Thoracic Imaging of Non-Small Cell Lung Cancer Treated With Anti-programmed Death Receptor-1 Therapy

Comparison of RECIST and iRECIST criteria in patients with advanced lung cancer treated with nivolumab

Background

Systemic therapy in lung cancer is mainstay of treatment as most patients present in advanced stages, with rising importance of new immunotherapy agents.

Purpose

To compare the RECIST 1.1 and the immunotherapy Response Evaluation Criteria in Solid Tumors (iRECISTs) criteria for response assessment in lung cancer patients on immunotherapy. To find the incidence of pseudoprogression and associated imaging patterns.

Material and Methods

Retrospective study in 28 patients treated with immunotherapy for advanced metastatic NSCLC. End points were progression-free survival (PFS) and overall survival (OS). Response assessments were separately tabulated according to RECIST 1.1 and iRECIST and classified into dichotomous groups of responders and nonresponders. Agreement in assessments between RECIST 1.0 and iRECIST examined using Cohen kappa (κ) coefficient with 95% confidence intervals. Kaplan-Meier survival analysis was done for PFS and OS. Differences between RECIST 1.1 and iRECIST for both responder and nonresponder were evaluated by the log rank test, Breslow (Generalized Wilcoxon) test, and Tarone-Ware test.

Results

Incidence of pseudoprogression was 7% (2/28). The RECIST1.1 and iRECIST were in disagreement in two patients. The agreement between RECIST and iRECIST was almost perfect. The PFS and the OS are significantly longer in duration for responders in comparison to nonresponders for both RECIST and iRECIST and the difference between two assessment criteria is not significant.

Conclusion

Although iRECIST aims to monitor treatment more precisely than conventional response criteria, this must be weighed against how infrequent pseudoprogression is and the cost of this therapy, both financially and in the potential delay in changing to a more effective treatment.

Circulating regulatory T cells predict efficacy and atypical responses in lung cancer patients treated with PD-1/PD-L1 inhibitors

Background

Immune checkpoint inhibitors (ICIs) have become the standard of care for a variety of cancers, including non-small cell lung cancer (NSCLC). In this study, we investigated the frequency of pseudoprogression and hyperprogression in lung cancer patients treated with ICIs in the real world and aimed to discover a novel candidate marker to distinguish pseudoprogression from hyperprogression soon after ICI treatment.

Methods

This study included 74 patients with advanced NSCLC who were treated with PD-1/PD-L1 inhibitors at Chungnam National University Hospital (CNUH) between January 2018 and August 2020. Chest X-rays were examined on day 7 after the first ICI dose to identify changes in the primary mass, and the response was assessed by computed tomography (CT). We evaluated circulating regulatory T (Treg) cells using flow cytometry and correlated the findings with clinical outcomes.

Results

The incidence of pseudoprogression was 13.5%, and that of hyperprogression was 8.1%. On day 7 after initiation of treatment, the frequency of CD4⁺CD25⁺CD127^loFoxP3⁺ Treg cells was significantly decreased compared with baseline (P = 0.038) in patients who experienced pseudoprogression and significantly increased compared with baseline (P = 0.024) in patients who experienced hyperprogression. In the responder group, the frequencies of CD4⁺CD25⁺CD127^loFoxP3⁺ Treg cells and PD-1⁺CD4⁺CD25⁺CD127^loFoxP3⁺ Treg cells were significantly decreased 7 days after commencement of treatment compared with baseline (P = 0.034 and P < 0.001, respectively).

Conclusion

Circulating Treg cells represent a promising potential dynamic biomarker to predict efficacy and differentiate atypical responses, including pseudoprogression and hyperprogression, after immunotherapy in patients with NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00262-021-03018-y.

Response Prediction and Evaluation Using PET in Patients with Solid Tumors Treated with Immunotherapy

Simple Summary

In cancer treatment, immunotherapy is increasingly becoming important as a component of first-line treatment and has improved the prognosis of patients since its introduction. A large group of patients, however, do not respond to immunotherapy, and predicting a treatment response remains challenging. Furthermore, evaluating a response using conventional computed tomography (CT) scans is not straightforward due to the different mechanism of action of immunotherapy compared to chemotherapy. This review provides an overview of positron emission tomography (PET) in predicting and evaluating treatment response to immunotherapy.

Abstract

In multiple malignancies, checkpoint inhibitor therapy has an established role in the first-line treatment setting. However, only a subset of patients benefit from checkpoint inhibition, and as a result, the field of biomarker research is active. Molecular imaging with the use of positron emission tomography (PET) is one of the biomarkers that is being studied. PET tracers such as conventional ¹⁸F-FDG but also PD-(L)1 directed tracers are being evaluated for their predictive power. Furthermore, the use of artificial intelligence is under evaluation for the purpose of response prediction. Response evaluation during checkpoint inhibitor therapy can be challenging due to the different response patterns that can be observed compared to traditional chemotherapy. The additional information provided by PET can potentially be of value to evaluate a response early after the start of treatment and provide the clinician with important information about the efficacy of immunotherapy. Furthermore, the use of PET to stratify between patients with a complete response and those with a residual disease can potentially guide clinicians to identify patients for which immunotherapy can be discontinued and patients for whom the treatment needs to be escalated. This review provides an overview of the use of positron emission tomography (PET) to predict and evaluate treatment response to immunotherapy.

Immune Checkpoint Inhibitors with or without Radiotherapy in Non-Small Cell Lung Cancer Patients with Brain Metastases: A Systematic Review and Meta-Analysis

This study aimed to evaluate the radiologic response and adverse event rates of immune checkpoint inhibitor (ICI) therapy with or without radiotherapy for the treatment of non-small cell lung cancer (NSCLC) brain metastases. A systematic literature search was performed up to January 3, 2020. Studies evaluating the intracranial objective response rates (ORR) and/or disease control rates (DCR) of ICI with or without radiotherapy for treating NSCLC brain metastases were included. Consequently, twelve studies satisfied inclusion criteria. ICI combined with radiotherapy (pooled ORR, 95%; DCR, 97%) showed better local efficacy compared to ICI monotherapy (pooled ORR, 24%; DCR, 44%; p < 0.01 for both ORR and DCR). Grade 3 or 4 central nervous system (CNS)-related adverse event rates were not different (5% vs. 4%; p = 0.93). In conclusion, ICI combined with radiotherapy showed better intracranial efficacy than ICI monotherapy for treating NSCLC brain metastases. CNS-related grade 3 or 4 adverse event rate was not statistically different between the two groups. Several prospective trials are needed to compare the efficacy of ICI combined with radiotherapy and ICI monotherapy.

Pseudoprogression and hyperprogression in lung cancer: a comprehensive review of literature

PURPOSE

Immune checkpoint inhibitors are associated with clinical benefit in lung cancer. However, response patterns to immunotherapy, including pseudoprogression and hyperprogression, are difficult to diagnose, and their mechanisms remain unclear. This review aimed to describe two response patterns observed in lung cancer, namely pseudoprogression and hyperprogression, including their epidemiology, diagnostic characteristics, and plausible mechanisms.

METHODS

We performed a comprehensive literature search in the PubMed database, using keywords "pseudoprogression", "hyperprogression", and "lung cancer", among others. The literature was examined for pseudoprogression and hyperprogression characteristics and plausible mechanisms.

RESULTS

Pseudoprogression manifests in multiple forms; however, the immune system-related response criteria and biopsy data are helpful to make accurate diagnosis. Serological biomarkers, such as neutrophil-to-lymphocyte ratio (NLR) and circulating tumor DNA (ctDNA), might help distinguish pseudoprogression from true progression. The incidence of hyperprogression ranges within 5-19.2%, depending on definition. The unique response pattern of rapid progression is observed not only with immunotherapy, but also with other treatment regimens. Molecular mutations and amplifications may result in hyperprogression; however, the exact mechanism remains unclear.

CONCLUSION

Atypical response patterns, such as pseudoprogression and hyperprogression, are increasingly common in clinical practice. Immune-related response criteria can help diagnose pseudoprogression. Molecular mechanisms of hyperprogression remain unclear. Biomarkers for pseudoprogression and hyperprogression are required.

18FDG PET/CT in the early assessment of non-small cell lung cancer response to immunotherapy: frequency and clinical significance of atypical evolutive patterns

PURPOSE

This prospective study aimed (1) to assess the non-small cell lung cancer (NSCLC) evolutive patterns to immunotherapy using FDG-PET and (2) to describe their association with clinical outcome.

DESIGN

Fifty patients with metastatic NSCLC were included before pembrolizumab or nivolumab initiation. FDG-PET scan was performed at baseline and after 7 weeks of treatment (PET_interim1) and different criteria/parameters of tumor response were assessed, including PET response criteria in solid tumors (PERCIST). If a first PERCIST progressive disease (PD) without clinical worsening was observed, treatment was continued and a subsequent FDG-PET (PET_interim2) was performed at 3 months of treatment. Pseudo-progression (PsPD) was defined as a PERCIST response/stability on PET_interim2 after an initial PD. If a second PERCIST PD was assessed on PET_interim2, a homogeneous progression of lesions (termed immune homogeneous progressive-disease: iPD_homogeneous) was distinguished from a heterogeneous evolution (termed immune dissociated-response: iDR). A durable clinical benefit (DCB) of immunotherapy was defined as treatment continuation over a 6-month period. The association between PET evolutive profiles and DCB was assessed.

RESULTS

Using PERCIST on PET_interim1, 42% (21/50) of patients showed a response or stable disease, most of them (18/21) reached a DCB. In contrast, 58% (29/50) showed a PD, but more than one-third (11/29) were misclassified as they finally reached a DCB. No standard PET_interim1 criteria could accurately distinguished responding from non-responding patients. Treatment was continued in 19/29 of patients with a first PERCIST PD; the subsequent PET_interim2 demonstrated iPD_homogeneous, iDR and PsPD in 42% (8/19), 26% (5/19), and 32% (6/19), respectively. Whereas no patients with iPD_homogeneous experienced a DCB, all patients with iDR and PsPD reached a clinical benefit to immunotherapy.

CONCLUSION

In patients with a first PD on PERCIST and treatment continuation, a subsequent PET identifies more than half of them with iDR and PsPD, both patterns being strongly associated with a clinical benefit of immunotherapy.

Unusual radiologic manifestation of pseudoprogression in pulmonary metastases after durvalumab treatment in metastatic bladder urothelial cancer

Durvalumab is an immune checkpoint inhibitor that blocks PD-L1. Unlike cytotoxic chemotherapy or molecularly targeted agents, immune checkpoint inhibitors occasionally present distinct response patterns, including radiologic pseudoprogression (initial tumor enlargement with subsequent tumor regression) and immune-related adverse events in normal tissues. We report a case of unusual computed tomography (CT) findings of pseudoprogression of pulmonary metastases in a patient with metastatic bladder cancer after durvalumab treatment: multiple pulmonary metastases turned into ground-glass opacity on first follow-up CT; on second follow-up CT, and after sustained treatment of the PD-L1 inhibitor, the lesion was resolved.

Immune RECIST criteria and symptomatic pseudoprogression in non-small cell lung cancer patients treated with immunotherapy

Background

Uncommon response during immunotherapy is a new challenging issue in oncology practice. Recently, new criteria for evaluation of response to immunotherapy immune response evaluation criteria in solid tumors (iRECIST) were accepted. According to iRECIST, worsening of performance status (PS) accompanied to pseudoprogression reflects most probably the true progression of the malignant disease.

Methods

A systematic review of the literature was made by using several electronic database with the following search criteria: symptomatic pseudoprogression, atypical response, immunotherapy and lung cancer.

Results

In the literature, we identified five reports of seven patients treated with immunotherapy that met the inclusion criteria. We also report our experience of patient with pseudoprogression and almost complete response after one dose of immunotherapy.

Conclusions

As seen from our review, iRECIST criteria might be insufficient in distinguishing true progression from pseudoprogression in some patients with advanced NSCLC treated with immunotherapy. More precise assessment methods are urgently needed.