Radiographic assessment and therapeutic decisions at RECIST progression in EGFR-mutant NSCLC treated with EGFR tyrosine kinase inhibitors

Advanced non-small-cell lung cancer treated with first-line pembrolizumab plus chemotherapy: tumor response dynamics as a marker for survival

OBJECTIVES

The study investigated tumor burden dynamics on computed tomography (CT) scans in patients with advanced non-small-cell lung cancer (NSCLC) during first-line pembrolizumab plus chemotherapy, to provide imaging markers for overall survival (OS).

METHODS

The study included 133 patients treated with first-line pembrolizumab plus platinum-doublet chemotherapy. Serial CT scans during therapy were assessed for tumor burden dynamics during therapy, which were studied for the association with OS.

RESULTS

There were 67 responders, with overall response rate of 50%. The tumor burden change at the best overall response ranged from - 100.0% to + 132.1% (median of - 30%). Higher response rates were associated with younger age (p < 0.001) and higher programmed cell death-1 (PD-L1) expression levels (p = 0.01). Eighty-three patients (62%) showed tumor burden below the baseline burden throughout therapy. Using an 8-week landmark analysis, OS was longer in patients with tumor burden below the baseline burden in the first 8 weeks than in those who experienced ≥ 0% increase (median OS: 26.8 vs. 7.6 months, hazard ratio (HR): 0.36, p < 0.001). Tumor burden remained below their baseline throughout therapy was associated with significantly reduced hazards of death (HR: 0.72, p = 0.03) in the extended Cox models, after adjusting for other clinical variables. Pseudoprogression was noted in only one patient (0.8%).

CONCLUSIONS

Tumor burden staying below the baseline burden throughout the therapy was predictive of prolonged overall survival in patients with advanced NSCLC treated with first-line pembrolizumab plus chemotherapy, and may be used as a practical marker for therapeutic decisions in this widely used combination regimen.

CLINICAL RELEVANCE STATEMENT

The analysis of tumor burden dynamics on serial CT scans in reference to the baseline burden can provide an additional objective guide for treatment decision making in patients treated with first-line pembrolizumab plus chemotherapy for their advanced NSCLC.

KEY POINTS

• Tumor burden remaining below baseline burden during therapy predicted longer survival during first-line pembrolizumab plus chemotherapy. • Pseudoprogression was noted in 0.8%, demonstrating the rarity of the phenomenon. • Tumor burden dynamics may serve as an objective marker for treatment benefit to guide treatment decisions during first-line pembrolizumab plus chemotherapy.

Prediction Model for Tumor Volume Nadir in EGFR -mutant NSCLC Patients Treated With EGFR Tyrosine Kinase Inhibitors

PURPOSE

In patients with advanced non-small cell lung cancer (NSCLC) and oncogenic driver mutations treated with effective targeted therapy, a characteristic pattern of tumor volume dynamics with an initial regression, nadir, and subsequent regrowth is observed on serial computed tomography (CT) scans. We developed and validated a linear model to predict the tumor volume nadir in EGFR -mutant advanced NSCLC patients treated with EGFR tyrosine kinase inhibitors (TKI).

MATERIALS AND METHODS

Patients with EGFR -mutant advanced NSCLC treated with EGFR-TKI as their first EGFR-directed therapy were studied for CT tumor volume kinetics during therapy, using a previously validated CT tumor measurement technique. A linear regression model was built to predict tumor volume nadir in a training cohort of 34 patients, and then was validated in an independent cohort of 84 patients.

RESULTS

The linear model for tumor nadir prediction was obtained in the training cohort of 34 patients, which utilizes the baseline tumor volume before initiating therapy (V 0 ) to predict the volume decrease (mm 3 ) when the nadir volume (V p ) was reached: V 0 -V p =0.717×V 0 -1347 ( P =2×10 -16 ; R2 =0.916). The model was tested in the validation cohort, resulting in the R2 value of 0.953, indicating that the prediction model generalizes well to another cohort of EGFR -mutant patients treated with EGFR-TKI. Clinical variables were not significant predictors of tumor volume nadir.

CONCLUSION

The linear model was built to predict the tumor volume nadir in EGFR -mutant advanced NSCLC patients treated with EGFR-TKIs, which provide an important metrics in treatment monitoring and therapeutic decisions at nadir such as additional local abrasive therapy.

Tumor Volume Nadir in Patients With ALK-Rearranged Non-Small-Cell Lung Cancer Treated With Alectinib

PURPOSE

Patients with oncogene-driven advanced non-small-cell lung cancer (NSCLC) treated with effective targeted therapy demonstrate characteristic tumor volume dynamics with initial response, nadir, and subsequent regrowth. This study investigated tumor volume nadir and time to nadir in patients with ALK-rearranged advanced NSCLC treated with alectinib.

MATERIALS AND METHODS

In patients with advanced ALK-rearranged NSCLC treated with alectinib monotherapy, tumor volume dynamics were evaluated on serial computed tomography (CT) scans using a previously validated CT tumor measurement technique. A linear regression model was built to predict tumor volume nadir. Time-to-event analyses were performed to evaluate time to nadir.

RESULTS

Among 45 patients who experienced initial volume decrease, 37 patients (25 with tumor regrowth and 12 without regrowth but >6 months follow-up) were studied for nadir volume (V_p). The linear model to predict tumor volume nadir was built using the baseline tumor volume (V₀): V₀-V_p = .696 × V₀ + 5,326 (P < 2 × 10^-16; adjusted R² = 0.86). The percent volume changes at nadir (median, -90.9%, mean, -85.3%) showed larger decrease in patients who were treated with alectinib as first-line therapy than in the ≥2nd-line group and were independent of V₀ and clinical variables. Time to nadir had a median of 11.5 months and was longer in the first-line group (P = .04).

CONCLUSION

The tumor nadir volume in patients with ALK-rearranged advanced NSCLC treated with alectinib can be predicted by the liner regression model and consists of approximately 30% of the baseline volume minus 5 cm³, providing additional insights into precision therapy monitoring and potential guides for local ablative therapy to prolong disease control.

Concurrent TP53 Mutations Facilitate Resistance Evolution in EGFR-Mutant Lung Adenocarcinoma

INTRODUCTION

Patients with EGFR-mutant NSCLC experience variable duration of benefit on EGFR tyrosine kinase inhibitors. The effect of concurrent genomic alterations on outcome has been incompletely described.

METHODS

In this retrospective study, targeted next-generation sequencing data were collected from patients with EGFR-mutant lung cancer treated at the Dana-Farber Cancer Institute. Clinical data were collected and correlated with somatic mutation data. Associations between TP53 mutation status, genomic features, and mutational processes were analyzed.

RESULTS

A total of 269 patients were identified for inclusion in the cohort. Among 185 response-assessable patients with pretreatment specimens, TP53 alterations were the most common event associated with decreased first-line progression-free survival and decreased overall survival, along with DNMT3A, KEAP1, and ASXL1 alterations. Reduced progression-free survival on later-line osimertinib in 33 patients was associated with MET, APC, and ERBB4 alterations. Further investigation of the effect of TP53 alterations revealed an association with worse outcomes even in patients with good initial radiographic response, and faster acquisition of T790M and other resistance mechanisms. TP53-mutated tumors had higher mutational burdens and increased mutagenesis with exposure to therapy and tobacco. Cell cycle alterations were not independently predictive, but portended worse OS in conjunction with TP53 alterations.

CONCLUSIONS

TP53 alterations associate with faster resistance evolution independent of mechanism in EGFR-mutant NSCLC and may cooperate with other genomic events to mediate acquisition of resistance mutations to EGFR tyrosine kinase inhibitors.

MRI-Based Radiomics Nomogram as a Potential Biomarker to Predict the EGFR Mutations in Exon 19 and 21 Based on Thoracic Spinal Metastases in Lung Adenocarcinoma

RATIONALE AND OBJECTIVES

Preoperative identifications of epidermal growth factor receptor (EGFR) mutation subtypes based on the MRI image of spinal metastases are needed to provide individualized therapy, but has not been previously investigated. This study aims to develop and evaluate an MRI-based radiomics nomogram for differentiating the exon 19 and 21 in EGFR mutation from spinal bone metastases in patients with primary lung adenocarcinoma.

MATERIALS AND METHODS

A total of 76 patients underwent T1-weighted and T2-weighted fat-suppressed MRI scans were enrolled in this study, 38 were positive for EGFR mutation in exon 19 and 38 were in exon 21.MRI imaging features were extracted and selected from each MRI pulse sequence, and used to form the radiomics signature. A radiomics nomogram was developed integrating the radiomics signature and important clinical factors with receiver operating characteristic, calibration and decision curve analysis to assess the nomogram. Clinical characteristics were analyzed with Mann-Whitney U and Chi-Square tests to identify the most important factors.

RESULTS

A total of 6 features were selected as the most discriminative predictors from the two MRI pulse sequences. The nomogram integrating the combined radiomics signature, age and CEA level generated good prediction performance in the training (AUCs, nomogram vs. combined radiomics signature vs. clinical model, 0.90 vs. 0.87 vs. 0.59) and validation (AUCs, nomogram vs. combined radiomics signature vs. clinical model, 0.88 vs. 0.86 vs. 0.72) cohort. DCA analysis confirmed the potential clinical utility of the nomogram.

CONCLUSION

This study demonstrated that MRI features from spinal bone metastases can be used to prognosticate EGFR mutation subtypes in exon 19 and 21. The developed pre-treatment nomogram can potentially guide treatments for lung adenocarcinoma patients.

Systemic Therapy for Oligoprogression in Patients with Metastatic NSCLC Harboring Activating EGFR Mutations

After a variable period of activity of the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment, patients with advanced non-small cell lung cancer (NSCLC) harboring EGFR mutations develop resistance to these TKIs. In some cases, an oligoprogression is diagnosed, and its management is still controversial. The oligoprogression represents an intermediate stage of metastatic NSCLC between localized and widely disseminated disease, and is characterized by a limited number and/or sites of metastases in which a disease progression appears, together with a more indolent tumor biology. Currently, the management of oligoprogressed NSCLC involves local treatment, including radiotherapy and/or surgery, to control the progressive lesions. Systemic therapy should also be a potential approach to boost the activity of EGFR-TKIs. However, considering the lack of large trials addressing this topic, the optimal therapeutic strategies remain undefined and should be evaluated on an individualized basis. In this paper, we review the most relevant scientific evidence of continuing the systemic therapy with the same EGFR-TKI for the management of patients with NSCLC harboring EGFR mutations and oligoprogressed to first-line EGFR-TKIs, also discussing the controversies and potential future directions.

Efficacy and safety of first-line osimertinib treatment and postprogression patterns of care in patients with epidermal growth factor receptor activating mutation-positive advanced non-small cell lung cancer (Reiwa study): study protocol of a multicentre, real-world observational study

INTRODUCTION

Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is widely used as the first-line treatment for EGFR mutation-positive non-small cell lung cancer (NSCLC). Nevertheless, most cases ultimately acquire resistance to osimertinib, and no effective treatment has been currently established for cases having progressive disease (PD) with osimertinib. In clinical practice, EGFR-TKI therapy could be continued beyond response evaluation criteria in solid tumours (RECIST)-defined PD cases when they are clinically stable. Currently, the progression pattern of osimertinib and criteria for identifying patients who might benefit from osimertinib beyond PD are unknown. In addition, the efficacy and safety of osimertinib as the first-line treatment in real-world clinical practice remain unclear in Japan. This multicentre study was designed to evaluate the real-world data on first-line osimertinib and its post-treatment.

METHODS AND ANALYSIS

The study enrols patients with EGFR mutation-positive, advanced or recurrent NSCLC who received EGFR-TKI as the first-line therapy after 1 September 2018, from October 2019 to August 2020, and those started on osimertinib will be followed up until August 2022. We will evaluate the efficacy and safety of the first-line osimertinib treatment, adherence to it, progression patterns on RECIST PD and subsequent treatment.

ETHICS AND DISSEMINATION

All participating patients will provide written informed consent before entering the study. The protocol, amendments and patients' informed consent forms will be approved before study commencement by the institutional review board or independent ethics committee at each participation site (Lead Ethics Committee; Japan Red Cross Medical Center (26 April 2019, order number 976)). Patients will be anonymised before registration into the study and their anonymised data will be collected from the case report form. The results of this study will be presented at the national and international conferences and submitted for publication.

TRIAL REGISTRATION NUMBER

UMIN000038683.

Post-chemotherapy and targeted therapy imaging of the chest in lung cancer

Non-small-cell lung cancer (NSCLC) is frequently diagnosed when it is not amenable to local therapies; therefore, systemic agents are the mainstay of therapy for many patients. In recent years, treatment of advanced NSCLC has evolved from a general approach primarily involving chemotherapy to a more personalised strategy in which biomarkers such as the presence of genomic tumour aberrations and the expression of immune proteins such as programmed death-ligand 1 (PD-L1), in combination with other elements of clinical information such as histology and clinical stage, guide management. For instance, pathways resulting in uncontrolled growth and proliferation of tumour cells due to epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements may be targeted by tyrosine kinase inhibitors (TKIs). In this article, we review the current state of medical oncology, imaging characteristics of mutations, pitfalls in response assessments and the imaging of complications.

Tumor Response Dynamics During First-Line Pembrolizumab Therapy in Patients With Advanced Non-Small-Cell Lung Cancer

The objectives of the study were to characterize the tumor burden dynamics on serial computed tomography scans in patients with advanced non-small-cell lung cancer treated with first-line pembrolizumab and to identify imaging markers for prolonged overall survival (OS).

MATERIALS AND METHODS

Eighty-eight patients treated with first-line pembrolizumab monotherapy were evaluated on serial computed tomography scans to characterize their quantitative tumor burden during therapy. Tumor burden dynamics were studied for the association with OS.

RESULTS

The overall response rate was 42% (37/88), with the median tumor burden changes at the best overall response of -18.3% (range, -100.0% to +103.6%). Response rates were higher in men than in women (P = .05) and in patients with higher programmed cell death ligand-1 expression levels (P = .02). Tumor burden stayed below the baseline burden throughout therapy in 55 patients (63%). In an 8-week landmark analysis, patients with tumor burden below the baseline burden during the first 8 weeks of therapy had longer OS compared with patients who had ≥ 0% increase (median OS, 30.7 v 16.2 months; hazard ratio [HR] = 0.44; P = .01). In the extended Cox models, patients whose tumor burden stayed below the baseline burden throughout therapy had significantly reduced hazards of death (HR = 0.41, P = .003, univariate; HR = 0.35, P = .02, multivariate). Only one patient (1.1%) experienced pseudoprogression with initial tumor increase and subsequent tumor regression.

CONCLUSION

In patients with advanced non-small-cell lung cancer treated with first-line single-agent pembrolizumab, tumor burden reduction below the baseline burden during therapy was an independent marker for prolonged OS, which may serve as a practical guide for treatment decisions.

Tumor Volume Analysis as a Predictive Marker for Prolonged Survival in Anaplastic Lymphoma Kinase-rearranged Advanced Non-Small Cell Lung Cancer Patients Treated With Crizotinib

PURPOSE

Targeted inhibition of anaplastic lymphoma kinase (ALK) has been widely used for the treatment of advanced non-small cell lung cancer (NSCLC) with ALK rearrangements. We performed tumor volume analysis of ALK-rearranged advanced NSCLC treated with crizotinib to identify an early predictive marker for prolonged survival.

MATERIALS AND METHODS

Cases of 42 patients with ALK-rearranged advanced NSCLC (16 men, 26 women; median age: 55.7 y) treated with crizotinib as their first ALK-directed therapy were retrospectively studied. Tumor volume measurements of dominant lung lesions were performed on baseline computed tomography and follow-up computed tomography at 8 weeks of therapy. The relationships between the 8-week volume change (%) and overall survival (OS) were investigated.

RESULTS

The 8-week tumor volume change ranged from -99.3% to 117.5% (median: -57.7%). Using the 25th percentile of the 8-week volume change of -74%, 11 patients with >74% volume decrease at 8 weeks had a significantly longer OS compared with 31 patients with ≤74% decrease (median OS: 92.0 vs. 22.8 mo; P=0.0048). In multivariable analyses using Cox proportional hazards models, the 8-week volume decrease of >74% was significantly associated with longer OS (hazard ratio=0.14, 95% confidence interval: 0.03-0.59; Cox P=0.008) after adjusting for tumor stage (stage IV vs. recurrent NSCLC, hazard ratio=5.6, 95% confidence interval: 1.29-24.3; P=0.02).

CONCLUSIONS

The 8-week tumor volume decrease of >74% is significantly associated with longer OS in patients with ALK-rearranged NSCLC treated with crizotinib.

Tumor volume dynamics and tumor growth rate in ALK-rearranged advanced non-small-cell lung cancer treated with crizotinib

Purpose

The purpose of the study is to investigate volumetric tumor burden dynamics and tumor growth rates in ALK-rearranged advanced NSCLC patients during crizotinib monotherapy.

Methods

The study included 44 ALK-rearranged advanced NSCLC patients treated with crizotinib monotherapy as their initial ALK-directed therapy, who had at least one measurable lung lesion and at least two follow-up CT scans, and experienced tumor volume increase while on crizotinib. The tumor volume (in mm³) of the dominant lung lesion was measured on serial CT scans during therapy for analysis of tumor growth rates after the volume nadir.

Results

A total of 231 volume measurements from the nadir to the end of crizotinib therapy or the last follow-up in 44 patients were analyzed in a linear mixed-effects model, fitting time (in months since baseline) as a random effect. When measured from the volume nadir, the tumor growth rate of the logarithm of tumor volume (log_eV) was 0.04/month (SE = 0.012, P = 0.0011) in the unadjusted model. When adjusted for the baseline volume (log_eV₀), the growth rate was again 0.04/month (SE = 0.011, P = 0.0004). When adjusted for clinical variables and log_eV₀, the growth rate was 0.045/month (SE = 0.012, P = 0.0002), indicating that the tumor growth rate after nadir in this cohort remains very close to 0.04/month regardless of log_eV₀ or clinical factors.

Conclusions

Tumor volume growth rate after nadir in ALK-rearranged NSCLC patients treated with crizotinib was obtained, providing objective reference values that can inform physicians when deciding to keep their patients on ALK directed therapy with slowly progressing lung cancer.

3D radiomics predicts EGFR mutation, exon-19 deletion and exon-21 L858R mutation in lung adenocarcinoma

BACKGROUND

To establish a radiomic approach to identify epidermal growth factor receptor (EGFR) mutation status in lung adenocarcinoma patients based on CT images, and to distinguish exon-19 deletion and exon-21 L858R mutation.

METHODS

Two hundred sixty-three patients who underwent pre-surgical contrast-enhanced CT and molecular testing were included, and randomly divided into the training (80%) and test (20%) cohort. Tumor images were three-dimensionally segmented to extract 1,672 radiomic features. Clinical features (age, gender, and smoking history) were added to build classification models together with radiomic features. Subsequently, the top-10 most relevant features were used to establish classifiers. For the classifying tasks including EGFR mutation, exon-19 deletion, and exon-21 L858R mutation, four logistic regression models were established for each task.

RESULTS

The training and test cohort consisted of 210 and 53 patients, respectively. Among the established models, the highest accuracy and sensitivity among the four models were 75.5% (61.7-86.2%) and 92.9% (76.5-99.1%) to classify EGFR mutation, respectively. The highest specificity values were 86.7% (69.3-96.2%) and 70.4% (49.8-86.3%) to classify exon-19 deletion and exon-21 L858R mutation, respectively.

CONCLUSIONS

CT radiomics can sensitively identify the presence of EGFR mutation, and increase the certainty of distinguishing exon-19 deletion and exon-21 L858R mutation in lung adenocarcinoma patients. CT radiomics may become a helpful non-invasive biomarker to select EGFR mutation patients for invasive sampling.

Detection of response to tumor microenvironment-targeted cellular immunotherapy using nano-radiomics

Immunotherapies, including cell-based therapies, targeting the tumor microenvironment (TME) result in variable and delayed responses. Thus, it has been difficult to gauge the efficacy of TME-directed therapies early after administration. We investigated a nano-radiomics approach (quantitative analysis of nanoparticle contrast-enhanced three-dimensional images) for detection of tumor response to cellular immunotherapy directed against myeloid-derived suppressor cells (MDSCs), a key component of TME. Animals bearing human MDSC-containing solid tumor xenografts received treatment with MDSC-targeting human natural killer (NK) cells and underwent nanoparticle contrast-enhanced computed tomography (CT) imaging. Whereas conventional CT-derived tumor metrics were unable to differentiate NK cell immunotherapy tumors from untreated tumors, nano-radiomics revealed texture-based features capable of differentiating treatment groups. Our study shows that TME-directed cellular immunotherapy causes subtle changes not effectively gauged by conventional imaging metrics but revealed by nano-radiomics. Our work provides a method for noninvasive assessment of TME-directed immunotherapy potentially applicable to numerous solid tumors.

Imaging of Novel Oncologic Treatments in Lung Cancer Part 1: Systemic Therapies

Thoracic tumors are a leading cause of cancer-related morbidity and mortality. In recent years, developments in oncologic treatments for these tumors have ushered in an era of targeted therapy, and, in many cases, these novel treatments have replaced conventional strategies to become standard therapeutic options, particularly in those with lung cancer. Targeted medical therapies for lung cancer now include angiogenesis inhibitors, tyrosine kinase inhibitors, and immunotherapeutic agents. Several novel ablative therapies have also gained widespread acceptance as alternatives to conventional surgical options in appropriately selected patients. Tumors treated with targeted medical therapies can respond to treatment differently when compared with conventional therapies. For example, pseudoprogression is a well-described phenomenon in patients receiving checkpoint inhibitor immunotherapy in which an initial increase in tumor burden is followed by a decrease in tumor burden and sometimes partial or complete response, while the frequent cavitating responses seen when antiangiogenic agents are used can be difficult to quantify using existing response assessment criteria. In some cases, novel response assessment criteria are needed to adequately capture response. In addition, numerous treatment-related side effects have been described, which are important to recognize, both to ensure appropriate treatment and to avoid misclassification as worsening tumor. Imaging plays a vital role in the assessment of patients receiving targeted medical therapy, and it is essential that thoracic radiologists are familiar with the rationale underpinning these treatments and the expected posttherapy findings.

Diffusion-Weighted Magnetic Resonance Imaging for Early Detection of Chemotherapy Resistance in Non-Small Cell Lung Cancer

Background

The aim of this study was to examine the role of magnetic resonance imaging-diffusion weighted imaging (MRI-DWI) in the early detection of chemotherapy resistance in non-small cell lung cancer (NSCLC) patients.

Material/Methods

MRI-DWI and computed tomography (CT) were carried out in 75 patients with newly diagnostic NSCLC before and after first, second, fourth, and sixth cycles of chemotherapy. Resistance to chemotherapy was assessed based on the change in the largest tumor diameter after chemotherapy. Diffusion of water molecule in each lesion was quantitatively measured by apparent diffusion coefficient (ADC). The diagnostic results of DWI after first and second cycle of chemotherapy were analyzed by the area under receiver operating characteristics curve (ROC).

Results

Among the patients, 43 patients were chemo-resistance while 32 patients were chemo-sensitive. The ADC changing rate between second and first cycle of chemotherapy was significantly higher in chemo-sensitive patients compared with chemo-resistance patients (t=3.236, P=0.002). The ROC showed cutoff values of the ADC changing rate after first and second cycles of chemotherapy for resistance/sensitive discrimination were 23.6% and 5.56%, respectively. DWI after first and second cycles of therapy showed sensitivities of 55.8% and 55.8%, specificities of 65.6% and 87.5%, and area under ROC of 0.568 and 0.733, respectively.

Conclusions

ADC changing rate between first and second cycles of chemotherapy could sensitively distinguish chemo-sensitive and chemo-resistant tumors at earlier stages, which may direct treatment adjustment and improve the prognosis of patients.

A Radiologist's Guide to the Changing Treatment Paradigm of Advanced Non-Small Cell Lung Cancer: The ASCO 2018 Molecular Testing Guidelines and Targeted Therapies

OBJECTIVE. The purpose of this article is to provide an imaging-based guide of the modern genomic classifications and targeted therapies for advanced non-small cell lung cancer (NSCLC) with an emphasis on the relevance of the 2018 American Society of Clinical Oncology molecular testing guidelines for radiologists. CONCLUSION. Knowledge of the radiologic relevance of lung cancer driver mutations and modern targeted agents is essential for imaging interpretation of advanced NSCLC in the modern age of precision medicine.

The beginning of the end for conventional RECIST - novel therapies require novel imaging approaches

Owing to improvements in our understanding of the biological principles of tumour initiation and progression, a wide variety of novel targeted therapies have been developed. Developments in biomedical imaging, however, have not kept pace with these improvements and are still mainly designed to determine lesion size alone, which is reflected in the Response Evaluation Criteria in Solid Tumors (RECIST). Imaging approaches currently used for the evaluation of treatment responses in patients with solid tumours, therefore, often fail to detect successful responses to novel targeted agents and might even falsely suggest disease progression, a scenario known as pseudoprogression. The ability to differentiate between responders and nonresponders early in the course of treatment is essential to allowing the early adjustment of treatment regimens. Various imaging approaches targeting a single dedicated tumour feature, as described in the hallmarks of cancer, have been successful in preclinical investigations, and some have been evaluated in pilot clinical trials. However, these approaches have largely not been implemented in clinical practice. In this Review, we describe current biomedical imaging approaches used to monitor responses to treatment in patients receiving novel targeted therapies, including a summary of the most promising future approaches and how these might improve clinical practice.

Prognostic Impact of Longitudinal Monitoring of Radiomic Features in Patients with Advanced Non-Small Cell Lung Cancer

Tumor growth dynamics vary substantially in non-small cell lung cancer (NSCLC). We aimed to develop biomarkers reflecting longitudinal change of radiomic features in NSCLC and evaluate their prognostic power. Fifty-three patients with advanced NSCLC were included. Three primary variables reflecting patterns of longitudinal change were extracted: area under the curve of longitudinal change (AUC1), beta value reflecting slope over time, and AUC2, a value obtained by considering the slope and area over the longitudinal change of features. We constructed models for predicting survival with multivariate cox regression, and identified the performance of these models. AUC2 exhibited an excellent correlation between patterns of longitudinal volume change and a significant difference in overall survival time. Multivariate regression analysis based on cut-off values of radiomic features extracted from baseline CT and AUC2 showed that kurtosis of positive pixel values and surface area from baseline CT, AUC2 of density, skewness of positive pixel values, and entropy at inner portion were associated with overall survival. For the prediction model, the areas under the receiver operating characteristic curve (AUROC) were 0.948 and 0.862 at 1 and 3 years of follow-up, respectively. Longitudinal change of radiomic tumor features may serve as prognostic biomarkers in patients with advanced NSCLC.

The Dandelion Dilemma Revisited for Oligoprogression: Treat the Whole Lawn or Weed Selectively?

Oligoprogressive disease is a relatively new clinical concept describing progression at only a few sites of metastasis in patients with otherwise controlled widespread disease. In the era of well-tolerated targeted treatments, resistance inevitably occurs and overcoming this is a challenge. Local ablative therapy for oligoprogressive disease may allow the continuation of systemic treatments by overcoming the few sub-clones that have developed resistance. Stereotactic body radiotherapy is now frequently used in treating oligometastatic disease using ablative doses with minimally invasive techniques and acceptable toxicity. We discuss the current retrospective clinical evidence base supporting the use of local ablative therapy for oligoprogression in metastatic patients on targeted treatments within multiple tumour sites. As there is currently a lack of published prospective data available, the best management for these patients remains unclear. We discuss current trials in recruitment and the potential advancements in treating this group of patients with stereotactic radiotherapy.

The Expression Pattern of p120-Catenin is Associated With Acquired Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer

BACKGROUND

Previous research connects p120-catenin (p120ctn) with epidermal growth factor receptor (EGFR) signaling pathways, which presents a potential role for p120ctn in EGFR tyrosine kinase inhibitor (EGFR-TKIs) resistance. However, a direct correlation between the expression pattern of p120ctn in solid tumors and the therapeutic effect of EGFR-TKIs has not yet been demonstrated.

METHODS AND RESULTS

In this study, the expression pattern of p120ctn was examined in patients with the EGFR gene mutation in lung adenocarcinoma, and p120ctn was found to have different patterns of expression even in the same mutation type. The therapeutic effect of EGFR-TKIs was investigated in these patients, and patients with an abnormal expression of p120ctn were found to be more likely to have drug resistance. A gefitinib-resistant lung cancer cell line was established and alterations in the p120ctn expression pattern were also observed in vitro.

CONCLUSIONS

Therefore, this study demonstrates that the expression pattern of p120ctn is associated with acquired resistance to EGFR-TKIs in lung cancer, providing information toward addressing the problem of drug resistance in patients with non-small cell lung cancer.

Tumor Response Assessment for Precision Cancer Therapy: Response Evaluation Criteria in Solid Tumors and Beyond

Objective assessment of tumor responses and treatment results has been the basis for the advancement of cancer therapies, and imaging plays a key role to provide a "common language" to describe the results of cancer treatment. Although Response Evaluation Criteria in Solid Tumors (RECIST) has been the most widely accepted method for assessing tumor response in the past decades, the limitations of RECIST have increasingly becoming recognized, especially with the recent advances of precision-medicine approaches to cancer. This article reviews the current concept of tumor response evaluations based on RECIST, describes the limitations of RECIST, and proposes strategies to overcome the limitations. The article emphasizes specific limitations in the setting of precision cancer therapy and cancer immunotherapy and discusses the important insights provided by the cutting-edge investigations in the emerging fields.

Automated image analysis tool for tumor volume growth rate to guide precision cancer therapy: EGFR-mutant non-small-cell lung cancer as a paradigm

PURPOSE

To develop an automated analytic module for calculation of tumor growth rate from serial CT scans and to apply the module and evaluate reproducibility in a pilot cohort of advanced NSCLC patients with EGFR mutations treated with EGFR tyrosine kinase inhibitors.

MATERIALS AND METHODS

The module utilized a commercially available image-processing workstation equipped with a validated tumor volume measurement tool. An automated analytic software module was programmed with the capability to record and display serial tumor volume changes and to calculate tumor volume growth rate over time and added to the workstation. The module was applied to evaluate the tumor growth rate in a pilot cohort of 24 EGFR-mutant patients treated with EGFR inhibitors, and reproducibility references as tested by two independent thoracic radiologists.

RESULTS

The module analyzed chest CT scans from 24 patients (5 males, 19 females; median age: 61) with a median of 8 scans per patient, totaling 227 scans and provided a graphical display with an automated and instant calculation of tumor growth rate after the nadir volume for each patient. High inter and intraobserver agreements were noted for tumor growth rates, with concordance correlation coefficients of 0.9323 and 0.9668, respectively. Interpretation of slow versus fast tumor growth using previously identified threshold of ≤0.15/month had a perfect interobserver agreement (κ = 1.00), and an excellent intraobserver agreement (κ = 0.895).

CONCLUSIONS

The present study describes the development of an image analytic module for assessing tumor growth rate and the data demonstrates the functionality and reproducibility of the module in a pilot cohort of EGFR-mutant NSCLC patients treated with EGFR-TKI. The image analytic module is an initial step for clinical translation of the tumor growth rate approach to guide cancer treatment in precision oncology.

Non-Small Cell Lung Cancer with Resistance to EGFR-TKI Therapy: CT Characteristics of T790M Mutation-positive Cancer

Purpose To evaluate the clinical and CT characteristics of T790M mutation-positive non-small cell lung cancer (NSCLC) after epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy failure. Materials and Methods A retrospective study of 304 patients with NSCLC who underwent rebiopsy after first-line EGFR-TKI therapy was conducted. Rebiopsy methods included CT- or fluoroscopy-guided lung biopsies (n = 105), endobronchial US- or bronchofibroscopy-guided biopsies (n = 66), pleural fluid analysis (n = 47), other solid organ biopsies (n = 43), US-guided axillary or supraclavicular lymph node biopsies (n = 31), and cerebrospinal fluid analysis (n = 12). CT findings at the initial diagnosis and rebiopsy were analyzed. Progression-free survival, the duration from the start of TKI therapy to rebiopsy, and survival were calculated. Results At rebiopsy, 144 (47.4%) patients were T790M mutation positive. The percentages of T790M mutation-positive NSCLCs were similar in 106 patients with rebiopsy of the lungs (53 [50%] of 106) and in 77 patients with rebiopsy of the primary lung lesions (36 [47%] of 77). T790M mutation positivity was associated with peripheral tumors (odds ratio [OR], 2.6; P = .01), pleural tag (OR, 5.0; P < .001), and air bronchogram (OR, 4.0; P = .006) at CT after TKI failure. The duration from the start of TKI therapy to rebiopsy was longer in T790M mutation-positive than in T790M mutation-negative patients (20.5 vs 13.6 months; P < .001). Cumulative survival from the time of rebiopsy to the last follow-up was significantly longer in patients with T790M mutation-positive lung cancers (P = .014). However, median survival time after rebiopsy was not statistically different between patients with and those without T790M mutation. Conclusion Peripheral tumor location with vascular convergence, the presence of a pleural tag, and air bronchogram of lung lesions at CT at the time of rebiopsy were significantly associated with T790M mutation in patients with non-small cell lung cancer after first-line epidermal growth factor receptor-tyrosine kinase inhibitor therapy failure. © RSNA, 2018 Online supplemental material is available for this article.

Characteristics and outcomes of patients with EGFR-mutation positive non-small-cell lung cancer receiving gefitinib beyond radiological progression

BACKGROUND

This study aimed to analyze the characteristics and outcomes of patients suffering from non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor mutations (EGFRm+) receiving gefitinib who remained clinically stable following confirmation of progressive disease (PD) using Response Evaluation Criteria in Solid Tumors (RECIST) (R-PD) and identify those who benefited from tyrosine kinase inhibitor therapy beyond PD.

RESEARCH DESIGN AND METHODS

The clinical courses of patients with EGFRm+ advanced NSCLC who received first-line gefitinib were investigated. Clinical PD (C-PD) was defined as one or more of the following: (1) symptomatic PD, (2) worsening performance status resulting from PD, (3) threat to a major organ(s), or (4) unequivocal multiorgan PD.

RESULTS

Of 529 patients, 258 experienced R-PD without C-PD. Among 258 patients, 91 received gefitinib beyond R-PD. Females were more likely to receive gefitinib beyond R-PD and exhibit a longer time from R-PD to C-PD than males (median days, 175 vs. 79.5). Survival beyond R-PD tended to be longer for elderly patients who received gefitinib beyond PD than for those who did not (median days, 458 vs. 336), but this was not the case for non-elderly patients (median days, 481 vs. 487).

CONCLUSIONS

Some patients may benefit from continuation of gefitinib beyond PD.

Tumor Response Dynamics of Advanced Non-small Cell Lung Cancer Patients Treated with PD-1 Inhibitors: Imaging Markers for Treatment Outcome

Purpose: We evaluated tumor burden dynamics in patients with advanced non-small cell lung cancer (NSCLC) treated with commercial PD-1 inhibitors to identify imaging markers associated with improved overall survival (OS).Experimental Design: The study included 160 patients with advanced NSCLC treated with commercial nivolumab or pembrolizumab monotherapy as a part of clinical care. Tumor burden dynamics were studied for the association with OS.Results: Tumor burden change at best overall response (BOR) ranged from -100% to +278% (median, +3.5%). Response rate (RR) was 18% (29/160). Current and former smokers had a higher RR than never smokers (P = 0.04). Durable disease control for at least 6 months was noted in 26 patients (16%), which included 10 patients with stable disease as BOR. Using a landmark analysis, patients with <20% tumor burden increase from baseline within 8 weeks of therapy had longer OS than patients with ≥20% increase (median OS, 12.4 vs. 4.6 months, P < 0.001). Patients with <20% tumor burden increase throughout therapy had significantly reduced hazards of death (HR, 0.24; Cox P < 0.0001) after adjusting for smoking (HR, 0.86; P = 0.61) and baseline tumor burden (HR, 1.55; P = 0.062), even though some patients met criteria for RECIST progression while on therapy. One patient (0.6%) had atypical response pattern consistent with pseudoprogression.Conclusions: Objective response or durable disease control was noted in 24% of patients with advanced NSCLC treated with commercial PD-1 inhibitors. A tumor burden increase of <20% from baseline during therapy was associated with longer OS, proposing a practical marker of treatment benefit. Pseudoprogression is rare in NSCLCs treated with PD-1 inhibitors. Clin Cancer Res; 23(19); 5737-44. ©2017 AACR.

Immune-Related Tumor Response Dynamics in Melanoma Patients Treated with Pembrolizumab: Identifying Markers for Clinical Outcome and Treatment Decisions

Purpose: Characterize tumor burden dynamics during PD-1 inhibitor therapy and investigate the association with overall survival (OS) in advanced melanoma.Experimental Design: The study included 107 advanced melanoma patients treated with pembrolizumab. Tumor burden dynamics were assessed on serial CT scans using irRECIST and were studied for the association with OS.Results: Among 107 patients, 96 patients had measurable tumor burden and 11 had nontarget lesions alone at baseline. In the 96 patients, maximal tumor shrinkage ranged from -100% to 567% (median, -18.5%). Overall response rate was 44% (42/96; 5 immune-related complete responses, 37 immune-related partial responses). Tumor burden remained <20% increase from baseline throughout therapy in 57 patients (55%). Using a 3-month landmark analysis, patients with <20% tumor burden increase from baseline had longer OS than patients with ≥20% increase (12-month OS rate: 82% vs. 53%). In extended Cox models, patients with <20% tumor burden increase during therapy had significantly reduced hazards of death [HR = 0.19; 95% confidence interval (CI), 0.08-0.43; P < 0.0001 univariate; HR = 0.18; 95% CI, 0.08-0.41; P < 0.0001, multivariable]. Four patients (4%) experienced pseudoprogression; 3 patients had target lesion increase with subsequent response, which was noted after confirmed immune-related progressive disease (irPD). One patient without measurable disease progressed with new lesion that subsequently regressed.Conclusions: Tumor burden increase of <20% from the baseline during pembrolizumab therapy was associated with longer OS, proposing a practical marker for treatment decision guides that needs to be prospectively validated. Pseudoprogressors may experience response after confirmed irPD, indicating a limitation of the current strategy for immune-related response evaluations. Evaluations of patients without measurable disease may require further attention. Clin Cancer Res; 23(16); 4671-9. ©2017 AACR.

Somatic Mutations Drive Distinct Imaging Phenotypes in Lung Cancer

Tumors are characterized by somatic mutations that drive biological processes ultimately reflected in tumor phenotype. With regard to radiographic phenotypes, generally unconnected through present understanding to the presence of specific mutations, artificial intelligence methods can automatically quantify phenotypic characters by using predefined, engineered algorithms or automatic deep-learning methods, a process also known as radiomics. Here we demonstrate how imaging phenotypes can be connected to somatic mutations through an integrated analysis of independent datasets of 763 lung adenocarcinoma patients with somatic mutation testing and engineered CT image analytics. We developed radiomic signatures capable of distinguishing between tumor genotypes in a discovery cohort (n = 353) and verified them in an independent validation cohort (n = 352). All radiomic signatures significantly outperformed conventional radiographic predictors (tumor volume and maximum diameter). We found a radiomic signature related to radiographic heterogeneity that successfully discriminated between EGFR⁺ and EGFR^- cases (AUC = 0.69). Combining this signature with a clinical model of EGFR status (AUC = 0.70) significantly improved prediction accuracy (AUC = 0.75). The highest performing signature was capable of distinguishing between EGFR⁺ and KRAS⁺ tumors (AUC = 0.80) and, when combined with a clinical model (AUC = 0.81), substantially improved its performance (AUC = 0.86). A KRAS⁺/KRAS^- radiomic signature also showed significant albeit lower performance (AUC = 0.63) and did not improve the accuracy of a clinical predictor of KRAS status. Our results argue that somatic mutations drive distinct radiographic phenotypes that can be predicted by radiomics. This work has implications for the use of imaging-based biomarkers in the clinic, as applied noninvasively, repeatedly, and at low cost. Cancer Res; 77(14); 3922-30. ©2017 AACR.

Molecular Targeted Therapy in Modern Oncology: Imaging Assessment of Treatment Response and Toxicities

Oncology is a rapidly evolving field with a shift toward personalized cancer treatment. The use of therapies targeted to the molecular features of individual tumors and the tumor microenvironment has become much more common. In this review, anti-angiogenic and other molecular targeted therapies are discussed, with a focus on typical and atypical response patterns and imaging manifestations of drug toxicities.

Continuing EGFR inhibition beyond progression in advanced non-small cell lung cancer

The majority of patients with epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) respond to first-line EGFR tyrosine kinase inhibitors (TKIs), but nearly all inevitably acquire resistance and develop disease progression. Conventional practice would be to switch treatments to second-line therapy. However, continuing TKIs beyond progression is becoming increasingly commonplace in patients with indolent, small volume asymptomatic growth, who may potentially continue to derive ongoing clinical benefit and to avoid a 'withdrawal tumour flare'. Nevertheless, there are limitations to our current criteria for assessing disease response, which are based on radiological assessments without considering symptomatic benefit, or the complex molecular and clinical heterogeneity of tumour growth and drug response patterns. In this article, we review the rationale for continuing EGFR inhibitors in patients with EGFR mutant NSCLC beyond disease progression and discuss strategies that have been pursued in the context of molecularly and clinically heterogeneous populations of tumour growth depending on the different clinical scenarios encountered. We discuss the management of systemic disease progression, including continuing EGFR TKIs alone, introducing a drug holiday, or combining TKIs with chemotherapy or other molecularly targeted agents. We also focus on approaches in managing patients with indolent, small volume asymptomatic growth (non-CNS oligometastatic disease progression) and those with oligometastatic EGFR mutant NSCLC with involvement of the central nervous system. We envision future precision medicine strategies through the use of next generation sequencing strategies of serial tumour rebiopsies and circulating plasma DNA to individualise the management for such patients during disease progression.

[Limitations of active therapeutic and palliative care in chronic respiratory disease]

The issue of intensive and palliative care in patients with chronic disease frequently arises. This review aims to describe the prognostic factors of chronic respiratory diseases in stable and in acute situations in order to improve the management of these complex situations. The various laws on patients' rights provide a legal framework and define the concept of unreasonable obstinacy. For patients with chronic obstructive pulmonary disease, the most robust decision factors are good knowledge of the respiratory disease, the comorbidities, the history of previous exacerbations and patient preferences. In the case of idiopathic pulmonary fibrosis, it is necessary to know if there is a prospect of transplantation and to assess the reversibility of the respiratory distress. In the case of amyotrophic lateral sclerosis, treatment decisions depend on the presence of advance directives about the use of intubation and tracheostomy. For lung cancer patients, general condition, cancer history and the tumor treatment plan are important factors. A multidisciplinary discussion that takes into account the patient's medical history, wishes and the current state of knowledge permits the taking of a coherent decision.

Unravelling signal escape through maintained EGFR activation in advanced non-small cell lung cancer (NSCLC): new treatment options

The discovery of activating epidermal growth factor receptor (EGFR) mutations has opened up a new era in the development of more effective treatments for patients with non-small cell lung cancer (NSCLC). However, patients with EGFR-activating mutated NSCLC treated with EGFR tyrosine kinase inhibitors (TKIs) ultimately develop acquired resistance (AR). Among known cases of patients with AR, 70% of the mechanisms involved in the development of AR to EGFR TKI have been identified and may be categorised as either secondary EGFR mutations such as the T790M mutation, activation of bypass track signalling pathways such as MET amplification, or histologic transformation. EGFR-mutant NSCLC tumours maintain oncogenic addiction to the EGFR pathway beyond progression with EGFR TKI. Clinical strategies that can be implemented in daily clinical practice to potentially overcome this resistance and prolong the outcome in this subgroup of patients are presented.

Immune-related response evaluations during immune-checkpoint inhibitor therapy: establishing a "common language" for the new arena of cancer treatment

The recent study by Hodi et al. published in the Journal of Clinical Oncology has evaluated unconventional response patterns during PD-1 inhibitor therapy using immune-related response criteria (irRC) in comparison with RECIST1.1, which constitutes an important step to further understand immune-related response phenomena. This commentary discusses the key observations in the study in terms of their implications and pitfalls, and describes unmet needs that remain to be addressed. The article also emphasizes the important role of tumor response criteria as a “common language” to describe the results of cancer treatment, and discusses future directions for further advances of the field of immuno-oncology.

Volumetric Tumor Response and Progression in EGFR-mutant NSCLC Patients Treated with Erlotinib or Gefitinib

RATIONALE AND OBJECTIVES

The aims of this study were to investigate the association between 8-week tumor volume decrease and survival in an independent cohort of epidermal growth factor receptor (EGFR)-mutant advanced non-small cell lung cancer (NSCLC) patients treated with first-line erlotinib or gefitinib, and to assess the rate of their volumetric tumor growth after the volume nadir.

MATERIALS AND METHODS

In patients with advanced NSCLC harboring sensitizing EGFR mutations treated with first-line erlotinib or gefitinib, computed tomography (CT) tumor volumes of dominant lung lesions were analyzed for (1) the association with survival, and (2) the volumetric tumor growth rate after the volume nadir.

RESULTS

In 44 patients with the 8-week follow-up CT, the 8-week tumor volume decrease (%) was significantly associated with longer overall survival when fitted as a continuous variable in a Cox model (P = 0.01). The growth rate of the logarithm of tumor volume (logeV), obtained using a linear mixed-effects model adjusting for time since baseline, was 0.096/month (SE: 0.013/month; 95% confidence interval [CI]: 0.071-0.12/month), which was similar to the rate of 0.12/month (SE: 0.015/month; 95%CI: 0.090-0.15/month) observed in the previous report.

CONCLUSIONS

The 8-week tumor volume decrease was validated as a marker for longer survival in the independent cohort of EGFR-mutant NSCLC patients treated with first-line erlotinib or gefitinib. The volumetric tumor growth rate after the nadir in this cohort was similar to that of the previous cohort, indicating the reproducibility of the observation among different patient cohorts.

Is there a role of nab-paclitaxel in the treatment of advanced non-small cell lung cancer? The data suggest yes

Nab-paclitaxel is a novel therapeutic agent, which was approved in combination with carboplatin in the first-line treatment of advanced non-small cell lung cancer (NSCLC) regardless of histologic subtype in the United States of America by the Food and Drug Administration in 2012 and by the European Commission in 2015. This approval was based on the results of a phase III clinical trial showing superior response rates compared with solvent-based paclitaxel in combination with carboplatin. This review will focus on the early development and clinical data to date supporting the use of nab-paclitaxel in advanced NSCLC. The clinical question central to this review is whether nab-paclitaxel has a place in the current therapeutic landscape of advanced NSCLC.

Personalized chemotherapy of lung cancer: What the radiologist should know

Lung cancer is the leading cause of deaths due to cancer in France. More than half of lung cancers are discovered at an advanced-stage. New anticancer treatment strategies (i.e., the so-called personalized or targeted therapy) have recently been introduced and validated for non-small-cell lung cancer (NSCLC), in addition to or in association with standard chemotherapy. Personalized therapy includes tyrosine kinase inhibitors (TKIs), antiangiogenic treatments and immunotherapy. Because these treatments may be responsible for atypical thoracic adverse effects and responses as compared to standard chemotherapy, RECIST 1.1 criteria may be inadequate to evaluate the responses to these agents. The goal of this article was to review personalized treatment strategies for NSCLC, to consider the therapy-specific responses and thoracic complications induced by these new therapeutic agents and finally to discuss future directions for the personalized assessment of tumor response.

Clinical Characteristics and Continued Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Administration in EGFR-mutated Non-Small Cell Lung Cancer with Skeletal Metastasis

PURPOSE

The aim of this study was to analyze clinical characteristics of skeletal metastasis in epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC) and treatment outcomes of continued EGFR tyrosine kinase inhibitor (TKI) therapy in patients presenting with skeletal metastasis progression.

MATERIALS AND METHODS

Of the 216 patients treated with EGFR-TKI for management of stage III-IV NSCLC between 2006 and 2012 in Seoul St. Mary's Hospital, 76 patients with confirmed EGFR-mutated NSCLC with skeletal metastases during therapy were analyzed retrospectively.

RESULTS

Of 76 patients with EGFR mutant lung cancer with skeletal metastasis, 37 patients developed first progressive disease (PD) in skeletal regions. EGFR-TKI was continued in these 37 patients after first PD in skeletal regions. Median time to first PD of skeletal regions was 8.9 months (95% confidence interval [CI], 4.8 to 13.0). Median time of continued EGFR-TKI after first PD of skeletal regions was 8.0 months (95% CI, 2.9 to 13.0) in patients with disease progression of preexisting regions, 5.6 months (95% CI, 4.5 to 6.7) in patients showing new localized regions, and 3.3 months (95% CI, 1.1 to 5.5) in patients with multiple new metastatic regions (p=0.006). Median time of postskeletal metastasis progression survival was 23.0 months (95% CI, 13.5 to 32.5), 15.0 months (95% CI, 3 to 34.7), and 7.0 months (95% CI, 6.0 to 8.0) (p=0.004) in the above described patient groups, respectively. Overall, seven patients (18.9%) had more than one episode of skeletal progression of disease without extraskeletal PD.

CONCLUSION

Continued EGFR-TKI treatment with adequate local treatment after progression of skeletal metastasis may be considered for patients who show disease progression in preexisting regions or local progression.

Translation in solid cancer: are size-based response criteria an anachronism?

The purpose of translation is the development of effective medicinal products based on validated science. A parallel objective is to obtain marketing authorization for the translated product. Unfortunately, in solid cancer, these two objectives are not mutually consistent as evidenced by the contrast between major advances in science and the continuing dismal record of pharmaceutical productivity. If the problem is unrelated to science, then the process of translation may require a closer examination, namely, the criteria for regulatory approval. This realization is important because, in this context, the objective of translation is regulatory approval, and science does not passively translate into useful medicinal products. Today, in solid cancer, response criteria related to tumor size are less useful than during the earlier cytotoxic drugs era; advanced imaging and biomarkers now allow for tracking of the natural history of the disease in the laboratory and the clinic. Also, it is difficult to infer clinical benefit from tumor shrinkage since it is rarely sustained. Accordingly, size-based response criteria may represent an anachronism relative to translation in solid cancer and it may be appropriate to align preclinical and clinical effort and shift the focus to local invasion and metastasis. The shift from a cancer cell-centric model to a stroma centric model offers novel opportunities not only to interupt the natural history of the disease, but also to rethink the relevance of outdated criteria of clinical response. Current evidence favors the opinion that, in solid cancer, a different, broader, and contextual approach may lead to interventions that could delay local invasion and metastasis. All elements supporting this shift, especially advanced imaging, are in place.

Verification of wild-type EGFR status in non-small cell lung carcinomas using a mutant-enriched PCR on selected cases

EGFR genotyping is required for targeted therapy of lung adenocarcinoma. Because a false-negative result might prevent a patient from receiving appropriate targeted therapies, it is desirable to recheck equivocal results of EGFR genotyping. A cohort of 346 lung cancers was tested with a commercial kit for EGFR mutations; nine of the cases had upward real-time amplification curves at late cycles. They were also investigated using mutant-enriched PCR with peptide nucleic acid-locked nucleic acid (PNA-sequencing). Six of the nine equivocal cases harbored EGFR mutations. These cases likely had a small amount of mutant DNA near the detection limit of the commercial kit. Twenty nonequivocal, wild-type cases were reconfirmed using PNA-sequencing. We noticed a College of American Pathologists proficiency test material that showed a suspicious upward curve and eventually proved to have an H773_V774insPH in exon 20, for which a specific primer was not designed in the commercial kit. Further study using cloned DNA fragments showed that the upward curve most likely resulted from cross-reaction between similar, but nonidentical, sequences. It is desirable to keep the number of false-negative results as low as possible, but rechecking all wild-type cases is impractical. The late upward curves we observed helped identify suspicious cases for rechecking. A second method, such as PNA-sequencing, is recommended to verify wild-type cases.

Advanced non-small-cell lung cancer with epidermal growth factor receptor mutations: current evidence and future perspectives

The identification of activating mutations in the tyrosine kinase domain of the EGF receptor (EGFR) predictive of response to tyrosine kinase inhibitors (TKIs) led to a therapeutic revolution in the treatment of patients with metastatic non-small-cell lung cancer (NSCLC). To date, eight randomized clinical trials have demonstrated that first-line treatment with TKIs in advanced NSCLC patients harboring activating EGFR mutations is associated with significant improvement in response rate, progression-free survival, quality of life and tolerability, compared with platinum-based chemotherapy. These results prompted the EGFR TKIs as the current standard first-line treatment of patients with advanced NSCLC harboring activating EGFR mutations. However, there are several questions that need to be addressed, including the best choice among different EGFR TKIs, the treatment of resistant disease and of patients with specific clinical conditions. Ongoing and future, well-designed trials should answer all these questions.

State of the art: Response assessment in lung cancer in the era of genomic medicine

Tumor response assessment has been a foundation for advances in cancer therapy. Recent discoveries of effective targeted therapy for specific genomic abnormalities in lung cancer and their clinical application have brought revolutionary advances in lung cancer therapy and transformed the oncologist's approach to patients with lung cancer. Because imaging is a major method of response assessment in lung cancer both in clinical trials and practice, radiologists must understand the genomic alterations in lung cancer and the rapidly evolving therapeutic approaches to effectively communicate with oncology colleagues and maintain the key role in lung cancer care. This article describes the origin and importance of tumor response assessment, presents the recent genomic discoveries in lung cancer and therapies directed against these genomic changes, and describes how these discoveries affect the radiology community. The authors then summarize the conventional Response Evaluation Criteria in Solid Tumors and World Health Organization guidelines, which continue to be the major determinants of trial endpoints, and describe their limitations particularly in an era of genomic-based therapy. More advanced imaging techniques for lung cancer response assessment are presented, including computed tomography tumor volume and perfusion, dynamic contrast material-enhanced and diffusion-weighted magnetic resonance imaging, and positron emission tomography with fluorine 18 fluorodeoxyglucose and novel tracers. State-of-art knowledge of lung cancer biology, treatment, and imaging will help the radiology community to remain effective contributors to the personalized care of lung cancer patients.

Tumor volume decrease at 8 weeks is associated with longer survival in EGFR-mutant advanced non-small-cell lung cancer patients treated with EGFR TKI

BACKGROUND

The study investigated whether tumor volume changes at 8 weeks of therapy is associated with outcomes in advanced non-small-cell lung cancer (NSCLC) patients harboring sensitizing epidermal growth factor receptor (EGFR) mutations treated with EGFR tyrosine kinase inhibitors (TKIs).

METHODS

In 56 advanced NSCLC patients with sensitizing EGFR mutations treated with first-line erlotinib or gefitinib, tumor volumes of dominant lung lesions were measured on baseline and follow-up computed tomography, and were analyzed for association with survival.

RESULTS

Among 56 eligible patients, the median tumor volume was 17.8 cm (range, 1.3-172.7 cm) on the baseline scans. Forty-nine patients had follow-up computed tomography at approximately 8 weeks; the median tumor volume at 8 weeks was 7.1 cm (range, 0.4-62.3 cm), with the median proportional volume change of -59% (range, -90% to +91%) from baseline. The proportional volume change at 8 weeks was associated with survival (p = 0.02). Using the cutoff value of 38% volume decrease (75th percentile) at 8 weeks, patients with volume decrease more than 38% (n = 37) had a median overall survival of 43.5 months compared with 16.3 months among those with volume decrease of 38% or less (n = 12; p = 0.01). The median progression-free survival for patients with more than 38% volume decrease was 12.6 months, compared with 5.5 months for those with 38% or lesser volume decrease (p = 0.2).

CONCLUSION

The proportional volume change at 8 weeks is associated with overall survival in EGFR-mutant advanced NSCLC patients treated with first-line EGFR-TKIs. The observation of the study, if confirmed in larger study cohorts, indicates that tumor volume analysis at 8 weeks may provide an early marker for survival, and contribute to therapeutic decision making by identifying patients who may benefit from additional anticancer therapy after 8 weeks of EGFR-TKI therapy.