Histopathologic Changes After Yttrium-90 Radioembolization of Colorectal Liver Metastases: A Pilot Feasibility Study

PURPOSE

To evaluate the histopathologic changes and potential correlations of tissue radiation absorbed dose (TAD) after 90Y transarterial radioembolization (TARE) for colorectal liver metastases (CLM).

MATERIALS AND METHODS

This prospective pilot study assessed 12 patients with 13 (CLM) through PET/CT--guided biopsies before, immediately (T0) and 3 weeks (T3) after TARE. Subsequent sampling from the same location was enabled by fiducial placement. Biopsy samples were evaluated with hematoxylin-eosin (H&E), TUNEL, Ki67, OxPhos, caspase-3 (CC3), and pH2AX antibodies. Proliferation changes (Ki67) and double-strand DNA breaks (DSBs) were evaluated quantitatively. TAD was calculated on post-TARE PET/CT scan of the biopsy needle location at T0 and T3.

RESULTS

Median TAD at 3 weeks post-TARE was 162 (IQ R:92-211) Gy. DSBs decreased significantly from T0 (median 77%; IQR:75-100%) to T3 (median 14%; IQR:0-54%, p=0.03). A decrease in Ki67 was also documented (median: 73%, IQR:70-80% at T0 vs 41%, IQR:0-66% at T3, p=0.05). There was a strong negative correlation between TAD and DSBs at T0 (r(9)=0.68) and a strong negative correlation at T3 (r(10)=-0.855), (p=0.042 and p=0.002, respectively). There was a strong negative correlation between TAD and Ki67 at both T0 (r(9)=-0.733; p=0.025) and T3 (r(10)=-0.681; p=0.03). Tumors that exhibited caspase-3 activation (8/13, 62%) at either T0 or T3 time point were more likely to develop progression (7/8, 88% vs 1/5, 20%, p=0.015).

CONCLUSION

Post-TARE biopsy can be used to assess TAD and histopathologic changes. Significant decreases in double-strand DNA breaks and proliferation index were noted post TARE. Post-TARE CC3 activation deserves further exploration.

Imaging Considerations before and after Liver-Directed Locoregional Treatments for Metastatic Colorectal Cancer

Colorectal cancer is a leading cause of cancer-related death. Liver metastases will develop in over one-third of patients with colorectal cancer and are a major cause of morbidity and mortality. Even though surgical resection has been considered the mainstay of treatment, only approximately 20% of the patients are surgical candidates. Liver-directed locoregional therapies such as thermal ablation, Yttrium-90 transarterial radioembolization, and stereotactic body radiation therapy are pivotal in managing colorectal liver metastatic disease. Comprehensive pre- and post-intervention imaging, encompassing both anatomic and metabolic assessments, is invaluable for precise treatment planning, staging, treatment response assessment, and the prompt identification of local or distant tumor progression. This review outlines the value of imaging for colorectal liver metastatic disease and offers insights into imaging follow-up after locoregional liver-directed therapy.

Three-Dimensional Margin as a Predictor of Local Tumor Progression after Microwave Ablation: Intraprocedural versus 4-8-Week Postablation Assessment

PURPOSE

To evaluate the prognostic accuracy of intraprocedural and 4-8-week (current standard) post-microwave ablation zone (AZ) and margin assessments for prediction of local tumor progression (LTP) using 3-dimensional (3D) software.

MATERIALS AND METHODS

Data regarding 100 colorectal liver metastases (CLMs) in 75 patients were collected from 2 prospective fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT)-guided microwave ablation (MWA) trials. The target CLMs and theoretical 5- and 10-mm margins were segmented and registered intraprocedurally and at 4-8 weeks after MWA contrast-enhanced CT (or magnetic resonance [MR] imaging) using the same methodology and 3D software. Tumor and 5- and 10-mm minimal margin (MM) volumes not covered by the AZ were defined as volumes of insufficient coverage (VICs). The intraprocedural and 4-8-week post-MWA VICs were compared as predictors of LTP using receiver operating characteristic curve analysis.

RESULTS

The median follow-up time was 19.6 months (interquartile range, 7.97-36.5 months). VICs for 5- and 10-mm MMs were predictive of LTP at both time assessments. The highest accuracy for the prediction of LTP was documented with the intra-ablation 5-mm VIC (area under the curve [AUC], 0.78; 95% confidence interval, 0.66-0.89). LTP for a VIC of 6-10-mm margin category was 11.4% compared with 4.3% for >10-mm margin category (P < .001).

CONCLUSIONS

A 3D 5-mm MM is a critical endpoint of thermal ablation, whereas optimal local tumor control is noted with a 10-mm MM. Higher AUCs for prediction of LTP were achieved for intraprocedural evaluation than for the 4-8-week postablation 3D evaluation of the AZ.

Yttrium-90 Transarterial Radioembolization of Primary Lung Cancer Metastases to the Liver

PURPOSE

To assess whether yttrium-90 transarterial radioembolization (TARE) is safe and effective in the treatment of primary lung cancer metastases to the liver (LCML).

METHODS AND METHODS

This retrospective study included 57 patients with LCML who were treated with 79 TARE treatments. Histology included non-small cell lung cancer (NSCLC) (n = 27), small cell lung cancer (SCLC) (n = 17), and lung carcinoid (LC) (n = 13). Survival was calculated using Kaplan-Meier method; differences between groups were estimated using log rank test. Cox proportional hazards model was used to determine factors influencing survival. Adverse events were graded using the Society of Interventional Radiology Adverse Events Classification.

RESULTS

Median overall survival (OS) was as follows: NSCLC, 8.3 months (95% confidence interval [CI], 6.3-16.4 months); SCLC, 4.1 months (95% CI, 1.9-6.6 months); and LC, 43.5 months (95% CI, 7.8-61.4 months). For NSCLC, presence of bilobar vs unilobar disease (hazard ratio [HR], 5.24; 95% CI, 1.64-16.79; P = .002); more tumors, 2-5 vs 1 (HR, 4.88; 95% CI, 1.17-20.37; P = .003) and >5 vs 1 (HR, 3.75; 95% CI, 0.95-6.92; P = .05); and lobar vs segmental treatment (HR, 2.56; 95% CI, 0-NA; P = .002) were negative predictors of OS. For SCLC, receipt of >2 lines of chemotherapy vs ≤2 lines (HR, 3.16; 95% CI, 0.95-10.47; P = .05) was a negative predictor of OS. For LC, tumor involvement of >50% was a negative predictor of OS (HR, 3.77 × 1015; 95% CI, 0-NA; P = .002). There were 11 of 79 severe or life-threatening adverse events within 30 days (abdominal pain, altered mental status, nausea/vomiting, acalculous/aseptic cholecystitis, hyponatremia, pancreatitis, renal failure, and death from pneumonia).

CONCLUSIONS

TARE has an acceptable safety profile for the treatment of LCML, with survival benefits best seen in LC tumors.

The Importance of Optimal Thermal Ablation Margins in Colorectal Liver Metastases: A Systematic Review and Meta-Analysis of 21 Studies

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths in the US. Thermal ablation (TA) can be a comparable alternative to partial hepatectomy for selected cases when eradication of all visible tumor with an ablative margin of greater than 5 mm is achieved. This systematic review and meta-analysis aimed to encapsulate the current clinical evidence concerning the optimal TA margin for local cure in patients with colorectal liver metastases (CLM).

METHODS

MEDLINE, EMBASE, and the CENTRAL databases were systematically searched from inception until 1 May 2023, in accordance with the PRISMA Guidelines. Measure of effect included the risk ratio (RR) with 95% confidence interval (CI) using the random-effects model.

RESULTS

Overall, 21 studies were included, comprising 2005 participants and 2873 ablated CLMs. TA with margins less than 5 mm were associated with a 3.6 times higher risk for LTP (n = 21 studies, RR: 3.60; 95% CI: 2.58-5.03; p-value < 0.001). When margins less than 5 mm were additionally confirmed by using 3D software, a 5.1 times higher risk for LTP (n = 4 studies, RR: 5.10; 95% CI: 1.45-17.90; p-value < 0.001) was recorded. Moreover, a thermal ablation margin of less than 10 mm but over 5 mm remained significantly associated with 3.64 times higher risk for LTP vs. minimal margin larger than 10 mm (n = 7 studies, RR: 3.64; 95% CI: 1.31-10.10; p-value < 0.001).

CONCLUSIONS

This meta-analysis solidifies that a minimal ablation margin over 5 mm is the minimum critical endpoint required, whereas a minimal margin of at least 10 mm yields optimal local tumor control after TA of CLMs.

Percutaneous image-guided ablation for hepatic metastases

The presence of hepatic metastases indicates advanced disease and is associated with significant morbidity and mortality, especially when the hepatic disease is not amenable to locoregional treatments. The primary tumour of origin, the distribution and extent of metastatic disease, the underlying liver reserve, the patient performance status and the presence of comorbidities are factors that determine whether a patient will benefit from hepatectomy or local curative-intent treatments. For patients with metastatic colorectal cancer, the most common primary cancer that spreads to the liver, several studies have demonstrated a survival benefit for patients who can be treated with hepatectomy and/or percutaneous ablation, compared to those treated with chemotherapy alone. Despite advances in surgical techniques increasing the percentage of patients eligible for surgery, most patients have unresectable disease or are poor surgical candidates. Percutaneous ablation can be used to provide local disease control and prolong survival for both surgical and non-surgical candidates. This is typically offered to patients with small hepatic metastases that can be ablated with optimal (≥10 mm) or at least adequate minimum ablation margins (≥5 mm), as high local tumour control rates can be achieved for these patients which are comparable to surgical resection. This review summarizes available evidence and outcomes following percutaneous ablation of the most frequently encountered types of hepatic metastases in the clinical practice of interventional oncology. Patient selection, technical considerations, follow-up protocols and oncologic outcomes are presented and discussed.

Safety and Efficacy of Hepatic Artery Embolization in Heavily Treated Patients with Intrahepatic Cholangiocarcinoma: Analysis of Clinicopathological and Radiographic Parameters Associated with Better Overall Survival

The safety and efficacy of hepatic artery embolization (HAE) in treating intrahepatic cholangiocarcinoma (IHC) was evaluated. Initial treatment response, local tumor progression-free survival (L-PFS), and overall survival (OS) were evaluated in 34 IHC patients treated with HAE. A univariate survival analysis and a multivariate Cox proportional hazard analysis to identify independent factors were carried out. Objective response (OR) at 1-month was 79.4%. Median OS and L-PFS from the time of HAE was 13 (CI = 95%, 7.4-18.5) and 4 months (CI = 95%, 2.09-5.9), respectively. Tumor burden < 25% and increased tumor vascularity on preprocedure imaging and surgical resection prior to embolization were associated with longer OS (p < 0.05). Multivariate logistic regression analysis demonstrated that tumor burden < 25% and hypervascular tumors were independent risk factors. Mean post-HAE hospital stay was 4 days. Grade 3 complication rate was 8.5%. In heavily treated patients with IHC, after exhausting all chemotherapy and other locoregional options, HAE as a rescue treatment option appeared to be safe with a mean OS of 13 months. Tumor burden < 25%, increased target tumor vascularity on pre-procedure imaging, and OR on 1 month follow-up images were associated with better OS. Further studies with a control group are required to confirm the effectiveness of HAE in IHC.

Yttrium-90 Activity Quantification in PET/CT-Guided Biopsy Specimens from Colorectal Hepatic Metastases Immediately after Transarterial Radioembolization Using Micro-CT and Autoradiography

PURPOSE

To evaluate the yttrium-90 (90Y) activity distribution in biopsy tissue samples of the treated liver to quantify the dose with higher spatial resolution than positron emission tomography (PET) for accurate investigation of correlations with microscopic biological effects and to evaluate the radiation safety of this procedure.

MATERIALS AND METHODS

Eighty-six core biopsy specimens were obtained from 18 colorectal liver metastases (CLMs) immediately after 90Y transarterial radioembolization (TARE) with either resin or glass microspheres using real-time 90Y PET/CT guidance in 17 patients. A high-resolution micro-computed tomography (micro-CT) scanner was used to image the microspheres in part of the specimens and allow quantification of 90Y activity directly or by calibrating autoradiography (ARG) images. The mean doses to the specimens were derived from the measured specimens' activity concentrations and from the PET/CT scan at the location of the biopsy needle tip for all cases. Staff exposures were monitored.

RESULTS

The mean measured 90Y activity concentration in the CLM specimens at time of infusion was 2.4 ± 4.0 MBq/mL. The biopsies revealed higher activity heterogeneity than PET. Radiation exposure to the interventional radiologists during post-TARE biopsy procedures was minimal.

CONCLUSIONS

Counting the microspheres and measuring the activity in biopsy specimens obtained after TARE are safe and feasible and can be used to determine the administered activity and its distribution in the treated and biopsied liver tissue with high spatial resolution. Complementing 90Y PET/CT imaging with this approach promises to yield more accurate direct correlation of histopathological changes and absorbed dose in the examined specimens.

Advancements and Future Outlook of PET/CT-Guided Interventions

Advancements in minimally invasive technology, coupled with imaging breakthroughs, have empowered the field of interventional radiology to achieve unparalleled precision in image-guided diagnosis and treatment while simultaneously reducing periprocedural morbidity. Molecular imaging, which provides valuable physiological and metabolic information alongside anatomical localization, can expand the capabilities of image-guided interventions. Among various molecular imaging techniques, positron emission tomography (PET) stands out for its superior spatial resolution and ability to acquire quantitative data. PET has emerged as a crucial tool for oncologic imaging and plays a pivotal role in both staging and the assessment of treatment responses. Typically used in combination with computed tomography (CT) (PET/CT) and occasionally with magnetic resonance imaging MRI (PET/MRI), PET as a hybrid imaging approach offers enhanced insights into disease progression and response. In recent years, PET has also found its way into image-guided interventions, especially within the rapidly expanding field of interventional oncology. This review aims to explore the current and evolving role of metabolic imaging, specifically PET, in interventional oncology. By delving into the unique advantages and applications of PET in guiding oncological interventions and assessing response, we seek to highlight the increasing significance of this modality in the realm of interventional radiology.

Factors affecting outcomes of Yttrium-90 radioembolization in heavily pretreated patients with intrahepatic cholangiocarcinoma

PURPOSE

Transarterial radioembolization (TARE) is a liver-directed treatment for unresectable intrahepatic cholangiocarcinoma (ICC). The aim of this study is to evaluate factors affecting outcomes of TARE in heavily pretreated ICC patients.

METHODS

We evaluated pretreated ICC patients who received TARE from January 2013 to December 2021. Prior treatments included systemic therapy, hepatic resection, and liver-directed therapies, including hepatic arterial infusion chemotherapy, external beam radiation, transarterial embolization, and thermal ablation. Patients were classified based on history of hepatic resection and genomic status based on next-generation sequencing (NGS). The primary endpoint was overall survival (OS) after TARE.

RESULTS

Fourteen patients with median age 66.1 years (range, 52.4-87.5), 11 females and 3 males, were included. Prior therapies included systemic in 13/14 patients (93%), liver resection in 6/14 (43%), and liver-directed therapy in 6/14 (43%). Median OS was 11.9 months (range, 2.8-81.0). Resected patients had significantly longer median OS compared to unresected patients (16.6 versus 7.9 months; p = 0.038). Prior liver-directed therapy (p = 0.043), largest tumor diameter > 4 cm (p = 0.014), and > 2 hepatic segments involvement (p = 0.001) were associated with worse OS. Nine patients underwent NGS; 3/9 (33.3%) and had a high-risk gene signature (HRGS), defined as alterations in TP53, KRAS, or CDKN2A. Patients with a HRGS had worse median OS (10.0 versus 17.8 months; p = 0.024).

CONCLUSIONS

TARE may be used as salvage therapy in heavily treated ICC patients. Presence of a HRGS may predict worse OS after TARE. Further investigation with more patients is recommended to validate these results.

Gradient-based Volumetric PET Parameters on Immediate Pre-ablation FDG-PET Predict Local Tumor Progression in Patients with Colorectal Liver Metastasis Treated by Microwave Ablation

PURPOSE

This study aimed to evaluate the optimal method of segmentation of colorectal liver metastasis (CLM) on immediate pre-ablation PET scans and assess the prognostic value of quantitative pre-ablation PET parameters with regards to local tumor control. A secondary objective was to correlate the target tumor size estimation by PET methods with the tumor measurements on anatomical imaging.

METHODOLOGY

A prospectively accrued cohort of 55 CLMs (46 patients) treated with real-time ¹⁸F-FDG-PET/CT-guided percutaneous microwave ablation was followed-up for a median of 10.8 months (interquartile: 5.5-20.2). Total lesion glycolysis (TLG) and metabolic tumor volume (MTV) values of each CLM were derived from pre-ablation ¹⁸F-FDG-PET with gradient and threshold PET segmentation methodologies. The event was defined as local tumor progression (LTP). Time-dependent receiver operating characteristic (ROC) curve analyses were used to assess area under the curves (AUCs). Intraclass correlation (ICC) and 95.0% confidence interval (CI) were performed to measure the linear relationships between the continuous variables.

RESULTS

AUCs for prediction of LTP obtained from time-dependent ROC analysis for the gradient technique were higher in comparison to the threshold methodologies (AUCs for TLG and volume were: 0.790 and 0.807, respectively). ICC between PET gradient-based and anatomical measurements were higher in comparison to threshold methodologies (ICC for the longest diameter: 733 (95.0% CI 0.538-0.846), ICC for the shortest diameter: .747 (95.0% CI 0.546-0.859), p-values < 0.001).

CONCLUSIONS

The gradient-based technique had a higher AUC for prediction of LTP after microwave ablation of CLM and showed the highest correlation with anatomical imaging tumor measurements.

Anal Carcinoma, Version 2.2023, NCCN Clinical Practice Guidelines in Oncology

This discussion summarizes the NCCN Clinical Practice Guidelines for managing squamous cell anal carcinoma, which represents the most common histologic form of the disease. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is necessary. Primary treatment of perianal cancer and anal canal cancer are similar and include chemoradiation in most cases. Follow-up clinical evaluations are recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. Biopsy-proven evidence of locally recurrent or persistent disease after primary treatment may require surgical treatment. Systemic therapy is generally recommended for extrapelvic metastatic disease. Recent updates to the NCCN Guidelines for Anal Carcinoma include staging classification updates based on the 9th edition of the AJCC Staging System and updates to the systemic therapy recommendations based on new data that better define optimal treatment of patients with metastatic anal carcinoma.

Real-Time Split-Dose PET/CT-Guided Ablation Improves Colorectal Liver Metastasis Detection and Ablation Zone Margin Assessments without the Need for Repeated Contrast Injection

BACKGROUND

Real-time split-dose PET can identify the targeted colorectal liver metastasis (CLM) and eliminate the need for repeated contrast administration before and during thermal ablation (TA). This study aimed to assess the added value of pre-ablation real-time split-dose PET when combined with non-contract CT in the detection of CLM for ablation and the evaluation of the ablation zone and margins.

METHODS

A total of 190 CLMs/125 participants from two IRB-approved prospective clinical trials using PET/CT-guided TA were analyzed. Based on detection on pre-TA imaging, CLMs were categorized as detectable, non-detectable, and of poor conspicuity on CT alone, and detectable, non-detectable, and low FDG-avidity on PET/CT after the initial dose. Ablation margins around the targeted CLM were evaluated using a 3D volumetric approach.

RESULTS

We found that 129/190 (67.9%) CLMs were detectable on CT alone, and 61/190 CLMs (32.1%) were undetectable or of poor conspicuity, not allowing accurate depiction and targeting by CT alone. Thus, the theoretical 5- and 10-mm margins could not be defined in these tumors (32.1%) using CT alone. When TA intraprocedural PET/CT images are obtained and inspected (fused PET/CT), only 4 CLM (2.1%) remained undetectable or had a low FDG avidity.

CONCLUSIONS

The addition of PET to non-contrast CT improved CLM detection for ablation targeting, margin assessments, and continuous depiction of the FDG avid CLMs during the ablation without the need for multiple intravenous contrast injections pre- and intra-procedurally.

Rectal Cancer, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Guidelines for Rectal Cancer focuses on management of malignant polyps and resectable nonmetastatic rectal cancer because important updates have been made to these guidelines. These recent updates include redrawing the algorithms for stage II and III disease to reflect new data supporting the increasingly prominent role of total neoadjuvant therapy, expanded recommendations for short-course radiation therapy techniques, and new recommendations for a “watch-and-wait” nonoperative management technique for patients with cancer that shows a complete response to neoadjuvant therapy. The complete version of the NCCN Guidelines for Rectal Cancer, available online at NCCN.org, covers additional topics including risk assessment, pathology and staging, management of metastatic disease, posttreatment surveillance, treatment of recurrent disease, and survivorship.

Optimizing 90Y Particle Density Improves Outcomes After Radioembolization

PURPOSE

To determine how particle density affects dose distribution and outcomes after lobar radioembolization.

METHODS

Matched pairs of patients, treated with glass versus resin microspheres, were selected by propensity score matching (114 patients), in this single-institution retrospective study. For each patient, tumor and liver particle density (particles/cm³) and dose (Gy) were determined. Tumor-to-normal ratio was measured on both ^99mTc-MAA SPECT/CT and post-⁹⁰Y bremsstrahlung SPECT/CT. Microdosimetry simulations were used to calculate first percentile dose, which is the dose in the cold spots between microspheres. Local progression-free survival (LPFS) and overall survival were analyzed.

RESULTS

As more particles were delivered, doses on ⁹⁰Y SPECT/CT became more uniform throughout the treatment volume: tumor and liver doses became more similar (p = 0.04), and microscopic cold spots between particles disappeared. For hypervascular tumors (tumor-to-normal ratio ≥ 2.6 on MAA scan), delivering fewer particles (< 6000 particles/cm³ treatment volume) was associated with better LPFS (p = 0.03). For less vascular tumors (tumor-to-normal ratio < 2.6), delivering more particles (≥ 6000 particles/cm³) was associated with better LPFS (p = 0.02). In matched pairs of patients, using the optimal particle density resulted in improved overall survival (11.5 vs. 6.8 months, p = 0.047), compared to using suboptimal particle density. Microdosimetry resulted in better predictions of LPFS (p = 0.03), and overall survival (p = 0.02), compared to conventional dosimetry.

CONCLUSION

The number of particles delivered can be chosen to maximize the tumor dose and minimize the liver dose, based on tumor vascularity. Optimizing the particle density resulted in improved LPFS and overall survival.

Immunofluorescence Assay of Ablated Colorectal Liver Metastases: The Frozen Section of Image-Guided Tumor Ablation?

PURPOSE

To validate an immunofluorescence assay (IFA) detecting residual viable tumor (VT) as intraprocedural thermal ablation (TA) zone assessment and demonstrate its prognostic value for local tumor progression (LTP) after colorectal liver metastasis (CLM) TA.

MATERIALS AND METHODS

This prospective study, approved by the institutional review board, included 99 patients with 155 CLMs ablated between November 2009 and January 2019. Tissue samples from the ablation zone (AZ) center and minimal margin underwent immunofluorescent microscopic examination interrogating cellular morphology and mitochondrial viability (IFA) within 30 minutes after ablation. The same tissue samples were subsequently evaluated with standard morphologic and immunohistochemical methods. The sensitivity, specificity, and overall accuracy of IFA versus standard morphologic and immunohistochemical examination were calculated. The LTP-free survival rates were evaluated for the 12-month follow-up period.

RESULTS

Of the 311 tissue samples stained, 304 (98%) were deemed evaluable. Of these specimens, 27% (81/304) were considered positive for the presence of VT. The accuracy of IFA was 94% (286/304). The sensitivity and specificity were 100% (63/63) and 93% (223/241), respectively. The 18 false-positive IFA assessments corresponded to samples that included viable cholangiocytes. The 12-month LTP-free survival was 59% versus 78% for IFA positive versus negative for VT AZs, respectively (P < .001). There was no difference in LTP between margin positive only and central AZ-positive tumors (25% vs 31%, P = 1).

CONCLUSIONS

The IFA assessment of the AZ can be completed intraprocedurally and serve as a valid real-time biomarker of complete tumor eradication or detect residual VT after TA. This method could improve tumor control by TA.

3D margin assessment predicts local tumor progression after ablation of colorectal cancer liver metastases

OBJECTIVE

To determine the feasibility and prognostic value of 3D measuring of the ablation margins using a dedicated image registration software.

METHODS

This retrospective study included 104 colorectal liver metastases in 68 consecutive patients that underwent microwave ablation between 08/2012 and 08/2019. The minimal ablation margin (MM) was measured in 2D using anatomic landmarks on contrast enhanced CT(CECT) 4-8 weeks post-ablation, and in 3D using an image registration software and immediate post-ablation CECT. Local tumor progression (LTP) was assessed by imaging up to 24 months after ablation. A blinded interventional radiologist provided feedback on the possibility of additional ablation after examining the 3D-margin measurements.

RESULTS

The 3D-margin assessment was completed in 79/104 (76%) tumors without the need for target manipulation. In 25/104 (24%) tumors, manipulation was required due to image misregistration. LTP was observed in 40/104 (38.5%) tumors: 92.5% vs 7.5% for those with margin <5mm vs ≥5mm, respectively (p = 0.0001). The 2D and 3D-assessments identified margin <5mm in 17/104 (16%), and in 74/104 (71%) ablated tumors, respectively (p < 0.01). The sensitivity and specificity of the 3D software for predicting LTP was 93% (37/40) and 42% (27/64), respectively. Additional ablation to achieve a MM of 5 mm would have been offered in 26/37 cases if the 3D-margin assessment was available intraoperatively.

CONCLUSION

Image registration software can measure ablation margins and detect MM under 5 mm intraoperatively, with significantly higher sensitivity than the 2D technique using landmarks on the post-ablation CECT. The identification of a margin under 5 mm is strongly associated with LTP.

Radioembolization With Chemotherapy for Colorectal Liver Metastases: A Randomized, Open-Label, International, Multicenter, Phase III Trial

PURPOSE

To study the impact of transarterial Yttrium-90 radioembolization (TARE) in combination with second-line systemic chemotherapy for colorectal liver metastases (CLM).

METHODS

In this international, multicenter, open-label phase III trial, patients with CLM who progressed on oxaliplatin- or irinotecan-based first-line therapy were randomly assigned 1:1 to receive second-line chemotherapy with or without TARE. The two primary end points were progression-free survival (PFS) and hepatic PFS (hPFS), assessed by blinded independent central review. Random assignment was performed using a web- or voice-based system stratified by unilobar or bilobar disease, oxaliplatin- or irinotecan-based first-line chemotherapy, and KRAS mutation status.

RESULTS

Four hundred twenty-eight patients from 95 centers in North America, Europe, and Asia were randomly assigned to chemotherapy with or without TARE; this represents the intention-to-treat population and included 215 patients in the TARE plus chemotherapy group and 213 patients in the chemotherapy alone group. The hazard ratio (HR) for PFS was 0.69 (95% CI, 0.54 to 0.88; 1-sided P = .0013), with a median PFS of 8.0 (95% CI, 7.2 to 9.2) and 7.2 (95% CI, 5.7 to 7.6) months, respectively. The HR for hPFS was 0.59 (95% CI, 0.46 to 0.77; 1-sided P < .0001), with a median hPFS of 9.1 (95% CI, 7.8 to 9.7) and 7.2 (95% CI, 5.7 to 7.6) months, respectively. Objective response rates were 34.0% (95% CI, 28.0 to 40.5) and 21.1% (95% CI, 16.2 to 27.1; 1-sided P = .0019) for the TARE and chemotherapy groups, respectively. Median overall survival was 14.0 (95% CI, 11.8 to 15.5) and 14.4 months (95% CI, 12.8 to 16.4; 1-sided P = .7229) with a HR of 1.07 (95% CI, 0.86 to 1.32) for TARE and chemotherapy groups, respectively. Grade 3 adverse events were reported more frequently with TARE (68.4% v 49.3%). Both groups received full chemotherapy dose intensity.

CONCLUSION

The addition of TARE to systemic therapy for second-line CLM led to longer PFS and hPFS. Further subset analyses are needed to better define the ideal patient population that would benefit from TARE.

Consensus Guidelines for the Definition of Time-to-Event End Points in Image-guided Tumor Ablation: Results of the SIO and DATECAN Initiative

There is currently no consensus regarding preferred clinical outcome measures following image-guided tumor ablation or clear definitions of oncologic end points. This consensus document proposes standardized definitions for a broad range of oncologic outcome measures with recommendations on how to uniformly document, analyze, and report outcomes. The initiative was coordinated by the Society of Interventional Oncology in collaboration with the Definition for the Assessment of Time-to-Event End Points in Cancer Trials, or DATECAN, group. According to predefined criteria, based on experience with clinical trials, an international panel of 62 experts convened. Recommendations were developed using the validated three-step modified Delphi consensus method. Consensus was reached on when to assess outcomes per patient, per session, or per tumor; on starting and ending time and survival time definitions; and on time-to-event end points. Although no consensus was reached on the preferred classification system to report complications, quality of life, and health economics issues, the panel did agree on using the most recent version of a validated patient-reported outcome questionnaire. This article provides a framework of key opinion leader recommendations with the intent to facilitate a clear interpretation of results and standardize worldwide communication. Widespread adoption will improve reproducibility, allow for accurate comparisons, and avoid misinterpretations in the field of interventional oncology research. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue.

Bronchial or Pulmonary Artery Chemoembolization for Unresectable and Unablatable Lung Metastases: A Phase I Clinical Trial

Background Lung chemoembolization is an emerging treatment option for lung tumors, but the optimal embolic, drug, and technique are unknown. Purpose To determine the technical success rate and safety of bronchial or pulmonary artery chemoembolization of lung metastases using ethiodized oil, mitomycin, and microspheres. Materials and Methods Patients with unresectable and unablatable lung, endobronchial, or mediastinal metastases, who failed systemic chemotherapy, were enrolled in this prospective, single-center, single-arm, phase I clinical trial (December 2019-September 2020). Pulmonary and bronchial angiography was performed to determine the blood supply to the lung metastases. Based on the angiographic findings, bronchial or pulmonary artery chemoembolization was performed using an ethiodized oil and mitomycin emulsion, followed by microspheres. The primary objectives were technical success rate and safety, according to the National Cancer Institute Common Terminology Criteria for Adverse Events. CIs of proportions were estimated with the equal-tailed Jeffreys prior interval, and correlations were evaluated with the Spearman test. Results Ten participants (median age, 60 years; interquartile range, 52-70 years; six women) were evaluated. Nine of the 10 participants (90%) had lung metastases supplied by the bronchial artery, and one of the 10 participants (10%) had lung metastases supplied by the pulmonary artery. The technical success rate of intratumoral drug delivery was 10 of 10 (100%) (95% CI: 78, 100). There were no severe adverse events (95% CI: 0, 22). The response rate of treated tumors was one of 10 (10%) according to the Response Evaluation Criteria in Solid Tumors and four of 10 (40%) according to the PET Response Criteria in Solid Tumors. Ethiodized oil retention at 4-6 weeks was correlated with reduced tumor size (ρ = -0.83, P = .003) and metabolic activity (ρ = -0.71, P = .03). Pharmacokinetics showed that 45% of the mitomycin dose underwent burst release in 2 minutes, and 55% of the dose was retained intratumorally with a half-life of more than 5 hours. The initial tumor-to-plasma ratio of mitomycin concentration was 380. Conclusion Lung chemoembolization was technically successful for the treatment of lung, mediastinal, and endobronchial metastases, with no severe adverse events. Clinical trial registration no. NCT04200417 © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Georgiades et al in this issue.

Radiation segmentectomy of hepatic metastases with Y-90 glass microspheres

PURPOSE

To evaluate safety and efficacy of radiation segmentectomy (RS) with ⁹⁰Y glass microspheres in patients with limited metastatic liver disease not amenable to resection or percutaneous ablation.

METHODS

Patients with ≤ 3 tumors treated with RS from 6/2015 to 12/2017 were included. Target tumor radiation dose was > 190 Gy based on medical internal radiation dose (MIRD) dosimetry. Tumor response, local tumor progression (LTP), LTP-free survival (LTPFS) and disease progression rate in the treated segment were defined using Choi and RECIST 1.1 criteria. Toxicities were evaluated using modified SIR criteria.

RESULTS

Ten patients with 14 tumors underwent 12 RS. Median tumor size was 3 cm (range 1.4-5.6). Median follow-up was 17.8 months (range 1.6-37.3). Response rates per Choi and RECIST 1.1 criteria were 8/8 (100%) and 4/9 (44%), respectively. Overall LTP rate was 3/14 (21%) during the study period. One-, two- and three-year LTPFS was 83%, 83% and 69%, respectively. Median LTPFS was not reached. Disease progression rate in the treated segment was 6/18 (33%). Median overall survival was 41.5 months (IQR 16.7-41.5). Median delivered tumor radiation dose was 293 Gy (range 163-1303). One major complication was recorded in a patient post-Whipple procedure who suffered anaphylactic reaction to prophylactic cefotetan and liver abscess in RS region 6.5 months post-RS. All patients were alive on last follow-up.

CONCLUSION

RS of ≤ 3 hepatic segments can safely provide a 2-year local tumor control rate of 83% in selected patients with limited metastatic liver disease and limited treatment options. Optimal dosimetry methodology requires further investigation.

Phase I study of transarterial chemoembolization of lung metastases

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Background: Lung chemoembolization (via the bronchial or pulmonary artery) is a new treatment option for unresectable and unablatable lung metastases. Methods: 10 patients with unresectable and unablatable lung, endobronchial, or mediastinal metastases, who failed systemic chemotherapy, were enrolled in this single center, single arm, phase I trial. Pulmonary and bronchial angiography was performed in all patients, to determine the blood supply to the lung metastases. Based on the angiographic findings, bronchial or pulmonary artery chemoembolization was performed, using a lipiodol / mitomycin emulsion, followed by spherical particles. Technical success, safety, efficacy, and pharmacokinetics were evaluated. Wilcoxon signed-rank test was used to compare change in size of treated versus untreated tumors. Results: On angiography, all patients had lung metastases that were hypervascular compared to normal lung. 90% of patients had lung metastases supplied by the bronchial artery, and 10% were supplied by the pulmonary artery. Technical success rate of intra-tumoral drug delivery was 100% (95% CI: 76-100%). There were no severe adverse events, and all patients met criteria for discharge 4 hours post procedure. Response rate of treated lesions was 10% by RECIST and 40% by PERCIST. Treated tumors were mostly stable to decreased in size after chemoembolization (median change in size: 0%; IQR: -11% to 2%; mean: -4%), and untreated tumors were mostly increased in size (median change in size: 10%; IQR: 0% to 17%; mean 9%; p= 0.02). Intra-tumoral lipiodol retention at 4-6 weeks was correlated with decreased tumor size and metabolic activity. Pharmacokinetics showed that 45% of the mitomycin dose underwent burst release in 2 minutes, and 55% of the dose was retained intratumorally with a half-life > 5 hours. Initial tumor-to-plasma ratio of mitomycin concentration was 380. Half-life of intratumoral lipiodol retention was 16 days. In vitro experiments showed 50% emulsion separation in 6.2 days, and 50% drug release in 7.1 hours. Conclusions: Lung chemoembolization can safely treat lung, mediastinal, and endobronchial metastases, with minimal systemic toxicity. High intratumoral drug concentrations after chemoembolization can overcome chemoresistance. Clinical trial information: NCT04200417.

Colon Cancer, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Colon Cancer focuses on systemic therapy options for the treatment of metastatic colorectal cancer (mCRC), because important updates have recently been made to this section. These updates include recommendations for first-line use of checkpoint inhibitors for mCRC, that is deficient mismatch repair/microsatellite instability-high, recommendations related to the use of biosimilars, and expanded recommendations for biomarker testing. The systemic therapy recommendations now include targeted therapy options for patients with mCRC that is HER2-amplified, or BRAF V600E mutation-positive. Treatment and management of nonmetastatic or resectable/ablatable metastatic disease are discussed in the complete version of the NCCN Guidelines for Colon Cancer available at NCCN.org. Additional topics covered in the complete version include risk assessment, staging, pathology, posttreatment surveillance, and survivorship.

Practice and prospects for PET/CT guided interventions

During the past 10 years, performing real-time molecular imaging with positron emission tomography (PET) in combination with computed tomography (CT) during interventional procedures has undergone rapid development. Keeping in mind the interest of the nuclear medicine readers, an update is provided of the current workflows using real-time PET/CT in percutaneous biopsies and tumor ablations. The clinical utility of PET/CT guided biopsies in cancer patients with lung, liver, lymphoma, and bone tumors are reviewed. Several technological developments, including the introduction of new PET tracers and robotic arms as well as opportunities provided through acquiring radioactive biopsy specimens are briefly reviewed.

The Role of Percutaneous Ablation in the Management of Colorectal Cancer Liver Metastatic Disease

Approximately 50% of colorectal cancer patients will develop metastases during the course of the disease. Local or locoregional therapies for the treatment of liver metastases are used in the management of oligometastatic colorectal liver disease, especially in nonsurgical candidates. Thermal ablation (TA) is recommended in the treatment of limited liver metastases as free-standing therapy or in combination with surgery as long as all visible disease can be eradicated. Percutaneous TA has been proven as a safe and efficacious therapy offering sustained local tumor control and improved patient survival. Continuous technological advances in diagnostic imaging and guidance tools, the evolution of devices allowing for optimization of ablation parameters, as well as the ability to perform margin assessment have improved the efficacy of ablation. This allows resectable small volume diseases to be cured with percutaneous ablation. The ongoing detailed information and increasing understanding of tumor biology, genetics, and tissue biomarkers that impact oncologic outcomes as well as their implications on the results of ablation have further allowed for treatment customization and improved oncologic outcomes even in those with more aggressive tumor biology. The purpose of this review is to present the most common indications for image-guided percutaneous ablation in colorectal cancer liver metastases, to describe technical considerations, and to discuss relevant peer-reviewed evidence on this topic. The growing role of imaging and image-guidance as well as controversies regarding several devices are addressed.

Iliac-enteric fistula managed by endovascular covered stent placement using extra-vascular microwire snaring: a case report

Background

Although snaring technique is a commonly used tool in the interventional radiologists’ armamentarium, there are no reports of its use in an extra-vascular space to achieve access across a pseudoaneurysm that was otherwise non-traversable.

Case presentation

We describe a case of an iliac-enteric fistula between a ruptured pseudoaneurysm of the external iliac artery and a surrounding contained colonic perforation, where access across the pseudoaneurysm was achieved only after snaring of the microwire from within the contained colonic perforation and back into the intra-vascular space, allowing the placement of a covered stent and control of the bleeding.

Conclusions

The described technique may be useful in situations where other, more conventional, endovascular techniques fail to achieve access across the bleeding pseudoaneurysm. While it was life-saving in this case, this technique should only be used in very limited scenarios, specifically in the palliative setting and when surgical management is not an option.

KRAS mutation effects on the 2-[18F]FDG PET uptake of colorectal adenocarcinoma metastases in the liver

Background

Deriving individual tumor genomic characteristics from patient imaging analysis is desirable. We explore the predictive value of 2-[18F]FDG uptake with regard to the KRAS mutational status of colorectal adenocarcinoma liver metastases (CLM).

Methods

2-[18F]FDG PET/CT images, surgical pathology and molecular diagnostic reports of 37 patients who underwent PET/CT-guided biopsy of CLM were reviewed under an IRB-approved retrospective research protocol. Sixty CLM in 39 interventional PET scans of the 37 patients were segmented using two different auto-segmentation tools implemented in different commercially available software packages. PET standard uptake values (SUV) were corrected for: (1) partial volume effect (PVE) using cold wall-corrected contrast recovery coefficients derived from phantom spheres with variable diameter and (2) variability of arterial tracer supply and variability of uptake time after injection until start of PET scan derived from the tumor-to-blood standard uptake ratio (SUR) approach. The correlations between the KRAS mutational status and the mean, peak and maximum SUV were investigated using Student’s t test, Wilcoxon rank sum test with continuity correction, logistic regression and receiver operation characteristic (ROC) analysis. These correlation analyses were also performed for the ratios of the mean, peak and maximum tumor uptake to the mean blood activity concentration at the time of scan: SUR_MEAN, SUR_PEAK and SUR_MAX, respectively.

Results

Fifteen patients harbored KRAS missense mutations (KRAS+), while another 3 harbored KRAS gene amplification. For 31 lesions, the mutational status was derived from the PET/CT-guided biopsy. The Student’s t test p values for separating KRAS mutant cases decreased after applying PVE correction to all uptake metrics of each lesion and when applying correction for uptake time variability to the SUR metrics. The observed correlations were strongest when both corrections were applied to SUR_MAX and when the patients harboring gene amplification were grouped with the wild type: p ≤ 0.001; ROC area under the curve = 0.77 and 0.75 for the two different segmentations, respectively, with a mean specificity of 0.69 and sensitivity of 0.85.

Conclusion

The correlations observed after applying the described corrections show potential for assigning probabilities for the KRAS missense mutation status in CLM using 2-[18F]FDG PET images.

Factors Associated With Local Tumor Control and Complications After Thermal Ablation of Colorectal Cancer Liver Metastases: A 15-year Retrospective Cohort Study

INTRODUCTION

The purpose of this study was to identify risk factors associated with local tumor progression-free survival (LTPFS) and complications after colorectal liver metastases (CLM) thermal ablation (TA).

PATIENTS AND METHODS

This retrospective analysis included 286 patients with 415 CLM undergoing TA (radiofrequency and microwave ablation) in 378 procedures from January 2003 to July 2017. Prior hepatic artery infusion (HAI), bevacizumab, pre-existing biliary dilatation, ablation modality, minimal ablation margin (MM), prior hepatectomy, CLM number, and size were analyzed as factors influencing complications and LTPFS. Statistical analysis included the Kaplan-Meier method, Cox proportional hazards model, competing risk analysis, univariate/multivariate logistic/exact logistic regressions, and the Fisher exact test. Complications were reported according to modified Society of Interventional Radiology guidelines.

RESULTS

The median follow-up was 31 months. There was no LTP for MM > 10 mm. Smaller tumor size, increased MM, and prior hepatectomy correlated with longer LTPFS. The major complications occurred following 28 (7%) of 378 procedures. There were no biliary complications in HAI-naive patients, versus 11% in HAI patients (P < .001), of which 7% were major. Biliary complications predictors in HAI patients included biliary dilatation, bevacizumab, and MM > 10 mm. In HAI patients, ablation with 6 to 10 mm and > 10 mm MM resulted in major biliary complication rates of 4% and 21% (P = .0011), with corresponding LTP rates of 24% and 0% (P = .0033). In HAI-naive patients, the LTP rates for 6 to 10 mm and > 10 mm MM were 27% and 0%, respectively.

CONCLUSIONS

No LTP was seen for MM > 10 mm. Biliary complications occurred only in HAI patients, especially in those with biliary dilatation, bevacizumab, and MM > 10 mm. In HAI patients, MM of 6 to 10 mm resulted in 76% local tumor control and 4% major biliary complications incidence.

Induction and characterization of pancreatic cancer in a transgenic pig model

BACKGROUND

Preclinical testing of new locoregional therapies for pancreatic cancer has been challenging, due to the lack of a suitable large animal model.

PURPOSE

To develop and characterize a porcine model of pancreatic cancer. Unlike small animals, pigs have similar physiology, drug dosing, and immune response to humans. Locoregional therapy in pigs can be performed using the same size catheters and devices as in humans.

METHODS

The Oncopig is a transgenic pig with Cre-inducible TP53R167H and KRASG12D mutations. In 12 Oncopigs, CT-guided core biopsy of the pancreas was performed. The core biopsy was incubated with an adenoviral vector carrying the Cre recombinase gene. The transformed core biopsy was injected back into the pancreas (head, tail, or both). The resulting tumors (n = 19) were characterized on multi-phase contrast-enhanced CT, and on pathology, including immunohistochemistry. Angiographic characterization of the tumors was performed in 3 pigs.

RESULTS

Pancreatic tumors developed at 19 out of 22 sites (86%) that were inoculated. Average tumor size was 3.0 cm at 1 week (range: 0.5-5.1 cm). H&E and immunohistochemical stains revealed undifferentiated carcinomas, similar to those of the pancreatobiliary system in humans. Neoplastic cells were accompanied by a major inflammatory component. 1 of 12 pigs only had inflammatory nodules without evidence of neoplasia. On multiphase CT, tumors were hypovascular compared to the normal pancreas. There was no pancreatic duct dilation. In 3 pigs, angiography was performed, and in all 3 cases, the artery supplying the pancreatic tumor could be catheterized using a 2.4 F microcatheter. Selective angiography showed the pancreatic tumor, without extra-pancreatic perfusion.

CONCLUSION

Pancreatic cancer can be induced in a transgenic pig. Intra-arterial procedures using catheters designed for human interventions were technically feasible in this large animal model.

Small Bowel Adenocarcinoma, Version 1.2020, NCCN Clinical Practice Guidelines in Oncology

Small bowel adenocarcinoma (SBA) is a rare malignancy of the gastrointestinal tract that has increased in incidence across recent years. Often diagnosed at an advanced stage, outcomes for SBA are worse on average than for other related malignancies, including colorectal cancer. Due to the rarity of this disease, few studies have been done to direct optimal treatment, although recent data have shown that SBA responds to treatment differently than colorectal cancer, necessitating a separate approach to treatment. The NCCN Guidelines for Small Bowel Adenocarcinoma were created to establish an evidence-based standard of care for patients with SBA. These guidelines provide recommendations on the workup of suspected SBA, primary treatment options, adjuvant treatment, surveillance, and systemic therapy for metastatic disease. Additionally, principles of imaging and endoscopy, pathologic review, surgery, radiation therapy, and survivorship are described.

NCCN Guidelines Insights: Rectal Cancer, Version 6.2020

The NCCN Guidelines for Rectal Cancer provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with rectal cancer. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines. These updates include clarifying the definition of rectum and differentiating the rectum from the sigmoid colon; the total neoadjuvant therapy approach for localized rectal cancer; and biomarker-targeted therapy for metastatic colorectal cancer, with a focus on new treatment options for patients with BRAF V600E- or HER2 amplification-positive disease.

Fluorodeoxyglucose-PET for Ablation Treatment Planning, Intraprocedural Monitoring, and Response

PET has become an essential tool for staging and response assessment in oncologic imaging. Over the past decade it has also evolved into a tool for image-guided interventions, specifically in the rapidly growing field of interventional oncology. PET-guided biopsies have greater sensitivity and diagnostic yield for fluorodeoxyglucose-avid lesions. Real-time PET imaging can also provide valuable image guidance during therapeutic minimally invasive procedures such as ablation of PET-avid tumors. The increasing use of PET in the assessment of therapeutic response results in earlier identification of disease that is amenable to image-guided therapies.

Immediate post-thermal ablation biopsy of colorectal liver metastases to predict oncologic outcomes

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Background: Thermal ablation (TA) is used as a local cure for selected colorectal liver metastases (CLM) with minimal risk. A critical limitation of TA has been early local tumor progression (LTP). The goal of this study is to establish the role of ablation zone (AZ) biopsy in predicting LTP. Methods: This institutional review board-approved prospective study included patients with CLM of 5cm or less in maximum diameter, with confined liver disease or stable, limited extrahepatic disease. Both radiofrequency(RF) and microwave(MW) ablation modalities were used. A biopsy of the center and margin of the AZ was performed immediately after ablation. The applicators were also examined for the presence of viable tumor cells. All samples containing morphologically identified tumor cells were further interrogated with immunohistochemistry to determine the proliferative and viability potential of the detected tumor cells. Ablation margin size was evaluated on the first CT scan performed 4–8 weeks after ablation and was confirmed by 3D assessment with Ablation Confirmation Software (Neuwave™). Variables were evaluated as predictors of time to LTP with the competing-risks model (uni- and multivariate analyses). Results: Between November 2009 and February 2019, 102 patients with 182 CLMs were enrolled. Mean tumor size was 2.0 cm (range, 0.6–4.8 cm). MW was used in 95/182 (52%) tumors and RF in 87/182 (48%). Median follow-up was 19 months. Technical effectiveness was evident in 178/182 (97%) ablated tumors on the first contrast material–enhanced CT at 4–8-weeks post-ablation. The cumulative incidence of LTP at 12 months was 19% (95% confidence interval [CI]: 14, 27). Samples from 64 (35%) of the 178 technically successful cases contained viable tumor. At univariate analysis, tumor size, minimal margin size, and biopsy results were significant in predicting LTP. In a multivariate model, margin size of less than 5 mm (P < .001; hazard ratio [HR], 4.3), and positive biopsy results (P = .02; HR, 1.8) remained significant. LTP within 12 months after TA was noted in 3% (95% CI: 1, 6) of tumor-negative biopsy CLMs with margins of at least 5 mm. Conclusions: Biopsy and pathologic examination of the AZ predicts LTP regardless of TA modality used. This can optimize ablation as a potential local cure for patients with limited CLM.

PET/CT Imaging Characteristics After Radioembolization of Hepatic Metastasis from Breast Cancer

PURPOSE

To define positron emission tomography/computed tomography (PET/CT) imaging characteristics during follow-up of patients with metastatic breast cancer (MBC) treated with yttrium-90 (Y90) radioembolization (RE).

MATERIALS AND METHODS

From January 2011 to October 2017, 30 MBC patients underwent 38 Y90 glass or resin RE treatments. Pre-RE PET/CT was performed on average 51 days before RE. There were 68 PET/CTs performed after treatment. Response was assessed using modified PERCIST criteria focusing on the hepatic territory treated with RE, normalizing SUVpeak to the mean SUV of liver uninvolved by tumor. An objective response (OR) was defined as a decrease in SUVpeak by at least 30%.

RESULTS

Of the 68 post-RE scans, 6 were performed at 0-30 days, 15 at 31-60 days, 9 at 61-90 days, 13 at 91-120 days, 14 scans at 121-180 days, and 11 scans at > 180 days after RE. Of the 30 patients, 25 (83%) achieved OR on at least one follow-up. Median survival was 15 months after the first RE administration. Highest response rates occurred at 30-90 days, with over 75% of cases demonstrating OR at that time. After 180 days, OR was seen in only 25%. There was a median TTP of 169 days among responders.

CONCLUSION

In MBC, follow-up PET/CT after RE demonstrates optimal response rates at 30-90 days, with progression noted after 180 days. These results help to guide the timing of imaging and also to inform patients of expected outcomes after RE.

Thermal Ablation of Metastatic Colon Cancer to the Liver

Colorectal cancer (CRC) is responsible for approximately 10% of cancer-related deaths in the Western world. Liver metastases are frequently seen at the time of diagnosis and throughout the course of the disease. Surgical resection is often considered as it provides long-term survival; however, few patients are candidates for resection. Percutaneous ablative therapies are also used in the management of this patient population. Different thermal ablation (TA) technologies are available including radiofrequency ablation, microwave ablation (MWA), laser, and cryoablation. There is growing evidence about the role of interventional oncology and image-guided percutaneous ablation in the management of metastatic colorectal liver disease. This article aims to outline the technical considerations, outcomes, and rational of TA in the management of patients with CRC liver metastases, focusing on the emerging role of MWA.

Rectal Cancer, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Rectal Cancer address diagnosis, staging, surgical management, perioperative treatment, management of recurrent and metastatic disease, disease surveillance, and survivorship in patients with rectal cancer. This portion of the guidelines focuses on the management of localized disease, which involves careful patient selection for curative-intent treatment options that sequence multimodality therapy usually comprised of chemotherapy, radiation, and surgical resection.

Anal Carcinoma, Version 2.2018, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Anal Carcinoma provide recommendations for the management of patients with squamous cell carcinoma of the anal canal or perianal region. Primary treatment of anal cancer usually includes chemoradiation, although certain lesions can be treated with margin-negative local excision alone. Disease surveillance is recommended for all patients with anal carcinoma because additional curative-intent treatment is possible. A multidisciplinary approach including physicians from gastroenterology, medical oncology, surgical oncology, radiation oncology, and radiology is essential for optimal patient care.

NCCN Guidelines Insights: Colon Cancer, Version 2.2018

The NCCN Guidelines for Colon Cancer provide recommendations regarding diagnosis, pathologic staging, surgical management, perioperative treatment, surveillance, management of recurrent and metastatic disease, and survivorship. These NCCN Guidelines Insights summarize the NCCN Colon Cancer Panel discussions for the 2018 update of the guidelines regarding risk stratification and adjuvant treatment for patients with stage III colon cancer, and treatment of BRAF V600E mutation-positive metastatic colorectal cancer with regimens containing vemurafenib.