Measures of response: RECIST, WHO, and new alternatives

Issues surrounding clinical trial endpoints in solid malignancies with a focus on metastatic non-small cell lung cancer

Relative to best supportive care alone, cytotoxic chemotherapy has an established role in prolonging overall survival (OS) in patients with or without previous treatment for metastatic non-small cell lung cancer (NSCLC). OS has been the principal endpoint influencing regulatory decisions regarding targeted therapies for metastatic NSCLC, including the vascular endothelial growth factor monoclonal antibody bevacizumab in the frontline setting and the epidermal growth factor receptor tyrosine kinase inhibitors gefitinib and erlotinib in patients after prior treatment. Progression-free survival (PFS), another common endpoint in oncology clinical trials, has been discussed as a potential surrogate for OS in metastatic NSCLC. A number of phase III clinical trials of investigational targeted agents for treatment of metastatic NSCLC are ongoing, with OS designated as the primary endpoint in some cases and PFS in others. Both endpoints have been developed largely to evaluate outcomes in unselected populations in which a fraction of patients are anticipated to derive significant benefit. New approaches are being considered for the evaluation of targeted agents. Recent high profile trials have been designed to assess PFS using a randomized discontinuation design and disease control rate after 8 weeks of treatment. With a series of recent advances toward increasingly personalized biomarker-directed anticancer therapies, the appropriateness of the traditional regulatory approach has been questioned.

Surrogate end points for survival in the target treatment of advanced non-small-cell lung cancer with gefitinib or erlotinib

BACKGROUND

It is controversial for the use of survival surrogate end points including response rate (RR), disease control rate (DCR), time to progression, and progression-free survival (PFS) in trials of molecular targeted agents. Our aim was to determine the correlations of these surrogates with survival in the treatment of advanced non-small-cell lung cancer (ANSCLC) with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib.

METHODS

Summary data of median survival time (MST) and surrogates from prospective trials of EGFR-TKIs in ANSCLC were identified. Patient- or trial-related characteristics were introduced as covariates. Simple and multivariate linear regression models were fitted for MST and each surrogate, respectively. And the significance of each surrogate as a survival marker was compared by calculating the area under their receiver operating characteristic (ROC) curves.

RESULTS

Sixty eligible trials (9,903 patients) were enrolled. RR, DCR, and PFS were all strongly associated with MST. In their simple linear regression models, the coefficient of determination (R(2)) was 0.83 (p < 0.000001), 0.58 (p < 0.0001), and 0.70 (p < 0.0001), respectively. And in their multivariate linear regression models, the standard coefficient was 0.71 (p < 0.001), 0.40 (p < 0.001), and 0.74 (p < 0.001), respectively, while RR and PFS were the preferred survival predictors in the ROC analysis.

CONCLUSION

RR or PFS may serve as an appropriate survival surrogate in the clinical trials of EGFR-TKIs for ANSCLC.

Observer variability in a phase II trial - assessing consistency in RECIST application

OBJECTIVE

To assess the consistency of Response Evaluation Criteria in Solid Tumours (RECIST) application in a phase II trial.

MATERIAL AND METHODS

Patients with metastatic non-resectable colorectal cancer treated with a combination of an antibody and a chemotherapeutic drug, were included. Computed tomography (CT) scans (thorax, abdomen and pelvis) were performed at baseline and after every fourth treatment cycle. RECIST was intended for response evaluation. The scans were consecutively read by a heterogeneous group of radiologists as a part of daily work and hereafter retrospectively reviewed by a dedicated experienced radiologist. Agreement on best overall response (BOR) between readers and reviewer was quantified using κ-coefficients and the discrepancy rate was correlated with the number of different readers per patient using a χ(2)-test.

RESULTS

One hundred patients with 396 CT scans were included. Discrepancies between the readers and the reviewer were found in 47 patients. The majority of discrepancies concerned the application of RECIST. With the review, BOR changed in 17 patients, although, only in six patients the change was potentially treatment altering. Overall, the κ-coefficient of agreement between readers and reviewer was 0.71 (good). However, in the subgroup of responding patients the κ-coefficient was 0.21 (fair). The number of patients with discrepancies was significantly higher with three or more different readers per patient than with less (p =0.0003).

CONCLUSION

RECIST was not consistently applied and the majority of the reader discrepancies were RECIST related. Post review, 17 patients changed BOR; six patients in a potentially treatment altering manner. Additionally, we found that the part of patients with discrepancies increased significantly with more than three different readers per patient. The findings support a peer-review approach where a few dedicated radiologists perform double blinded readings of all the on-going cancer trial patients' CT scans.

DCE and DW-MRI monitoring of vascular disruption following VEGF-Trap treatment of a rat glioma model

Vascular-targeted therapies have shown promise as adjuvant cancer treatment. As these agents undergo clinical evaluation, sensitive imaging biomarkers are needed to assess drug target interaction and treatment response. In this study, dynamic contrast enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DW-MRI) were evaluated for detecting response of intracerebral 9 L gliosarcomas to the antivascular agent VEGF-Trap, a fusion protein designed to bind all forms of Vascular Endothelial Growth Factor-A (VEGF-A) and Placental Growth Factor (PGF). Rats with 9 L tumors were treated twice weekly for two weeks with vehicle or VEGF-Trap. DCE- and DW-MRI were performed one day prior to treatment initiation and one day following each administered dose. Kinetic parameters (K(trans), volume transfer constant; k(ep), efflux rate constant from extravascular/extracellular space to plasma; and v(p), blood plasma volume fraction) and the apparent diffusion coefficient (ADC) over the tumor volumes were compared between groups. A significant decrease in kinetic parameters was observed 24 hours following the first dose of VEGF-Trap in treated versus control animals (p < 0.05) and was accompanied by a decline in ADC values. In addition to the significant hemodynamic effect, VEGF-Trap treated animals exhibited significantly longer tumor doubling times (p < 0.05) compared to the controls. Histological findings were found to support imaging response metrics. In conclusion, kinetic MRI parameters and change in ADC have been found to serve as sensitive and early biomarkers of VEGF-Trap anti-vascular targeted therapy.

Size determination and response assessment of liver metastases with computed tomography--comparison of RECIST and volumetric algorithms

OBJECTIVE

To compare different three-dimensional volumetric algorithms (3D-algorithms) and RECIST for size measurement and response assessment in liver metastases from colorectal and pancreatic cancer.

METHODS

The volumes of a total of 102 liver metastases in 45 patients (pancreatic cancer, n=22; colon cancer, n=23) were estimated using three volumetric methods (seeded region growing method, slice-based segmentation, threshold-based segmentation) and the RECIST 1.1 method with volume calculation based on the largest axial diameter. Each measurement was performed three times by one observer. All four methods were applied to follow-up on 55 liver metastases in 29 patients undergoing systemic treatment (median follow-up, 3.5 months; range, 1-10 months). Analysis of variance (ANOVA) with post hoc tests was performed to analyze intraobserver variability and intermethod differences.

RESULTS

ANOVA showed significant higher volumes calculated according to the RECIST guideline compared to the other measurement methods (p<0.001) with relative differences ranging from 0.4% to 41.1%. Intraobserver variability was significantly higher (p<0.001) for RECIST and threshold based segmentation (3.6-32.8%) compared with slice segmentation (0.4-13.7%) and seeded region growing method (0.6-10.8%). In the follow-up study, the 3D-algorithms and the assessment following RECIST 1.1 showed a discordant classification of treatment response in 10-21% of the patients.

CONCLUSIONS

This study supports the use of volumetric measurement methods due to significant higher intraobserver reproducibility compared to RECIST. Substantial discrepancies in tumor response classification between RECIST and volumetric methods depending on applied thresholds confirm the requirement of a consensus concerning volumetric criteria for response assessment.

Size-based clinical response evaluation is insufficient to assess clinical response of sarcomas treated with isolated limb perfusion with TNF-α and melphalan

BACKGROUND

The clinical assessment of the response of sarcomas to preoperative treatment is usually defined using size-based evaluation standards. For nonresectable sarcomas, hyperthermic isolated limb perfusion with TNF-α and melphalan (TM-ILP) yields high response rates. Based on our experience, we assume that anatomic radiological response criteria are insufficient to assess the degree of regression after TM-ILP.

METHODS

The clinical response of 35 sarcomas to TM-ILP was assessed by unidimensional, bidimensional, and tridimensional size-based anatomical criteria, and responders were identified according to the established thresholds. The same tumors were investigated for pathological response according to the Salzer-Kuntschik regression scale (>90% devitalization) and reviewed for cystic degeneration, hemorrhage, and predominant necrotic or fibrosclerotic regression phenotype.

RESULTS

None of the clinical response criteria were able to reliably identify the pathologic responders. The extent of size changes showed no association with the pathological degree of regression. The number of clinical responders was low compared with the number of pathological responders (RECIST N = 1, WHO N = 3, volumetry N = 3, pathology N = 19). The occurrence of hemorrhage and/or cystic degeneration was more frequently observed in predominant necrotic sarcomas and was associated with an increase in tumor size after TM-ILP. Furthermore, we identified the fibrosclerotic phenotype of regression to be more significantly strongly associated with posttherapeutic shrinkage than necrosis.

CONCLUSIONS

Size-based clinical response evaluation is insufficient to assess clinical response in TM-ILP-treated sarcomas. The size changes of tumors after therapy reflect the type of regression rather than the extent of destruction.

Tumor response assessment by modified Choi criteria in localized high-risk soft tissue sarcoma treated with chemotherapy

BACKGROUND

The objective of this study was to compare the prognostic relevance of Response Evaluation Criteria in Solid Tumors (RECIST) versus Choi criteria for the assessment of response in patients with high-risk soft tissue sarcoma of the extremities or trunk wall who received preoperative chemotherapy with or without radiotherapy in a phase 3 trial.

METHODS

Patients received 3 cycles of preoperative epirubicin + ifosfamide with or without radiotherapy. The diagnostic concordance between RECIST and Choi criteria and their correlation with overall survival (OS) and freedom from progression (FFP) were evaluated in a univariate Cox regression model.

RESULTS

In 243 of 321 eligible patients, RECIST, Choi criteria, and histology were predictive for OS and FFP. In the subgroup of 69 patients who received chemotherapy alone and were evaluable by both RECIST and Choi criteria, Choi criteria were associated significantly with OS and FFP, whereas RECIST predicted only FFP, and the pattern of agreement observed between the 2 criteria was unsatisfactory. On a dichotomous scale, comparing objective response (complete and partial responses) and lack of response (stable and progressive disease) to preoperative chemotherapy according to RECIST and Choi criteria, only Choi criteria were predictive of OS and FFP, and fair agreement between RECIST and Choi criteria was observed. When lack of progression and progression were compared (complete and partial responses + stable disease vs progressive disease), both assessment criteria were significantly predictive of OS and FFP, and there was substantial agreement between the 2 criteria.

CONCLUSIONS

Response to chemotherapy with or without radiotherapy was associated with a better outcome in patients with high-risk soft tissue sarcoma. Choi criteria were better predictors than RECIST in patients who received preoperative chemotherapy alone.

MDCT necrosis quantification in the assessment of hepatocellular carcinoma response to yttrium 90 radioembolization therapy: comparison of two-dimensional and volumetric techniques

RATIONALE AND OBJECTIVES

The purpose of this study is to evaluate the reproducibility and agreement of tumor necrosis quantification performed by two-dimensional and volumetric methods in a cohort of patients with hepatocellular carcinoma (HCC) treated with yttrium-90 ((90)Y) radioembolization.

MATERIALS AND METHODS

Twenty-nine consecutive patients (21 men, 8 women; mean age 66.6 years; age range, 44-90 years) with HCC treated with (90)Y radioembolization that underwent liver multidetector computed tomography (MDCT) were included. Two independent radiologists evaluated the necrosis proportion of the lesions with two-dimensional (2D) measurements according to the European Association for the Study of the Liver guidelines, and with a volumetric method using a voxel-by-voxel analysis. Interobserver reproducibility for each method was assessed by using within-subject coefficients of variation (WSCV), intraclass correlation coefficients (ICC), and Lin's concordance correlation coefficients (LCC). Agreement between both methods was assessed by using the Bland-Altman plot and the paired t-test.

RESULTS

The volumetric method was more reproducible (WSCV = 27.8%; ICC = 0.914; LCC = 0.909) than the 2D (WSCV = 43.8%; ICC = 0.723; LCC = 0.841). There was a significant difference in the mean calculated necrosis proportions based on 2D and volumetric methods (P = .0129).

CONCLUSION

Voxel-by-voxel quantification of HCC necrosis is a more reproducible method than 2D analysis.

Evaluation of hepatocellular carcinoma size using two-dimensional and volumetric analysis: effect on liver transplantation eligibility

RATIONALE AND OBJECTIVES

Milan criteria recommends selection of candidates with hepatocellular carcinoma (HCC) for liver transplantation based on strict tumor size thresholds. The purpose of this study is to compare the effect of two-dimensional and three-dimensional tumor measurements on the selection of candidates for liver transplantation using Milan criteria.

MATERIALS AND METHODS

This retrospective Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board. Patient-informed consent was waived. Forty-five HCCs in 19 patients, evaluated with triphasic multidetector row computed tomography scans, were included in the analysis. The largest diameters in each two-dimensional orthogonal plane (Max2D) and within three-dimensional tumor boundaries (Max3D) were calculated for each lesion. Diameters were compared and the eligibility based on lesion size for liver transplantation was assessed.

RESULTS

The mean Max2D diameter of HCC was 3.2 ± 0.9 cm and the mean Max3D diameter was 3.5 ± 1.2 cm. There was a significant difference between the mean Max2D and Max3D diameters (P < .001). Among the 45 lesions, 22 of them (48.9%) were ineligible for transplantation according to Max2D diameter, whereas 29 of them (64.44%) were ineligible when Max3D diameter was applied (P < .001).

CONCLUSION

HCC diameter based on 3D measurements is significantly different than the conventional 2D measurements and may affect eligibility for liver transplantation.

Response to treatment series: part 2, tumor response assessment--using new and conventional criteria

OBJECTIVE

Conventional anatomic imaging biomarkers, including World Health Organization (WHO) criteria and Response Evaluation Criteria in Solid Tumors (RECIST), although effective, have limitations. This article will discuss the conventional and newer morphologic imaging biomarkers for the assessment of tumor response to therapy.

CONCLUSION

Applying established methods of assessing tumor response to therapy allows consistency in image interpretation and facilitates communication with oncologists. Because of the new methods of treatment, assessment of necrosis and volumetric information will need to be incorporated into size-based criteria.

Quantified visual scoring of metastatic melanoma patient treatment response using computed tomography: improving on the current standard

To assess whether quantitative visual scoring (QVS) is a better early predictor of progression-free survival (PFS) in patients on chemotherapy for metastatic melanoma using CT than the currently used Response Evaluation Criteria in Solid Tumors (RECIST) standard. Retrospective evaluation of 65 consecutive patients with metastatic melanoma on treatment who had a baseline and follow-up CT after two cycles of therapy. QVS was used to code imaging findings on the radiology reports considering size change, brain metastases, new lesions, mixed lesion response, and the number of organ systems involved. RECIST 1.1 criteria placed patients in the progressive disease, stable disease, or partial response groups. Multiple regression analysis was used to correlate the various independent variables with PFS. The Cox hazard proportions ratio, median survival, and Kaplan-Meier curves of the different prognostic groups were calculated. QVS of size change was found more sensitive in detecting patients deteriorating (57.1% versus 37.5%) or improving (23.8% versus 10.7%), more correlated with the median PFS for the deteriorating (1.8 versus 1.7 months), stable (5.6 versus 4.0 month), and improving (8.3 versus 5.5 months) categories and more predictive of PFS (Cox hazard proportion ratio of 3.070 versus 1.860) than RECIST 1.1 categorization. Multiple regression analysis demonstrated QVS of lesion size correlated most closely with PFS among the variables assessed (r = 0.519, p < 0.0001). QVS in this study was superior to standard RECIST categorization in terms of discriminating treated metastatic melanoma patients likely to have longer PFS.

PET imaging of early response to the tyrosine kinase inhibitor ZD4190

PURPOSE

We evaluated noninvasive positron emission tomography (PET) imaging for monitoring tumor response to the VEGFR-2 tyrosine kinase (TK) inhibitor ZD4190 during cancer therapy.

EXPERIMENTAL DESIGN

Orthotopic MDA-MB-435 tumor-bearing mice were treated with ZD4190 (100 mg/kg orally per day for three consecutive days). Tumor growth was monitored by caliper measurement. During the therapeutic period, longitudinal PET scans were acquired using (18)F-FDG, (18)F-FLT and (18)F-FPPRGD2 as imaging tracers to evaluate tumor glucose metabolism, tumor cell proliferation, and angiogenesis, respectively. Imaging metrics were validated by immunohistochemical analysis of Ki67, GLUT-1, F4/80, CD31, murine integrin β3, and human integrin αvβ3.

RESULTS

Three consecutive daily oral administrations of 100 mg/kg of ZD4190 were effective in delaying MDA-MB-435 tumor growth. A significant difference in tumor volume was observed on day 7 between the treatment group and the control group (p < 0.01). After the final treatment, tumor growth resumed after a short delay. In the control tumors, (18)F-FPPRGD2 uptake was stable between days 0 and 7. In ZD4190-treated tumors, (18)F-FPPRGD2 uptake had decreased significantly relative to baseline by 26.74 ± 8.12% (p < 0.05) on day 1 and by 41.19 ± 6.63% (p < 0.01) on day 3, then had returned to baseline on day 7. Tumor uptake of (18)F-FLT had also decreased on both day 1 and day 3 after initiation of ZD4190 treatment. No significant change in (18)F-FDG uptake in ZD4190-treated tumors was observed, however, compared with the control group. All of the imaging findings were supported by ex vivo analysis of related biomarkers.

CONCLUSION

The longitudinal imaging results demonstrated the usefulness of quantitative (18)F-FLT and (18)F-FPPRGD2 PET imaging in evaluating the early antiproliferative and antiangiogenic effects of ZD4190. The quantification data from the PET imaging were consistent with the pattern of initial growth inhibition with treatment, followed by tumor relapse after treatment cessation.

Translational imaging endpoints to predict treatment response to novel targeted anticancer agents

Response Evaluation Criteria in Solid Tumors (RECIST) and World Health Organization (WHO) Criteria have been traditionally used for the evaluation of therapeutic response to chemotherapeutic treatment regimens. They determine anatomic criteria for patients response to anti-cancer therapy based on morphological measurements of each target lesion. While this assessment is justified for cytotoxic (chemotherapeutic) drugs, it is now recognized that morphological imaging protocols are poorly suited to the evaluation of the efficacy of novel signal transduction inhibitors (STIs) which exhibit cytostatic rather than cytotoxic properties. New imaging technologies are now designed to evaluate, in a functional manner, modifications in tumor metabolic activity, cellularity, and vascularization before a reduction in tumor volume can be detected. Introduction of physiological imaging end-points, derived from dynamic contrast-enhanced (DCE) imaging protocols--including magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US)--allow for early assessment of disruption in tumor perfusion and permeability for targeted anti-angiogenic agents. Diffusion-weighted MRI (DWI) provides another physiological imaging end-point since tumor necrosis and cellularity are seen early in response to anti-angiogenic treatment. Changes in glucose and phospholipid turnover, based on metabolic MRI and positron emission tomography (PET), provide reliable markers for therapeutic response to novel receptor-targeting agents. Finally, novel molecular imaging techniques of protein and gene expression have been developed in animal models followed by a successful human application for gene therapy-based protocols.

Quantitative proton MR spectroscopy as a biomarker of tumor necrosis in the rabbit VX2 liver tumor

PURPOSE

To compare metabolic magnetic resonance (MR) imaging findings (ie, quantification of tumor choline concentration) with percentage of necrosis on pathologic examination in rabbits bearing VX2 liver tumors.

MATERIALS AND METHODS

VX2 tumors were implanted in the livers of 16 rabbits. MR imaging was performed with a 1.5-T MR scanner and extremity coil, and a hydrogen-1 ((1)H) proton MR spectroscopy ((1)H MRS) imaging protocol was used. Rabbits were euthanized immediately after imaging, and the tumor was harvested and sliced at 4-mm intervals in the axial plane. Choline concentration was calculated and was compared with the percentage of tumor necrosis on pathologic examination.

RESULTS

Mean tumor size at pathologic examination was 16 mm (range, 12-22 mm). Mean percentage of necrosis at pathologic examination was 22% (range, 4%-44%). Choline concentration showed a relatively high inverse correlation with percentage of necrosis on pathologic examination, with an r value of 0.78 (P < .002).

CONCLUSIONS

Choline concentration showed a relatively high inverse correlation with tumor necrosis on pathologic examination. Therefore, (1)H MRS may be useful to assess tumor necrosis.

Elastic phantoms generated by microfluidics technology: validation of an imaged-based approach for accurate measurement of the growth rate of lung nodules

This paper focuses on validating our approach for monitoring the development of lung nodules detected in successive chest low-dose computed tomography (LDCT) scans of a patient. Our methodology for monitoring detected lung nodules includes 3D LDCT data registration, which is a non-rigid technique and involves two steps: (i) global target-to-prototype alignment of one scan to another using the experience gained from a prior appearance model, followed by (ii) local alignment to correct for intricate relative deformations. We propose a new approach for validating the accuracy of our algorithm for elastic lung phantoms constructed with state-of-the-art microfluidics technology and in vivo data. Fabricated from a flexible transparent polymer, i.e. polydimethylsiloxane (PDMS), the phantoms mimic the contractions and expansions of the lung and nodules as seen during normal breathing. The in vivo data in our study had been collected from a small control group of four subjects and a larger test group of 27 subjects with known ground truth (biopsy diagnosis. The growth rate and diagnostic results for both phantoms and in vivo data confirm the high accuracy of our algorithm.

Role of the EASL, RECIST, and WHO response guidelines alone or in combination for hepatocellular carcinoma: radiologic-pathologic correlation

BACKGROUND & AIMS

We sought to study receiver-operating characteristics (ROC) of the European Association for the Study of the Liver (EASL), Response Evaluation Criteria in Solid Tumors (RECIST), and World Health Organization (WHO) guidelines for assessing response following locoregional therapies individually and in various combinations.

METHODS

Eighty-one patients with hepatocellular carcinoma underwent liver explantation following locoregional therapies. Response was assessed using EASL, RECIST, and WHO. Kappa statistics were used to determine inter-method agreement. Uni/multivariate logistic regression analyses were performed to determine the variables predicting complete pathologic necrosis. Numerical values were assigned to the response classes: complete response=0, partial response=1, stable disease=2, and progressive disease=3. Various mathematical combinations of EASL and WHO were tested to calculate scores and their ROCs were studied using pathological examination of the explant as the gold standard.

RESULTS

Median times (95% CI) to the WHO, RECIST, and EASL responses were 5.3 (4-11.5), 5.6 (4-11.5), and 1.3months (1.2-1.5), respectively. Kappa coefficients for WHO/RECIST, WHO/EASL, and RECIST/EASL were 0.78, 0.28, and 0.31, respectively. EASL response demonstrated significant odds ratios for predicting complete pathologic necrosis on uni/multivariate analyses. Calculated areas under the ROC curves were: RECIST: 0.63, WHO: 0.68, EASL: 0.82, EASL+WHO: 0.82, EASL×WHO: 0.85, EASL+(2×WHO): 0.79 and (2×EASL)+WHO: 0.85. An EASL×WHO Score of ⩽1 had 90.2% sensitivity for predicting complete pathologic necrosis.

CONCLUSIONS

The product of WHO and EASL demonstrated better ROC than the individual guidelines for assessment of tumor response. EASL×WHO scoring system provides a simple and clinically applicable method of response assessment following locoregional therapies for hepatocellular carcinoma.

A novel method for volumetric MRI response assessment of enhancing brain tumors

Current radiographic response criteria for brain tumors have difficulty describing changes surrounding postoperative resection cavities. Volumetric techniques may offer improved assessment, however usually are time-consuming, subjective and require expert opinion and specialized magnetic resonance imaging (MRI) sequences. We describe the application of a novel volumetric software algorithm that is nearly fully automated and uses standard T1 pre- and post-contrast MRI sequences. T1-weighted pre- and post-contrast images are automatically fused and normalized. The tumor region of interest is grossly outlined by the user. An atlas of the nasal mucosa is automatically detected and used to normalize levels of enhancement. The volume of enhancing tumor is then automatically calculated. We tested the ability of our method to calculate enhancing tumor volume with resection cavity collapse and when the enhancing tumor is obscured by subacute blood in a resection cavity. To determine variability in results, we compared narrowly-defined tumor regions with tumor regions that include adjacent meningeal enhancement and also compared different contrast enhancement threshold levels used for the automatic calculation of enhancing tumor volume. Our method quantified enhancing tumor volume despite resection cavity collapse. It detected tumor volume increase in the midst of blood products that incorrectly caused decreased measurements by other techniques. Similar trends in volume changes across scans were seen with inclusion or exclusion of meningeal enhancement and despite different automated thresholds for tissue enhancement. Our approach appears to overcome many of the challenges with response assessment of enhancing brain tumors and warrants further examination and validation.

Pediatric phase I trial and pharmacokinetic study of dasatinib: a report from the children's oncology group phase I consortium

PURPOSE Dasatinib is an orally available tyrosine kinase inhibitor with low nanomolar activity against SRC family kinases, BCR-ABL, c-KIT, EPHA2, and the PDGF-β receptor. Dasatinib was found to have selective activity in several tumor models in the Pediatric Preclinical Testing Program. PATIENTS AND METHODS A phase I study of dasatinib in pediatric patients with refractory solid tumors or imatinib-refractory, Philadelphia chromosome-positive leukemia was performed. Dose levels of 50, 65, 85, and 110 mg/m²/dose, administered orally twice daily for 28 days, with courses repeated without interruption, were studied. Pharmacokinetic studies were performed with the initial dose.

RESULTS

A total of 39 patients (solid tumors, n = 28; chronic myeloid leukemia [CML], n = 9; acute lymphoblastic leukemia, n = 2) were enrolled. No dose-limiting toxicities (DLTs) were observed at the 50, 65, and 85 mg/m² dose levels. At 110 mg/m², two of six patients experienced DLT including grade 2 diarrhea and headache. In children with leukemia, grade 4 hypokalemia (50 mg/m²), grade 3 diarrhea (85 mg/m²), and grade 2 creatinine elevation (50 mg/m²) were observed. DLT in later courses included pleural effusions, hemangiomatosis, and GI hemorrhage. There were three complete cytogenetic responses, three partial cytogenetic responses, and two partial/minimal cytogenetic responses observed in evaluable patients with CML. CONCLUSION Overall, drug disposition and tolerability of dasatinib were similar to those observed in adult patients.

Diffusion-weighted MRI for assessment of early cancer treatment response

Recent clinical practice for the management for cancer patients has begun to change from a statistical "one-size fits all" approach to medicine to more individualized care. Pre-treatment biomarkers (i.e. genetically and histologically based) have a growing role in providing guidance related to the appropriate therapy and likelihood of response; they do not take into account heterogeneity within the tumor mass. Thus, a biomarker which could be utilized to measure actual tumor response early following treatment initiation would provide an important opportunity to evaluate treatment effects on an individual patient basis. Diffusion weighted magnetic resonance imaging (DW-MRI) offers the opportunity to monitor treatment-associated alterations in tumor microenvironment using quantification of changes in tumor water diffusion values as a surrogate imaging biomarker. Results obtained thus far using DW-MRI have shown that changes in tumor diffusion values can be detected early following treatment initiation which correlate with traditional outcome measures. Sensitive imaging biomarkers are providing for the first time a means of assessing 3 dimensional tumor response early in the treatment cycle. This review highlights the development of DW-MRI and its proposed usefulness in the clinical management of cancer patients. The utility of DW-MRI for assessing therapeutic-induced response is further evaluated on tumors residing in the brain, head and neck and bone.

Improving CT prediction of treatment response in patients with metastatic colorectal carcinoma using statistical learning theory

Background

Significant interest exists in establishing radiologic imaging as a valid biomarker for assessing the response of cancer to a variety of treatments. To address this problem, we have chosen to study patients with metastatic colorectal carcinoma to learn whether statistical learning theory can improve the performance of radiologists using CT in predicting patient treatment response to therapy compared with the more traditional RECIST (Response Evaluation Criteria in Solid Tumors) standard.

Results

Predictions of survival after 8 months in 38 patients with metastatic colorectal carcinoma using the Support Vector Machine (SVM) technique improved 30% when using additional information compared to WHO (World Health Organization) or RECIST measurements alone. With both Logistic Regression (LR) and SVM, there was no significant difference in performance between WHO and RECIST. The SVM and LR techniques also demonstrated that one radiologist consistently outperformed another.

Conclusions

This preliminary research study has demonstrated that SLT algorithms, properly used in a clinical setting, have the potential to address questions and criticisms associated with both RECIST and WHO scoring methods. We also propose that tumor heterogeneity, shape, etc. obtained from CT and/or MRI scans be added to the SLT feature vector for processing.

Evaluating the extent of cell death in 3D high frequency ultrasound by registration with whole-mount tumor histopathology

PURPOSE

High frequency ultrasound imaging, 10-30 MHz, has the capability to assess tumor response to radiotherapy in mouse tumors as early as 24 h after treatment administration. The advantage of this technique is that the image contrast is generated by changes in the physical properties of dying cells. Therefore, a subject can be imaged before and multiple times during the treatment without the requirement of injecting specialized contrast agents. This study is motivated by a need to provide metrics of comparison between the volume and localization of cell death, assessed from histology, with the volume and localization of cell death surrogate, assessed as regions with increased echogeneity from ultrasound images.

METHODS

The mice were exposed to radiation doses of 2, 4, and 8 Gy. Ultrasound images ivere collected from each tumor before and 24 h after exposure to radiation using a broadband 25 MHz center frequency transducer. After radiotherapy, tumors exhibited hyperechoic regions in ultrasound images that corresponded to areas of cell death in histology. The ultrasound and histological images were rigidly registered. The tumors and regions of cell death were manually outlined on histological images. Similarly, the tumors and hyperechoic regions were outlined on the ultrasound images. Each set of contours was converted to a volumetric mesh in order to compare the volumes and the localization of cell death in histological and ultrasound images.

RESULTS

A shrinkage factor of 17 +/- 2% was calculated from the difference in the tumor volumes evaluated from histological and ultrasound images. This was used to correct the tumor and cell death volumes assessed from histology. After this correction, the average absolute difference between the volume of cell death assessed from ultrasound and histological images was 11 +/- 14% and the volume overlap was 70 +/- 12%.

CONCLUSIONS

The method provided metrics of comparison between the volume of cell death assessed from histology and that assessed from ultrasound images. It was applied here to evaluate the capability of ultrasound imaging to assess early tumor response to radiotherapy in mouse tumors. Similarly, it can be applied in the future to evaluate the capability of ultrasound imaging to assess early tumor response to other modalities of cancer treatment. The study contributes to an understanding of the capabilities and limitation of ultrasound imaging at noninvasively detecting cell death. This provides a foundation for future developments regarding the use of ultrasound in preclinical and clinical applications to adapt treatments based on tumor response to cancer therapy.

Inflammatory breast cancer: the disease, the biology, the treatment

Inflammatory breast cancer (IBC) is a rare and aggressive form of invasive breast cancer accounting for 2.5% of all breast cancer cases. It is characterized by rapid progression, local and distant metastases, younger age of onset, and lower overall survival compared with other breast cancers. Historically, IBC is a lethal disease with less than a 5% survival rate beyond 5 years when treated with surgery or radiation therapy. Because of its rarity, IBC is often misdiagnosed as mastitis or generalized dermatitis. This review examines IBC's unique clinical presentation, pathology, epidemiology, imaging, and biology and details current multidisciplinary management of the disease, which comprises systemic therapy, surgery, and radiation therapy.

Phase I study of everolimus plus weekly paclitaxel and trastuzumab in patients with metastatic breast cancer pretreated with trastuzumab

PURPOSE

To determine the recommended dose of everolimus, a mammalian target of rapamycin inhibitor, combined with paclitaxel and trastuzumab in patients with human epidermal growth factor receptor 2 (HER2)-overexpressing metastatic breast cancer pretreated with trastuzumab.

METHODS

In this phase Ib, multicenter, dose-escalation study, patients were treated with everolimus 5 mg/d, 10 mg/d, or 30 mg/wk in combination with paclitaxel (80 mg/m(2) days 1, 8, and 15 every 4 weeks) and trastuzumab (2 mg/kg weekly). End points included end-of-cycle 1 dose-limiting toxicity (DLT) rate (primary end point), safety, relative dose intensity of study drugs, overall response rate (ORR), and pharmacokinetics.

RESULTS

Of 33 patients enrolled, 31 were pretreated with taxanes, and 32 were resistant to trastuzumab. Patients received a median of two lines of chemotherapy in the metastatic setting (range, 0 to 17 lines). Three patients experienced cycle 1 DLTs: febrile neutropenia (5 mg/d), stomatitis (10 mg/d), and confusion (30 mg/wk). Grade 3 to 4 neutropenia was the most common toxicity observed (n = 17 patients [52%]). On the basis of observed DLTs and overall safety, 10 mg/d was recommended for additional development. Twenty-seven patients had measurable disease and were evaluable for efficacy. Among these patients, ORR was 44%. Overall disease was controlled for 6 months or more in 74%. Median progression-free survival was 34 weeks (95% CI, 29.1 to 40.7 weeks). Among 11 patients who were resistant to both trastuzumab and taxane, a similar level of antitumor activity was observed (ORR, 55%).

CONCLUSION

Everolimus combined with weekly paclitaxel and trastuzumab was generally well tolerated and had encouraging antitumor activity in patients with trastuzumab-pretreated and -resistant metastatic HER2-overexpressing breast cancer.

Optical molecular imaging and its emerging role in colorectal cancer

Colorectal cancer remains a major cause of morbidity and mortality in the United States. The advent of molecular therapies targeted against specific, stereotyped cellular mutations that occur in this disease has ushered in new hope for treatment options. However, key questions regarding optimal dosing schedules, dosing duration, and patient selection remain unanswered. In this review, we describe how recent advances in molecular imaging, specifically optical molecular imaging with fluorescent probes, offer potential solutions to these questions. We begin with an overview of optical molecular imaging, including discussions on the various methods of design for fluorescent probes and the clinically relevant imaging systems that have been built to image them. We then focus on the relevance of optical molecular imaging to colorectal cancer. We review the most recent data on how this imaging modality has been applied to the measurement of treatment efficacy for currently available as well as developmental molecularly targeted therapies. We then conclude with a discussion on how this imaging approach has already begun to be translated clinically for human use.

Inherited hepatocellular carcinoma

Inherited liver disorders that cause chronic inflammation, fibrosis, and cirrhosis can lead to the development of liver cancer. Because of the rarity and diversity of some of these syndromes, the relative risk of developing HCC in these patients and the age at which tumours typically arise cannot be accurately estimated. Among patients with hereditary hemachromatosis (HH), the annual incidence of HCC is 4% once cirrhosis has been established. Fibrosis and portal hypertension associated with HH can be partially reversed with therapeutic phlebotomy, but it is unclear whether this treatment alters the incidence of HCC in these patients. Importantly, it seems likely that coincidence of these genetic disorders with known HCC risk factors such as alcoholism and viral hepatitis would amplify their oncogenic potential. For this reason, patients with known genetic disorders of the liver should be repeatedly counselled to avoid environmental and toxic injury to the liver. Treatment of HCC in patients with inherited liver disease mirrors that of HCC associated with other etiologies. Unfortunately, there are case series which suggest these patients with inherited liver disease and HCC tend to present at more advanced stages and are therefore not eligible for curative therapies, causing overall decreased survival relative to patients with HCC of viral or other etiologies.

PTEN, PIK3CA, p-AKT, and p-p70S6K status: association with trastuzumab response and survival in patients with HER2-positive metastatic breast cancer

Phosphatase and tensin homolog (PTEN) is a key modulator of trastuzumab sensitivity in HER2-overexpressing breast cancer. Because PTEN opposes the downstream signaling of phosphoinositide 3-kinase (PI3K), we investigated the role of PTEN and other components of the PI3K pathway in trastuzumab resistance. We analyzed the status of PTEN, p-AKT-Ser473, and p-p70S6K-Thr389 using immunohistochemistry. PIK3CA mutation status was analyzed by direct sequencing. Primary tumor tissue was available from 137 patients with HER2-overexpressing metastatic breast cancer who had received trastuzumab-based chemotherapy. We observed that each of the four biomarkers alone did not significantly correlate with trastuzumab response, whereas PTEN loss alone significantly correlated with shorter survival times (P = 0.023). PI3K pathway activation, defined as PTEN loss and/or PIK3CA mutation, was associated with a poor response to trastuzumab (P = 0.047) and a shorter survival time (P = 0.015). PTEN loss was significantly associated with a poor response to trastuzumab (P = 0.028) and shorter survival time (P = 0.008) in patients who had received first-line trastuzumab and in patients with estrogen receptor- (P = 0.029) and progesterone receptor-negative tumors (P = 0.033). p-AKT-Ser473 and p-p70S6K-Thr389 each had a limited correlation with trastuzumab response. When these markers were combined with PTEN loss, an increased correlation with patient outcome was observed. In conclusion, PI3K pathway activation plays a pivotal role in trastuzumab resistance. Our findings may facilitate the evaluation of tumor response to trastuzumab-based and targeted therapies.

18-Fluorodeoxyglucose positron emission tomography as a tool for response prediction in solid tumours

Current response guidelines for the treatment of solid tumours are based on CT criteria. Over the last decades new techniques have emerged to evaluate cancer therapy. FDG-PET scanning is a more functional imaging technique, which can measure differences in metabolic activity. Although it has a low specificity, studies show that it can outperform classical CT scanning criteria. Especially in lung, breast and oesophageal cancer it can predict response earlier in the neo-adjuvant setting. This could reduce the use of ineffective cancer therapies, reducing costs and patient toxicity, and direct patients sooner towards effective therapy. The main problem with FDG-PET remains the difficulty in defining thresholds for response, as there is clearly a lack in large prospective randomized studies validating the use of FDG-PET in response guidelines.We give an overview of data on response prediction in solid tumours by the application of PET.

Cancer imaging: novel concepts in clinical magnetic resonance imaging

Cancer is a major public health problem in the Western world. Imaging is of crucial importance in oncology, because it may reduce cancer-related morbidity and mortality. To improve tumour evaluation, there is a need for functional imaging modalities that go beyond gross assessment of anatomical abnormalities and allow visualization and quantification of biochemical processes in vivo. Magnetic resonance imaging (MRI) not only provides anatomical information, but also offers a wide range of functional sequences that may aid the evaluation of cancerous lesions. Furthermore, MRI provides the opportunity to guide and monitor anticancer therapies noninvasively. The aim of this review is to highlight some of the most promising developments of MRI in the functional assessment of cancer and the guidance and monitoring of (novel) anticancer therapies.

Consequences of chemotherapy on resection of colorectal liver metastases

The response rate of colorectal metastases to chemotherapy, ranging from 50 to 60%, has been shown to be a prognostic factor. Complete pathologic and radiological response rates are approximately 4 and 7%, respectively. Hepatotoxic effects of oxaliplatin and irinotecan on the non-tumoral liver parenchyma have been reported and are incriminated in vascular changes (sinusoidal obstruction syndrome [SOS]) and chemotherapy-associated steatohepatitis (CASH). Oxaliplatin-based regimens are associated with an increased risk of vascular lesions and irinotecan-based regimens are associated with increased risks of steatosis and steatohepatitis. SOS increases morbidity after major liver resection, mostly after administration of more than six cycles of neoadjuvant systemic chemotherapy. CASH increases morbidity and mortality rates after hepatectomy. Preliminary results have shown that the addition of targeted molecular therapy (bevacizumab or cetuximab) to conventional chemotherapy does not increase the postoperative morbidity or mortality rates after hepatectomy and does not create additional injury to the non-tumoral liver parenchyma. However, bevacizumab may impair regeneration of the future remnant. Chemotherapy may reduce the sensitivity of CT scan and PET scan in the detection of metastases.

Quantitative imaging in oncology patients: Part 1, radiology practice patterns at major U.S. cancer centers

OBJECTIVE

The objective of our study was to examine radiologists' opinions and practice patterns concerning tumor measurements in cancer patients.

MATERIALS AND METHODS

An electronic mail survey was sent to 565 abdominal imaging radiologists at 55 U.S. National Cancer Institute (NCI)-funded cancer centers. The survey contained questions about departmental demographics, procedures for interpretation of imaging in oncologic patients, and opinions concerning the role of radiologists in using the Response Evaluation Criteria in Solid Tumors (RECIST) system for tumor measurements.

RESULTS

Two hundred ninety-six responses (52%) were received. The distribution of the size of the respondents' abdominal imaging groups was as follows: 1-5 (16/295, 5%), 6-10 (112/295, 38%), 11-15 (77/295, 26%), and > 20 (73/295, 25%). Most respondents dictate some but not all tumor measurements in the first clinical scan (236/270, 87%). For follow-up imaging, 95% (255/268) of respondents dictate tumor measurements for selected index lesions. Most respondents believe inclusion of tumor measurements in the first scan is the responsibility of the radiologist (248/262, 95%). Ninety percent of respondents (235/261) believe inclusion of several index lesion measurements is satisfactory to document disease activity. Eighty-two percent (214/260) of respondents were familiar with RECIST. Forty-two percent (110/262) of respondents' departments have a centralized process for approval of industry-sponsored oncologic trials in which imaging is an important component of the protocol end point.

CONCLUSION

Most oncologic imaging at NCI-sponsored cancer centers includes tumor measurements on initial and follow-up imaging. Very few radiology departments have a centralized process for approval of clinical trial protocols that require imaging.

A resource for the assessment of lung nodule size estimation methods: database of thoracic CT scans of an anthropomorphic phantom

A number of interrelated factors can affect the precision and accuracy of lung nodule size estimation. To quantify the effect of these factors, we have been conducting phantom CT studies using an anthropomorphic thoracic phantom containing a vasculature insert to which synthetic nodules were inserted or attached. Ten repeat scans were acquired on different multi-detector scanners, using several sets of acquisition and reconstruction protocols and various nodule characteristics (size, shape, density, location). This study design enables both bias and variance analysis for the nodule size estimation task. The resulting database is in the process of becoming publicly available as a resource to facilitate the assessment of lung nodule size estimation methodologies and to enable comparisons between different methods regarding measurement error. This resource complements public databases of clinical data and will contribute towards the development of procedures that will maximize the utility of CT imaging for lung cancer screening and tumor therapy evaluation.

Serum efficacy biomarkers for oncology

Considerable interest has emerged in serum biomarkers that can be used to evaluate early effects of cancer therapeutics. Such efficacy biomarkers are expected to become valuable both for routine clinical care and for anticancer drug development. Here, we review the literature on serum efficacy biomarkers. We discuss how data using such markers can be interpreted, particularly with regard to the issue of specificity of different markers. An important question is whether biomarker response evaluation is expected to be congruent with evaluation by traditional anatomical methods. We argue that they may not be - biomarkers are expected to provide information with regard to induction of tumor cell death that will not necessarily reflect clinical outcome.

Molecular and clinical aspects of targeting the VEGF pathway in tumors

Tumor angiogenesis is a complex process resulting from many signals from the tumor microenvironment. From preclinical animal models to clinical trials and practice, targeting tumors with antiangiogenic therapy remains an exciting area of study. Although many scientific advances have been achieved, leading to the development and clinical use of antiangiogenic drugs such as bevacizumab, sorafenib, and sunitinib, these therapies fall short of their anticipated benefits and leave many questions unanswered. Continued research into the complex signaling cascades that promote tumor angiogenesis may yield new targets or improve upon current therapies. In addition, the development of reliable tools to track tumor responses to antiangiogenic therapy will enable a better understanding of current therapeutic efficacy and may elucidate mechanisms to predict patient response to therapy.

CT volume measurement for prognostic evaluation of unresectable hepatocellular carcinoma after TACE

AIM: To analyze the value of computed tomography (CT) volume measurements for evaluation of the survival rate of unresectable hepatocellular carcinoma (HCC) patients after transcatheter arterial chemoembolization (TACE).

METHODS: One hundred and sixty-six unresectable HCC patients after TACE were involved in this retrospective study. Hepatic CT scan was performed for all patients before and 4 wk to 2 mo after TACE to define the morphologic features of HCC including its largest diameter, volume, product of the greatest axial dimension, tumor to liver volume ratio (TTLVR), and tumor shrinkage ratio. Clinical variables used in the study included gender, age, pattern of tumor growth, number of lesions, Child-Pugh classification of liver function, repeated TACE times, pre- or post-treatment α-fetoprotein (AFP) level, portal vein cancerous thrombus, tumor metastasis, degree of lipiodol retention within the tumor, and percutaneous ethanol injection. The correlation between survival time and clinical variables of patients or lesions was analyzed by combining morphologic features with the corresponding clinical and general data as input. A Cox proportional hazard model was used to analyze prognostic factors. The Kaplan-Meier method was used to calculate the cumulative survival time. Influence of the parameters on prognosis was analyzed by the log-rank test.

RESULTS: The overall 6, 12, 24, 36 and 60 mo cumulative survival rates were 78.92%, 49.85%, 23.82%, 15.60% and 8.92%, respectively. The median survival time was 12 mo. Univariate and multivariate analysis showed that only 4 parameters were the independent prognostic factors including TTLVR (χ² = 14.328, P < 0.001), portal vein cancerous thrombus (χ² = 5.643, P = 0.018), repeated TACE times (χ² = 8.746, P = 0.003), and post-treatment serum AFP level (χ² = 5.416, P = 0.020). When the TTLVR value was less than 70%, the survival time was inversely correlated with the TTLVR value.

CONCLUSION: CT volume measurement technique can predict the prognosis of unresectable HCC patients after TACE.

Response rates: a valuable signal of promising activity?

A main criterion to identify activity in phase II studies is the response rates achieved in a well-defined subset of patients. The response could be defined as a measure of tumor shrinkage. For 30 years, metric methods have been used to assess this response. The World Health Organization was the first organization to propose a unified definition for response status. Over time, the latter evolved and 10 years ago an international consensus panel proposed the Response Evaluation Criteria in Solid Tumors criteria. Although these guidelines for response assessment have limitations and biases, they have nevertheless been proven useful and advantageous. This article reviews those criteria and describes their use.

Volume assessment accuracy in computed tomography: a phantom study

There is a broad push in the cancer imaging community to eventually replace linear tumor measurements with three‐dimensional evaluation of tumor volume. To evaluate the potential accuracy of volume measurement in tumors by CT, a gelatin phantom consisting of 55 polymethylmethacrylate (PMMA) spheres spanning diameters from 1.6 mm to 25.4 mm was fabricated and scanned using thin slice (0.625 mm) CT (GE LightSpeed 16). Nine different reconstruction combinations of field of view dimension (FOV=20,30,40 cm) and CT kernel (standard, lung, bone) were analyzed. Contiguous thin‐slice images were averaged to produce CT images with greater thicknesses (1.25, 2.50, 5.0 mm). Simple grayscale thresholding techniques were used to segment the PMMA spheres from the gelatin background, where a total of 1800 spherical volumes were evaluated across the permutations studied. The geometric simplicity of the phantom established upper limits on measurement accuracy. In general, smaller slice thickness and larger sphere diameters produced more accurate volume assessment than larger slice thickness and smaller sphere diameter. The measured volumes were smaller than the actual volumes by a common factor depending on slice thickness; overall, 0.625 mm slices produced on average 18%, 1.25 mm slices produced 22%, 2.5 mm CT slices produced 29%, and 5.0 mm slices produced 39% underestimates of volume (mm³). Field of view did not have a significant effect on volume accuracy. Reconstruction algorithm significantly affected volume accuracy (p<0.0001), with the lung kernel having the smallest error, followed by the bone and standard kernels. The results of this investigation provide guidance for CT protocol development and may guide the development of more advanced techniques to promote quantitatively accurate CT volumetric analysis of tumors.

PACS number: 87.57.Q‐

Phage display peptide probes for imaging early response to bevacizumab treatment

Early evaluation of cancer response to a therapeutic regimen can help increase the effectiveness of treatment schemes and, by enabling early termination of ineffective treatments, minimize toxicity, and reduce expenses. Biomarkers that provide early indication of tumor therapy response are urgently needed. Solid tumors require blood vessels for growth, and new anti-angiogenic agents can act by preventing the development of a suitable blood supply to sustain tumor growth. The purpose of this study is to develop a class of novel molecular imaging probes that will predict tumor early response to an anti-angiogenic regimen with the humanized vascular endothelial growth factor antibody bevacizumab. Using a bevacizumab-sensitive LS174T colorectal cancer model and a 12-mer bacteriophage (phage) display peptide library, a bevacizumab-responsive peptide (BRP) was identified after six rounds of biopanning and tested in vitro and in vivo. This 12-mer peptide was metabolically stable and had low toxicity to both endothelial cells and tumor cells. Near-infrared dye IRDye800-labeled BRP phage showed strong binding to bevacizumab-treated tumors, but not to untreated control LS174T tumors. In addition, both IRDye800- and (18)F-labeled BRP peptide had significantly higher uptake in tumors treated with bevacizumab than in controls treated with phosphate-buffered saline. Ex vivo histopathology confirmed the specificity of the BRP peptide to bevacizumab-treated tumor vasculature. In summary, a novel 12-mer peptide BRP selected using phage display techniques allowed non-invasive visualization of early responses to anti-angiogenic treatment. Suitably labeled BRP peptide may be potentially useful pre-clinically and clinically for monitoring treatment response.

Targeting activated integrin alphavbeta3 with patient-derived antibodies impacts late-stage multiorgan metastasis

Advanced metastatic disease is difficult to manage and specific therapeutic targets are rare. We showed earlier that metastatic breast cancer cells use the activated conformer of adhesion receptor integrin alphavbeta3 for dissemination. We now investigated if targeting this form of the receptor can impact advanced metastatic disease, and we analyzed the mechanisms involved. Treatment of advanced multi-organ metastasis in SCID mice with patient-derived scFv antibodies specific for activated integrin alphavbeta3 caused stagnation and regression of metastatic growth. The antibodies specifically localized to tumor lesions in vivo and inhibited alphavbeta3 ligand binding at nanomolar levels in vitro. At the cellular level, the scFs associated rapidly with high affinity alphavbeta3 and dissociated extremely slowly. Thus, the scFvs occupy the receptor on metastatic tumor cells for prolonged periods of time, allowing for inhibition of established cell interaction with natural alphavbeta3 ligands. Potential apoptosis inducing effects of the antibodies through interaction with caspase-3 were studied as potential additional mechanism of treatment response. However, in contrast to a previous concept, neither the RGD-containing ligand mimetic scFvs nor RGD peptides bound or activated caspase-3 at the cellular or molecular level. This indicates that the treatment effects seen in the animal model are primarily due to antibody interference with alphavbeta3 ligation. Inhibition of advanced metastatic disease by treatment with cancer patient derived single chain antibodies against the activated conformer of integrin alphavbeta3 identifies this form of the receptor as a suitable target for therapy.

Imaging of neuroendocrine gastroenteropancreatic tumours

The role of imaging in functioning endocrine tumours (FETs) is primarily to detect the tumour, that is, to verify lesion number and location. Radiological detection of carcinoid tumours is limited by typical tumour location throughout the gastrointestinal tract or appendix and is therefore dependent on the tumour being large enough to make it recognisable in that site. The most common FET is insulinoma, which is commonly characterised by the typical appearance of a hypervascular lesion at multidetector-row computed tomography and magnetic resonance imaging. A particularly important role is played by intraoperative ultrasound in defining the exact number of lesions, their relationship with adjacent vascular structures and the pancreatic duct for the purposes of correct surgical planning (enucleation or resection). In the setting of nonfunctioning endocrine tumours (NFETs), which manifest late as large masses causing compression symptoms or as incidental findings, imaging is not primarily aimed at tumour detection, as this is relatively easy given the large size of the lesions. Rather, its role is to characterise the tumour and, in particular, to differentiate pancreatic NFET from ductal adenocarcinoma, as in comparison, malignant NFETs have a more favourable prognosis (5-year survival rate 40% compared with 3%-5% for adenocarcinoma) and therefore require different treatment approaches. As NFET are often malignant, they also require accurate staging and appropriate follow-up. In 80% of cases, NFETs have a "typical" imaging appearance: location in the pancreatic head, large dimensions (diameter between 5 and 15 cm, >10 cm in 30% of cases), capsule, sharp and regular margins owing to the expansile and noninfiltrative growth pattern, solid density and arterial hypervascularity. Some 20% of NFETs display different imaging characteristics ("atypical" appearance) as a result of arterial hypovascularity due to the presence of abundant fibrous stroma. Lastly, a small percentage of NFETs has yet a different appearance ("unusual") due to the cystic nature and/or diffuse location throughout the pancreatic parenchyma.

Prediction of breast cancer sensitivity to neoadjuvant chemotherapy based on status of DNA damage repair proteins

Introduction

Various agents used in breast cancer chemotherapy provoke DNA double-strand breaks (DSBs). DSB repair competence determines the sensitivity of cells to these agents whereby aberrations in the repair machinery leads to apoptosis. Proteins required for this pathway can be detected as nuclear foci at sites of DNA damage when the pathway is intact. Here we investigate whether focus formation of repair proteins can predict chemosensitivity of breast cancer.

Methods

Core needle biopsy specimens were obtained from sixty cases of primary breast cancer before and 18-24 hours after the first cycle of neoadjuvant epirubicin plus cyclophosphamide (EC) treatment. Nuclear focus formation of DNA damage repair proteins was immunohistochemically analyzed and compared with tumor response to chemotherapy.

Results

EC treatment induced nuclear foci of γH2AX, conjugated ubiquitin, and Rad51 in a substantial amount of cases. In contrast, BRCA1 foci were observed before treatment in the majority of the cases and only decreased after EC in thirteen cases. The presence of BRCA1-, γH2AX-, or Rad51-foci before treatment or the presence of Rad51-foci after treatment was inversely correlated with tumor response to chemotherapy. DNA damage response (DDR) competence was further evaluated by considering all four repair indicators together. A high DDR score significantly correlated with low tumor response to EC and EC + docetaxel whereas other clinicopathological factors analyzed did not.

Conclusions

High performing DDR focus formation resulted in tumor resistance to DNA damage-inducing chemotherapy. Our results suggested an importance of evaluation of DDR competence to predict breast cancer chemosensitivity, and merits further studying into its usefulness in exclusion of non-responder patients.