacking.

CONCLUSION

The clinical evidence of combined treatment with TARE and ICI must be considerably improved. This innovative therapy concept must be studied in new trials assessing the immunological data, including cellular phenotypes, activation, functions, and biomarkers. This may provide valid, sensitive, and specific models in order to evaluate the optimal therapy concept and/or the therapy combination for the best patient outcome.

Posterior Reversible Encephalopathy Syndrome After 90Y-Resin Microspheres Radioembolization

A 66-year-old man with colorectal carcinoma and liver-only metastases underwent radioembolization using Y-loaded, resin-based microspheres. One day after radioembolization, the patient experienced severe hypertension and multiple seizures. On MRI, symmetric edematous areas in the cerebellum and the parietal and occipital lobe were observed, a typical finding for posterior reversible encephalopathy syndrome (PRES). The PRES is associated with, for example, renal failure or blood pressure fluctuations leading to cerebral endothelial dysfunction. Antihypertensive and antiepileptic therapies led to normotensive blood pressure and neurological remission. Therefore, newly developed neurological symptoms accompanied by high blood pressure fluctuations after radioembolization should lead to PRES as differential diagnosis.

Angiogenesis in 90Y-Radioembolization of Colorectal Liver Metastases

In order to evaluate the role of angiogenesis in ⁹⁰Y-radioembolization for colorectal cancer liver metastasis an overview was provided of angiogenic growth factors and their function, the angiogenic mechanisms in colorectal cancer, the role of hypoxia, and the advances in antiangiogenic therapy. Last, the use of circulating angiogenic growth factors in ⁹⁰Y-radioembolization was reviewed. Two literature searches were conducted. A search query in PubMed on angiogenesis in colorectal cancer, and a systematic search in PubMed (Medline), Embase, and the Cochrane Library (October 2018) with synonyms for "radioembolization" and "angiogenic growth factor." The first search yielded 3 relevant publications on the role of angiogenic growth factors in colorectal cancer, hypoxia, and antiangiogenic therapy. The second search yielded two prospective studies on circulating angiogenic factors and their relationship with response and survival after ⁹⁰Y-radioembolization for colorectal cancer liver metastases. Rises in circulating angiogenic growth factors after radioembolization were seen in both studies. High baseline values of Ang-2 and IL-8 correlated with shorter survival and post ⁹⁰Y-radiembolization rises in Ang-2 and HGF correlated with early progression. Various angiogenic growth factors play a role in the development and progression of colorectal cancer. Several factors show correlation with poor outcomes after ⁹⁰Y-radioembolization and might be used for patient selection in the future, however, validation in larger comparative studies is required.

Multi-modal image analysis for semi-automatic segmentation of the total liver and liver arterial perfusion territories for radioembolization

Purpose

We have developed a multi-modal imaging approach for SIRT, combining ^99mTc-MAA SPECT/CT and/or ⁹⁰Y PET, ¹⁸F-FDG PET/CT, and contrast-enhanced CBCT for voxel-based dosimetry, as a tool for treatment planning and verification. For radiation dose prediction calculations, a segmentation of the total liver volume and of the liver perfusion territories is required.

Method

In this paper, we proposed a procedure for multi-modal image analysis to assist SIRT treatment planning. The pre-treatment ¹⁸F-FDG PET/CT, ^99mTc-MAA SPECT/CT, and contrast-enhanced CBCT images were registered to a common space using an initial rigid, followed by a deformable registration. The registration was scored by an expert using Likert scores. The total liver was segmented semi-automatically based on the PET/CT and SPECT/CT images, and the liver perfusion territories were determined based on the CBCT images. The segmentations of the liver and liver lobes were compared to the manual segmentations by an expert on a CT image.

Result

Our methodology showed that multi-modal image analysis can be used for determination of the liver and perfusion territories using CBCT in SIRT using all pre-treatment studies. The results for image registration showed acceptable alignment with limited impact on dosimetry.

The image registration performs well according to the expert reviewer (scored as perfect or with little misalignment in 94% of the cases). The semi-automatic liver segmentation agreed well with manual liver segmentation (dice coefficient of 0.92 and an average Hausdorff distance of 3.04 mm). The results showed disagreement between lobe segmentation using CBCT images compared to lobe segmentation based on CT images (average Hausdorff distance of 14.18 mm), with a high impact on the dosimetry (differences up to 9 Gy for right and 21 Gy for the left liver lobe).

Conclusion

This methodology can be used for pre-treatment dosimetry and for SIRT planning including the determination of the activity that should be administered to achieve the therapeutical goal. The inclusion of perfusion CBCT enables perfusion-based definition of the liver lobes, which was shown to be markedly different from the anatomical definition in some of the patients.

Multi-Objective Design Optimization of a Shape Memory Alloy Flexural Actuator

This paper presents a computational model and design optimization strategy for shape memory alloy (SMA) flexural actuators. These actuators consist of curved SMA wires embedded within elastic structures; one potential application is positioning microcatheters inside blood vessels during clinical treatments. Each SMA wire is shape-set to an initial curvature and inserted along the neutral axis of a straight elastic member (cast polydimethylsiloxane, PDMS). The elastic structure preloads the SMA, reducing the equilibrium curvature of the composite actuator. Temperature-induced phase transformations in the SMA are achieved via Joule heating, enabling strain recovery and increased bending (increased curvature) in the actuator. Actuator behavior is modeled using the homogenized energy framework, and the effects of two critical design parameters (initial SMA curvature and flexural rigidity of the elastic sleeve) on activation curvature are investigated. Finally, a multi-objective genetic algorithm is utilized to optimize actuator performance and generate a Pareto frontier, which is subsequently experimentally validated.

The Tipping Point: Key Oncologic Imaging Findings Resulting in Critical Changes in the Management of Malignant Tumors of the Gastrointestinal Tract

OBJECTIVE

The purpose of this article is to review tumor staging systems for gastrointestinal tumors including pancreatic adenocarcinoma, hepatocellular carcinoma, cholangiocarcinoma, gastric adenocarcinoma, small bowel adenocarcinoma, rectal carcinoma, and anal carcinoma and identify the key imaging findings ("tipping points"), which change patient management based on changes in tumor staging.

CONCLUSION

For all malignant gastrointestinal tumors, there are key imaging findings ("tipping points") including tumor size, tumor extension, lymphadenopathy, vascular invasion, and distant metastasis that dictate patient management and prognosis, based on changes in tumor stage. In interpreting these imaging studies, radiologists should be cognizant of these "tipping points" to guide patient management.

Current status and future perspectives on treatment of liver metastasis in colorectal cancer (Review)

Liver metastasis is the most common site of colorectal cancer (CRC) metastasis. Approximately half of all colorectal cancer patients will develop liver metastases. Although radical surgery is the standard treatment modality, only 10-20% of patients are deemed eligible for resection. Despite advances in survival with chemotherapy, surgical resection is still considered the only curative option for patients with liver metastases. Much effort has been expended to address patients with metastatic liver disease. The majority of evidence stated a significant survival benefit with surgical resection to reach an overall 5-year survival rate of 35-55% after hepatic resection. However, still majority of patients will experience disease recurrence even after a successful resection. In this review, we describe current status and controversies related to treatment options for CRC liver metastases and its potential for enhancing oncologic outcomes and improving quality of life.

Treating hepatocellular carcinoma with 90Y-bearing microspheres: a review

Hepatocellular carcinoma (HCC) is a disease usually diagnosed in its advanced-stage, and is frequently not amenable to curative surgical treatment. Also, HCC is resistant to chemotherapy and less vulnerable to radiation therapy compared to normal hepatic parenchyma. Both of these facts render the efficacy of adjuvant and palliative treatments problematic. Selective internal radiation therapy (SIRT) with ⁹⁰Y-bearing microspheres is characterized by preferentially delivering substantially high doses of radiation to a liver tumor dose simultaneously limiting the damage to its non-tumorous cells, providing an opportunity for effective local tumor control and even tumor regression therapy. The current article reviews the specific characters, dosimetry, possible applications, and special considerations toward the pre-existing radiation therapy of ⁹⁰Y microsphere SIRT in treating HCC.

Selective internal radiation therapy for liver metastases from colorectal cancer

Liver metastases are often the dominant site of metastatic disease in colorectal cancer. Selective internal radiation therapy (SIRT) involves embolising radiolabeled spheres (SIR-Spheres) into the arterial supply of the liver. This review assesses the effectiveness and toxicity of SIRT in the treatment of metastatic colorectal cancer liver metastasis when given alone or with systemic or regional hepatic artery chemotherapy. We reviewed only randomised controlled trials comparing SIRT and chemotherapy (systemic and/or regional) with chemotherapy alone, or comparing SIRT alone with best supportive care. Only four randomized trials were identified. Due to heterogeneity of the patients and treatments received it was not possible to perform a formal meta-analysis, therefore this is a descriptive analysis only. All studies included patients with either liver only or liver dominant metastatic colorectal cancer. Two trials compared SIRT alone and SIRT with chemotherapy first line. The first with only 21 patients revealed a significant improvement in PFS and median survival with SIRT. The larger second study SIRFLOX of 530 patients comparing SIRT and current standard first line FOLFOX chemotherapy (+/- bevacizumab) with standard FOLFOX+/-bevacizumab alone. There was no improvement in overall PFS with addition of SIRT. In chemotherapy refractory patients SIRT and systemic chemotherapy (fluorouracil) improved progression free survival but not overall survival. A final study (63 patients) compared SIRT and regional chemotherapy (floxuridine) with regional chemotherapy alone in first line showed no significant difference in progression free survival and median survival. There remains a lack of evidence that SIRT improves survival or quality of life in patients with metastatic colorectal cancer. The overall survival results from SIRFLOX combined with FOXFIRE and FOXFIRE Global are awaited.

Radioembolization With Yttrium-90 Resin Microspheres in Hepatocellular Carcinoma: A Multicenter Prospective Study

OBJECTIVES

The aim of this prospective study was to reveal the efficacy and safety of Yttrium-90 (Y) radioembolization in Korean patients with hepatocellular carcinoma (HCC).

METHODS

A total of 40 HCC patients were prospectively recruited from 7 centers. The response to treatment was assessed on the basis of the modified Response Evaluation Criteria in Solid Tumors criteria. The time to progression and overall survival were also evaluated, and the assessment of safety was done according to National Cancer Institute Common Terminology Criteria, Version 3.0.

RESULTS

Forty-two treatments of Y radioembolization were carried out. Median follow-up was 29 months. At 3 months, the complete response, partial response (PR), and stable disease were seen in 4 (10.0%), 19 (47.5%), and 15 (37.5%) patients, respectively. The response rate was 57.5% (23/40), and disease control rate was 95% (38/40) at 3 months. The response rate at 6 months was 63.9% (23/36), and disease control rate was 83.3% (30/36). The median time to progression was 18 months. During follow-up, 10 HCC-related deaths occurred and the 3-year survival rate was 75%. In 19 patients with Barcelona Clinic Liver Cancer-B stage, the 3-year survival rate was 50%. The tumor number (>5) was the only significant predictor associated with survival. The most common adverse event was abdominal pain of mild to moderate degree, and all the complications were manageable. Twenty-six (65%) patients underwent other treatments such as transarterial chemoembolization because of local progression or remnant viable lesion.

CONCLUSIONS

Y radioembolization might be a safe and effective treatment modality in intermediate-stage to advanced-stage HCC.

Prognostic significance of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in patients treated with selective internal radiation therapy

BACKGROUND

Elevated neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios (PLR) may represent markers of a suboptimal host immune response to cancer and have been shown to correlate with prognosis in multiple tumor types across different treatment modalities, including radiation therapy. Limited data suggest that NLR may predict for survival and disease control in patients receiving selective internal radiation therapy (SIRT). The correlation between clinical outcomes and change in NLR and PLR after SIRT has not been evaluated.

METHODS

We retrospectively reviewed 339 consecutive patients with primary (n=37) or metastatic (n=79) liver cancer treated with SIRT from 2006 to 2014. Complete blood counts with differential were available for 116 patients both before and after (median, 29 and 20 days, respectively) SIRT. Survival and progression were calculated from date of initial SIRT. Patient and tumor characteristics evaluated for ability to predict overall survival (OS) and progression free survival (PFS) included pre- and post-treatment neutrophil, platelet, and lymphocyte counts (LCs), as well as NLR, PLR, and relative change in NLR and PLR. Cutoff values were determined for variables that were significant on multivariate analysis (MVA) for OS and/or PFS.

RESULTS

Median follow-up of surviving patients was 12 months. Median OS was 8 months from SIRT and 20 months from date of liver metastasis diagnosis. Significant factors on univariate analysis (UVA) for both lower OS and PFS included higher post-treatment neutrophil count (NC), higher post-treatment NLR, higher liver tumor volume, higher percentage liver tumor burden, and worse Eastern Cooperative Oncology Group (ECOG) performance status. Significant factors on MVA for lower OS and PFS were ECOG performance status ≥2, higher liver tumor volume, higher pretreatment PLR, and increase in PLR after SIRT. Post-treatment increase in PLR >3-fold was the most predictive early marker for increased risk of death when compared with those whose PLR did not increase or increased <3-fold. Pretreatment PLR >78 was the most predictive serum marker associated with improved OS prior to therapy.

CONCLUSIONS

This is the largest study to evaluate the association between NLR and PLR with clinical outcomes in patients receiving SIRT, with results that confirm that pre- and/or post-treatment NLR and/or PLR are predictive of clinical outcomes. The largest increase in risk of death as well as local and extrahepatic disease progression was related to change in PLR, a datum not well reported in the literature. The impact of SIRT on blood count changes and the underlying implications of these ratios should be further characterized in a prospective study.

Locoregional Therapies for Primary and Secondary Hepatic Malignancies

Management of hepatic malignancies is a multidisciplinary task with the involvement of hepatologists, medical/surgical oncologists, transplant surgeons, and interventional radiologists. The patients should be selected for a specific targeted therapy after multidisciplinary consensus. Interventional oncology has established its role in the management of hepatic malignancies. Image-guided locoregional therapies decrease the rate of systemic toxicity without compromising tumoricidal effect.

Serious hepatic complications of selective internal radiation therapy with yttrium-90 microsphere radioembolization for unresectable liver tumors

AIM

Selective internal radiation therapy with yttrium-90 microsphere radioembolization has been used to treat unresectable liver tumors and its acute toxicity has been well described. Subacute and long-term hepatic complications related to radioembolization however may be underreported in the literature. This retrospective study describes the incidence and sequelae of serious hepatic complications in patients who underwent radioembolization for unresectable liver tumors.

METHODS

A retrospective review of clinical notes of patients who received radioembolization for unresectable liver tumors from 2001 to 2011 at two Australian institutions was performed to identify those who developed clinically significant hepatic complications. Relevant clinical data were obtained and analyzed to determine their incidence and sequelae.

RESULTS

A total of 205 patients were identified, of whom 10 (4.9%) developed serious hepatic complications with 7 (3.4%) attributable to radioembolization-induced liver disease. None had preexisting underlying liver disease or progressive hepatic metastases at the time of developing hepatic complication. The median time to the onset of hepatic complications was 3.5 months (range 1-67 months); six patients had a complete resolution eventually, including one patient who subsequently underwent hepatic metastasectomy safely. Three patients died as a result of fulminant hepatic failure.

CONCLUSION

Selective internal radiation therapy with radioembolization was associated with serious hepatic complications with an incidence of 4.9% and a mortality rate of 1.5% in 205 patients from two Australian institutions. The risk of serious hepatic toxicity therefore needs to be discussed when counseling patients regarding this potential treatment option.

Gastroenteropancreatic neuroendocrine tumour arising in Meckel's diverticulum coexisting with colon adenocarcinoma

Although colon cancer is the third most common cause of cancer-related death worldwide, the prevalence of gastroenteropancreatic neuroendocrine tumours (GEP-NETs) remains rare. To date, very few cases of GEP-NETs within Meckel’s diverticulum and synchronous colorectal cancer have been reported. Although the coexistence of these two tumour types is uncommon, it is important to be aware of their disease patterns. We present a rare case of a patient with an intestinal GEP-NET arising in Meckel’s diverticulum coexisting with metastatic colon adenocarcinoma, and we discuss the clinical manifestations and the diagnostic procedures and treatment modalities used. This case report underlines the importance of being aware of this particular coexistence, as well as the unlikely metastatic spread of GEP-NETs and the importance of a multidisciplinary approach to cancer treatment. Finally, individualizing the treatment according to the stages of the primaries will result in durable cancer control, particularly in synchronous double malignancy.

Regional Radiation Pneumonitis After SIRT of a Subcapsular Liver Metastasis: What is the Effect of Direct Beta Irradiation?

We herein present a patient undergoing selective internal radiation therapy with an almost normal lung shunt fraction of 11.5%, developing histologically proven radiation pneumonitis. Due to a predominance of pulmonary consolidations in the right lower lung and its proximity to a large liver metastases located in the dome of the right liver lobe a Monte Carlo simulation was performed to estimate the effect of direct irradiation of the lung parenchyma. According to our calculations direct irradiation seems negligible and RP is almost exclusively due to ectopic draining of radioactive spheres.

A small-scale anatomical dosimetry model of the liver

Radionuclide therapy is a growing and promising approach for treating and prolonging the lives of patients with cancer. For therapies where high activities are administered, the liver can become a dose-limiting organ; often with a complex, non-uniform activity distribution and resulting non-uniform absorbed-dose distribution. This paper therefore presents a small-scale dosimetry model for various source-target combinations within the human liver microarchitecture. Using Monte Carlo simulations, Medical Internal Radiation Dose formalism-compatible specific absorbed fractions were calculated for monoenergetic electrons; photons; alpha particles; and (125)I, (90)Y, (211)At, (99m)Tc, (111)In, (177)Lu, (131)I and (18)F. S values and the ratio of local absorbed dose to the whole-organ average absorbed dose was calculated, enabling a transformation of dosimetry calculations from macro- to microstructure level. For heterogeneous activity distributions, for example uptake in Kupffer cells of radionuclides emitting low-energy electrons ((125)I) or high-LET alpha particles ((211)At) the target absorbed dose for the part of the space of Disse, closest to the source, was more than eight- and five-fold the average absorbed dose to the liver, respectively. With the increasing interest in radionuclide therapy of the liver, the presented model is an applicable tool for small-scale liver dosimetry in order to study detailed dose-effect relationships in the liver.

Current status of imaging and emerging techniques to evaluate liver metastases from colorectal carcinoma

Colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. Liver is a common site of tumor spread and in approximately 30% of the cases; synchronous liver disease is present at the time of diagnosis. Early detection of liver metastases is crucial to appropriately select patients who may benefit from hepatic resection among those needing chemotherapy, to improve 5-year survival. Advances in imaging techniques have contributed greatly to the management of these patients. Multidetector computed tomography is the most useful test for initial staging and in posttreatment surveillance settings. Magnetic resonance imaging is considered superior to multidetector computed tomography and positron emission tomography for the detection and characterization of small lesions and for liver evaluation in the presence of background fatty liver changes. Positron emission tomography-computed tomography has a problem-solving role in the detection of distant metastasis and in posttreatment evaluation. The advanced imaging methods also serve a role in selecting appropriate patients for radiologically targeted therapies and in monitoring response to conventional and novel therapies.

Safety of repeated radioembolizations in patients with advanced primary and secondary liver tumors and progressive disease after first selective internal radiotherapy

The purpose of this study was to assess the safety of repeated (90)Y radioembolization with resin microspheres in patients with extensive primary and secondary liver tumors after failure of first radioembolization.

METHODS

Between 2007 and 2011, 21 patients (12 women, 9 men; mean age, 61.0 y) with nonresectable advanced liver tumors (breast cancer liver metastases, n = 7; colorectal liver metastases, n = 5; hepatocellular carcinoma, n = 8; cholangiocellular carcinoma, n = 1) were repeatedly treated by radioembolization. Safety was the primary endpoint. Whole-liver treatment was achieved with sequential treatment sessions in most patients, with selective embolization of the left and right liver lobes within 6 wk. Toxicity was documented prospectively and according to Common Terminology Criteria for Adverse Events 4.0 criteria based on laboratory parameters; magnetic-resonance tomography; and clinical examinations 3 d, 6 wk, and every 3 mo after selective internal radiotherapy (SIRT). Metric variables were evaluated using the Student t test. Overall survival was assessed by Kaplan-Meier statistics.

RESULTS

Patients received an average of 1.6 whole-liver treatments performed in 3.0 unilobar radioembolizations (liver lobes sequentially). The mean total activity administered was 2.57 GBq. No radioembolization-induced liver disease was observed in any of the patients. Three patients showed reversible grade III to IV toxicities according to laboratory values, which returned to pretreatment levels after 6 wk. In 1 patient, a treatment-related duodenal ulcer occurred. Median overall survival was 18 mo after first radioembolization.

CONCLUSION

In advanced liver tumors, repeated whole-liver treatments with (90)Y radioembolization can be performed with an acceptable toxicity profile.

The role of SPECT/CT in radioembolization of liver tumours

Radioembolization (RE) with (90)Y microspheres is a promising catheter-based therapeutic option for patients with unresectable primary and metastatic liver tumours. Its rationale arises from the dual blood supply of liver tissue through the hepatic artery and the portal vein. Metastatic hepatic tumours measuring >3 mm derive 80 - 100 % of their blood supply from the arterial rather than the portal hepatic circulation. Typically, an angiographic evaluation combined with (99m)Tc-macroaggregated albumin ((99m)Tc-MAA) scan precedes therapy to map the tumour feeding vessels as well as to avoid the inadvertent deposition of microspheres in organs other than the liver. Prior to administration of (99m)Tc-MAA, prophylactic coil embolization of the gastroduodenal artery is recommended to avoid extrahepatic deposition of the microspheres. SPECT/CT allows direct correlation of anatomic and functional information in patients with unresectable liver disease. SPECT/CT is recommended to assess intrahepatic distribution as well as extrahepatic gastrointestinal uptake in these patients. Pretherapeutic SPECT/CT is an important component of treatment planning including catheter positioning and dose finding. A post-therapy bremsstrahlung (BS) scan should follow RE to verify the distribution of the administered tracer. BS SPECT/CT imaging enables better localization and definition of intrahepatic and possible extrahepatic sphere distribution and to a certain degree allows posttreatment dosimetry. In this paper we address the usefulness and significance of SPECT/CT in therapy planning and therapy monitoring of RE.

Pilot study of angiogenic response to yttrium-90 radioembolization with resin microspheres

PURPOSE

To investigate the impact of radioembolization with yttrium-90 resin microspheres on the regulation of angiogenesis through observation of serial changes in a spectrum of angiogenic markers and other cytokines after therapy.

MATERIALS AND METHODS

This prospective pilot study enrolled 22 patients with liver-dominant disease deriving from biopsy-proven hepatocellular carcinoma (HCC) (n = 7) or metastatic colorectal carcinoma (mCRC) (n = 15). Circulating angiogenic markers were measured from serum samples drawn at baseline and at time points after therapy ranging from 6 hours to 120 days. Using multiplex enzyme-linked immunosorbent assay, several classic angiogenesis factors (vascular endothelial growth factor [VEGF], angiopoietin-2 [Ang-2], basic fibroblast growth factor [bFGF], platelet-derived growth factor subunit BB [PDGF-BB], thrombospondin-1 [Tsp-1]) and nonclassic factors (follistatin, leptin, interleukin [IL]-8) were evaluated.

RESULTS

Increases in cytokine levels ≥ 50% over baseline were observed in more than half of all patients studied for many cytokines, including classic angiogenic factors such as VEGF, Ang-2, and Tsp-1 as well as nonclassic factors IL-8 and follistatin (range, 36%-82% for all cytokines). Baseline cytokine levels in patients with overall survival (OS) < 6 months differed significantly from patients with longer survival for Ang-2 (P = .033) and IL-8 (P = .041). Patients with OS ≤ 6 months exhibited transient increases in VEGF and PDGF-BB after therapy compared with patients with OS > 6 months.

CONCLUSIONS

Radioembolization is associated with early transient increases in many angiogenic cytokines. In this small sample size, some of these changes were associated with worse OS. This research has important implications for future studies of radioembolization with antiangiogenic therapy performed during and after the procedure.

Superiority of proximal embolization of the gastroduodenal artery with the Amplatzer vascular plug 4 before yttrium-90 radioembolization: a retrospective comparison with coils in 134 patients

PURPOSE

To evaluate the effectiveness of proximal embolization of the gastroduodenal artery (GDA) using the Amplatzer Vascular Plug 4 (AVP 4) compared with pushable coils to avoid hepaticoenteric collaterals of the GDA stump, which may serve as pathways for nontarget embolization.

MATERIALS AND METHODS

One hundred thirty-four patients scheduled for 90-yttrium radioembolization (Y-90 RE) using either plugs (n = 67) or standard coils (n = 67) for GDA occlusion were retrospectively analyzed. Parameters recorded were length of the perfused GDA stump, distance device to the GDA origin, perfused proximal side branches after embolization, and durability of vessel occlusion at Y-90 RE.

RESULTS

Length of the residually perfused GDA stump was 3.89 ± 2.86 mm for the AVP 4, which was significantly shorter compared with 5.78 ± 3.85 mm for coils (p = 0.005). Distance of the plug to the GDA origin was 1.41 ± 2.60 mm, which was also significantly shorter than 4.73 ± 3.44 mm for coils (p < 0.001). This resulted in significantly fewer patients with residually perfused side branches in the AVP 4 group (n = 2; 3.0%) compared with the coil group (n = 18; 26.9%; p < 0.001). At Y-90 RE, no GDA reperfusion was found after plug embolization compared with 2 cases after coil embolization (3.0%; p = 0.156). Only one patient had a radiation-induced duodenal ulcer after coil embolization, whereas no Y-90-related toxicity was identified after plug embolization.

CONCLUSION

Use of the AVP 4 for embolization of the GDA allowed an optimal proximal and more effective target vessel occlusion compared with coil embolization, which can avoid complications caused by extrahepatic gastrointestinal deposition of Y-90 microspheres by way of residually perfused proximal side branches.

Experimental microsphere targeting in a representative hepatic artery system

Recent work employing the computational fluid-particle modeling of the hepatic arteries has identified a correlation between particle release position and downstream branch distribution for direct tumor-targeting in radioembolization procedures. An experimental model has been constructed to evaluate the underlying simulation theory and determine its feasibility for future clinical use. A scaled model of a generalized hepatic system with a single inlet and five outlet branches was fabricated to replicate the fluid dynamics in the hepatic arteries of diseased livers. Assuming steady flow, neutrally buoyant microspheres were released from controlled locations within the inlet of the model and the resulting output distributions were recorded. Fluid and particle transport simulations were conducted with identical parameters. The resulting experimentally and simulation-derived microsphere distributions were compared. The experimental microsphere distribution exhibited a clear dependence on injection location that correlated very strongly with the computationally predicted results. Individual branch targeting was possible for each of the five outputs. The experimental results validate the simulation methodology for achieving targeted microsphere distributions in a known geometry under constant flow conditions.

Practical vascular anatomy in the preparation of radioembolization

As the incidence of primary and metastatic liver cancer continues to increase, the use of minimally invasive techniques as a treatment option is becoming more common. Radioembolization, a form of intra-arterial brachytherapy, is a technique where particles of glass or resin, impregnated with the isotope 90yttrium (90Y), are infused through a catheter directly into the hepatic arteries. This modality is based on the fact that hepatic malignancies receive their blood supply from the hepatic artery, whereas normal hepatocytes are perfused mostly from the portal circulation, which allows delivery of high doses to the tumor vasculature with relative sparing of normal liver tissue. This has been shown to be effective for both primary and metastatic tumors. A variety of complications may be related to hepatic intra-arterial treatments, especially to the gastroduodenal region. These complications are known to come from inadvertent extrahepatic infusion of 90Y particles, through arteries originating from the hepatic arterial branches such as the falciform artery, cystic artery, arteries from the pancreaticoduodenal arcade, gastroduodenal artery, or right gastric artery. Surgeons and interventional radiologists rely on accurate imaging and assessment of the hepatic arterial supply. It is important to know the common anatomic variations and technical considerations before radioembolization. We recommend an aggressive occlusion of all the above-mentioned arteries; further, clinicians should watch out for any other aberrant branches, and if in doubt, they ought to be coiled.

Value of diffusion weighted MR imaging as an early surrogate parameter for evaluation of tumor response to high-dose-rate brachytherapy of colorectal liver metastases

Background

To assess the value of diffusion weighted imaging (DWI) as an early surrogate parameter for treatment response of colorectal liver metastases to image-guided single-fraction ¹⁹²Ir-high-dose-rate brachytherapy (HDR-BT).

Methods

Thirty patients with a total of 43 metastases underwent CT- or MRI-guided HDR-BT. In 13 of these patients a total of 15 additional lesions were identified, which were not treated at the initial session and served for comparison. Magnetic resonance imaging (MRI) including breathhold echoplanar DWI sequences was performed prior to therapy (baseline MRI), 2 days after HDR-BT (early MRI) as well as after 3 months (follow-up MRI). Tumor volume (TV) and intratumoral apparent diffusion coefficient (ADC) were measured independently by two radiologists. Statistical analysis was performed using univariate comparison, ANOVA and paired t test as well as Pearson's correlation.

Results

At early MRI no changes of TV and ADC were found for non-treated colorectal liver metastases. In contrast, mean TV of liver lesions treated with HDR-BT increased by 8.8% (p = 0.054) while mean tumor ADC decreased significantly by 11.4% (p < 0.001). At follow-up MRI mean TV of non-treated metastases increased by 50.8% (p = 0.027) without significant change of mean ADC values. In contrast, mean TV of treated lesions decreased by 47.0% (p = 0.026) while the mean ADC increased inversely by 28.6% compared to baseline values (p < 0.001; Pearson's correlation coefficient of r = -0.257; p < 0.001).

Conclusions

DWI is a promising imaging biomarker for early prediction of tumor response in patients with colorectal liver metastases treated with HDR-BT, yet the optimal interval between therapy and early follow-up needs to be elucidated.

Radioembolization for hepatocellular carcinoma using TheraSphere®

BACKGROUND/AIM

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. Radioembolization with yttrium-90 (Y90) microspheres is a new concept in radiation therapy for HCC. This review focuses on the indications, efficacy, side effects, and future direction of Y90 therapy, using TheraSphere® , in HCC patients.

RESULTS

Comprehensive literature reviews have described the clinical and scientific evidence of Y90 therapy. The Radioembolization Brachytherapy Oncology Consortium has concluded that there is sufficient evidence to support the safe and effective use of this locoregional therapy in HCC patients, including those with portal vein thrombosis.

CONCLUSIONS

There are currently no randomized clinical trials done on TheraSphere® and none of the studies so far have shown a survival benefit. Thus, although it represents a very promising therapy with excellent initial results, it cannot be fully recommended yet, till well-designed, large, randomized clinical studies are conducted showing survival benefits.

Colorectal liver metastases

BACKGROUND

Despite major advances in therapies for liver metastases, colorectal cancer remains one of the commonest causes of cancer-related deaths in the UK.

SOURCES OF DATA

The international literature on the management of colorectal liver metastases (CLM) was reviewed.

AREAS OF AGREEMENT

Due to a combination of highly active systemic agents and low perioperative mortality achieved by high-volume centres, a growing number of patients are being offered liver resection with curative intent. Patients with bilobar and/or extrahepatic disease who would previously have received palliative treatment only, are undergoing major surgery with good results. This review focuses on preoperative evaluation, surgical planning and the role of adjuvant therapies in the management of patients with CLM.

AREAS OF CONTROVERSY

Can ablative therapies match the outcomes of surgical resection? How can even more patients be rendered resectable?

GROWING POINTS

The use of other therapies, such as radiofrequency ablation and selective internal radiation therapy.

AREAS TIMELY FOR DEVELOPING RESEARCH

New chemotherapy regimens for neo-adjuvant therapy and the development of new modalities of liver tumour ablation.

Survival outcomes of a salvage patient population after radioembolization of hepatic metastases with yttrium-90 microspheres

PURPOSE

To determine in a retrospective study the potential benefit on survival outcomes of radioembolization using yttrium-90 ((90)Y) resin microspheres in a cohort of patients presenting with chemotherapy-refractory liver metastases, primarily from colorectal cancer (CRC).

MATERIALS AND METHODS

Over 3 years, 249 patients were referred to the authors' center to determine suitability for radioembolization as treatment for hepatic metastases. All patients were defined as salvage, having failed first-line and second-line chemotherapies. These patients were divided into group 1 (CRC) and group 2 (all other cancers, eg, breast, neuroendocrine) and assessed for overall survival (OS) as a whole and according to group.

RESULTS

Using (90)Y resin microspheres, 208 patients were treated, undergoing 223 radioembolization treatments. The median OS was 8.3 months for the whole cohort, 7.9 months for group 1, and 8.7 months for group 2. At the 3-month follow-up, there was an overall adverse event rate of 9%. At the end of the data collection period, 62 patients were still alive.

CONCLUSIONS

Radioembolization shows promise as an effective and safe treatment for patients with chemotherapy-refractory hepatic metastases providing an extension to survival in the salvage setting.

A retrospective analysis of selective internal radiation therapy (SIRT) with yttrium-90 microspheres in patients with unresectable hepatic malignancies

AIM

To evaluate the efficacy and safety of selective internal radiation therapy (SIRT).

MATERIALS AND METHODS

A retrospective analysis was undertaken of all patients who underwent SIRT at a single institution. Diagnostic and therapeutic angiograms, computed tomography (CT) images, positron-emission tomography (PET) images, and planar isotope images were analysed. The response to SIRT was analysed using radiological data and tumour markers. Overall survival, complications, and side effects of SIRT were also analysed.

RESULTS

The initial 12 patients were included on an intention-to-treat basis, between 21/09/2005 and 07/05/2008. All patients had advanced disease and multiple prior courses of chemotherapy. One patient did not receive yttrium-90 due to complex vascular anatomy; the remaining 11 patients underwent 13 SIRT treatment episodes following work-up angiography. A response was seen using PET in 80% of patients. Using CT, the response of the tumour to therapy in the treated hepatic segments demonstrated a 20% partial response, stable disease in 50%, and progressive disease in 30%. Estimated median survival was 229 days, with 64% of patients still alive at the time of writing. No major complications were observed, although 82% of patients experienced side-effects following SIRT, mainly nausea, vomiting, and abdominal pain.

CONCLUSIONS

There have been no complications in the 12 SIRT patients. Tumour response was seen in four out of five patients who underwent PET. Objective CT response rates were mixed and are perhaps partially explained by advanced disease and limitations of using measurements to assess response. This complex and potentially hazardous service has been successfully and safely established.

Yttrium-90 radioembolization in the management of liver malignancies

Primary and secondary liver tumors are common. Locoregional therapies are establishing a role in the management of liver tumors due to the limited roles of surgical and systemic therapies. Our review presents some general concepts associated with yttrium-90 radioembolization and its specific utilization in various primary and secondary liver malignancies.

State of the art: radiolabeled microspheres treatment for liver malignancies

IMPORTANCE OF THE FIELD

Metastatic tumours of the liver are responsible for significant morbidity and mortality, and only a small percentage is resectable with curative intent. Hepatic artery radioembolization (RE) with yttrium-90 ((90)Y)-loaded microspheres is an alternative treatment for patients with unresectable primary or secondary liver tumours, especially in cases of metastatic colorectal cancer (mCRC) and hepatocellular carcinoma (HCC).

AREAS COVERED IN THIS REVIEW

Data from recent relevant clinical trials with (90)Y-RE are discussed, focusing on response rate assessments and treatment outcome.

WHAT THE READER WILL GAIN

Current data show that (90)Y-RE combined with radiosensitizing chemotherapy is a safe and efficient modality that extends the time to progression in liver mCRC and unresectable HCC, although no survival benefits have been demonstrated. The treatment response after (90)Y-RE seems to be better assessed using metabolic response assessments with serial fluorodeoxyglucose positron emission tomography (FDG-PET) in cases of FDG-avid tumours than with morphological criteria measured on computed tomography or magnetic resonance imaging (RECIST or WHO trials). Predictive models using multimodality imaging approaches (PET-SPECT-CT image fusion algorithms) have been proposed to better select patients for (90)Y-RE. The optimal routine role of radioembolization remains to be defined; the complexity and wide availability of available therapeutic alternatives confuses the role of a locoregional treatment in a generalized disease.

TAKE HOME MESSAGE

(90)Y-RE is a safe and efficient treatment modality in salvage therapy of colorectal cancer metastatic to the liver and in unresectable HCC. However, it has still to find its place as a first- or second-line treatment of mCRC in combination with or as an alternative to available biological agents. The role of (90)Y-RE in other solid tumour types metastatic to the liver is much more uncertain and investigations in clinical situations in which disease is strictly limited to the liver are required. Pretherapeutic work-up, initially developed to explore hepatic vasculature and to assess lung shunting, might be able to predict treatment outcome, allowing a better patient selection.

Pathology of non-Helicobacter pylori gastritis: extending the histopathologic horizons

The development of modern endoscopic techniques, easier and greater access to healthcare, and interest in Helicobacter pylori infection and its implications have all led to a significant increase in upper endoscopies. In turn, gastroenterologists and pathologists have been recognizing an ever-increasing number of patterns of mucosal injury. Consequently, there is now an interest in a wider aspect of non-neoplastic gastric pathology, namely, non-HP (H. pylori) gastritis. In this review, we present major clinico-pathological entities, based on either the salient morphological features or the underlying etiologies.

Selective internal radiation therapy for liver metastases from colorectal cancer

BACKGROUND

Liver metastases are often the dominant site of metastatic disease in colorectal cancer. Selective internal radiation therapy (SIRT) involves embolising radiolabeled spheres (SIR-Spheres) into the arterial supply of the liver with the aim of improving the control of liver metastases.

OBJECTIVES

To assess the effectiveness and toxicity of SIRT in the treatment of metastatic colorectal cancer liver metastasis when given alone or with systemic or regional hepatic artery chemotherapy.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane library 2008 issue 2, MEDLINE (1966 to October 2008), EMBASE (1980 to October 2008), and Pubmed (October 2008). The proceedings of ASCO (1985 to 2008) and ASCO GI (2004 to 2008) were also searched. The manufacturers of SIR-Spheres were contacted and asked whether they were aware of any other unpublished studies.

SELECTION CRITERIA

Randomised controlled trials comparing SIRT and chemotherapy (systemic and/or regional) with chemotherapy alone, or comparing SIRT alone with best supportive care in patients with metastatic colorectal cancer.

DATA COLLECTION AND ANALYSIS

Two authors (AT/TP) extracted data and assessed the trial quality. The study authors were contacted and individual patient data was obtained. Results were analysed separately for patients with and without extra-hepatic disease.

MAIN RESULTS

A single study of 21 patients compared SIRT and systemic chemotherapy (fluorouracil and leucovorin) with chemotherapy alone. There was a significant improvement in progression free survival and median survival associated with SIRT, both for the total studied population and for those disease limited to the liver. There was an increase in toxicity with the use of SIRT. A second study of 63 eligible patients compared SIRT and regional chemotherapy (floxuridine) with regional chemotherapy alone. There was no significant difference in progression free survival and median survival seen with SIRT, in either the total patient group or in the 22 patients with disease limited to the liver. There was no significant increase in toxicity with the addition of SIRT to regional chemotherapy. There were no randomised studies comparing SIRT with best supportive care in patients with refractory disease, and no randomised studies assessing the effect of SIRT in patients with resectable liver metastases.

AUTHORS' CONCLUSIONS

There is a need for well designed, adequately powered phase III trials assessing the effect of SIRT when used with modern combination chemotherapy regimens. Further studies are also needed for patients with refractory disease with a particular focus on the impact on quality of life.