Randomised trial of SIR-Spheres plus chemotherapy vs. chemotherapy alone for treating patients with liver metastases from primary large bowel cancer

New frontiers in radioembolization

Radioembolization is a locoregional transarterial therapy that combines radionuclide and micron-sized beads to deliver radiation internally to the target tumors based on the arterial blood flow. While initially developed as a palliative treatment option, radioembolization is now used for curative intent treatment, neoadjuvant therapy, and method to downstage or bridge for liver transplant. Radioembolization has become increasingly utilized and is an important therapeutic option for the management of hepatocellular carcinoma and liver metastasis. This article provides an overview of the techniques, challenges, and novel developments in radioembolization, including new dosimetry techniques, radionuclides, and new target tumors.

Selective Internal Radiotherapy in Liver Tumors: Early Promise Yet to be Fulfilled

Selective intra-arterial radiotherapy (SIRT) is a technique which has evolved over the past 30 years. In present this is primarily used to treat primary and secondary tumors in the liver. The technique normally depends on the delivery of a therapeutic radiopharmaceutical or radiolabeled particulate via a radiologically placed intra-arterial catheter in the hepatic artery. This is because most of these tumors have a single arterial blood supply but normal hepatocytes are supplied by both the hepatic artery and portal vein. Initially, this was done with I-131 labelled poppy seed oil but this technique was only used in a few centers. The technique became more popular when Y-90 particulates become widely available. Early results were promising but in phase 3 randomized controlled trials resulted in disappointing results compared to systemic chemotherapy. More recent work however, have shown that increasing the radiation dose to the tumor to at least 60Gy and combining with more effective systemic therapies are starting to produce better clinical results. There have also been advances in the angiographic methods used to make this into a day-case technique and the use of new radionuclides such as Ho-166 and Re-188 provides a wider range of possible SIRT techniques.

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.

Current status of yttrium-90 microspheres radioembolization in primary and metastatic liver cancer

Liver malignancy, including primary liver cancer and metastatic liver cancer, has become one of the most common causes of cancer-related death worldwide due to the high malignant degree and limited systematic treatment strategy. Radioembolization with yttrium-90 (90Y)-loaded microspheres is a relatively novel technology that has made significant progress in the local treatment of liver malignancy. The different steps in the extensive work-up of radioembolization for patients with an indication for treatment with 90Y microspheres, from patient selection to follow up, both technically and clinically, are discussed in this paper. It describes the application and development of 90Y microspheres in the treatment of liver cancer.

Clinical perspectives on dosimetry in molecular radiotherapy

Molecular radiotherapy is the use of systemically administered unsealed radioactive sources to treat cancer. Theragnostics is the term used to describe paired radiopharmaceuticals localising to a specific target, one optimised for imaging, the other for therapy. For many decades, molecular radiotherapy has developed empirically. Standard administered activity schedules have been used without the prior estimation of the resulting tumour radiation absorbed dose by theragnostic imaging, or its subsequent measurement by serial scanning. This pragmatic approach has benefited many patients, however others who should have benefited have failed to do so as the radiation absorbed dose in the tumour was suboptimal. The accurate prediction and measurement of tumour and organ at risk radiation absorbed doses allows treatment to be personalised, and offers the prospect of improved clinical outcomes. To deliver this for all molecular radiotherapy patients would require not only a significant financial investment in equipment and skilled personnel, but also a change in attitude of those who believe that simple - or simplistic - schedules are easier to deliver, and that accurate dosimetry is too much trouble. Further clinical studies are required to demonstrate beyond doubt that the advantages of individualised treatment planning outweigh the inconvenience, and that the expense is justified by enhanced results.

Updated Management of Colorectal Cancer Liver Metastases: Scientific Advances Driving Modern Therapeutic Innovations

Colorectal cancer is the second leading cause of cancer-related deaths in the United States and accounts for an estimated 1 million deaths annually worldwide. The liver is the most common site of metastatic spread from colorectal cancer, significantly driving both morbidity and mortality. Although remarkable advances have been made in recent years in the management for patients with colorectal cancer liver metastases, significant challenges remain in early detection, prevention of progression and recurrence, and in the development of more effective therapeutics. In 2017, our group held a multidisciplinary state-of-the-science symposium to discuss the rapidly evolving clinical and scientific advances in the field of colorectal liver metastases, including novel early detection and prognostic liquid biomarkers, identification of high-risk cohorts, advances in tumor-immune therapy, and different regional and systemic therapeutic strategies. Since that time, there have been scientific discoveries translating into therapeutic innovations addressing the current management challenges. These innovations are currently reshaping the treatment paradigms and spurring further scientific discovery. Herein, we present an updated discussion of both the scientific and clinical advances and future directions in the management of colorectal liver metastases, including adoptive T-cell therapies, novel blood-based biomarkers, and the role of the tumor microbiome. In addition, we provide a comprehensive overview detailing the role of modern multidisciplinary clinical approaches used in the management of patients with colorectal liver metastases, including considerations toward specific molecular tumor profiles identified on next generation sequencing, as well as quality of life implications for these innovative treatments.

Economic evaluations of radioembolization with yttrium-90 microspheres in liver metastases of colorectal cancer: a systematic review

BACKGROUND

Transarterial radioembolization with yttrium-90 (Y-90 TARE) microspheres therapy has demonstrated positive clinical benefits for the treatment of liver metastases from colorectal cancer (lmCRC). This study aims to conduct a systematic review of the available economic evaluations of Y-90 TARE for lmCRC.

METHODS

English and Spanish publications were identified from PubMed, Embase, Cochrane, MEDES health technology assessment agencies, and scientific congress databases published up to May 2021. The inclusion criteria considered only economic evaluations; thus, other types of studies were excluded. Purchasing-power-parity exchange rates for the year 2020 ($US PPP) were applied for cost harmonisation.

RESULTS

From 423 records screened, seven economic evaluations (2 cost-analyses [CA] and 5 cost-utility-analyses [CUA]) were included (6 European and 1 USA). All included studies (n = 7) were evaluated from a payer and the social perspective (n = 1). Included studies evaluated patients with unresectable liver-predominant metastases of CRC, refractory to chemotherapy (n = 6), or chemotherapy-naïve (n = 1). Y-90 TARE was compared to best supportive care (BSC) (n = 4), an association of folinic acid, fluorouracil and oxaliplatin (FOLFOX) (n = 1), and hepatic artery infusion (HAI) (n = 2). Y-90 TARE increased life-years gained (LYG) versus BSC (1.12 and 1.35 LYG) and versus HAI (0.37 LYG). Y-90 TARE increased the quality-adjusted-life-year (QALY) versus BSC (0.81 and 0.83 QALY) and versus HAI (0.35 QALY). When considering a lifetime horizon, Y-90 TARE reported incremental cost compared to BSC (range 19,225 to 25,320 $US PPP) and versus HAI (14,307 $US PPP). Y-90 TARE reported incremental cost-utility ratios (ICURs) between 23,875 $US PPP/QALY to 31,185 $US PPP/QALY. The probability of Y-90 TARE being cost-effective at £ 30,000/QALY threshold was between 56% and 57%.

CONCLUSIONS

Our review highlights that Y-90 TARE could be a cost-effective therapy either as a monotherapy or when combined with systemic therapy for treating ImCRC. However, despite the current clinical evidence on Y-90 TARE in the treatment of ImCRC, the global economic evaluation reported for Y-90 TARE in ImCRC is limited (n = 7), therefore, we recommend future economic evaluations on Y-90 TARE versus alternative options in treating ImCRC from the societal perspective.

Intra-Arterial Delivery of Radiopharmaceuticals in Oncology: Current Trends and the Future of Alpha-Particle Therapeutics

A paradigm shift is underway in cancer diagnosis and therapy using radioactivity-based agents called radiopharmaceuticals. In the new strategy, diagnostic imaging measures the tumor uptake of radioactive agent “X” in a patient’s specific cancer, and if uptake metrics are realized, the patient can be selected for therapy with radioactive agent “Y”. The X and Y represent different radioisotopes that are optimized for each application. X–Y pairs are known as radiotheranostics, with the currently approved route of therapy being intravenous administration. The field is now evaluating the potential of intra-arterial dosing of radiotheranostics. In this manner, a higher initial concentration can be achieved at the cancer site, which could potentially enhance tumor-to-background targeting and lead to improved imaging and therapy. Numerous clinical trials are underway to evaluate these new therapeutic approaches that can be performed via interventional radiology. Of further interest is changing the therapeutic radioisotope that provides radiation therapy by β- emission to radioisotopes that also decay by α-particle emissions. Alpha (α)-particle emissions provide high energy transfer to the tumors and have distinct advantages. This review discusses the current landscape of intra-arterially delivered radiopharmaceuticals and the future of α-particle therapy with short-lived radioisotopes.

A Primer on Radiopharmaceutical Therapy

The goal of this article is to serve as a primer for the United States-based radiation oncologist who may be interested in learning more about radiopharmaceutical therapy (RPT). Specifically, we define RPT, review the data behind its current and anticipated indications, and discuss important regulatory considerations for incorporating it into clinical practice. RPT represents an opportunity for radiation oncologists to leverage 2 key areas of expertise, namely therapeutic radiation therapy and oncology, and apply them in a distinct context in collaboration with nuclear medicine and medical oncology colleagues. Although not every radiation oncologist will incorporate RPT into their day-to-day practice, it is important to understand the role for this modality and how it can be appropriately used in select patients.

Temporary Reversal of Hepatoenteric Collaterals during 90Y Radioembolization Planning and Administration

PURPOSE

This paper aims to evaluate the safety and efficacy of the temporary redirection of blood flow of hepatoenteric collaterals using a balloon catheter in the common hepatic artery (CHA) to prevent the nontarget deposition of ⁹⁰Y microspheres.

MATERIALS AND METHODS

In this retrospective single-center study of patients who received ⁹⁰Y radioembolization (RE) from September 2010 to September 2015, diagnostic (67 patients) or treatment (72 patients) angiograms with the attempted use of a balloon catheter in the CHA to temporarily direct blood flow away from the hepatoenteric arteries were analyzed. SPECT/CT nuclear scintigraphy was performed after both diagnosis and treatment.

RESULTS

Overall, only 12 hepatoenteric arteries in 11 patients required embolization due to persistent hepatoenteric flow despite the use of the balloon occlusion technique in a total of 86 patients. Physicians performed the ⁹⁰Y RE using balloon occlusion with glass (n = 22) or resin (n = 50) microspheres. Over 80% administration of the prescribed ⁹⁰Y dose was accomplished in 34 (67%) resin and 20 (95%) glass microsphere patients. Post-treatment ⁹⁰Y RE scintigraphy confirmed the absence of extrahepatic activity in all patients. One grade 2 gastrointestinal ulcer was present after 90 days of follow-up.

CONCLUSION

Temporary CHA occlusion with a balloon catheter is a reliable and reproducible alternative to the conventional coil embolization of hepatoenteric arteries during diagnostic Tc-99m macroaggregated albumin and therapeutic ⁹⁰Y RE delivery.

Prognostic Factors for Effectiveness Outcomes After Transarterial Radioembolization in Metastatic Colorectal Cancer: Results From the Multicentre Observational Study CIRT

BACKGROUND

Transarterial radioembolisation (TARE) with Yttrium-90 resin microspheres is a treatment option for patients with metastatic colorectal cancer in the liver (mCRC). A better understanding of the prognostic factors and treatment application can improve survival outcomes.

METHODS

We analysed the safety and effectiveness of 237 mCRC patients included in the prospective observational study CIRSE Registry for SIR-Spheres Therapy (CIRT) for independent prognostic factors for overall survival (OS), progression-free survival (PFS) and hepatic progression-free survival (hPFS) using the Cox proportional-hazard model.

RESULTS

The median OS was 9.8 months, median PFS was 3.4 months and median hPFS was 4.2 months. Independent prognostic factors for an improved overall survival were the absence of extra-hepatic disease (P= .0391), prior locoregional procedures (P= .0037), an Aspartate transaminase to Platelet Ratio Index (APRI) value of ≤0.40 (P< .0001) and International Normalized Ratio (INR) ≤1 (P= .0078). Partition model dosimetry resulted in improved OS outcomes compared to the body surface area model (P = .0120). Independent predictors for PFS were APRI >0.40 (P = .0416) and prior ablation (P = .0323), and for hPFS these were 2 to 5 tumor nodules (P = .0148), Albumin-bilirubin (ALBI) grade 3 (P = .0075) and APRI >0.40 (P = .0207). During the study, 95 of 237 (40.1%) patients experienced 197 adverse events, with 28 of 237 (11.8%) patients having a grade 3 or higher adverse events.

CONCLUSION

Including easy-to-acquire laboratory markers INR, APRI, ALBI and using partition model dosimetry can identify mCRC patients that may benefit from TARE.

The American Brachytherapy Society consensus statement for permanent implant brachytherapy using Yttrium-90 microsphere radioembolization for liver tumors

PURPOSE

To develop a multidisciplinary consensus for high quality multidisciplinary implementation of brachytherapy using Yttrium-90 (90Y) microspheres transarterial radioembolization (90Y TARE) for primary and metastatic cancers in the liver.

METHODS AND MATERIALS

Members of the American Brachytherapy Society (ABS) and colleagues with multidisciplinary expertise in liver tumor therapy formulated guidelines for 90Y TARE for unresectable primary liver malignancies and unresectable metastatic cancer to the liver. The consensus is provided on the most recent literature and clinical experience.

RESULTS

The ABS strongly recommends the use of 90Y microsphere brachytherapy for the definitive/palliative treatment of unresectable liver cancer when recommended by the multidisciplinary team. A quality management program must be implemented at the start of 90Y TARE program development and follow-up data should be tracked for efficacy and toxicity. Patient-specific dosimetry optimized for treatment intent is recommended when conducting 90Y TARE. Implementation in patients on systemic therapy should account for factors that may enhance treatment related toxicity without delaying treatment inappropriately. Further management and salvage therapy options including retreatment with 90Y TARE should be carefully considered.

CONCLUSIONS

ABS consensus for implementing a safe 90Y TARE program for liver cancer in the multidisciplinary setting is presented. It builds on previous guidelines to include recommendations for appropriate implementation based on current literature and practices in experienced centers. Practitioners and cooperative groups are encouraged to use this document as a guide to formulate their clinical practices and to adopt the most recent dose reporting policies that are critical for a unified outcome analysis of future effectiveness studies.

EANM procedure guideline for the treatment of liver cancer and liver metastases with intra-arterial radioactive compounds

Primary liver tumours (i.e. hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC)) are among the most frequent cancers worldwide. However, only 10-20% of patients are amenable to curative treatment, such as resection or transplant. Liver metastases are most frequently caused by colorectal cancer, which accounts for the second most cancer-related deaths in Europe. In both primary and secondary tumours, radioembolization has been shown to be a safe and effective treatment option. The vast potential of personalized dosimetry has also been shown, resulting in markedly increased response rates and overall survival. In a rapidly evolving therapeutic landscape, the role of radioembolization will be subject to changes. Therefore, the decision for radioembolization should be taken by a multidisciplinary tumour board in accordance with the current clinical guidelines. The purpose of this procedure guideline is to assist the nuclear medicine physician in treating and managing patients undergoing radioembolization treatment. PREAMBLE: The European Association of Nuclear Medicine (EANM) is a professional non-profit medical association that facilitates communication worldwide among individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. These guidelines are intended to assist practitioners in providing appropriate nuclear medicine care for patients. They are not inflexible rules or requirements of practice and are not intended, nor should they be used, to establish a legal standard of care. The ultimate judgment regarding the propriety of any specific procedure or course of action must be made by medical professionals taking into account the unique circumstances of each case. Thus, there is no implication that an approach differing from the guidelines, standing alone, is below the standard of care. To the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set out in the guidelines when, in the reasonable judgment of the practitioner, such course of action is indicated by the condition of the patient, limitations of available resources or advances in knowledge or technology subsequent to publication of the guidelines. The practice of medicine involves not only the science but also the art of dealing with the prevention, diagnosis, alleviation and treatment of disease. The variety and complexity of human conditions make it impossible to always reach the most appropriate diagnosis or to predict with certainty a particular response to treatment. Therefore, it should be recognised that adherence to these guidelines will not ensure an accurate diagnosis or a successful outcome. All that should be expected is that the practitioner will follow a reasonable course of action based on current knowledge, available resources and the needs of the patient to deliver effective and safe medical care. The sole purpose of these guidelines is to assist practitioners in achieving this objective.

Quantitative and qualitative evaluation of liver metastases with intraprocedural cone beam CT prior to transarterial radioembolization as a predictor of treatment response

Purpose

To investigate, by quantitative and qualitative enhancement measurements, the correlation between tumor enhancement on cone beam computed tomography (CBCT) images and treatment response at 6 months in patients undergoing transarterial radioembolization (TARE) for liver metastases.

Materials and Methods

36 patients (56% male; median age 62.5 years) with 104 metastases were retrospectively included. Quantitative and qualitative enhancement of liver metastases were evaluated on CBCT images before TARE. Quantitative analysis consisted of lesion enhancement measurements (ROI HU lesion - ROI HU relative to inferior vena cava). Qualitative analysis consisted of subjective enhancement pattern analysis (diffuse, sparse, rim-like or non-enhancing). Morphologic tumor response was evaluated according to RECIST 1.1 criteria on follow-up CT or MR imaging.

Results

At a mean follow up of 6.5 ± 3.7 months, progressive disease (PD) was found in 4 patients, partial response (PR) in 11 and stable disease (SD) in 21. Relative lesion enhancement was significantly different between these groups (-37.5±154.2 HU vs. 103.8±93.4 vs. 181±144 HU in PD vs. SD vs. PR group, respectively; p<0.01). ROC analysis of relative lesion enhancement to predict progressive disease showed an area under the curve of 0.86 (p<0.01). For qualitative lesion enhancement analysis, no difference between groups was found.

Conclusion

Quantitative enhancement measurements derived from intraprocedural contrast enhanced CBCT may identify responders to TARE in patients with liver metastases.

Biliary-Caval Fistula following Y90 Radioembolization

The safety of radioembolization with yttrium-90 ( ⁹⁰ Y) is well documented and major complications are rare. Previous studies have demonstrated that biliary complications following ⁹⁰ Y, including bile duct injury and hepatic abscess formation, occur at an increased rate in patients who have had prior biliary surgery and interventions. This article reviews a case of a patient who developed recurrent cholangitis and sepsis as well as a biliary-caval fistula following radioembolization. Additionally, we review current data regarding biliary complications following radioembolization in patients with prior biliary intervention.

Extrahepatic Applications of Yttrium-90 Radioembolization

While initially described and now accepted as treatment for primary and secondary malignancies in the liver, radioembolization therapy has expanded to include treatment for other disease pathologies and other organ systems. Advantages and limitations for these treatments exist and must be compared against more traditional treatments for these processes. This article provides an overview of the current applications for radioembolization outside of the liver, for both malignant and nonmalignant disease.

Radioembolization in the Setting of Systemic Therapies

90 Yttrium (Y90) radioembolization has been shown to improve outcomes for primary and metastatic liver cancers, but there is limited understanding of the optimal timing and safety of combining systemic therapies with Y90 treatment. Both therapeutic effects and toxicities could be synergistic depending on the timing and dosing of different coadministration paradigms. In particular, patients with liver-only or liver-dominant metastatic disease progression are often on systemic therapy when referred to interventional radiology for consideration of Y90 treatment. Interventional radiologists are frequently asked to offer insight into whether or not to hold systemic therapy, and for how long, prior to and following transarterial therapy. This study reviews the current evidence regarding the timing and safety of systemic therapy with Y90 treatment for hepatocellular carcinoma, metastatic colorectal carcinoma, intrahepatic cholangiocarcinoma, metastatic neuroendocrine tumors, and other hepatic metastases. A particular focus is placed on the timing, dosing, and toxicities of combined therapy.

Hepatic Arterial Buffer Response in Liver Radioembolization and Potential Use for Improved Cancer Therapy

Simple Summary

Radioembolization of hepatic tumors is performed by injecting ⁹⁰Y or ¹⁶⁶Ho loaded spheres into the hepatic artery. A twofold tumor to normal liver absorbed dose ratio is commonly obtained. In order to improve tumoral cell killing while preserving lobule function, co-injection of arterial vasoconstrictor has been proposed, but without success: the hepatic arterial buffer response quickly inhibits the arterioles vasoconstriction. The aim of the study is to investigate whether it is possible to take benefit from this buffer response, by co-infusing a mesenteric arterial vasodilator in order to dump the hepatic lobules arterial flow. Animal studies evidencing such mechanism are reviewed. Some potential mesenteric vasodilators are identified and their safety profile discussed. A four to sixfold improvement of the tumoral to normal tissue dose ratio is expected, pushing the therapy towards a real curative intention, especially in hepatocellular carcinoma (HCC), more frequent in obese subjects, and where ultra-selective spheres delivery is often not possible.

Abstract

Liver radioembolization is a treatment option for unresectable liver cancers, performed by infusion of ⁹⁰Y or ¹⁶⁶Ho loaded spheres in the hepatic artery. As tumoral cells are mainly perfused via the liver artery unlike hepatic lobules, a twofold tumor to normal liver dose ratio is commonly obtained. To improve tumoral cell killing while preserving lobules, co-infusion of arterial vasoconstrictor has been proposed but with limited success: the hepatic arterial buffer response (HABR) and hepatic vascular escape mechanism hamper the arterioles vasoconstriction. The proposed project aims to take benefit from the HABR by co-infusing a mesenteric arterial vasodilator: the portal flow enhancement inducing the vasoconstriction of the intra sinusoids arterioles barely impacts liver tumors that are mainly fed by novel and anarchic external arterioles. Animal studies were reviewed and dopexamine was identified as a promising safe candidate, reducing by four the hepatic lobules arterial flow. A clinical trial design is proposed. A four to sixfold improvement of the tumoral to normal tissue dose ratio is expected, pushing the therapy towards a real curative intention, especially in HCC where ultra-selective spheres delivery is often not possible.

Review of Intra-Arterial Therapies for Colorectal Cancer Liver Metastasis

Simple Summary

Colorectal cancer liver metastasis occurs in more than 50% of patients with colorectal cancer and is thought to be the most common cause of death from this cancer. The mainstay of treatment for inoperable liver metastasis has been combination systemic chemotherapy with or without the addition of biological targeted therapy with a goal for disease downstaging, for potential curative resection, or more frequently, for disease control. For patients with dominant liver metastatic disease or limited extrahepatic disease, liver-directed intra-arterial therapies including hepatic arterial chemotherapy infusion, chemoembolization and radioembolization are alternative treatment strategies that have shown promising results, most commonly in the salvage setting in patients with chemo-refractory disease. In recent years, their role in the first-line setting in conjunction with concurrent systemic chemotherapy has also been explored. This review aims to provide an update on the current evidence regarding liver-directed intra-arterial treatment strategies and to discuss potential trends for the future.

Abstract

The liver is frequently the most common site of metastasis in patients with colorectal cancer, occurring in more than 50% of patients. While surgical resection remains the only potential curative option, it is only eligible in 15–20% of patients at presentation. In the past two decades, major advances in modern chemotherapy and personalized biological agents have improved overall survival in patients with unresectable liver metastasis. For patients with dominant liver metastatic disease or limited extrahepatic disease, liver-directed intra-arterial therapies such as hepatic arterial chemotherapy infusion, chemoembolization and radioembolization are treatment strategies which are increasingly being considered to improve local tumor response and to reduce systemic side effects. Currently, these therapies are mostly used in the salvage setting in patients with chemo-refractory disease. However, their use in the first-line setting in conjunction with systemic chemotherapy as well as to a lesser degree, in a neoadjuvant setting, for downstaging to resection have also been investigated. Furthermore, some clinicians have considered these therapies as a temporizing tool for local disease control in patients undergoing a chemotherapy ‘holiday’ or acting as a bridge in patients between different lines of systemic treatment. This review aims to provide an update on the current evidence regarding liver-directed intra-arterial treatment strategies and to discuss potential trends for the future.

Two-stage hepatectomy with radioembolization for bilateral colorectal liver metastases: A case report

BACKGROUND

Two-stage hepatectomy (TSH) is a well-established surgical technique, used to treat bilateral colorectal liver metastases (CRLM) with a small future liver remnant (FLR). However, in classical TSH, drop-out is reported to be around 25%-40%, due to insufficient FLR increase or progression of disease. Trans-arterial radioembolization (TARE) has been described to control locally tumor growth of liver malignancies such as hepatocellular carcinoma, but it has been also reported to induce a certain degree of contralateral liver hypertrophy, even if at a lower rate compared to portal vein embolization or ligation.

CASE SUMMARY

Herein we report the case of a 75-year-old female patient, where TSH and TARE were combined to treat bilateral CRLM. According to computed tomography (CT)-scan, the patient had a hepatic lesion in segment VI-VII and two other confluent lesions in segment II-III. Therefore, one-stage posterior right sectionectomy plus left lateral sectionectomy (LLS) was planned. The liver volumetry estimated a FLR of 38% (segments I-IV-V-VIII). However, due to a more than initially planned, extended right resection, simultaneous LLS was not performed and the patient underwent selective TARE to segments II-III after the first surgery. The CT-scan performed after TARE showed a reduction of the treated lesion and a FLR increase of 55%. Carcinoembryonic antigen and CA 19.9 decreased significantly. Nearly three months later after the first surgery, LLS was performed and the patient was discharged without any postoperative complications.

CONCLUSION

According to this specific experience, TARE was used to induce liver hypertrophy and simultaneously control cancer progression in TSH settings for bilateral CRLM.

Transarterial Radioembolization of Hepatocellular Carcinoma, Liver-Dominant Hepatic Colorectal Cancer Metastases, and Cholangiocarcinoma Using Yttrium90 Microspheres: Eight-Year Single-Center Real-Life Experience

Liver tumors are common and may be unamenable to surgery or ablative treatments. Consequently, other treatments have been devised. To assess the safety and efficacy of transarterial radioembolization (TARE) with Yttrium-90 for hepatocellular carcinoma (HCC), liver-dominant hepatic colorectal cancer metastases (mCRC), and cholangiocarcinoma (CCA), performed according to current recommendations, we conducted a single-center retrospective study in 70 patients treated with TARE (HCC, n = 44; mCRC, n = 20; CCA, n = 6). Safety and toxicity were assessed using the National Cancer Institute Common Terminology Criteria. Treatment response was evaluated every 3 months on imaging studies using Response Evaluation Criteria in Solid Tumors (RECIST) or mRECIST criteria. Overall survival and progression-free survival were estimated using the Kaplan-Meier method. The median delivered dose was 1.6 GBq, with SIR-Spheres® or TheraSphere® microspheres. TARE-related grade 3 adverse events affected 17.1% of patients. Median follow-up was 32.1 months. Median progression-free survival was 5.6 months and median overall time from TARE to death was 16.1 months and was significantly shorter in men. Progression-free survival was significantly longer in women (HR, 0.49; 95%CI, 0.26-0.90; p = 0.031). Risk of death or progression increased with the number of systemic chemotherapy lines. TARE can be safe and effective in patients with intermediate- or advanced-stage HCC, CCA, or mCRC refractory or intolerant to appropriate treatments.

Three-dimensional regions-of-interest-based intra-operative four-dimensional soft tissue perfusion imaging using a standard x-ray system with no gantry rotation: A simulation study for a proof of concept

PURPOSE

Many interventional procedures aim at changing soft tissue perfusion or blood flow. One problem at present is that soft tissue perfusion and its changes cannot be assessed in an interventional suite because cone-beam computed tomography is too slow (it takes 4-10 s per volume scan). In order to address the problem, we propose a novel method called IPEN for Intra-operative four-dimensional soft tissue PErfusion using a standard x-ray system with No gantry rotation.

METHODS

IPEN uses two input datasets: (a) the contours and locations of three-dimensional regions-of-interest (ROIs) such as arteries and sub-sections of cancerous lesions, and (b) a series of x-ray projection data obtained from an intra-arterial contrast injection to contrast enhancement to wash-out. IPEN then estimates a time-enhancement curve (TEC) for each ROI directly from projections without reconstructing cross-sectional images by maximizing the agreement between synthesized and measured projections with a temporal roughness penalty. When path lengths through ROIs are known for each x-ray beam, the ROI-specific enhancement can be accurately estimated from projections. Computer simulations are performed to assess the performance of the IPEN algorithm. Intra-arterial contrast-enhanced liver scans over 25 s were simulated using XCAT phantom version 2.0 with heterogeneous tissue textures and cancerous lesions. The following four sub-studies were performed: (a) The accuracy of the estimated TECs with overlapped lesions was evaluated at various noise (dose) levels with either homogeneous or heterogeneous lesion enhancement patterns; (b) the accuracy of IPEN with inaccurate ROI contours was assessed; (c) we investigated how overlapping ROIs and noise in projections affected the accuracy of the IPEN algorithm; and (d) the accuracy of the perfusion indices was assessed.

RESULTS

The TECs estimated by IPEN were sufficiently accurate at a reference dose level with the root-mean-square deviation (RMSD) of 0.0027 ± 0.0001 cm^-1 or 13 ± 1 Hounsfield unit (mean ± standard deviation) for the homogeneous lesion enhancement and 0.0032 ± 0.0005 cm^-1 for the heterogeneous enhancement (N = 20 each). The accuracy was degraded with decreasing doses: The RMSD with homogeneous enhancement was 0.0220 ± 0.0003 cm^-1 for 20% of the reference dose level. Performing 3 × 3 pixel averaging on projection data improved the RMSDs to 0.0051 ± 0.0002 cm^-1 for 20% dose. When the ROI contours were inaccurate, smaller ROI contours resulted in positive biases in TECs, whereas larger ROI contours produced negative biases. The bias remained small, within ± 0.0070 cm^-1 , when the Sorenson-Dice coefficients (SDCs) were larger than 0.81. The RMSD of the TEC estimation was strongly associated with the condition of the problem, which can be empirically quantified using the condition number of a matrix A z that maps a vector of ROI enhancement values z to projection data and a weighted variance of projection data: a linear correlation coefficient (R) was 0.794 (P < 0.001). The perfusion index values computed from the estimated TECs agreed well with the true values (R ≥ 0.985, P < 0.0001).

CONCLUSION

The IPEN algorithm can estimate ROI-specific TECs with high accuracy especially when 3 × 3 pixel averaging is applied, even when lesion enhancement is heterogeneous, or ROI contours are inaccurate but the SDC is at least 0.81.

Taiwan Society of Colon and Rectal Surgeons (TSCRS) Consensus for Cytoreduction Selection in Metastatic Colorectal Cancer

BACKGROUND

Taiwan has witnessed a surge in the incidence of colorectal cancer (CRC), of which 40-60% metastasize. Continuous updating of cytoreductive strategies in metastatic CRC (mCRC) has contributed to median overall survival reaching 40 months. In this changing scenario, to standardize the approaches across Taiwan, a group of experts from the Taiwan Society of Colon and Rectal Surgeons (TSCRS) convened to establish evidence- and opinion-based recommendations for defining the criteria of "resectability" in mCRC.

METHODS

Over the course of one-on-one consultations, lasting 30-40 min each, with 30 medical specialists (19 colorectal surgeons, 4 general surgeons, and 7 medical oncologists) from 16 hospitals in Taiwan followed by a 2-h meeting with 8 physician experts (3 general surgeons, 4 colorectal surgeons, and 1 thoracic surgeon), 12 key questions on cytoreduction were addressed. This was further contextualized based on published literature.

RESULTS

The final consensus includes eight recommendations regarding the criteria for metastasis resection, role of local control treatment in liver potentially resectable patients, management of synchronous liver metastases, approach for peritoneal metastasis, place for resection in multiple-organ metastasis, and general criteria for resectability.

CONCLUSIONS

mCRC patients undergoing R0 resection have the greatest survival advantage following surgery. Our role as a multidisciplinary team (MDT) should be to treat potentially resectable mCRC patients as rapidly and safely as possible, and achieve R0 resection as far as possible and for as long as possible (continuum of care). This TSCRS consensus statement aims to help build clinical capacity within the MDTs, while making better use of existing healthcare resources.

Impact of Genomic Mutation and Timing of Y90 Radioembolization in Colorectal Liver Metastases

PURPOSE

To investigate timing of Yttrium-90 radioembolization (Y90) during treatment course, genomics, and other clinical factors as predictors of overall survival (OS) in colorectal liver metastasis (CRLM) that have progressed on at least one line of chemotherapy.

MATERIALS AND METHODS

This was a retrospective study from 2013 to 2018 of patients with CRLM and genomic analysis prior to Y90 at a multihospital tertiary referral center. OS from liver metastasis diagnosis and predictors of OS were analyzed using Kaplan-Meier estimation with log-rank and Cox regression analyses.

RESULTS

Overall, 58 patients with CRLM who progressed on at least one line of chemotherapy who had genomic analysis prior to Y90 were identified. Median OS after hepatic metastasis was 29.9 months. Of these, 16 (28%) patients received Y90 after failure of the first-line systemic chemotherapy. There was significantly prolonged OS in patients receiving Y90 immediately following failure of the first-line chemotherapy folinic acid, fluorouracil, oxaliplatin ((FOLFOX) ± bevacizumab) versus following multiple lines of chemotherapy (median OS of 46.3 vs. 26.6 months, P = 0.005). The presence of genetic mutation in tumor, MAPK pathway wild type, left-sided primary tumor, low MELD score, and non-diffuse unilobar disease were also found to be predictors prolonged survival on log-rank analysis (P's < 0.05). On multivariate analysis, receiving Y90 after failure of the first line of chemotherapy, low baseline MELD score, and baseline ECOG performance score of 0 were all found to be independent predictors of prolonged OS from the time of metastatic disease diagnosis (P's < 0.05).

CONCLUSION

In patients with CRLM, receiving Y90 after failing the first line of chemotherapy, lack of genetic mutation, low MELD score, and lower tumor burden appear to be independent predictors of prolonged OS.

LEVEL OF EVIDENCE

Level 4, case-control study.

Role of yttrium-90 selective internal radiation therapy in the treatment of liver-dominant metastatic colorectal cancer: an evidence-based expert consensus algorithm

Surgical resection of colorectal liver metastases is associated with greater survival compared with non-surgical treatment, and a meaningful possibility of cure. However, the majority of patients are not eligible for resection and may require other non-surgical interventions, such as liver-directed therapies, to be converted to surgical eligibility. Given the number of available therapies, a general framework is needed that outlines the specific roles of chemotherapy, surgery, and locoregional treatments [including selective internal radiation therapy (SIRT) with Y-90 microspheres]. Using a data-driven, modified Delphi process, an expert panel of surgical oncologists, transplant surgeons, and hepatopancreatobiliary (HPB) surgeons convened to create a comprehensive, evidence-based treatment algorithm that includes appropriate treatment options for patients stratified by their eligibility for surgical treatment. The group coined a novel, more inclusive phrase for targeted locoregional tumor treatment (a blanket term for resection, ablation, and other emerging locoregional treatments): local parenchymal tumor destruction therapy. The expert panel proposed new nomenclature for 3 distinct disease categories of liver-dominant metastatic colorectal cancer that is consistent with other tumor types: (I) surgically treatable (resectable); (II) surgically untreatable (borderline resectable); (III) advanced surgically untreatable (unresectable) disease. Patients may present at any point in the algorithm and move between categories depending on their response to therapy. The broad intent of therapy is to transition patients toward individualized treatments where possible, given the survival advantage that resection offers in the context of a comprehensive treatment plan. This article reviews what is known about the role of SIRT with Y-90 as neoadjuvant, definitive, or palliative therapy in these different clinical situations and provides insight into when treatment with SIRT with Y-90 may be appropriate and useful, organized into distinct treatment algorithm steps.

Incidence of Radioembolization-Induced Liver Disease and Liver Toxicity Following Repeat 90Y-Radioembolization: Outcomes at a Large Tertiary Care Center

PURPOSE

The complication profile following repeat Y-radioembolization (RE) is not well understood, and repeat RE is sometimes avoided because of concerns for RE-induced liver disease (REILD) and liver toxicity. The purpose of this study was to examine the incidence of REILD and liver toxicity following repeat Y-RE and to identify potential risk factors.

METHODS

A retrospective analysis of patients undergoing repeat RE to the same hepatic lobe between 2013 and 2018 was performed. Baseline factors were evaluated as predictors of liver toxicity, mortality, and REILD, which was defined as the presence symptomatic ascites or jaundice in the absence of biliary obstruction within 8 weeks following RE. Post-RE complications were graded according to the Common Terminology Criteria for Adverse Events version 5.

RESULTS

A total of 39 patients underwent repeat RE with 14 (35.9%) experiencing Common Terminology Criteria for Adverse Events toxicity of grade 2 or greater, 3 (10.3%) grade 3, and no grade 4 or greater. A Model for End Stage Liver Disease score of 8 or greater was associated with grade 2 toxicity or greater (26.7% vs 75%; P = 0.013). Only 3 patients (7.7%) experienced REILD due to symptomatic ascites without jaundice. Greater than 2 REs were associated with a greater rate of 6-month mortality (12% vs 58.3%, P = 0.003), 12-month mortality (28% vs 75%, P = 0.007), and REILD (0% vs 21.4%, P = 0.016). Age, sex, microsphere type, cirrhosis, Child-Pugh, and Eastern Cooperative Oncology Group status were not significantly associated with complications, REILD, or survival.

CONCLUSIONS

Repeat Y-RE appears to be well tolerated with a low rate of high-grade adverse events and REILD.

Quality of life in the FOXFIRE, SIRFLOX and FOXFIRE-global randomised trials of selective internal radiotherapy for metastatic colorectal cancer

Selective internal radiotherapy (SIRT) is a liver-directed treatment involving the injection of yttrium-90 microspheres into the blood supply of liver tumours. There are very few studies assessing health-related quality of life (HRQOL) in patients treated with SIRT. Patients with liver metastases from colorectal cancer (CRC) were randomised in the FOXFIRE (FFr; ISRCTN83867919), SIRFLOX (SF; NCT00724503) and FOXFIRE-Global (FFrG; NCT01721954) trials of first-line oxaliplatin-fluorouracil (FOLFOX) chemotherapy combined with SIRT versus FOLFOX alone. HRQOL was assessed using the three-level EQ-5D, European Organisation for Research and Treatment of Cancer Quality of Life (EORTC QLQ-C30) and EORTC Colorectal Liver Metastases cancer module (EORTC QLQ-LMC21) at baseline, ≤3 months, 6 months, 12 months and annually thereafter from randomisation, and at disease progression. Analyses were conducted on an intention-to-treat basis. In total, 554 patients were randomised to SIRT + FOLFOX and 549 patients to FOLFOX alone. HRQOL was statistically significant lower in SIRT + FOLFOX patients ≤3 months after SIRT administration in all three instruments, particularly global health, physical and role functioning and symptoms of fatigue, nausea/vomiting and appetite loss. By accepted thresholds, these differences were deemed not clinically important. Differences between SIRT + FOLFOX and FOLFOX alone over the 2-year follow up and at disease progression were also not clinically important. Although there is some decrease in HRQOL for up to 3 months following SIRT, the addition of SIRT to FOLFOX chemotherapy does not change HRQOL to a clinically important degree in metastatic CRC patients.

Quality of life in patients with liver tumors treated with holmium-166 radioembolization

Holmium-166 radioembolization is a palliative treatment option for patients with unresectable hepatic malignancies. Its influence on quality of life has not been evaluated yet. Since quality of life is very important in the final stages of disease, the aim of this study was to evaluate the effect of holmium-166 radioembolization on quality of life. Patients with hepatic malignancies were treated with holmium-166 radioembolization in the HEPAR I and II studies. The European Organization for Research and Treatment of Cancer QLQ-C30 and LMC21 questionnaires were used to evaluate quality of life at baseline, 1 week, 6 weeks and at 6, 9 and 12 months after treatment. The course of the global health status and symptom and functioning scales were analyzed using a linear mixed model. Quality of life was studied in a total of 53 patients with a compliance of 94%. Role functioning was the most affected functioning scale. Fatigue and pain were the most affected symptom scales. Changes in almost all categories were most notable at 1 week after treatment. A higher WHO performance score at baseline decreased global health status, physical functioning, role functioning and social functioning and it increased symptoms of fatigue, dyspnea and diarrhea. Quality of life in salvage patients with liver metastases treated with holmium-166 radioembolization was not significantly affected over time, although a striking decline was seen during the first week post-treatment. A WHO performance score > 0 at baseline significantly influenced quality of life.

History and development of radioembolization: an old idea with modern applications

The current review documents the major hallmarks in the history and development of radioembolization, the origins of which date back to the late 1940s. Radioembolization was initially abandoned because of the increased incidence of adverse effects and lack of commercial interest; however, it regained avid interest in clinical trials and has achieved established clinical utility in the last 15 years. This review focuses on the main stations of the evolution of radioembolization, namely, initial animal and human experimental studies, production of Y-microspheres, development of current therapeutic agents (resin and glass spheres and labeled Lipiodol), prediction and prevention of inadvertent, extrahepatic shunt side effects, initial prospective studies, and large randomized trials till final approval from the relevant official bodies. The historical knowledge of the initial concepts of the method and the limitations encountered may pave the way toward further evolution and possible new applications.

Radioembolization for the Treatment of Primary and Metastatic Liver Cancers

Radioembolization using ⁹⁰Y microspheres (glass or resin) has been introduced as an effective intraarterial therapy for unresectable primary and metastatic liver cancers. Although the basic therapeutic effect of chemoembolization results from ischemia, the therapeutic efficacy of radioembolization comes from radiation. Furthermore, compared with surgical resection and local ablation therapy, radioembolization is available with less limitation on the sites or number of liver cancers. The radioisotope ⁹⁰Y is a β-radiation emitter without γ-radiation, with the emission of secondary bremsstrahlung photons and small numbers of positrons. Administration of ⁹⁰Y microspheres into the hepatic artery can deliver a high dose of radiation selectively to the target tumor with limited radiation exposure to the surrounding normal parenchyma, and has low systemic toxicity. In general, radioembolization has been considered for patients with unresectable primary or metastatic liver-only or liver-dominant cancers with no ascites or other clinical signs of liver failure, life expectancy of > 12 weeks, and good performance status. Here, we review the current radioactive compounds, pretreatment assessment, and indications for radioembolization in patients with hepatocellular carcinoma, intrahepatic cholangiocarcinoma, and liver metastases from colorectal cancer.

Cryotherapy for liver metastases

BACKGROUND

The liver is affected by two of the most common groups of malignant tumours: primary liver tumours and liver metastases from colorectal carcinoma. Liver metastases are significantly more common than primary liver cancer and long-term survival rates reported for patients after radical surgical treatment is approximately 50%. However, R0 resection (resection for cure) is not feasible in the majority of patients. Cryotherapy is performed with the use of an image-guided cryoprobe which delivers liquid nitrogen or argon gas to the tumour tissue. The subsequent process of freezing is associated with formation of ice crystals, which directly damage exposed tissue, including cancer cells.

OBJECTIVES

To assess the beneficial and harmful effects of cryotherapy compared with no intervention, other ablation methods, or systemic treatments in people with liver metastases.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE Ovid, Embase Ovid, and six other databases up to June 2018.

SELECTION CRITERIA

Randomised clinical trials assessing beneficial and harmful effects of cryotherapy and its comparators for liver metastases, irrespective of the location of the primary tumour.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We extracted information on participant characteristics, interventions, study outcomes, and data on the outcomes important for our review, as well as information on the design and methodology of the trials. Two review authors independently assessed risk of bias in each study. One review author performed data extraction and a second review author checked entries.

MAIN RESULTS

We found no randomised clinical trials comparing cryotherapy versus no intervention or versus systemic treatments; however, we identified one randomised clinical trial comparing cryotherapy with conventional surgery. The trial was conducted in Ukraine. The trial included 123 participants with solitary, or multiple unilobar or bilobar liver metastases; 63 participants received cryotherapy and 60 received conventional surgery. There were 36 women and 87 men. The primary sites for the metastases were colon and rectum (66.6%), stomach (7.3%), breast (6.5%), skin (4.9%), ovaries (4.1%), uterus (3.3%), kidney (3.3%), intestines (1.6%), pancreas (1.6%), and unknown (0.8%). The trial was not reported sufficiently enough to assess the risk of bias of the randomisation process, allocation concealment, or presence of blinding. It was also not possible to assess incomplete outcome data and selective outcome reporting bias. The certainty of evidence was low because of risk of bias and imprecision.The participants were followed for up to 10 years (minimum five months). The trial reported that the mortality at 10 years was 81% (51/63) in the cryotherapy group and 92% (55/60) in the conventional surgery group. The calculated by us relative risk (RR) with 95% Confidence Interval (CI) was: RR 0.88, 95% CI 0.77 to 1.02. We judged the evidence as low-certainty evidence. Regarding adverse events and complications, separately and in total, our calculation showed no evidence of a difference in recurrence of the malignancy in the liver: 86% (54/63) of the participants in the cryotherapy group and 95% (57/60) of the participants in the conventional surgery group developed a new malignancy (RR 0.90, 95% CI 0.80 to 1.01; low-certainty evidence). The frequency of reported complications was similar between the cryotherapy group and the conventional surgery group, except for postoperative pain. Both insignificant and pronounced pain were reported to be more common in the cryotherapy group while intense pain was reported to be more common in the conventional surgery group. However, the authors did not report whether there was any evidence of a difference. There were no intervention-related mortality or bile leakages.We identified no evidence for health-related quality of life, cancer mortality, or time to progression of liver metastases. The study reported tumour response in terms of the carcinoembryonic antigen level in 69% of participants, and reported results in the form of a graph for 30% of participants. The carcinoembryonic antigen level was lower in the cryotherapy group, and decreased to normal values faster in comparison with the control group (P < 0.05).

FUNDING

the trial did not provide information on funding.

AUTHORS' CONCLUSIONS

The evidence for the effectiveness of cryotherapy versus conventional surgery in people with liver metastases is of low certainty. We are uncertain about our estimate and cannot determine whether cryotherapy compared with conventional surgery is beneficial or harmful. We found no evidence for the benefits or harms of cryotherapy compared with no intervention, or versus systemic treatments.

HITM-SIR: phase Ib trial of intraarterial chimeric antigen receptor T-cell therapy and selective internal radiation therapy for CEA+ liver metastases

Effective chimeric antigen receptor-modified T-cell (CAR-T) therapy for liver metastases (LM) will require innovative solutions to ensure efficient delivery and minimization of systemic toxicity. We previously demonstrated the safety of CAR-T hepatic artery infusions (HAI). We subsequently conducted the phase 1b HITM-SIR trial, in which six patients (pts) with CEA⁺ LM received anti-CEA CAR-T HAIs and selective internal radiation therapy (SIRT). The primary endpoint was safety with secondary assessments of biologic activity. Enrolled pts had a mean LM size of 6.4 cm, 4 pts had >10 LM, and pts received an average of two lines of prior systemic therapy. No grade 4 or 5 toxicities were observed, and there were no instances of severe cytokine-release syndrome (CRS) or neurotoxicity. The mean transduction efficiency was 60.4%. Following CAR-T HAI, reduced levels of GM-CSF-R, IDO, and PD-L1 were detected in LM, and serum CEA levels were stable or decreased in all subjects. Median survival time was 8 months (mean 11, range 4-31). Anti-CEA CAR-T HAI with subsequent SIRT was well tolerated, and biologic responses were demonstrated following failure of conventional therapy. HAI of CAR-T was once again confirmed not to be associated with severe CRS or neurotoxicity.

Dose volume histogram-based optimization of image reconstruction parameters for quantitative 90 Y-PET imaging

PURPOSE

⁹⁰ Y-microsphere radioembolization or selective internal radiation therapy is increasingly being used as a treatment option for tumors that are not candidates for surgery and external beam radiation therapy. Recently, volumetric ⁹⁰ Y-dosimetry techniques have been implemented to explore tumor dose-response on the basis of 3D ⁹⁰ Y-activity distribution from PET imaging. Despite being a theranostic study, the optimization of quantitative ⁹⁰ Y-PET image reconstruction still uses the mean activity concentration recovery coefficient (RC) as the objective function, which is more relevant to diagnostic and detection tasks than is to dosimetry. The aim of this study was to optimize ⁹⁰ Y-PET image reconstruction by minimizing errors in volumetric dosimetry via the dose volume histogram (DVH). We propose a joint optimization of the number of equivalent iterations (the product of the iterations and subsets) and the postreconstruction filtration (FWHM) to improve the accuracy of voxel-level ⁹⁰ Y dosimetry.

METHODS

A modified NEMA IEC phantom was used to emulate clinically relevant ⁹⁰ Y-PET imaging conditions through various combinations of acquisition durations, activity concentrations, sphere-to-background ratios, and sphere diameters. PET data were acquired in list mode for 300 min in a single-bed position; we then rebinned the list mode PET data to 60, 45, 30, 15, and 5 min per bed, with 10 different realizations. Errors in the DVH were calculated as root mean square errors (RMSE) of the differences in the image-based DVH and the expected DVH. The new optimization approach was tested in a phantom study, and the results were compared with the more commonly used objective function of the mean activity concentration RC.

RESULTS

In a wide range of clinically relevant imaging conditions, using 36 equivalent iterations with a 5.2-mm filtration resulted in decreased systematic errors in volumetric ⁹⁰ Y dosimetry, quantified as image-based DVH, in ⁹⁰ Y-PET images reconstructed using the ordered subset expectation maximization (OSEM) iterative reconstruction algorithm with time of flight (TOF) and point spread function (PSF) modeling. Our proposed objective function of minimizing errors in DVH, which allows for joint optimization of ⁹⁰ Y-PET iterations and filtration for volumetric quantification of the ⁹⁰ Y dose, was shown to be superior to conventional RC-based optimization approaches for image-based absorbed dose quantification.

CONCLUSION

Our proposed objective function of minimizing errors in DVH, which allows for joint optimization of iterations and filtration to reduce errors in the PET-based volumetric quantification ⁹⁰ Y dose, is relevant to dosimetry in therapy procedures. The proposed optimization method using DVH as the objective function could be applied to any imaging modality used to assess voxel-level quantitative information.

The physics of radioembolization

Radioembolization is an established treatment for chemoresistant and unresectable liver cancers. Currently, treatment planning is often based on semi-empirical methods, which yield acceptable toxicity profiles and have enabled the large-scale application in a palliative setting. However, recently, five large randomized controlled trials using resin microspheres failed to demonstrate a significant improvement in either progression-free survival or overall survival in both hepatocellular carcinoma and metastatic colorectal cancer. One reason for this might be that the activity prescription methods used in these studies are suboptimal for many patients.In this review, the current dosimetric methods and their caveats are evaluated. Furthermore, the current state-of-the-art of image-guided dosimetry and advanced radiobiological modeling is reviewed from a physics' perspective. The current literature is explored for the observation of robust dose-response relationships followed by an overview of recent advancements in quantitative image reconstruction in relation to image-guided dosimetry.This review is concluded with a discussion on areas where further research is necessary in order to arrive at a personalized treatment method that provides optimal tumor control and is clinically feasible.

Factors Affecting Oncologic Outcomes of 90Y Radioembolization of Heavily Pre-Treated Patients With Colon Cancer Liver Metastases

INTRODUCTION

The purpose of this study was to identify predictors of overall (OS) and liver progression-free survival (LPFS) following Yttrium-90 radioembolization (RAE) of heavily pretreated patients with colorectal cancer liver metastases (CLM), as well as to create and validate a predictive nomogram for OS.

MATERIALS AND METHODS

Metabolic, anatomic, laboratory, pathologic, genetic, primary disease, and procedure-related factors, as well as pre- and post-RAE therapies in 103 patients with CLM treated with RAE from September 15, 2009 to March 21, 2017 were analyzed. LPFS was defined by Response Evaluation Criteria In Solid Tumors 1.1 and European Organization for Research and Treatment of Cancer criteria. Prognosticators of OS and LPFS were selected using univariate Cox regression, adjusted for clustering and competing risk analysis (for LPFS), and subsequently tested in multivariate analysis (MVA). The nomogram was built using R statistical software and internally validated using bootstrap resampling.

RESULTS

Patients received RAE at a median of 30.9 months (range, 3.4-161.7 months) after detection of CLM. The median OS and LPFS were 11.3 months (95% confidence interval, 7.9-15.1 months) and 4 months (95% confidence interval, 3.3-4.8 months), respectively. Of the 40 parameters tested, 6 were independently associated with OS in MVA. These baseline parameters included number of extrahepatic disease sites (P < .001), carcinoembryonic antigen (P < .001), albumin (P = .005), alanine aminotransferase level (P < .001), tumor differentiation level (P < .001), and the sum of the 2 largest tumor diameters (P < .001). The 1-year OS of patients with total points of < 25 versus > 80 was 90% and 10%, respectively. Bootstrap resampling showed good discrimination (optimism corrected c-index = 0.745) and calibration (mean absolute prediction error = 0.299) of the nomogram. Only baseline maximum standardized uptake value was significant in MVA for LPFS prediction (P < .001; SHR = 1.06).

CONCLUSION

The developed nomogram included 6 pre-RAE parameters and provided good prediction of survival post-RAE in heavily pretreated patients. Baseline maximum standardized uptake value was the single significant predictor of LPFS.

Correlation of radiation dose and activity with clinical outcomes in metastatic colorectal cancer after selective internal radiation therapy using yttrium-90 resin microspheres

PURPOSE

Yttrium-90 (Y)-resin microspheres are prescribed using activity. We evaluated overall survival (OS) and radiographic tumor response after selective internal radiation therapy (SIRT) with resin microspheres in patients with liver metastases from colorectal cancer.

PATIENTS AND METHODS

We retrospectively reviewed 60 metastatic colorectal cancer patients treated at our institution with SIRT using Y-resin microspheres. Each patient underwent pre-SIRT MRI or computed tomography imaging of the liver with intravenous contrast. Patients underwent post-treatment imaging at 2-3-month intervals with response assessed according to unidimensional Response Evaluation Criteria in Solid Tumors (RECIST) criteria as well as published three-dimensional volumetric criteria. We then related the prescribed activity established by the body surface area method and the corresponding prescribed dose to radiographic treatment response and OS.

RESULTS

The median follow-up after the first SIRT treatment was 8.9 months. The mean prescribed activity and the prescribed dose were 26.6 mCi and 52.8 Gy, respectively. OS was not significantly associated with either prescribed activity or prescribed dose. Prescribed dose was also not related to response. However, a significant relationship was found between a higher prescribed activity and an improved radiographic response by RECIST (P=0.04) at the second follow-up.

CONCLUSION

The prescribed activity of Y-resin microspheres may be correlated with radiographic response by RECIST criteria at 4-6 months post-treatment. For a more accurate prediction of response, a valid dose calculation model based on post-Y PET dosimetry is likely needed given the heterogeneous dose delivery seen in SIRT.

Effect of Primary Tumor Side on Survival Outcomes in Untreated Patients With Metastatic Colorectal Cancer When Selective Internal Radiation Therapy Is Added to Chemotherapy: Combined Analysis of Two Randomized Controlled Studies

BACKGROUND

The primary tumor side is emerging as a major prognostic factor for patients with metastatic colorectal cancer (mCRC). We examined the survival data from 2 randomized studies to determine whether the outcomes differ between patients with mCRC with right-sided primary (RSP) tumors and those with left-sided primary (LSP) tumors after selective internal radiation therapy (SIRT) plus mFOLFOX6 (folinic acid [leucovorin], 5-fluorouracil, oxaliplatin) chemotherapy, versus chemotherapy alone.

PATIENTS AND METHODS

Separate and combined analyses were performed on the data from the SIRFLOX and FOXFIRE global trials, which compared chemotherapy plus SIRT with chemotherapy alone for patients with mCRC liver metastases. The primary tumor side data were prospectively collected. The principal outcome measure was overall survival (OS) stratified by treatment and primary tumor side.

RESULTS

In the combined analysis of all 739 patients enrolled, SIRT had no effect on OS (median OS, 24.3 vs. 24.6 months; hazard ratio [HR], 1.021; P = .810). For the 179 patients (24.2%) with a RSP tumor, OS was improved with the addition of SIRT (median, 22.0 vs. 17.1 months HR, 0.641; P = .008). The addition of SIRT was not associated with a significant difference in OS among the 540 patients with a LSP tumor (median, 24.6 vs. 26.6 months; HR, 1.120; P = .264). A test of treatment interaction by primary tumor side was statistically significant for RSP and SIRT (P = .002).

CONCLUSION

The addition of SIRT for patients with RSP tumors, but not for those with LSP tumors, was associated with a statistically and clinically significant OS gain.

Liver-Directed Therapies for Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (IHC) are primary liver cancers where all or most of the tumor burden is usually confined to the liver. Therefore, locoregional liver-directed therapies can provide an opportunity to control intrahepatic disease with minimal systemic side effects. The English medical literature and clinical trials were reviewed to provide a synopsis on the available liver-directed percutaneous therapies for HCC and IHC. Locoregional liver-directed therapies provide survival benefit for patients with HCC and IHC compared to best medical treatment and have lower comorbid risks compared to surgical resection. These treatment options should be considered, especially in patients with unresectable disease.

Phase I/II Trial of Anticarcinoembryonic Antigen Radioimmunotherapy, Gemcitabine, and Hepatic Arterial Infusion of Fluorodeoxyuridine Postresection of Liver Metastasis for Colorectal Carcinoma

OBJECTIVES

Report the feasibility, toxicities, and long-term results of a Phase I/II trial of ⁹⁰Y-labeled anticarcinoembryonic antigen (anti-CEA) (cT84.66) radioimmunotherapy (RIT), gemcitabine, and hepatic arterial infusion (HAI) of fluorodeoxyuridine (FUdR) after maximal hepatic resection of metastatic colorectal cancer to the liver.

METHODS

Patients with metastatic colorectal cancer to the liver postresection or ablation to minimum disease were eligible. Each cohort received HAI of FUdR for 14 days on a dose escalation schedule. The maximum HAI FUdR dose level planned was 0.2 mg/kg/day, which is the standard dose for HAI FUdR alone. On day 9, ⁹⁰Y-cT84.66 anti-CEA at 16.6 mCi/m² as an i.v. bolus infusion and on days 9-11 i.v. gemcitabine at 105 mg/m² were given. Patients could receive up to three cycles every 6 weeks of protocol therapy. Four additional cycles of HAI FUdR were allowed after RIT.

RESULTS

Sixteen patients were treated on this study. A maximum tolerated dose of 0.20 mg/kg/day of HAI FUdR combined with RIT at 16.6 mCi/m² and gemcitabine at 105 mg/m² was achieved with only 1 patient experiencing grade 3 reversible toxicity (mucositis). After surgery, 10 patients had no evidence of visible disease and remained without evidence of disease after completion of protocol therapy. The remaining 6 patients demonstrated radiological visible disease after surgery and after protocol therapy 2 patients had a CR, 1 patient had PR, 2 had stable disease, and 1 had progression. With a median follow-up of 41.8 months (18.7-114.6), median progression free survival was 9.6 months. Two patients demonstrated long-term disease control out to 45+ and 113+ months.

CONCLUSION

This study demonstrates the safety, feasibility, and potential utility of HAI FUdR, RIT, and systemic gemcitabine. The trimodality approach does not have higher hematologic toxicities than seen in prior RIT-alone studies. Future efforts evaluating RIT in colorectal cancer should integrate RIT with systemic and regional therapies in the minimal tumor burden setting.

90Y Resin Microspheres Radioembolization for Colon Cancer Liver Metastases Using Full-Strength Contrast Material

OBJECTIVES

To assess safety and efficacy of ⁹⁰Y resin microspheres administration using undiluted non-ionic contrast material (UDCM) {100% Omnipaque-300 (Iohexol)} in both the "B" and "D" lines.

MATERIALS AND METHODS

We reviewed all colorectal cancer liver metastases patients treated with ⁹⁰Y resin microspheres radioembolization (RAE) from 2009 to 2017. As of April 2013, two experienced operators started using UDCM (study group) instead of standard sandwich infusion (control group). Occurrence of myelosuppression (leukopenia, neutropenia, erythrocytopenia or/and thrombocytopenia), stasis, nontarget delivery (NTD), median fluoroscopy radiation dose (FRD), median infusion time (IT), liver progression-free (LPFS) and overall survivals (OS) was evaluated. Complications within 6 months post-RAE were reported according to CTCAE v3.0 criteria.

RESULTS

Study and control groups comprised 23(28%) and 58(72%) patients, respectively. Median follow-up was 9.1 months. There was no statistically significant difference in myelosuppression incidence within 6 months post-RAE between groups. Median FRD and IT for study and control groups were 44.6 vs. 97.35 Gy/cm² (p = 0.048) and 31 vs. 39 min (p = 0.006), respectively. A 38% lower stasis incidence in study group was not significant (p = 0.34). NTD occurred in 1/27(4%) study vs. 5/73(7%) control group procedures (p = 1). Grade 1-2 and grade 3-4 toxicities between study and control group patients were 36%(8/22) vs. 45%(26/58), p = 0.61 and 9%(2/22) vs. 16%(9/58), p = 0.72, respectively. There was no difference in LPFS and OS between groups.

CONCLUSION

Administration of ⁹⁰Y resin microspheres using UDCM in both lines is safe and effective, resulting in lower fluoroscopy radiation dose and shorter infusion time, without evidence of myelosuppression or increased stasis incidence.

Long-term survival with transarterial chemoembolization and radioembolization in a patient with cancers of unknown primary

Cancers of unknown primary (CUP) are histologically proven metastatic malignant tumors without an identified primary site before treatment. The common characteristics are early dissemination, lower response to chemotherapy and poor prognosis with short life expectancy. Treatment was directed according to the presence of localized or disseminated disease. The most frequent site of metastasis is the liver, which is a suitable target organ for arterial-directed therapies. We report a case of 53-year-old woman who was diagnosed with CUP and suspected with intracellular cholangiocellular carcinoma (ICC), presented with a very large, unresectable, chemotherapy-refractory hepatic mass and treated with transarterial chemoembolization and transarterial radioembolization and surprisingly followed for 48 months with minimally progressive and stable disease. Arterial-directed therapies, an important therapeutic option in unresectable liver tumors, can provide survival benefit even for ICC and CUP which are very large in size.

Single-institution experience with selective internal radiation therapy (SIRT) for the treatment of unresectable colorectal liver metastases

BACKGROUND

Liver metastases are the commonest cause of death for patients with colorectal cancer. Growing evidence supports the use of selective internal radiation therapy (SIRT) in combination with conventional chemotherapy regimens for liver-only or liver-dominant unresectable metastatic colorectal cancer.

AIMS

To measure and evaluate outcomes of the first 20 consecutive patients with unresectable colorectal liver metastasis selected for SIRT in addition to their chemotherapy at a single Irish institution.

METHODS

Retrospective case series was performed. Patient charts and medical records were reviewed.

RESULTS

All 20 patients (100%) selected for angiographic workup were subsequently successfully treated with radioembolization. All patients were discharged 1 day post-SIRT. At initial imaging evaluation, 12 (60%) had a partial response in their liver, 2 (10%) had stable disease, and 6 (30%) had liver-specific progressive disease. Median follow up was 10 months (range 6-26). At last follow up, 14 (70%) patients were alive and 6 (30%) deceased. Most recent imaging demonstrated 2 (10%) with a complete response, 7 (35%) had a partial response, 2 (10%) had stable disease, and 9 (45%) had progressive disease within their liver. One patient was downstaged to hepatic resection, and one with a complete hepatic response had his primary sigmoid tumor resected 11 months post-SIRT.

CONCLUSIONS

SIRT is a safe and effective therapy for certain patients with unresectable colorectal liver metastases. This case series supports our opinion that selected patients should be offered SIRT in concert with their medical oncologist, concomitant with their chemotherapy. Larger multi-center studies are required to more clearly define the patient groups that will derive most benefit from SIRT.