RECIST 1.1, irRECIST 1.1, and mRECIST: How to Do

Technical Feasibility and Safety of Image-Guided Biphasic Monopolar Pulsed Electric Field Ablation of Metastatic and Primary Malignancies

PURPOSE

To assess the technical feasibility and safety of image-guided percutaneous biphasic monopolar pulsed electric field (PEF) ablation of primary and metastatic tumors.

MATERIALS AND METHODS

With institutional review board (IRB) approval and Health Insurance Portability and Accountability Act (HIPAA) compliance, this retrospective, single-institution study cohort of 17 patients (mean age, 53.5 years; range, 20-94 years) with overall progressive disease underwent 26 PEF ablation procedures for 30 metastatic (90%) and primary (10%) target lesions in the thorax (n = 20), abdomen (n = 7), and head and neck (n = 3). Concurrent systemic therapy was used in 14 of the 17 patients (82%). Follow-up imaging was scheduled for 1, 3, and 6 months after PEF ablation, and target and off-target lesion sizes were recorded. The overall response was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria with imaging immediately before PEF serving as baseline. Adverse events (AEs) were determined by the Society of Interventional Radiology (SIR) classification.

RESULTS

PEF ablation procedures were well tolerated and technically feasible for all 17 patients. The mean initial sizes of the target and off-target tumors were 2.6 cm (standard deviation [SD] ± 1.5; range, 0.4-6.9 cm) and 2.2 cm (SD ± 1.1; range, 1.0-5.2 cm), respectively. Overall, 15 of the 30 (50%) target lesions and 12 of the 24 (50%) off-target lesions were unchanged or decreased in size at the patient's last follow-up. Eight patients had overall stable disease (47%) at the last follow-up. Of the 26 AEs, there were 9 mild (35%) and 1 moderate (4%) AE.

CONCLUSIONS

All PEF procedures were technically feasible with 1 moderate AE and stable disease for 47% of patients with a median follow-up period of 3 months.

Real-life multi-center retrospective analysis on nivolumab in difficult-to-treat patients with advanced hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. The landscape of the systemic treatment for advanced HCC is changing quickly, and recently, the standard of care became either atezolizumab plus bevacizumab or tremelimumab plus durvalumab in the single tremelimumab regular interval durvalumab regimen. Nivolumab monotherapy has proven to be effective sometimes for advanced HCC and could be a valuable treatment option for patients outside current treatment indications and reimbursement criteria for the standard of care. This is a particular population of interest.

AIM

To evaluate the real-world effectiveness of nivolumab monotherapy in patients with advanced HCC who are not eligible for other treatment.

METHODS

We conducted a retrospective, multicentric study including 29 patients with advanced HCC from 3 Belgian tertiary hospitals. All patients had had prior chemotherapy or were intolerant or ineligible for treatments. All study subjects received nivolumab 3 mg/kg in monotherapy, administered once every two weeks intravenously. Treatment continued until disease progression, severe adverse events or death. Data were retrieved from patients' medical records. The outcome parameters such as radiological response according to response evaluation criteria in solid tumors (RECIST) criteria, the biological response through the evolution of the alpha-fetoprotein (AFP) level, and clinical response considering both the Child-Pugh (CP) score and the World Health Organization (WHO) performance status (PS) were reported. A safety profile was also reported. Statistical analysis was performed using the SPSS Statistics 27 statistical software package.

RESULTS

The radiological overall response rate (defined as complete or partial response according to the immune RECIST and modified RECIST criteria) to nivolumab monotherapy was 24.1%. The biological overall response rate (defined as a decrease of ≥ 25% in AFP blood level) was 20.7%. Radiological and biological responses were significantly associated both with each other (P < 0.001) and with overall survival (P < 0.005 for radiological response and P < 0.001 for biological response). Overall survival was 14.5 mo (+/- 2.1), and progression-free survival was 10.9 mo (+/- 2.3). After 4 mo of treatment, 78.3% of patients remained clinically stable or even showed improvement in WHO PS. Grade 3 adverse events occurred in 17.2% of patients, none had grade 4 adverse events, and no patients ceased nivolumab due to adverse events.

CONCLUSION

Nivolumab monotherapy is a good treatment choice in frail patients with HCC who are ineligible for the standard of care or other validated systemic treatments.

Safety, antitumor activity, and pharmacokinetics of dostarlimab, an anti-PD-1, in patients with advanced solid tumors: a dose-escalation phase 1 trial

PURPOSE

New immuno-oncology therapies targeting programmed cell death receptor 1 (PD-1) have improved patient outcomes in a broad range of cancers. The objective of this analysis was to evaluate the PK, pharmacodynamics (PDy), and safety of dostarlimab monotherapy in adult patients with previously-treated advanced solid tumors who participated in parts 1 and 2A of the phase 1 GARNET study.

METHODS

Part 1 featured a 3 + 3 weight-based dose-escalation study, in which 21 patients received dostarlimab 1, 3, or 10 mg/kg intravenously every 2 weeks. The 2 fixed-dose nonweight-based dosing regimens of dostarlimab 500 mg every 3 weeks (Q3W) and 1000 mg every 6 weeks (Q6W) were evaluated using a modified 6 + 6 design in part 2A (n = 13). In parts 1 and 2A, treatment with dostarlimab could continue for up to 2 years or until progression, unacceptable toxicity, patient withdrawal, investigator's decision, or death.

RESULTS

The dostarlimab PK profile was dose proportional, and maximal achievable receptor occupancy (RO) was observed at all dose levels in the weight-based and fixed-dose cohorts. Trough dostarlimab concentration after administration of dostarlimab 500 mg Q3W was similar to that after dostarlimab 1000 mg Q6W, the values of which (≈40 µg/mL) projected well above the lowest dostarlimab concentration required for full peripheral RO. No dose-limiting toxicities were observed.

CONCLUSIONS

Dostarlimab demonstrated consistent and predictable PK and associated PDy. The observed safety profile was acceptable and characteristic of the anti-PD-1 drug class.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02715284. Registration date: March 9, 2016.

18F-PSMA-1007 PET/CT for response assessment in patients with metastatic renal cell carcinoma undergoing tyrosine kinase or checkpoint inhibitor therapy: preliminary results

Introduction

Tyrosine kinase (TKI) and checkpoint inhibitors (CI) prolonged overall survival in metastatic renal cell carcinoma (mRCC). Early prediction of treatment response is highly desirable for the individualization of patient management and improvement of therapeutic outcome; however, serum biochemistry is unable to predict therapeutic efficacy. Therefore, we compared ¹⁸F-PSMA-1007 PET imaging for response assessment in mRCC patients undergoing TKI or CI therapy compared to CT-based response assessment as the current imaging reference standard.

Methods

¹⁸F-PSMA-1007 PET/CT was performed in mRCC patients prior to initiation of systemic treatment and 8 weeks after therapy initiation. Treatment response was evaluated separately on ¹⁸F-PSMA-PET and CT. Changes on PSMA-PET (SUV_mean) were assessed on a per patient basis using a modified PERCIST scoring system. Complete response (CR_PET) was defined as absence of any uptake in all target lesions on posttreatment PET. Partial response (PR_PET) was defined as decrease in summed SUV_mean of > 30%. The appearance of new, PET-positive lesions or an increase in summed SUV_mean of > 30% was defined as progressive disease (PD_PET). A change in summed SUV_mean of ± 30% defined stable disease (SD_PET). RECIST 1.1 criteria were used for response assessment on CT. Results of radiographic response assessment on PSMA-PET and CT were compared.

Results

Overall, 11 mRCC patients undergoing systemic treatment were included. At baseline PSMA-PET₁, all mRCC patients showed at least one PSMA-avid lesion. On follow-up PET₂, 3 patients showed CR_PET, 3 PR_PET, 4 SD_PET, and 1 PD_PET. According to RECIST 1.1, 1 patient showed PR_CT, 9 SD_CT, and 1 PD_CT. Overall, concordant classifications were found in only 2 cases (2 SD_CT + PET). Patients with CR_PET on PET were classified as 3 SD_CT on CT using RECIST 1.1. By contrast, the patient classified as PR_CT on CT showed PSMA uptake without major changes during therapy (SD_PET). However, among 9 patients with SD_CT on CT, 3 were classified as CR_PET, 3 as PR_PET, 1 as PD_PET, and only 2 as SD_PET on PSMA-PET.

Conclusion

On PSMA-PET, heterogeneous courses were observed during systemic treatment in mRCC patients with highly diverging results compared to RECIST 1.1. In the light of missing biomarkers for early response assessment, PSMA-PET might allow more precise response assessment to systemic treatment, especially in patients classified as SD on CT.

Deep learning workflow in radiology: a primer

Interest for deep learning in radiology has increased tremendously in the past decade due to the high achievable performance for various computer vision tasks such as detection, segmentation, classification, monitoring, and prediction. This article provides step-by-step practical guidance for conducting a project that involves deep learning in radiology, from defining specifications, to deployment and scaling. Specifically, the objectives of this article are to provide an overview of clinical use cases of deep learning, describe the composition of multi-disciplinary team, and summarize current approaches to patient, data, model, and hardware selection. Key ideas will be illustrated by examples from a prototypical project on imaging of colorectal liver metastasis. This article illustrates the workflow for liver lesion detection, segmentation, classification, monitoring, and prediction of tumor recurrence and patient survival. Challenges are discussed, including ethical considerations, cohorting, data collection, anonymization, and availability of expert annotations. The practical guidance may be adapted to any project that requires automated medical image analysis.

[Radiological response assessment of modern immunotherapy using iRECIST]

CLINICAL/METHODICAL ISSUE

Modern immunotherapies in oncology show tumor response patterns differing from conventional chemotherapies including initial pseudo-progression.

STANDARD RADIOLOGICAL METHODS

Response evaluation criteria in solid tumors (RECIST 1.1) represent the currently most used response criteria for conventional chemotherapy of solid tumors. However, atypical response patterns of immunotherapies are not correctly classified using RECIST 1.1 so that the effectiveness is also incorrectly interpreted.

METHODICAL INNOVATIONS

In order to correctly interpret these atypical response patterns, special immune-related response criteria in solid tumors (iRECIST) have been published. In contrast to RECIST 1.1 according to iRECIST an initially unconfirmed progressive disease (iUPD) requires confirmation (iCPD) in clinically stable patients by subsequent control imaging after 4-8 weeks. New lesions are separately assessed within iRECIST.

PERFORMANCE

The iRECIST procedure allows a standardized objective assessment of a possible pseudo-progression which can occur in up to 10% of cases depending on the immunomodulating drug and tumor entity.

ACHIEVEMENTS

In principle, iRECIST was developed only for usage in trials testing modern immunotherapeutics.

PRACTICAL RECOMMENDATIONS

The iRECIST procedure might also be helpful as an additional objective response criterium for clinical treatment decisions, taking the limitations into account.

Immunotherapy and the role of imaging

Significant advances in the genetic and molecular characterization of cancer have led to the development of effective immunotherapies. These therapeutics help the host immune system recognize cancer as foreign, promote the immune system, and relieve the inhibition that allows growth and spread of tumors. Experience with various immunotherapies, particularly the immunomodulatory monoclonal antibody ipilimumab, has demonstrated that unique patterns of response may be encountered that cannot be adequately captured by traditional response criteria, such as the World Health Organization (WHO) criteria and Response Evaluation Criteria in Solid Tumors (RECIST), which have been used primarily with cytotoxic chemotherapies. In response to these observations, several novel response criteria have been developed to evaluate patients who receive immunotherapy, including immune-related response criteria (irRC), immune-related RECIST (irRECIST), and immune RECIST (iRECIST). These criteria are typically used in conjunction with RECIST version 1.1 in the clinical trial setting, because approval of new therapeutics by the US Food and Drug Administration relies on the responses derived from RECIST version 1.1. Finally, a wide variety of immune-related adverse events may affect patients who receive immunotherapy, many of which can be identified on imaging studies such as computed tomography, magnetic resonance imaging, and 2-deoxy-2-(fluorine-18)fluoro-D-glucose-positron emission tomography/computed tomography. In this review, the authors present the role of imaging in the evaluation of patients treated with immunotherapy, including the background and application of irRC, irRECIST, and iRECIST; the imaging of immune-related adverse events; and future directions in advanced imaging of immunotherapy. Cancer 2018;124:2906-22. © 2018 American Cancer Society.

Predicting response and toxicity to immune checkpoint inhibitors using routinely available blood and clinical markers

Immune checkpoint inhibitors (ICI) are an important development in the treatment of advanced cancer. A substantial proportion of patients treated with ICI do not respond, and additionally patients discontinue treatment due to adverse effects. While many novel biological markers related to the specific mechanisms of ICI actions have been investigated, there has also been considerable research to identify routinely available blood and clinical markers that may predict response to ICI therapy. If validated, these markers have the advantage of being easily integrated into clinical use for nominal expense. Several markers have shown promise, including baseline and post-treatment changes in leucocyte counts, lactate dehydrogenase and C-reactive protein. While promising, the results between studies have been inconsistent due to small sample sizes, follow-up time and variability in the assessed markers. To date, research on routinely available blood and clinical markers has focussed primarily on ICI use in melanoma, the use of ipilimumab and on univariate associations, but preliminary evidence is emerging for other cancer types, other ICIs and for combining markers in multivariable clinical prediction models.