Response criteria for immunotherapy and the radiologic patterns of immune-related adverse events.

Immunotherapy has revolutionized clinical outcomes in both early-stage and advanced-stage malignancies. Immunotherapy has improved patient survival in both solid and hematologic disorders with the potential added benefit of less toxicity compared to conventional cytotoxic chemotherapy. Imaging plays a fundamental role in monitoring treatment response and assessment of immune-related adverse events, e.g. pneumonitis, colitis, etc. Familiarity with the current strategies of immune-related response evaluation and their limitations is essential for radiologists to guide clinicians with their treatment decisions. Radiologists should be aware of the wide spectrum of immune-related adverse events and their various radiological features as well as the patterns of treatment response associated with immunotherapies.

Are radiologists ready to evaluate true response to immunotherapy?

BACKGROUND: Standardized response criteria for evaluating patients radiological imaging have an essential role in oncological management. Immunotherapy, using immune checkpoint inhibitors (ICIs), including drugs targeting cytotoxic T-lymphocyte-associated antigen 4 and programmed cell death protein 1 or its ligand, promise a new role that has demonstrated improvement management in cancers resistant to chemotherapy. This article reviews the literature to understand the most useful response evaluation criteria for optimal patient management under immunotherapy treatment. Areas that warrant further research are described. CONCLUSION: In conclusion, ICIs have become more widely accepted and used by medical oncologists. Radiologists face challenges in assessing tumor response and becoming more involved in the management of treatment. The latest published immune-RECIST criteria can be used in response assessment, but further prospective evaluation is needed with registration clinical trials to be definitively validated.

Cancer Imaging in Immunotherapy.

Immune therapeutics are revolutionizing cancer treatments. In tandem, new and confounding imaging characteristics have appeared that are distinct from those typically seen with conventional cytotoxic therapies. In fact, only 10% of patients on immunotherapy may show tumor shrinkage, typical of positive responses on conventional therapy. Conversely, those on immune therapies may initially demonstrate a delayed response, transient enlargement followed by tumor shrinkage, stable size, or the appearance of new lesions. New imaging response criteria, such as the immune-related Response Evaluation Criteria in Solid Tumors (irRECIST) and immune-related Response Criteria (irRC), are being implemented in many trials. However, FDA approval of emerging therapies, including immunotherapies, still relies on the current RECIST criteria. In this chapter, we review the traditional and new imaging response criteria for evaluation of solid tumors and briefly touch on some of the more commonly associated immunotherapy-induced adverse events.

Response evaluation for immunotherapy through semi-automatic software based on RECIST 1.1, irRC, and iRECIST criteria: comparison with subjective assessment.

BACKGROUND: Pseudoprogression is difficult to diagnose in patients undergoing immunotherapy. Subjective response assessment is still common in clinical practice. PURPOSE: To evaluate the differences between response evaluation criteria in solid tumors version 1.1 (RECIST 1.1), immune-related response criteria (irRC), and modified RECIST 1.1 for immunotherapy (iRECIST) through semi-automatic software, and to compare iRECIST-based response evaluation with subjective assessment. MATERIAL AND METHODS: The best overall response of each patient based on RECIST 1.1, irRC, and iRECIST was determined on CT scans through semi-automatic software and the differences between the criteria were evaluated. Criteria-based response evaluation through semi-automatic software was compared with subjective assessment on radiology report by correlating the best overall response to overall survival. RESULTS: A total of 21 patients were included (five patients with melanoma, 12 patients with non-small-cell lung cancer, and four patients with hepatocellular carcinoma). Two patients with progressive disease by RECIST 1.1 but non-progressive disease by irRC and iRECIST eventually experienced tumor response and had favorable outcomes, indicating pseudoprogression. The survival difference between patients with non-progressive disease and progressive disease was better stratified through iRECIST-based response evaluation (P = 0.078) than that through subjective assessment (P = 0.501). CONCLUSION: Pseudoprogression in immunotherapy may be captured through semi-automatic software utilizing irRC or iRECIST criteria. iRECIST-based response evaluation may provide a better survival stratification compared with subjective assessment.

[Tumour assessment criteria for immune checkpoint inhibitors]. / Critères d'évaluation de la réponse tumorale aux inhibiteurs des points de contrôle immunitaire.

The development of immune checkpoint inhibitors in thoracic oncology has led to a reconsideration of the rules for radiological tumor assessment. The RECIST criteria are widely used for the assessment of conventional treatments but are not suitable for anti-tumoral immunotherapy. The mechanism of action of this new class of drugs may induce specific patterns of response, which are not fully assessed by the RECIST criteria. Several new criteria have been proposed to better detect these patterns of response. The changes usually include confirmation of progression, new ways of assessing new lesions, and a larger role for clinical assessment. Nevertheless, harmonization and validation of these criteria remains indispensable. In this review, we will detail the different criteria that are currently available, and discuss their strengths and weaknesses.

The evolving landscape of criteria for evaluating tumor response in the era of cancer immunotherapy: From Karnofsky to iRECIST.

The objective response is an important endpoint to evaluate clinical activity of new anticancer drugs. Standardized criteria for evaluating response are needed for comparing results of different trials and represent the basis for advances in cancer therapy. Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 are the most used in clinical practice and in clinical trials; however, they are not able to capture atypical responses seen with immunotherapy drugs. We describe the evolution of response criteria with a special focus on the immune-related criteria.

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.

Cancer Imaging in Immunotherapy.

Immune therapeutics are revolutionizing cancer treatments. In tandem, new and confounding imaging characteristics have appeared that are distinct from those typically seen with conventional cytotoxic therapies. In fact, only 10% of patients on immunotherapy may show tumor shrinkage, typical of positive responses on conventional therapy. Conversely, those on immune therapies may initially demonstrate a delayed response, transient enlargement followed by tumor shrinkage, stable size, or the appearance of new lesions. New imaging response criteria such as the immune-related Response Evaluation Criteria in Solid Tumors (irRECIST) and immune-related Response Criteria (irRC) are being implemented in many trials. However, FDA approval of emerging therapies including immunotherapies still relies on the current RECIST criteria. In this review, we review the traditional and new imaging response criteria for evaluation of solid tumors and briefly touch on some of the more commonly associated immunotherapy-induced adverse events.

Defining Clinical Response Criteria and Early Response Criteria for Precision Oncology: Current State-of-the-Art and Future Perspectives.

In this era of precision oncology, there has been an exponential growth in the armamentarium of genomically targeted therapies and immunotherapies. Evaluating early responses to precision therapy is essential for "go" versus "no go" decisions for these molecularly targeted drugs and agents that arm the immune system. Many different response assessment criteria exist for use in solid tumors and lymphomas. We reviewed the literature using the Medline/PubMed database for keywords "response assessment" and various known response assessment criteria published up to 2016. In this article we review the commonly used response assessment criteria. We present a decision tree to facilitate selection of appropriate criteria. We also suggest methods for standardization of various response assessment criteria. The relevant response assessment criteria were further studied for rational of development, key features, proposed use and acceptance by various entities. We also discuss early response evaluation and provide specific case studies of early response to targeted therapy. With high-throughput, advanced computing programs and digital data-mining it is now possible to acquire vast amount of high quality imaging data opening up a new field of "omics in radiology"-radiomics that complements genomics for personalized medicine. Radiomics is rapidly evolving and is still in the research arena. This cutting-edge technology is poised to move soon to the mainstream clinical arena. Novel agents with new mechanisms of action require advanced molecular imaging as imaging biomarkers. There is an urgent need for development of standardized early response assessment criteria for evaluation of response to precision therapy.

WHO, RECIST, and immune-related response criteria: is it time to revisit pembrolizumab results?

In recent years, with the rise of immunotherapeutic agents for cancer treatment, we have observed a paradigm shift in oncology drug development. One common problem accompanying such paradigm shifts is how to build research strategies to fit the mechanism of action of the newer compounds. Developing immunotherapy in oncology requires us to address the unique characteristics of immunotherapeutic agents and to provide adequate tools for their evaluation, including the adjustment of clinical trial endpoints. Immunotherapy creates patterns of response different from those of chemotherapy, and thus they are not captured by the traditional World Health Organisation (WHO) tumour response criteria or the RECIST. Revisiting the results of pembrolizumab in patients with melanoma can help to evaluate the efficacy of the immune-related response criteria (irRC) as the gold standard for evaluating the clinical response of immunologic agents in oncology.

[Recommendations for radiological diagnosis and assessment of treatment response in lung cancer: a national consensus statement by the Spanish Society of Medical Radiology and the Spanish Society of Medical Oncology]. / Recomendaciones para el diagnóstico radiológico y la valoración de la respuesta terapéutica en el cáncer de pulmón. Consenso nacional de la Sociedad Española de Radiología Médica y la Sociedad Española de Oncología Médica.

The last decade has seen substantial progress in the diagnostic and therapeutic approach to lung cancer, thus meaning that its prognosis has improved. The Spanish Society of Medical Radiology (SERAM) and the Spanish Society of Medical Oncology (SEOM) have therefore produced a national consensus statement in order to make recommendations for radiological diagnosis and assessment of treatment response in patients with lung cancer. This expert group recommends multi-detector computed tomography (MDCT) as the technique of choice for investigating this disease. The radiology report should include a full assessment by the TNM staging system. Lastly, when the patient is on immunotherapy, response evaluation should employ not only Response Evaluation Criteria in Solid Tumours (RECIST 1.1) but also Immune-Related Response Criteria (irRC).