Intraobserver and interobserver variability in computed tomography size and attenuation measurements in patients with renal cell carcinoma receiving antiangiogenic therapy: implications for alternative response criteria

Inhibition of the Renin-Angiotensin System Improves Response to Neoadjuvant Therapy in Patients With Liver Metastasis of Colorectal Cancers

INTRODUCTION

Renin-angiotensin-aldosterone system inhibitors (RAAS-I) have been shown to prolong overall survival in patients with liver metastasized colorectal cancer in combination with antiangiogenic treatment. The effects of RAAS-I combined with neoadjuvant chemotherapy on colorectal cancer liver metastasis remain unexplored. We aimed to study the response of patients undergoing liver resection to RAAS-I in combination with neoadjuvant therapy to elucidate their potential benefits.

METHODS

Between February 2005 and May 2012, 62 patients fulfilled the inclusion criteria for distant metastasis (cM1) and comparable computed tomography or magnetic resonance tomography scans in the Picture Archiving Communication System of our center before and after neoadjuvant chemotherapy. Follow-up data and clinicopathological characteristics were collected from a prospective database and retrospectively investigated. The chemotherapeutic response to liver metastasis was evaluated according to the Response Evaluation Criteria in Solid Tumors criteria 1.1.

RESULTS

Comparing the average reduction of measured lesions, a significant response to chemotherapy was detected in the patients receiving RAAS-I (n = 24) compared to those who did not (n = 38) (P = 0.031). Interestingly, the effect was more distinctive when the size reduction was compared between high responses with more than 50% size reduction of all measured lesions (P = 0.011). In the subgroup analysis of patients receiving bevacizumab treatment, high responses to chemotherapy were observed only in the RAAS-I cohort (28.6% versus 0%, P = 0.022).

CONCLUSIONS

For neoadjuvantly treated patients, concomitant antihypertensive treatment with RAAS-I showed a higher total size reduction of liver metastasis as a sign of treatment response, especially in combination with antiangiogenic treatment with bevacizumab.

Quantitative SSTR-PET/CT for predicting response and survival outcomes in patients with pancreatic neuroendocrine tumors receiving CAPTEM

BACKGROUND

This study aimed to evaluate the predictive and monitoring role of somatostatin receptor (SSTR) positron emission tomography-computed tomography (PET/CT) and clinical parameters in patients with neuroendocrine liver metastases (NELM) from pancreatic neuroendocrine tumors (pNET) receiving capecitabine and temozolomide (CAPTEM).

PATIENTS AND METHODS

This retrospective study included twenty-two patients with pNET and NELM receiving CAPTEM who underwent pre- and post-therapeutic 68Ga-DOTATATE/-TOC PET/CT. Imaging (including standardized uptake value [SUV] of target lesions [NELM and pNET], normal spleen and liver) and clinical (Chromogranin A [CgA], Ki-67) parameters were assessed. Treatment outcome was evaluated as response according to RECIST 1.1, progression free survival (PFS) and overall survival (OS).

RESULTS

The median PFS (mPFS) was 7 months. Responders had a significantly longer mPFS compared to non-responders (10 vs. 4 months p = 0.022). Median OS (mOS) was 33 months (mOS: responders = 80 months, non-responders = 24 months p = 0.182). Baseline imaging showed higher SUV in responders, including absolute SUV, tumor-to-spleen (T/S), and tumor-to-liver (T/L) ratios (p < 0.02). All SUV parameters changed only in the responders during follow-up. Univariable Cox regression analysis identified baseline Tmax/Smean ratio and percentage change in size of pNETs as significant factors associated with PFS. A baseline Tmax/Smean ratio < 1.5 was associated with a shorter mPFS (10 vs. 4 months, (p < 0.05)). Prognostic factors for OS included age, percentage change in CgA and in T/S ratios in univariable Cox regression.

CONCLUSIONS

SSTR-PET/CT can be useful for predicting response and survival outcomes in pNET patients receiving CAPTEM: Higher baseline SUV values, particularly Tmax/Smean ratios of liver metastases were associated with better response and prolonged PFS.

Treatment Assessment of pNET and NELM after Everolimus by Quantitative MRI Parameters

Assessment of treatment response to targeted therapies such as everolimus is difficult, especially in slow-growing tumors such as NETs. In this retrospective study, 17 patients with pancreatic neuroendocrine tumors (pNETs) and hepatic metastases (NELMs) (42 target lesions) who received everolimus were analyzed. Intralesional signal intensities (SI) of non-contrast T1w, T2w and DCE imaging, and apparent diffusion coefficients (ADCmean and ADCmin) of DWI, were measured on baseline and first follow-up MRI after everolimus initiation. Response assessment was categorized according to progression-free survival (PFS), with responders (R) showing a PFS of ≥11 months. ADCmin of NELMs decreased in Rs whereas it increased in non-responders (NR). Percentual changes of ADCmin and ADCmean differed significantly between response groups (p < 0.03). By contrast, ADC of the pNETs tended to increase in Rs, while there was no change in NRs. Tumor-to-liver (T/L) ratio of T1 SI of NELMs increased in Rs and decreased in NRs, and percentual changes differed significantly between response groups (p < 0.02). T1 SI of the pNETs tended to decrease in Rs and increase in Ns. The quotient of pretherapeutic and posttherapeutic ADCmin values (DADCmin) and length of everolimus treatment showed significant association with PFS in univariable Cox analysis. In conclusion, quantitative MRI, especially DWI, seems to allow treatment assessment of pNETs with NELMs under everolimus. Interestingly, the responding NELMs showed decreasing ADC values, and there might be an opposite effect on ADC and T1 SI between NELMs and pNETs.

iRECIST-based versus non-standardized free text reporting of CT scans for monitoring metastatic renal cell carcinoma: a retrospective comparison

Purpose

Therapy decision for patients with metastatic renal cell carcinoma (mRCC) is highly dependent on disease monitoring based on radiological reports. The purpose of the study was to compare non-standardized, common practice free text reporting (FTR) on disease response with reporting based on response evaluation criteria in solid tumors modified for immune-based therapeutics (iRECIST).

Methods

Fifty patients with advanced mRCC were included in the retrospective, single-center study. CT scans had been evaluated and FTR prepared in accordance with center’s routine practice. For study purposes, reports were re-evaluated using a dedicated computer program that applied iRECIST. Patients were followed up over a period of 22.8 ± 7.9 months in intervals of 2.7 ± 1.8 months.

Weighted kappa statistics was run to assess strength of agreement. Logistic regression was used to identify predictors for different rating.

Results

Agreement between FTR and iRECIST-based reporting was moderate (kappa 0.38 [95% CI 0.2–0.6] to 0.70 [95% CI 0.5–0.9]). Tumor response or progression according to FTR were not confirmed with iRECIST in 19 (38%) or 11 (22%) patients, respectively, in at least one follow-up examination. With FTR, new lesions were frequently not recognized if they were already identified in the recent prior follow-up examination (odds ratio for too favorable rating of disease response compared to iRECIST: 5.4 [95% CI 2.9–10.1].

Conclusions

Moderate agreement between disease response according to FTR or iRECIST in patients with mRCC suggests the need of standardized quantitative radiological assessment in daily clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-03997-0.

Interobserver and intraobserver variability of RECIST assessment in ovarian cancer

OBJECTIVES

Measurement of Response Evaluation Criteria In Solid Tumors (RECIST) relies on reproducible unidimensional tumor measurements. This study assessed intraobserver and interobserver variability of target lesion selection and measurement, according to RECIST version 1.1 in patients with ovarian cancer.

METHODS

Eight international radiologists independently viewed 47 images demonstrating malignant lesions in patients with ovarian cancer and selected and measured lesions according to RECIST V.1.1 criteria. Thirteen images were viewed twice. Interobserver variability of selection and measurement were calculated for all images. Intraobserver variability of selection and measurement were calculated for images viewed twice. Lesions were classified according to their anatomical site as pulmonary, hepatic, pelvic mass, peritoneal, lymph nodal, or other. Lesion selection variability was assessed by calculating the reproducibility rate. Lesion measurement variability was assessed with the intra-class correlation coefficient.

RESULTS

From 47 images, 82 distinct lesions were identified. For lesion selection, the interobserver and intraobserver reproducibility rates were high, at 0.91 and 0.93, respectively. Interobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass and other lesions. Intraobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass, hepatic, nodal, and other lesions. Selection reproducibility was lowest for peritoneal lesions (interobserver reproducibility rate 0.76 and intraobserver reproducibility rate 0.69). For lesion measurement, the overall interobserver and intraobserver intraclass correlation coefficients showed very good concordance of 0.84 and 0.94, respectively. Interobserver intraclass correlation coefficient showed very good concordance for hepatic, pulmonary, peritoneal, and other lesions, and ranged from 0.84 to 0.97, but only moderate concordance for lymph node lesions (0.58). Intraobserver intraclass correlation coefficient showed very good concordance for all lesions, ranging from 0.82 to 0.99. In total, 85% of total measurement variability resulted from interobserver measurement difference.

CONCLUSIONS

Our study showed that while selection and measurement concordance were high, there was significant interobserver and intraobserver variability. Most resulted from interobserver variability. Compared with other lesions, peritoneal lesions had the lowest selection reproducibility, and lymph node lesions had the lowest measurement concordance. These factors need consideration to improve response assessment, especially as progression free survival remains the most common endpoint in phase III trials.

Porphyromonas gingivalis infection exacerbates oesophageal cancer and promotes resistance to neoadjuvant chemotherapy

BACKGROUND

The effect of Porphyromonas gingivalis (Pg) infection on oesophageal squamous cell carcinoma (ESCC) prognosis, chemotherapeutic efficacy, and oesophageal cancer cell apoptosis resistance and proliferation remain poorly understood.

METHODS

Clinicopathological data from 312 ESCC oesophagectomy patients, along with the computed tomography imaging results and longitudinal cancerous tissue samples from a patient subset (n = 85) who received neoadjuvant chemotherapy (NACT), were analysed. Comparison of overall survival and response rate to NACT between Pg-infected and Pg-uninfected patients was made by multivariate Cox analysis and Response Evaluation Criteria in Solid Tumours v.1.1 criteria. The influence of Pg on cell proliferation and drug-induced apoptosis was examined in ESCC patients and validated in vitro and in vivo.

RESULTS

The 5-year overall survival was lower in Pg-positive patients, and infection was associated with multiple clinicopathological factors and pathologic tumour, node, metastasis stage. Of the 85 patients who received NACT, Pg infection was associated with a lower response rate and 5-year overall survival. Infection with Pg resulted in apoptosis resistance in ESCC and promoted ESCC cell viability, which was confirmed in longitudinal cancerous tissue samples. Pg-induced apoptosis resistance was dependent on fimbriae and STAT3.

CONCLUSIONS

Pg infection is associated with a worse ESCC prognosis, reduced chemotherapy efficacy, and can potentiate the aggressive behaviour of ESCC cells.

Comparison of CT Texture Analysis Software Platforms in Renal Cell Carcinoma: Reproducibility of Numerical Values and Association With Histologic Subtype Across Platforms

OBJECTIVE. The purpose of this article is to evaluate interobserver, intraobserver, and interplatform variability and compare the previously established association between texture metrics and tumor histologic subtype using three commercially available CT texture analysis (CTTA) software platforms on the same dataset of large (> 7 cm) renal cell carcinomas (RCCs). MATERIALS AND METHODS. CT-based texture analysis was performed on contrast-enhanced MDCT images of large (> 7 cm) untreated RCCs in 124 patients (median age, 62 years; 82 men and 42 women) using three different software platforms. Using this previously studied cohort, texture features were compared across platforms. Features were correlated with histologic subtype, and strength of association was compared between platforms. Single-slice and volumetric measures from one platform were compared. Values for interobserver and intraobserver variability on a tumor subset (n = 30) were assessed across platforms. RESULTS. Metrics including mean gray-level intensity, SD, and volume correlated fairly well across platforms (concordance correlation coefficient [CCC], 0.66-0.99; mean relative difference [MRD], 0.17-5.97%). Entropy showed high variability (CCC, 0.04; MRD, 44.5%). Mean, SD, mean of positive pixels (MPP), and entropy were associated with clear cell histologic subtype on almost all platforms (p < .05). Mean, SD, entropy, and MPP were highly reproducible on most platforms on both interobserver and intraobserver analysis. CONCLUSION. Select texture metrics were reproducible across platforms and readers, but other metrics were widely variable. If clinical models are developed that use CTTA for medical decision making, these differences in reproducibility of some features across platforms need to be considered, and standardization is critical for more widespread adaptation and implementation.

Identifying response in colorectal liver metastases treated with bevacizumab: development of RECIST by combining contrast-enhanced and diffusion-weighted MRI

OBJECTIVES

Response evaluation criteria in solid tumors (RECIST) often fail to identify clinically meaningful response to bevacizumab-containing therapy in colorectal liver metastasis (CRLM). This study aimed to develop RECIST by combining contrast-enhanced and diffusion-weighted magnetic resonance imaging (MRI).

METHODS

A total of 126 patients with CRLM who underwent hepatic resection after bevacizumab-containing chemotherapy were split into initial analyses cohort (N = 42, with 76 indexed liver metastases) and validation cohort (N = 84). In lesion-based analyses, percentage decrease of arterial enhancement area and percentage increase of apparent diffusion coefficient (ADC) value from baseline to post-chemotherapy were measured. Their optimal cutoff values for distinguishing pathology-confirmed major and minor response were determined. Then, the developed RECIST (D-RECIST) was established by combining functional and size-based items. Survival relevance of D-RECIST and RECIST was examined in the validation cohort.

RESULTS

Percentage decrease of arterial enhancement area and increase of ADC value significantly differed between lesions of pathologic major or minor response, with optimal cutoffs of approximately 33% and 19%, respectively. Patients defined as responders by D-RECIST had a significantly longer median disease-free survival (DFS) than non-responders (p = 0.021; 12.9 versus 8.6 months). No significant difference was observed with RECIST (p = 0.524). In a Cox regression model, D-RECIST- but not RECIST-defined responses independently predicted the DFS (p = 0.034 and 0.811).

CONCLUSIONS

D-RECIST-defined responses provided significant prognostic information, and thus may serve as a better response evaluation approach than RECIST in CRLM treated with bevacizumab-containing therapy.

KEY POINTS

• Changes in arterial enhancement area and apparent diffusion coefficient value are associated with pathological response in colorectal liver metastases treated with bevacizumab. • The MRI-based response criteria developed by combining size-based and functional features can provide significant prognostic information.

Retrospective comparison of approaches to evaluating inter-observer variability in CT tumour measurements in an academic health centre

BACKGROUND

A growing number of research studies have reported inter-observer variability in sizes of tumours measured from CT scans. It remains unclear whether the conventional statistical measures correctly evaluate the CT measurement consistency for optimal treatment management and decision-making. We compared and evaluated the existing measures for evaluating inter-observer variability in CT measurement of cancer lesions.

METHODS

13 board-certified radiologists repeatedly reviewed 10 CT image sets of lung lesions and hepatic metastases selected through a randomisation process. A total of 130 measurements under RECIST 1.1 (Response Evaluation Criteria in Solid Tumors) guidelines were collected for the demonstration. Intraclass correlation coefficient (ICC), Bland-Altman plotting and outlier counting methods were selected for the comparison. The each selected measure was used to evaluate three cases with observed, increased and decreased inter-observer variability.

RESULTS

The ICC score yielded a weak detection when evaluating different levels of the inter-observer variability among radiologists (increased: 0.912; observed: 0.962; decreased: 0.990). The outlier counting method using Bland-Altman plotting with 2SD yielded no detection at all with its number of outliers unchanging regardless of level of inter-observer variability. Outlier counting based on domain knowledge was more sensitised to different levels of the inter-observer variability compared with the conventional measures (increased: 0.756; observed: 0.923; improved: 1.000). Visualisation of pairwise Bland-Altman bias was also sensitised to the inter-observer variability with its pattern rapidly changing in response to different levels of the inter-observer variability.

CONCLUSIONS

Conventional measures may yield weak or no detection when evaluating different levels of the inter-observer variability among radiologists. We observed that the outlier counting based on domain knowledge was sensitised to the inter-observer variability in CT measurement of cancer lesions. Our study demonstrated that, under certain circumstances, the use of standard statistical correlation coefficients may be misleading and result in a sense of false security related to the consistency of measurement for optimal treatment management and decision-making.

Test-retest repeatability of ultrasonographic shear wave elastography in a rat liver fibrosis model: toward a quantitative biomarker for preclinical trials

PURPOSE

This study evaluated the test-retest repeatability and measurement variability of ultrasonographic shear wave elastography (SWE) for liver stiffness in a rat liver fibrosis model.

METHODS

In 31 Sprague-Dawley rats divided into three groups (high-dose, low-dose, and control), liver fibrosis was induced by intraperitoneal administration of thioacetamide for 8 weeks. A dedicated radiographer performed SWE to measure liver stiffness in kilopascals in two sessions at a 3-day interval. We calculated correlations between liver stiffness and histopathologic results, measurement variability in each session using coefficients of variation (CoVs) and interquartile/median (IQR/M), and test-retest repeatability between both sessions using the repeatability coefficient.

RESULTS

Different levels of liver fibrosis in each group were successfully induced in the animal model. The mean liver stiffness values were 8.88±1.48 kPa in the control group, 11.62±1.70 kPa in the low-dose group, and 11.91±1.73 kPa in the high-dose group. The correlation between collagen areas and liver stiffness values was moderate (r=0.6). In all groups, the second session yielded lower CoVs (i.e., more reliable results) for liver stiffness than the first session, suggesting a training effect for the operator. The mean IQR/M values were also lower in the second session than in the first session, which had four outliers (0.21 vs. 0.12, P<0.001). The test-retest repeatability coefficient was 3.75 kPa and decreased to 2.82 kPa after removing the four outliers.

CONCLUSION

The use of ultrasonographic SWE was confirmed to be feasible and repeatable for evaluating liver fibrosis in preclinical trials. Operator training might reduce variability in liver stiffness measurements.

Signal changes in T2-weighted MRI of liver metastases under bevacizumab-A practical imaging biomarker?

OBJECTIVE

The purpose of this study was to investigate signal changes in T2-weighted magnetic resonance imaging of liver metastases under treatment with and without bevacizumab-containing chemotherapy and to compare these signal changes to tumor contrast enhancement.

MATERIALS AND METHODS

Retrospective analysis of 44 patients, aged 36-84 years, who underwent liver magnetic resonance imaging including T2-weighted and dynamic contrast enhancement sequences. Patients received bevacizumab-containing (n = 22) or conventional cytotoxic chemotherapy (n = 22). Magnetic resonance imaging was obtained at baseline and at three follow-ups (on average 3, 6 and 9 months after initial treatment). Three independent readers rated the T2 signal intensity and the relative contrast enhancement of the metastases on a 5-point scale.

RESULTS

T2 signal intensity of metastases treated with bevacizumab showed a significant (p<0.001) decrease in T2 signal intensity after initial treatment and exhibit compared to conventionally treated metastases significantly (p<0.001 for each follow-up) hypointense (bevacizumab: 0.70 ± 0.83 before vs. -1.55 ± 0.61, -1.91 ± 0.62, and -1.97 ± 0.52; cytotoxic: 0.73 ± 0.79 before vs. -0.69 ± 0.81, -0.71 ± 0.68, and -0.75 ± 0.65 after 3, 6, and 9 months, respectively). T2 signal intensity was strongly correlated with tumor contrast enhancement (r = 0.71; p<0.001). Intra-observer agreement for T2-signal intensity was substantial (κ = 0.75). The agreement for tumoral contrast enhancement between the readers was considerably lower (κ = 0.39).

CONCLUSION

Liver metastases exhibit considerably hypointense in T2-weighted imaging after treatment with bevacizumab, in contrast to conventionally treated liver metastases. Therefore, T2-weighted imaging seems to reflect the effect of bevacizumab.

Chest computed tomography for staging renal tumours: validation and simplification of a risk prediction model from a large contemporary retrospective cohort

OBJECTIVES

To externally validate a nomogram recently proposed by Larcher et al. (BJU Int. 2017; 120: 490) and to develop a simplified model with comparable accuracy to guide on the need for staging chest computed tomography (CT) for patients with new renal masses.

PATIENTS AND METHODS

We analysed the data of 1082 consecutive patients with unilateral enhancing renal masses referred to urology multidisciplinary team meetings at two centres between 2011 and 2017. All patients underwent a staging chest CT at diagnosis. We fitted multivariable logistic regression models and tested the Larcher model performance using area under the receiver-operating curve (AUC), calibration and decision curve analysis.

RESULTS

Forty-two patients (3.9%) had a positive chest CT. The Larcher nomogram had an AUC of 83.8% (95% confidence interval [CI] 77.1-90.6), but was only moderately well calibrated (calibration-in-the-large = -0.61, slope = 0.82). Specifically, the nomogram overestimated the risk of positive chest CT, and the magnitude of miscalibration increased with increasing predicted risks. Using a stepwise backward approach, a new model was developed including tumour size, nodal stage and systemic symptoms. Compared with the Larcher model, the new model had a similar AUC (82.7% [95% CI 75.5-90.0]), but improved calibration and clinical net benefit. The predicted risk of positive chest CT was <1% in the low-risk group and 1.9-79.9% in the high-risk group.

CONCLUSION

The Larcher nomogram is an accurate prediction tool that was moderately well calibrated with our dataset. However, our simplified model has similar accuracy and uses more objective variables available from referral, so may be easier to incorporate into clinical practice. The low-risk group from our model (tumour size ≤4 cm and no systemic symptoms) had a risk of positive chest CT <1%, suggesting these patients may forego chest CT.

Intervention to Reduce Interobserver Variability in Computed Tomographic Measurement of Cancer Lesions Among Experienced Radiologists

While a growing number of research studies have reported the inter-observer variability in computed tomographic (CT) measurements, there are very few interventional studies performed. We aimed to assess whether a peer benchmarking intervention tool may have an influence on reducing interobserver variability in CT measurements and identify possible barriers to the intervention. In this retrospective study, 13 board-certified radiologists repeatedly reviewed 10 CT image sets of lung lesions and hepatic metastases during 3 noncontiguous time periods (T1, T2, T3). Each preselected case contained normal anatomy cephalad and caudal to the lesion of interest. Lesion size measurement under RECISTS 1.1 guidelines, choice of CT slice, and time spent on measurement were captured. Prior to their final measurements, the participants were exposed to the intervention designed to reduce the number of measurements deviating from the median. Chi-square test was performed to identify radiologist-dependent factors associated with the variability. The percent of deviating measurements during T1 and T2 were 20.0% and 23.1%, respectively. There was no statistically significant change in the number of deviating measurements upon the presentation of the intervention despite the decrease in percent from 23.1% to 17.7%. The identified barriers to the intervention include clinical disagreements among radiologists. Specifically, the inter-observer variability was associated with the controversy over the choice of CT image slice (P = 0.045) and selection of start-point, axis, and end-point (P = 0.011). Clinical disagreements rather than random errors were barriers to reducing interobserver variability in CT measurement among experienced radiologists. Future interventions could aim to resolve the disagreement in an interactive approach.

Evidence-based MR imaging follow-up strategy for desmoid-type fibromatosis

OBJECTIVES

To propose a follow-up strategy for desmoid-type fibromatosis (DF) based on tumor growth behavior and the signal on T2-weighted MRI.

METHODS

We retrospectively reviewed 296 MRI studies of 34 patients with histologically proven DF. In each study, tumor volume and T2 signal relatively normal striated muscle were assessed. Volume variation and monthly growth rates were analyzed to determine lesion growth behavior (progressing versus stable/regressing lesions). Growth behavior was correlated with T2 signal, tumor location, β-catenin status, treatment strategy, and follow-up duration. Interobserver variability of volume measurements and interobserver measurement variation ratio were assessed.

RESULTS

There were 25 women and 9 men with a mean age of 39.9 ± 19 (4-73) years. Mean follow-up time in the patients included was 55 ± 41 (12-148) months. In progressing lesions, the mean average monthly growth ratio was 10.9 ± 9.2 (1.1-42.5) %. Interobserver variability of volume measurements was excellent (ICC = 0.96). Mean interobserver measurement variation ratio was 20.4 ± 23.6%. The only factor correlated with tumor growth behavior was T2 signal ratio (p < 0.0001). Seventeen out of 34 (50%) patients presented a signal change over the threshold of 1 during follow-up. There were five occurrences of secondary growth after a period of stability with a mean delay until growth of 38.2 ± 44.2 (17-116) months.

CONCLUSION

DF growth rate was quantitatively assessed. A threshold for volume variation detection was established. DF growth behavior was significantly related to T2 signal. An evidence-based follow-up strategy is proposed.

KEY POINTS

• In progressing desmoid fibromatosis, the mean average monthly growth ratio was 10.9 ± 9.2%. • Lesions with muscle/tumor T2 signal ratios lower than 1 tended to be stable or regress over time. • Given the interobserver measurement variability and MRI in-plane spatial resolution, a variation higher than 42.6% in tumor volume is required to confirm punctual progression.

Quantitative diffusion-weighted magnetic resonance enterography in ileal Crohn's disease: A systematic analysis of intra and interobserver reproducibility

BACKGROUND

Magnetic resonance enterography (MRE) is increasingly attractive as a noninvasive and radiation-free tool for assessing Crohn’s disease (CD). Diffusion-weighted imaging (DWI) is recommended as an optional MRE sequence for CD by the European Society of Gastrointestinal and Abdominal Radiology, and has shown a superb potential as a quantitative modality for bowel inflammation evaluation. However, the measurement reproducibility of quantitative DWI analysis in MRE has not been ascertained so far. To facilitate the application of quantitative diffusion-weighted MRE in the clinical routine, systematic investigations of the intra and interobserver reproducibility of DWI quantitative parameters should be performed.

AIM

To evaluate the intra and interobserver reproducibility of quantitative analysis for diffusion-weighted MRE (DW-MRE) in ileal CD.

METHODS

Forty-four subjects (21 with CD and 23 control subjects) who underwent ileocolonoscopy and DW-MRE (b = 800 s/mm²) within one week were included. Two radiologists independently measured apparent diffusion coefficients (ADC) of the terminal ileum and signal intensity ratio (SR) of the terminal ileum to ipsilateral psoas muscle on DWI images (b = 800 s/mm²). Between- and within-reader agreements were assessed using intraclass correlation coefficients (ICC), coefficients of variation (CoV), and 95% limits of agreement of Bland-Altman plots (BA-LA LoA). Diagnostic performances of ADC and SR for identifying inflamed terminal ileum from the normal were evaluated by receiver operating characteristic (ROC) curve analysis.

RESULTS

There were no significant differences in ADC or SR values between the two sessions or between the two radiologists either in the CD or control group (paired t-test, P > 0.05). The intra and interobserver reproducibility of ADC (ICC: 0.952-0.984; CoV: 3.73-6.28%; BA-LA LoA: ±11.27% to ±15.88%) and SR (ICC: 0.969-0.989; CoV: 3.51%-4.64%; BA-LA LoA: ±10.62% to ±15.45%) was excellent for CD. Agreement of ADC measurements was slightly less in control subjects (ICC: 0.641-0.736; CoV: 10.47%-11.43%; BA-LA LoA: ± 26.59% to ± 30.83%). SR of normal terminal ileum demonstrated high intra and interobserver reproducibility (ICC: 0.944-0.974; CoV: 3.73%-6.28%; BA-LA LoA: ± 18.58% to ± 24.43%). ADC and SR of two readers had outstanding diagnostic efficiencies (area under the ROC curve: 0.923-0.988).

CONCLUSION

Quantitative parameters derived from DW-MRE have good to excellent intra and interobserver agreements with high diagnostic accuracy, and can serve as robust and efficient quantitative biomarkers for CD evaluation.

Validity of RECIST Version 1.1 for Response Assessment in Metastatic Cancer: A Prospective, Multireader Study

Purpose To determine the relationship between target lesion selection with use of Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 and classification of therapeutic response in patients with metastatic cancer undergoing systemic cytotoxic and/or targeted therapies. Materials and Methods This prospective multireader study was conducted between July 2015 and July 2017. Three hundred sixteen consecutive participants with metastatic cancer underwent 932 CT examinations to monitor systemic treatment. CT studies were independently read by three radiologists. Readers identified a maximum of five lesions total (and a maximum of two lesions per organ). Dedicated oncology tumor response software was used. The Fleiss κ statistic was used to analyze interreader agreement in the assignment of individual response classes (complete response, partial response, progressive disease, or stable disease) and in the differentiation between progressive and nonprogressive disease. Results Readers selected the same set of target lesions in 128 of the 316 participants (41%) and selected a different set in 188 (59%). When target lesion selection was concordant, agreement was high (assignment of treatment response category: κ = 0.97; 95% confidence interval [CI]: 0.91, 1.0; differentiation between progressive and nonprogressive disease: κ = 0.98; 95% CI: 0.90, 1.0). When target lesion selection was discordant, agreement was significantly reduced (assignment of treatment response category: κ = 0.58; 95% CI: 0.54, 0.62; differentiation between progressive and nonprogressive disease: κ = 0.6; 95% CI: 0.59, 0.70). With concordant target lesion selection, readers agreed regarding diagnosis of progression in 97.7% of participants (95% CI: 95.4%, 100.0%); with discordant target lesion selection, readers agreed in only 55.3% (95% CI: 47.9%, 62.6%) (P < .01). Conclusion In patients with metastatic cancer undergoing systemic treatment, different cancer sites may appear similarly suitable and thus likely to be selected as target lesions but may yield inconsistent or even conflicting results with Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. This indicates that the current, limited set of target lesions in RECIST 1.1 may not reflect overall tumor load or response to therapy. © RSNA, 2018 See also the editorial by Sosna in this issue.

Optimal Phase of Dynamic Computed Tomography for Reliable Size Measurement of Metastatic Neuroendocrine Tumors of the Liver: Comparison between Pre- and Post-Contrast Phases

Objective

The reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans.

Materials and Methods

The study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations.

Results

Of the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (−6.1–5.7 mm), followed by PVP (−7.9–7.1 mm) and AP (−8.5–7.4 mm) images. Intra-observer agreement showed the same trend: −2.8–2.9 mm and −2.9–2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, −2.8–2.9 mm and −3.0–3.2 mm, respectively, on PVP, and −3.2–4.2 mm and −3.4–3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images.

Conclusion

There was better inter- and intra-observer agreement in size measurements of NET liver metastases on precontrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.

Imaging Response of Antiangiogenic and Immune-Oncology Drugs in Metastatic Renal Cell Carcinoma (mRCC): Current Status and Future Challenges

This report aims to review criteria which have been proposed for treatment evaluation in mRCC under anti-angiogenic and immune-oncologic therapies and discuss future challenges for imagers. RECIST criteria seem to only partially reflect the clinical benefit derived from anti-angiogenic drugs in mRCC. New methods of analysis propose to better evaluate response to these drugs, including a new threshold for size criteria (-10%), attenuation (Choi and modified Choi criteria), functional imaging techniques (perfusion CT, ultrasound or MRI), and new PET radiotracers. Imaging of progression is one of the main future challenges facing imagers. It is progression and not response that will trigger changes in therapy, therefore it is tumour progression that should be identified by imaging techniques to guide the oncologist on the most appropriate time to change therapy. Yet little is known on dynamics of tumour progression, and much data still needs to be accrued to understand it. Finally, as immunotherapies develop, flare or pseudo-progression phenomena are observed. Studies need to be performed to determine whether imaging can distinguish between patients undergoing pseudo-progression for which therapy should be continued, or true progression for which the treatment must be changed.

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.

Initial computed tomography imaging details during first-line systemic therapy is of significant prognostic value in patients with naïve, unresectable metastatic renal cell carcinoma

Purpose

We aimed to determine the prognostic significance of computed tomography imaging parameters of unresectable primary renal tumor lesions, obtained at baseline and at first follow-up, on overall survival in naïve, unresectable metastatic renal cell carcinoma patients during first-line systemic therapy.

Materials and methods

Clinicopathological parameters of 56 patients treated between 2007 and 2015, including imaging parameters (such as the longest tumor diameter, necrotic area diameter, and attenuation in primary renal tumor lesions on baseline vs. follow-up computed tomography), were retrospectively reviewed to derive predictive factors of overall survival. The best overall response was measured according to the RECIST v1.1.

Results

The median treatment period was 206.3 days and the median follow-up was 14.6 months. Forty-four (78.6%) patients progressed after a median 4.6 months of progression-free survival, and 6 (10.7%) patients survived with a median overall survival of 12.5 months. Multivariate analysis showed that the baseline tumor diameter (hazard ratio [HR] 0.903) and mean attenuation (HR 0.936), change of tumor diameter (HR 0.714) and necrosis diameter (HR 0.861), change in the percentage of tumor diameter (HR 1.483) and of necrosis diameter (HR 1.028) between baseline and follow-up computed tomography images; treatment duration (HR 0.986) and baseline serum hemoglobin (HR 1.790) and albumin level (HR 0.060) were significant factors for overall survival (p<0.05).

Conclusion

The study showed that baseline and first follow-up computed tomography findings of primary renal lesions during first-line systemic therapy are useful and significant predictors of OS in patients with naïve unresectable mRCC.

Diffusion-weighted quantitative MRI of pleural abnormalities: Intra- and interobserver variability in the apparent diffusion coefficient measurements

PURPOSE

To assess intra- and interobserver variability in the apparent diffusion coefficient (ADC) measurements of pleural abnormalities.

MATERIALS AND METHODS

Diffusion-weighted magnetic resonance imaging was performed in 34 patients to characterize pleural abnormalities, with a 1.5T unit at b values of 0/150/500/800 sec/mm² . In two sessions held 3 months apart, on perfusion-free ADC maps, two independent readers measured the ADC of pleural abnormalities (two readings for each reader in each case) using different methods of region-of-interest (ROI) positioning. In three methods, freehand ROIs were drawn within tumor boundaries to encompass the entire lesion on one or more axial slices (whole tumor volume [WTV], three slices observer-defined [TSOD], single-slice [SS]), while in two methods one or more ROIs were placed on the more restricted areas (multiple small round ROI [MSR], one small round ROI [OSR]). Measurement variability between readings by each reader (intraobserver repeatability) and between readers in first reading (interobserver repeatability) were assessed using intraclass correlation coefficient (ICC) and coefficient of variation (CoV). Analysis of variance (ANOVA) was performed to compare ADC values between the different methods. The measurement time of each case for all methods in first reading was recorded and compared between methods and readers.

RESULTS

All methods demonstrated good (MSR, OSR) and excellent (WTV, TSOD, SS) intra- and interreader agreement, with best and worst repeatability in WTV (lower ICC, 0.977; higher CoV, 3.5%) and OSR (lower ICC, 0.625; higher CoV, 22.8%), respectively. The lower 95% confidence interval of ICC resulted in fair to moderate agreement for OSR (up to 0.379) and in excellent agreement for WTV, TSV, and SS (up to 0.918). ADC values of OSR and MSR were significantly lower compared to other methods (P < 0.001). The OSR and SS required less measurement time (10 and 21/22 sec, respectively) compared to the others (P < 0.0001), while the WTV required the longest measurement time (132/134 sec) (P < 0.0001).

CONCLUSION

ADC measurements of pleural abnormalities are repeatable. The SS method has excellent repeatability, similar to WTV, but requires significantly less measurement time. Thus, its use should be preferred in clinical practice.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:769-782.

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.

Metastatic renal cell carcinoma imaging evaluation in the era of anti-angiogenic therapies

During the last decade, the arsenal of anti-angiogenic (AAG) agents used to treat metastatic renal cell carcinoma (RCC) has grown and revolutionized the treatment of metastatic RCC, leading to improved overall survival compared to conventional chemotherapy and traditional immunotherapy agents. AAG agents include inhibitors of vascular endothelial growth factor receptor signaling pathways and mammalian target of rapamycin inhibitors. Both of these classes of targeted agents are considered cytostatic rather than cytotoxic, inducing tumor stabilization rather than marked tumor shrinkage. As a result, decreases in tumor size alone are often minimal and/or occur late in the course of successful AAG therapy, while tumor devascularization is a distinct feature of AAG therapy. In successful AAG therapy, tumor devascularization manifests on computed tomography images as a composite of a decrease in tumor size, a decrease in tumor attenuation, and the development of tumor necrosis. In this article, we review Response Evaluation Criteria in Solid Tumors (RECIST)-the current standard of care for tumor treatment response assessment which is based merely on changes in tumor length-and its assessment of metastatic RCC tumor response in the era of AAG therapies. We then review the features of an ideal tumor imaging biomarker for predicting metastatic RCC response to a particular AAG agent and serving as a longitudinal tumor response assessment tool. Finally, a discussion of the more recently proposed imaging response criteria and new imaging trends in metastatic RCC response assessment will be reviewed.

Early Tumour Shrinkage: A Tool for the Detection of Early Clinical Activity in Metastatic Renal Cell Carcinoma

BACKGROUND

The predictive role of objective remission remains undefined for targeted agents in metastatic renal cell carcinoma (mRCC); however, early tumour shrinkage (eTS) was shown to be predictive and/or prognostic for overall survival (OS) and progression-free survival (PFS) in mRCC in several small studies.

OBJECTIVE

To evaluate the degree of eTS following systemic therapy that may predict survival in mRCC.

DESIGN, SETTING, AND PARTICIPANTS

Data from 4334 patients with mRCC in phase 2 and 3 clinical trials between 2003 and 2013 were pooled for analyses. Early tumour shrinkage was assessed based on percentage change in sum of the longest diameters of target lesions at first postbaseline scan. Patients were categorised by a more or equal versus less optimal threshold of eTS, assessed using receiver operating characteristic (ROC) analysis. OS and PFS in patients with eTS were summarised using the Kaplan-Meier method.

INTERVENTION

Axitinib, bevacizumab, interferon α, sorafenib, sunitinib, or temsirolimus.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We measured optimal thresholds of eTS and eTS as a predictor of OS or PFS.

RESULTS AND LIMITATIONS

Optimal threshold of eTS for the prediction of OS and PFS was determined to be approximately 10%. In Cox proportional hazards models, compared with patients without eTS, those with eTS had significantly longer OS (hazard ratio [HR]: 0.615; p<0.0001; median: 28.5 vs 16.0 mo) and PFS (HR: 0.628; p<0.0001; median: 10.5 vs 5.3 mo). The major limitation was the retrospective nature of our analysis, including different lines and types of therapy, although subset analyses detected a similar predictive pattern for eTS across all lines and types of therapy.

CONCLUSIONS

Early tumour shrinkage ≥10% at first postbaseline assessment could serve as a putative early end point in patients with mRCC. A prospective evaluation of eTS in clinical trials is warranted.

PATIENT SUMMARY

Early tumour shrinkage may be used to identify patients with metastatic renal cell carcinoma who would benefit from treatment with antitumour agents.

TRIAL REGISTRATION

The clinical trials are registered on ClinicalTrials.gov (NCT00267748, NCT00338884, NCT00835978, NCT00065468, NCT00083889, NCT00631371, NCT00920816, NCT00077974, NCT00137423, NCT00054886, NCT00678392, and NCT00474786).

Sonographically Identified Echogenic Renal Masses Up to 1 cm in Size Are So Rarely Malignant They Can Be Safely Ignored

OBJECTIVES

The purpose of this study was to determine whether small echogenic renal masses up to 1 cm in size incidentally detected by sonography are rarely malignant and thus do not need further workup.

METHODS

We reviewed approximately 13,600 reports of all abdominal sonographic examinations performed between November 2001 and October 2007 that identified a small echogenic mass in a kidney. Patients with known malignancy of any kind, tuberous sclerosis, lesions larger than 1.0 cm, lesions with heterogeneous echogenicity, and lesions with posterior ring-down artifacts or posterior acoustic shadowing were excluded. All patients without magnetic resonance imaging or computed tomographic scans that completely characterized the lesions were excluded unless a follow-up study (sonography, magnetic resonance imaging, or contrast-enhanced computed tomography) at least 5 years later was available for comparison to prove that the lesion was benign.

RESULTS

A total of 120 lesions in 111 patients satisfied the inclusion criteria. Lesion sizes were 0 to 5 mm (n = 16) and 6 to 10 mm (n = 104). Of these, 54 lesions were characterized as definitely benign (47 angiomyolipomas and 7 other benign entities: calcifications in stones or within a cyst or calyx and cysts that were either simple on follow-up studies or complicated with hemorrhagic or proteinaceous content). For the remaining 66 lesions, follow-up results after at least 5 years were normal in 24 cases (which meant that the lesion was no longer visible), and the remaining 42 lesions were stable in size. The mean duration of follow-up for these 66 lesions was 7.4 years.

CONCLUSIONS

Small echogenic renal masses up to 1 cm in size that fulfill our study criteria are so likely to be benign that they can be safely ignored.

Real-world data in the molecular era-finding the reality in the real world

Real-world data (RWD) promises to provide a pivotal element to the understanding of personalized medicine. However, without true representation (or the reality) of the patient-disease biosystem and its molecular contributors, RWD may hamper rather than help this advancement. In this review article, we discuss RWD vs. clinical reality and the disconnects that exist currently (emphasizing molecular medicine), and methods of closing the gaps between RWD and reality.

Observer variability in RECIST-based tumour burden measurements: a meta-analysis

BACKGROUND

Response Evaluation Criteria in Solid Tumours (RECIST)-based tumour burden measurements involve observer variability, the extent of which ought to be determined.

METHODS

A literature search identified studies on observer variability during manual measurements of tumour burdens via computed tomography according to the RECIST guideline. The 95% limit of agreement (LOA) values of relative measurement difference (RMD) were pooled using a random-effects model.

RESULTS

Twelve studies were included. Pooled 95% LOAs of RMD in measuring unidimensional longest diameters of single lesions ranged from -22.1% (95% confidence interval [CI], -30.3% to -14.0%) to 25.4% (95% CI, 17.2% to 33.5%) between observers and -17.8% (95% CI, -23.6% to -11.9%) to 16.1% (95% CI, 10.1% to 21.8%) for a single observer. Pooled 95% LOAs of RMD in measuring the sum of multiple lesions ranged from -19.2% (95% CI, -23.7% to -14.9%) to 19.5% (95% CI, 15.2% to 23.9%) between observers, and -9.8% (95% CI, -19.0% to -0.3%) to 13.1% (95% CI, 3.6% to 22.6%) for a single observer. Pooled 95% LOA of RMD in calculating the interval change of tumour burden with a single lesion ranged from -31.3% (95% CI, -46.0% to -16.5%) to 30.3% (95% CI, 15.3% to 44.8%) between observers. Studies on calculating the interval change of tumour burden for a single observer or with multiple lesions were lacking.

CONCLUSION

Interobserver RMD in measuring single tumour burden and calculating its interval change may exceed the 20% cut-off for progression. Variability decreased when tumour burden was measured by a single observer or assessed by the sum of multiple lesions.

Predicting Overall Survival in Patients With Metastatic Melanoma on Antiangiogenic Therapy and RECIST Stable Disease on Initial Posttherapy Images Using CT Texture Analysis

OBJECTIVE

The purpose of this study was to use CT texture analysis to predict overall survival (OS) in patients with metastatic melanoma and stable disease (SD) according to the Response Evaluation Criteria in Solid Tumors (RECIST) on initial posttherapy CT images.

MATERIALS AND METHODS

This retrospective study included 42 patients with metastatic melanoma who received bevacizumab therapy in the context of a randomized prospective phase II clinical trial. Target lesions on the baseline and initial posttherapy contrast-enhanced CT examinations were evaluated by CT texture analysis using TexRAD software before and after image filtering in patients with RECIST SD on initial posttherapy images. Cox proportional hazards models were used to assess the associations of CT texture analysis measurements and of other patient factors with OS. The AUC was used to evaluate predictive accuracy.

RESULTS

In multivariate analysis (in 23 patients with RECIST SD; median OS, 1.51 years), absolute change in mean positive pixels at spatial scaling filter of 4 mm, change in tumor size, and baseline serum lactate dehydrogenase (LDH) level were predictors of OS (hazard ratio [HR] = 5.05 for decrease in mean positive pixels at spatial scaling filter of 4 mm vs increase, p = 0.007; HR = 4.14 for > 5% increase in tumor size vs otherwise, p = 0.025; and HR = 1.29 for every 100 IU/L increase in baseline LDH level, p = 0.068). A prognostic index containing these three factors was highly accurate for predicting OS at 18 months (AUC = 0.917).

CONCLUSION

In patients with metastatic melanoma and RECIST SD on initial post-therapy CT images, a model incorporating CT texture analysis of target lesions, tumor size changes, and baseline LDH levels was highly accurate in predicting OS.

RECIST 1.1 compared with RECIST 1.0 in patients with advanced renal cell carcinoma receiving vascular endothelial growth factor-targeted therapy

OBJECTIVE. Response Evaluation Criteria in Solid Tumors (RECIST) is the most widely accepted method to objectively assess response to therapy in renal cell carcinoma (RCC) treated with vascular endothelial growth factor (VEGF)-targeted therapy. Both RECIST 1.0 and 1.1 have been used to assess response to VEGF-targeted therapies; however, systematic comparisons are lacking. MATERIALS AND METHODS. Sixty-two patients with metastatic RCC treated with VEGF-targeted therapies were retrospectively studied. Tumor measurements and response assessment according to RECIST 1.1 and RECIST 1.0 were compared, including the number of target lesions, baseline measurements, response at each follow-up, best overall response, and time to progression (TTP). Morphologic changes and new enhancement were also assessed over the course of treatment, and TTP was evaluated using morphologic change criteria in combination with RECIST 1.1. RESULTS. The number of target lesions according to RECIST 1.1 was significantly fewer than by RECIST 1.0 (median, 2 vs 4; p < 0.0001). At first imaging follow-up, the percentage change of the sums of the diameter measurements by RECIST 1.1 and RECIST 1.0 were highly concordant (R = 0.857; mean shrinkage, 12.1% by RECIST 1.1 vs 10.8% by RECIST 1.0). Best response assessment was highly concordant between the two criteria (weighted κ = 0.819). There was no evidence of a difference in TTP by the two criteria, with a median TTP of 8.9 months (95% CI for the median, 5.5-13.9) by RECIST 1.1 and 8.9 months (95% CI for the median, 5.8-13.6) by RECIST 1.0. The median TTP by RECIST 1.1 alone was 8.9 months compared with 5.6 months for RECIST 1.1 and morphologic changes combined. CONCLUSION. RECIST 1.1 and RECIST 1.0 response assessments were overall highly concordant in patients with RCC treated with VEGF-targeted therapy, with fewer target lesions according to RECIST 1.1 but no difference in TTP.

Response assessment in metastatic melanoma treated with ipilimumab and bevacizumab: CT tumor size and density as markers for response and outcome

BACKGROUND

Investigate the tumor diameter and density changes in advanced melanoma patients treated with ipilimumab plus bevacizumab, compare response rates based on different response criteria, and study association between these measures and survival.

METHODS

Twenty-one advanced melanoma patients with 59 measurable lesions treated in a phase 1 trial of ipilimumab plus bevacizumab were retrospectively studied. Tumor diameter and density were measured on baseline and first follow-up CT. Responses were assigned using RECIST, MASS and Choi criteria. Diameter and density measures and responses by these criteria were studied for the association with survival.

RESULTS

Twenty-three (39%) lesions and 7 (33%) patients met the Choi density criteria for response (≥15% density decrease) at the first follow-up. The response rates were 14% (3/21, 95% CI: 3-36%) by RECIST and MASS, and 52% (11/21, 95% CI: 30-74%) by Choi criteria, when both size and density criteria were used. Larger baseline tumor diameter was significantly associated with shorter progression-free survival (PFS) and overall survival (OS) (log-rank p = 0.001 and 0.003; respectively). Diameter or density changes, or responses by RECIST, MASS or Choi criteria at the first follow-up, were not associated with PFS or OS.

CONCLUSION

Tumor density decrease meeting Choi criteria was noted in one-third of advanced melanoma patients at the first follow-up scan during ipilimumab plus bevacizumab therapy. While larger baseline tumor diameter was strongly associated with shorter survival, changes of diameter or density, or responses by three criteria did not predict survival. The role of density changes in evaluating response during ipilimumab and bevacizumab therapy for advanced melanoma remains to be further established.

10% Tumor diameter shrinkage on the first follow-up computed tomography predicts clinical outcome in patients with advanced renal cell carcinoma treated with angiogenesis inhibitors: a follow-up validation study

Vascular endothelial growth factor (VEGF)-targeted agents are standard therapies for metastatic renal cell carcinoma (mRCC), associated with variable tumor shrinkage. Response Evaluation Criteria in Solid Tumors (RECIST) is of limited utility in this setting, and other imaging changes are sought to reliably predict outcome early. We aim to validate 10% tumor shrinkage as the best early indicator of outcome. Methods. In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study, 66 mRCC patients with 165 lesions on clinical trials of VEGF-targeted agents underwent thoracic and abdominal computed tomography at baseline and at first follow-up after therapy. Measurements were performed according to RECIST and tumor shrinkage of ≥10% decrease in sum of the longest diameter (-10%SLD). Correlation with time-to-treatment failure (TTF) and overall survival (OS) were compared and stratified by response to the radiologic criteria. Receiver-operating characteristics (ROC) analysis yielded the optimal threshold change in SLD, defining patients with prolonged survival. Results. More than -10%SLD significantly differentiated responders from nonresponders (median TTF 8.4 vs. 4.1 months, p = .001), whereas partial response by RECIST did not (median TTF 6.9 vs. 5.5 months in responders vs. nonresponders, p = .34). -10%SLD was also significantly predictive of OS (median OS 35.1 vs. 15.0 months in responders vs. nonresponders, p = .003). ROC curve analysis yielded -9.3% in SLD as the optimal threshold for response/no response. Conclusion. Ten percent tumor shrinkage is validated as a reliable early predictor of outcome in mRCC patients receiving VEGF-targeted therapies and may provide a practical measure to guide therapeutic decisions.