Assessment of tumor response in malignant pleural mesothelioma

[Modern Radiological Approaches to the Diagnosis and Staging of Pleural Mesothelioma]

Pleural mesothelioma (PM) is a highly aggressive tumour, mainly associated with prior asbestos exposure. Symptoms typically do not manifest until 20 to 50 years after exposure. Depending on the histological subtype of PM, the prognosis varies, though the median survival time is only 12-18 months. Imaging plays a central role in the management of PM patients, particularly in assessing operability and treatment response. However, PM presents a unique challenge for radiology due to its rarity, complex morphology, and tendency to invade multiple tissue layers simultaneously. Contrast-enhanced computed tomography (CT) is the central imaging modality in the diagnosis, preoperative planning and therapy monitoring of pleural mesothelioma (PM). Ideally, CT should include both the thorax and abdomen to capture the entire pleural space. Tumour thickness and volume, as determined by CT, are important prognostic factors for patient survival in PM. In addition, PET/CT, using radioactively labelled fluorodeoxyglucose (18F-FDG), offers additional valuable insights into tumour metabolism. Since PM is typically metabolically active, PET/CT is particularly effective in detecting smaller lesions, occult metastases, and assessing morphologically ambiguous lesions. Magnetic resonance imaging (MRI), on the other hand, offers distinct advantages over CT, due to its superior soft tissue contrast, particularly in visualizing tumour extent and infiltration of adjacent structures. Dynamic contrast-enhanced imaging, diffusion-weighted imaging, and 4D sequences provide valuable additional information. On the basis of the "Best Practices" of the expert panel from the International Mesothelioma Interest Group (iMig), we provide an overview of the common imaging modalities, including conventional X-ray, CT, MRI, and PET/CT. Additionally, we discuss staging based on the TNM classification (Tumour, Node, Metastasis), which evaluates the local invasion of the tumour (T), lymph node involvement (N), and the presence of metastases (M). We also present examples of assessing treatment response and highlight recent developments in diagnostic imaging.

Cancer-Associated Fibroblasts Influence Survival in Pleural Mesothelioma: Digital Gene Expression Analysis and Supervised Machine Learning Model

The exact mechanism of desmoplastic stromal reaction (DSR) formation is still unclear. The interaction between cancer cells and cancer-associated fibroblasts (CAFs) has an important role in tumor progression, while stromal changes are a poor prognostic factor in pleural mesothelioma (PM). We aimed to assess the impact of CAFs paracrine signaling within the tumor microenvironment and the DSR presence on survival, in a cohort of 77 PM patients. DSR formation was evaluated morphologically and by immunohistochemistry for Fibroblast activation protein alpha (FAP). Digital gene expression was analyzed using a custom-designed CodeSet (NanoString). Decision-tree-based analysis using the "conditional inference tree" (CIT) machine learning algorithm was performed on the obtained results. A significant association between FAP gene expression levels and the appearance of DSR was found (p = 0.025). DSR-high samples demonstrated a statistically significant prolonged median survival time. The elevated expression of MYT1, KDR, PIK3R1, PIK3R4, and SOS1 was associated with shortened OS, whereas the upregulation of VEGFC, FAP, and CDK4 was associated with prolonged OS. CIT revealed a three-tier system based on FAP, NF1, and RPTOR expressions. We could outline the prognostic value of CAFs-induced PI3K signaling pathway activation together with FAP-dependent CDK4 mediated cell cycle progression in PM, where prognostic and predictive biomarkers are urgently needed to introduce new therapeutic strategies.

Mitogen signal-associated pathways, energy metabolism regulation, and mediation of tumor immunogenicity play essential roles in the cellular response of malignant pleural mesotheliomas to platinum-based treatment: a retrospective study

Background

Malignant pleural mesothelioma (MPM) is a rare malignant tumor associated with asbestos exposure, with infaust prognosis and overall survival below 20 months in treated patients. Platinum is still the backbone of the chemotherapy protocols, and the reasons for the rather poor efficacy of platinum compounds in MPM remain largely unknown. Therefore, we aimed to analyze differences in key signaling pathways and biological mechanisms in therapy-naïve samples and samples after chemotherapy in order to evaluate the effect of platinum-based chemotherapy.

Methods

The study cohort comprised 24 MPM tumor specimens, 12 from therapy-naïve and 12 from patients after platinum-based therapy. Tumor samples were screened using the NanoString nCounter platform for digital gene expression analysis with an appurtenant custom-designed panel comprising a total of 366 mRNAs covering the most important tumor signaling pathways. Significant pathway associations were identified by gene set enrichment analysis using the WEB-based GEne SeT AnaLysis Toolkit (WebGestalt)

Results

We have found reduced activity of TNF (normalized enrichment score: 2.03), IL-17 (normalized enrichment score: 1.93), MAPK (normalized enrichment score: 1.51), and relaxin signaling pathways (normalized enrichment score: 1.42) in the samples obtained after platinum-based therapy. In contrast, AMPK (normalized enrichment score: –1.58), mTOR (normalized enrichment score: –1.50), Wnt (normalized enrichment score: –1.38), and longevity regulating pathway (normalized enrichment score: –1.31) showed significantly elevated expression in the same samples.

Conclusions

We could identify deregulated signaling pathways due to a directed cellular response to platinum-induced cell stress. Our results are paving the ground for a better understanding of cellular responses and escape mechanisms, carrying a high potential for improved clinical management of patients with MPM.

Comparison of modified Response Evaluation Criteria in Solid Tumors, European Organization for Research and Treatment of Cancer criteria, and PET Response Criteria in Solid Tumors for evaluation of tumor response to chemotherapy and prognosis prediction in patients with unresectable malignant pleural mesothelioma

OBJECTIVE

To compare modified RECIST (mRECIST), EORTC criteria, and PERCIST for response evaluation and prognosis prediction in advanced malignant pleural mesothelioma (MPM) patients treated with chemotherapy.

METHODS

Patients with MPM and not curative surgery candidates (n = 75) underwent standard chemotherapy with cisplatin and pemetrexed. CT and [F]fluorodeoxyglucose PET/CT scans were performed at baseline and after three chemotherapy cycles. Chemotherapeutic response was evaluated according to mRECIST, EORTC, and PERCIST, then concordance among those was assessed using Cohen's κ coefficient. PFS and OS were examined using log-rank and Cox methods.

RESULTS

With EORTC, 27 patients had PMD, 23 SMD, 17 PMR, and eight CMR, while with PERCIST those were 28, 22, 11, and 14, respectively. Using mRECIST, 28 had PD, 29 SD, 18 PR, and 0 CR. Although there was high concordance between EORTC and PERCIST (82.7% of patients; κ = 0.83), that between mRECIST and EORTC (38.7%; κ = 0.27) and mRECIST and PERCIST (36.0%; κ = 0.26) was low. According to both EORTC and PERCIST, patients with no progression (CMR/PMR/SMD) showed significantly longer PFS and OS than PMD patients (EORTC: P = 0.0024 and P = 0.039, respectively, PERCIST: P = 0.0012 and P = 0.024, respectively), while according to mRECIST, those who achieved no progression (PR/SD) showed significantly longer PFS than PD patients (P = 0.011), but not significantly longer OS (P = 0.11).

CONCLUSION

EORTC and PERCIST are more accurate than mRECIST for evaluation of tumor response to chemotherapy and predicting prognosis in unresectable MPM patients.

A Phase II Study of Pazopanib in Patients with Malignant Pleural Mesothelioma: NCCTG N0623 (Alliance)

PURPOSE

Preclinical and clinical data have shown promise in using antiangiogenic agents to treat malignant pleural mesothelioma (MPM). We conducted this phase II study to evaluate the efficacy and toxicity of single-agent pazopanib in patients with MPM.

MATERIALS AND METHODS

Patients with MPM who had received 0-1 prior chemotherapy regimens were eligible to receive pazopanib at a dose of 800 mg daily. The primary endpoint was progression-free survival rate at 6 months (PFS6), with a preplanned interim analysis for futility. Secondary endpoints included overall survival (OS), PFS, adverse events assessment and clinical benefit (complete response, partial response [PR], and stable disease [SD]).

RESULTS

Thirty-four evaluable patients were enrolled, with a median age of 73 years (49-84). The trial was closed early because of lack of efficacy at the preplanned interim analysis. Only 8 patients (28.6%; 95% confidence interval [CI], 13.2-48.7%) in the first 28 evaluable were progression-free at 6 months. PFS6 was 32.4% (95% CI, 17.4-50.5). There were 2 PR (5.9%) and 16 SD (47.1%). The overall median PFS and OS were 4.2 months (95% CI, 2.0-6.0) and 11.5 months (95% CI: 5.3-18.2), respectively. The median PFS and OS for the previously untreated patients was 5.4 months (95% CI, 2.7-8.5) and 16.6 months (95% CI, 6.6-30.6), respectively; and 2.0 months (95% CI, 1.3-4.2) and 5.0 months (95% CI: 3.0-11.9), respectively, for the previously treated patients. Grade 3 or higher adverse events were observed in 23 patients (67.6%).

CONCLUSION

Single-agent pazopanib was poorly tolerated in patients with MPM. The primary endpoint of PFS6 was not achieved in the current study. ClinicalTrials.gov identification number. NCT00459862.

IMPLICATIONS FOR PRACTICE

Single-agent pazopanib did not meet its endpoint in this phase II trial in malignant mesothelioma. Pazopanib is well tolerated in mesothelioma patients with a manageable toxicity profile. There is a need to better identify signals of angiogenesis that can be targeted in mesothelioma. Encouraging findings in frontline treatment warrant further investigations in combination with chemotherapy or immunotherapy.

Clinical Implementation of a Free-Breathing, Motion-Robust Dynamic Contrast-Enhanced MRI Protocol to Evaluate Pleural Tumors

OBJECTIVE. The purpose of this study was to develop a motion insensitive clinical dynamic contrast-enhanced MRI (DCE-MRI) protocol to assess the response of pleural tumors in clinical trials. MATERIALS AND METHODS. Thirty-two patients with pleura-based lesions were administered contrast material and imaged with gradient-recalled echo DCE-MRI sequence variants: either a traditional cartesian k-space acquisition (FLASH), a time-resolved imaging with stochastic trajectories acquisition (TWIST), or a radial stack-of-stars acquisition (radial) sequence in addition to other standard-of-care imaging sequences. Each image acquisition's sensitivity to motion was evaluated by comparing the motion of the thoracic border in 3D throughout the acquisition. One-way ANOVA was used to compare the image quality between different acquisitions. The 95% CIs were calculated for mean thoracic border displacement. The effects of motion on kinetic parameter estimation were explored with simulations according to clinically acquired data. RESULTS. Radial was the most motion-robust sequence with subvoxel mean displacement in the superior-inferior direction (0.4 ± 1.2 [SD] mm). FLASH showed intermediate displacement (4.6 ± 2.0 mm), whereas TWIST was most sensitive to motion (6.4 ± 3.4 mm). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the images acquired with the radial sequence were on par or better than the FLASH and TWIST sequences when reconstructed with an improved density compensation algorithm. Simulations showed that motion on scans showing pleural-based lesions can lead to markedly inaccurate kinetic parameter estimation and inappropriate kinetic model convergence within a nested model analysis. CONCLUSION. A practical radial k-space trajectory sequence that provides motion-insensitive pharmacokinetic parameters was incorporated as part of the DCE-MRI protocol of pleural tumors. Validation and usefulness in clinical trials assessing response to therapy is needed.

Radiologic Considerations and Standardization of Malignant Pleural Mesothelioma Imaging Within Clinical Trials: Consensus Statement from the NCI Thoracic Malignancy Steering Committee - International Association for the Study of Lung Cancer - Mesothelioma Applied Research Foundation Clinical Trials Planning Meeting

Detailed guidelines pertaining to radiological assessment of malignant pleural mesothelioma are currently lacking due to the rarity of the disease, complex morphology, propensity to invade multiple planes simultaneously, and lack of specific recommendations within the radiology community about assessment, reporting, and follow-up. In March 2017, a multidisciplinary meeting of mesothelioma experts was co-sponsored by the National Cancer Institute Thoracic Malignancy Steering Committee, International Association for the Study of Lung Cancer, and the Mesothelioma Applied Research Foundation. One of the outcomes of this conference was the foundation of detailed, multidisciplinary consensus imaging and management guidelines. Here, we present the recommendations for radiologic assessment of malignant pleural mesothelioma in the setting of clinical trial enrollment. We discuss optimization of imaging parameters across modalities, standardized reporting, and response assessment within clinical trials.

Biomarkers for malignant pleural mesothelioma: a meta-analysis

Malignant pleural mesothelioma (MPM) is a rare but aggressive cancer, and early detection is associated with better survival. Mesothelin, fibulin-3 and osteopontin have been suggested as screening biomarkers. The study conducted a meta-analysis of the mean differences of mesothelin, osteopontin and fibulin-3 in blood and pleural samples. PubMed searches were conducted for studies that measured levels of mesothelin, osteopontin and fibulin-3 in participants with MPM compared with malignancy, benign lung disease or healthy participants. Thirty-two studies with mesothelin levels, 12 studies with osteopontin levels and 9 studies with fibulin-3 levels were included in the meta-analysis. Statistically significant mean differences were seen between MPM patients and all other comparison groups for mesothelin blood and pleural levels. Statistically significant differences in blood osteopontin levels were seen between participants with benign lung disease and healthy participants compared with participants with MPM, but not when comparing participants with cancer with MPM participants. There were not enough studies that reported osteopontin levels in pleural fluid to complete a meta-analysis. Statistically significant differences were seen in both blood and pleural levels of fibulin-3 in MPM patients compared with all other groups. On the basis of these results, mesothelin and fibulin-3 levels appear to be significantly lower in all control groups compared with those with MPM, making them good candidates for screening biomarkers. Osteopontin may be a useful biomarker for screening healthy individuals or those with benign lung disease but would not be useful for screening patients with malignancies.

The timing of chemotherapy in the management plan for medically operable early-stage malignant pleural mesothelioma

Introduction: Trimodality therapy (including surgery, chemotherapy and radiation therapy) represents an important management approach of early-stage malignant pleural mesothelioma (MPM). The oncological value, as well as the proper sequence of the three modalities, is still under investigations. Areas Covered: The article covers the timing of chemotherapy in the management plan with either a neoadjuvant approach or adjuvant approach. It evaluates also how to select patients for induction chemotherapy and how to assess the response to treatment. Expert Opinion: Management of patients with early-stage MPM must be completed in a multidisciplinary team in tertiary centers. Availability of newer prognostic and response assessment tools should facilitate the use of induction chemotherapy as well as the selection of patients who might benefit from radical surgery.

Prognostic and predictive role of [18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with unresectable malignant pleural mesothelioma (MPM) treated with up-front pemetrexed-based chemotherapy

The aim of this study was to evaluate the role of metabolic parameters analyzed at baseline and at interim FDG‐PET in predicting disease outcome in unresectable MPM patients receiving pemetrexed‐based chemotherapy. A consecutive series of MPM patients treated between February 2004 and July 2013 with first‐line pemetrexed‐based chemotherapy, and evaluated by FDG‐PET and CT scan at baseline and after two cycles of chemotherapy, was reviewed. Best CT scan response was assessed according to modified RECIST criteria. Progression‐free survival (PFS) and overall survival (OS) were correlated with FDG‐PET parameters, such as maximum standardized uptake value (SUV_max), total lesion glycolysis (TLG), and percentage changes in SUV_max (∆SUV) and TLG (∆TLG). Overall, 142 patients were enrolled; 77 (54%) received talc pleurodesis before chemotherapy. Baseline SUV_max and TLG showed a statistically significant correlation with PFS and OS (P < 0.05) in both group of patients (treated and untreated with pleurodesis). In 65 patients not receiving pleurodesis, SUV_max reduction ≥25% (∆SUV ≥ 25%) and TLG reduction ≥30% (∆TLG ≥ 30%) were significantly associated with longer PFS (P < 0.05). Patients showing both ∆SUV ≥ 25% and ∆TLG ≥ 30% responses had a significant reduction in the risk of disease progression (HR:0.31, P < 0.001) and death (HR:0.52, P = 0.044). Neither ∆SUV nor ∆TLG showed similar association with survival outcomes in patients treated with pleurodesis. Our study confirmed the prognostic role of baseline FDG‐PET in a large series of MPM patients treated with first‐line pemetrexed‐based chemotherapy. Moreover, use of ∆SUV ≥ 25% and ∆TLG ≥ 30% as cut‐off values to define early metabolic response supported the role of FDG‐PET in predicting disease outcome and treatment response in patients not receiving pleurodesis.

Metabolic response assessment with 18F-FDG-PET/CT is superior to modified RECIST for the evaluation of response to platinum-based doublet chemotherapy in malignant pleural mesothelioma

PURPOSE

Efficient monitoring of tumor responsiveness to chemotherapy is essential to mitigate high mortality risks and cytotoxic effects of chemotherapeutics. However, there is no consensus on the most suitable diagnostic technique/parameters for assessing response to chemotherapy in malignant pleural mesothelioma (MPM). We compared the tumor responsiveness of MPM patients as assessed using modified RECIST (mRECIST) criteria and integrated 18F-FDG-PET/CT.

METHODS

Histologically confirmed MPM patients (N=82) who were treated with three cycles of cisplatin and pemetrexed, or carboplatin and pemetrexed, were included. mRECIST and integrated 18F-FDG-PET/CT were used to evaluate MPM tumor response to chemotherapy. Metabolic non-responders were defined as those with a 25% or greater increase in SUVmax compared with the previous value. Time to progression (TTP) and overall survival (OS) were compared between metabolic-responders and non-responders.

RESULTS

After three cycles of chemotherapy, 62(75.6%) of the patients were classified as having SD, 15 (18%) with partial remission (PR), and 5 (6%) with progressive disease (PD), based on mRECIST criteria. The cumulative median OS was 728.0days (95% confidence interval [CI]: 545.9-910.1) and cumulative median TTP was 365.0days (95% CI: 296.9-433.1). For the 82 patients, the disease control rate was 93.9%, whereas the metabolic response rate was only 71.9% (p<0.001). All PD and PR patients were found to be metabolic responders on 18F-FDG-PET/CT; however, among the 62mRECIST SD patients, 18 (29%) were classified as metabolic non-responders. The median TTP for metabolic responders was 13.7 months, while it was 10.0 months for non-responders(p<0.001). Metabolic responders had a trend toward longer OS, although the difference did not reach statistical significance (metabolic responders:33.9 months; non-responders: 21.6 months; p>0.05).

CONCLUSION

Several mRECIST-confirmed SD MPM patients may be classified as metabolic non-responders on18F-FDGPET/CT. Metabolic response is significantly correlated with the median TTP, suggesting it should be included in the evaluation of the response to chemotherapy in MPM patients classified as mRECIST SD, to identify non-responders.

Screening of Pleural Mesotheliomas for DNA-damage Repair Players by Digital Gene Expression Analysis Can Enhance Clinical Management of Patients Receiving Platin-Based Chemotherapy

Background: Malignant pleural mesothelioma (MPM) is a rare, predominantly asbestos-related and biologically highly aggressive tumour leading to a dismal prognosis. Multimodality therapy consisting of platinum-based chemotherapy is the treatment of choice. The reasons for the rather poor efficacy of platinum compounds remain largely unknown.

Material and Methods: For this exploratory mRNA study, 24 FFPE tumour specimens were screened by digital gene expression analysis. Based on data from preliminary experiments and recent literature, a total of 366 mRNAs were investigated using a Custom CodeSet from NanoString. All statistical analyses were calculated with the R i386 statistical programming environment.

Results: CDC25A and PARP1 gene expression were correlated with lymph node spread, BRCA1 and TP73 expression levels with higher IMIG stage. NTHL1 and XRCC3 expression was associated with TNM stage. CHECK1 as well as XRCC2 expression levels were correlated with tumour progression in the overall cohort of patients. CDKN2A and MLH1 gene expression influenced overall survival in this collective. In the adjuvant treated cohort only, CDKN2A, CHEK1 as well as ERCC1 were significantly associated with overall survival. Furthermore, TP73 expression was associated with progression in this subgroup.

Conclusion: DNA-damage response plays a crucial role in response to platin-based chemotherapeutic regimes. In particular, CHEK1, XRCC2 and TP73 are strongly associated with tumour progression. ERCC1, MLH1, CDKN2A and most promising CHEK1 are prognostic markers for OS in MPM. TP73, CDKN2A, CHEK1 and ERCC1 seem to be also predictive markers in adjuvant treated MPMs. After a prospective validation, these markers may improve clinical and pathological practice, finally leading to a patients' benefit by an enhanced clinical management.

North American Multicenter Volumetric CT Study for Clinical Staging of Malignant Pleural Mesothelioma: Feasibility and Logistics of Setting Up a Quantitative Imaging Study

BACKGROUND

Clinical tumor (T), node, and metastasis staging is based on a qualitative assessment of features defining T descriptors and has been found to be suboptimal for predicting the prognosis of patients with malignant pleural mesothelioma (MPM). Previous work suggests that volumetric computed tomography (VolCT) is prognostic and, if found practical and reproducible, could improve clinical MPM classification.

METHODS

Six North American institutions electronically submitted clinical, pathologic, and imaging data on patients with stages I to IV MPM to an established multicenter database and biostatistical center. Two reference radiologists blinded to clinical data independently reviewed the scans; calculated clinical T, node, and metastasis stage by standard criteria; performed semiautomated tumor volume calculations using commercially available software; and submitted the findings to the biostatistical center. Study end points included the feasibility of a multi-institutional VolCT network, concordance of independent VolCT assessments, and association of VolCT with pathological T classification.

RESULTS

Of 164 submitted cases, 129 were evaluated by both reference radiologists. Discordant clinical staging of most cases confirmed the inadequacy of current criteria. The overall correlation between VolCT estimates was good (Spearman correlation 0.822), but some were significantly discordant. Root cause analysis of the most discordant estimates identified four common sources of variability. Despite these limitations, median tumor volume estimates were similar within subgroups of cases representing each pathological T descriptor and increased monotonically for each reference radiologist with increasing pathological T status.

CONCLUSIONS

The good correlation between VolCT estimates obtained for most cases reviewed by two independent radiologists and qualitative association of VolCT with pathological T status combine to encourage further study. The identified sources of user error will inform design of a follow-up prospective trial to more formally assess interobserver variability of VolCT and its potential contribution to clinical MPM staging.

A radiologist's guide to treatment response criteria in oncologic imaging: anatomic imaging biomarkers

OBJECTIVE

The purpose of this article is to describe the imaging biomarkers of treatment response and provide an overview of anatomic imaging biomarkers.

CONCLUSION

Imaging biomarkers of treatment response have evolved into the primary endpoint of response in most phase 2 studies. Anatomic imaging biomarkers are applied to depict change in tumor size in response to treatment and are currently the most commonly applied method of treatment response evaluation.

ERCC1, MLH1, MSH2, MSH6, and βIII-tubulin: resistance proteins associated with response and outcome to platinum-based chemotherapy in malignant pleural mesothelioma

INTRODUCTION

Platinum-based chemotherapy is besides the standard antifolate therapy with pemetrexed, the cornerstone for treatment of patients with malignant pleural mesothelioma (MPM), and its efficacy depends on several DNA repair enzymes. Therefore, these enzymes could be biomarkers for "tailoring" chemotherapy. This study evaluated enzymes involved in repair of platinum-caused DNA damage, potentially resulting in a biomarker panel associated with patient response and outcome to platinum-based chemotherapy.

MATERIAL AND METHODS

Pre- or posttreatment specimens from a total of 103 patients with MPM who were undergoing first-line chemotherapy were tested separately. Immunohistochemistry for ERCC1 (endonuclease excision repair cross-complementing 1), MLH1 (MutL homologue 1), MutS homologue (MSH) 2, MSH6, and βIII-tubulin protein expression, and pyrosequencing for ERCC1 codon 118 and C8092A polymorphisms were performed, and their results were correlated to clinicopathologic data.

RESULTS

ERCC1, MLH1, MSH2, MSH6, and βIII-tubulin were expressed in human MPM specimens at different intensities. When considering only pretreatment specimens, MSH6 protein levels were correlated to progression during chemotherapy (P = .0281). MLH1 protein levels (P = .0205), and ERCC1 codon 118 polymorphisms (P ≤ .0001) were significantly associated with progression-free survival. A significant association between ERCC1 protein levels and overall survival was noted (P = .032). Analyses of posttreatment specimens revealed significant associations between βIII-tubulin protein levels and progression-free survival (P = .0066). ERCC1 C8092A polymorphisms were significantly associated with progression-free survival and overall survival (P = .0463 and P = .0080, respectively) in this group.

CONCLUSIONS

Enzymes involved in DNA repair mechanisms are associated with patient response and outcome to platinum-based chemotherapy. Their assessment may be a helpful tool to tailor platinum-based chemotherapy of MPM patients who might expect the largest clinical benefit. Prospective validation of this biomarker panel is warranted.

Comparison of WHO and RECIST criteria for evaluation of clinical response to chemotherapy in patients with advanced breast cancer

When patients with advanced breast cancer (ABC) are treated with neoadjuvant chemotherapy (NACT), efficacy is monitored by the extent of tumor shrinkage. Since their publication in 1981, World Health Organization (WHO) guidelines have been widely practiced in clinical trials and oncologic practice, for standardized tumor response evaluation. With advances in cancer treatment and tumor imaging, a simpler criterion based on one-dimensional rather than bi-dimensional (WHO) tumor measurement, named Response Evaluation Criteria in Solid Tumors (RECIST) was introduced in 2000. Both approaches have four response categories: complete response, partial response, stable disease and progressive disease (PD). Bi-dimensional measurement data of 151 patients with ABC were analysed with WHO and RECIST criteria to compare their response categories and inter criteria reproducibility by Kappa statistics. There was 94% concordance and 9/151 patients were re-categorized with RECIST including 6/12 PD cases. RECIST therefore under-estimates and delays diagnosis of PD. This is undesirable because it may delay or negate switch over to alternate therapy. Analysis was repeated with a new criteria named RECIST-Breast (RECIST-B), with a lower threshold for PD (≥10% rather than ≥20% increase of RECIST). This showed higher concordance of 97% with WHO criteria and re-categorization of only 4/151 patients (1/12 PD cases). RECIST-B criteria therefore have advantages of both ease of measurement and calculations combined with excellent concordance with WHO criteria, providing a practical clinical tool for response evaluation and offering good comparison with past and current clinical trials of NACT using WHO guidelines.

Changes in pulmonary function tests predict radiological response to chemotherapy in malignant pleural mesothelioma

OBJECTIVES

Response to chemotherapy in malignant pleural mesothelioma (MPM) is usually evaluated by radiological criteria, but no common agreement exists on their validity, yet. The cytoreductive effect of chemotherapy on pleural thickening may make the lung more expansible, reducing the restrictive ventilatory impairment. The aim of this study was to evaluate the changes in pulmonary function following chemotherapy in patients with MPM and to correlate these findings with radiological changes.

METHODS

Between 2004 and 2011, 62 consecutive patients (74% males, median age 63 years) were prospectively investigated. Modified RECIST criteria were used for radiological evaluation of response to chemotherapy. All patients underwent pulmonary function tests before and after three cycles of platinum-based chemotherapy. Changes between baseline and post-chemotherapy pulmonary function values (Δ) and their differences were assessed by means of Student's paired and unpaired t-test, respectively. Receiver operating characteristic (ROC) curve analysis was performed on spirometric parameters significantly associated with response.

RESULTS

Thirty (48.4%) patients had a radiological stable disease (S), 23 (37.1%) a partial response (R) and 9 (14.5%) a progressive disease (P). ΔFEV1%pred (R: 18.1 ± 18.5%; S: 0.5 ± 9.3%; P: -11 ± 13.5%; P < 0.0001), ΔFVC%pred (R: 16.1 ± 11.8%; S: 0.4 ± 11.2%; P: -9.2 ± 14.6%; P < 0.0001) and ΔVC%pred (R: 12.9 ± 15.7%; S: 1.5 ± 12.1%; P: -6.1 ± 13.2%; P = 0.001) were significantly associated with radiological response. A significant correlation was observed between ΔFEV1%pred (r = 0.46, P = 0.01), ΔFVC%pred (r = 0.43, P = 0.02) and % change in linear tumour measurement. ROC curve analysis using dichotomized radiological response (P/S vs R) as classification variables showed AUC = 0.88 (95%CI: 0.77-0.95) for ΔFEV1%pred (optimal cut-off value: +7%, sensitivity: 83%, specificity: 82%, PPV: 73%, NPV: 89%) and AUC = 0.86 (95%CI: 0.75-0.94) for ΔFVC%pred (optimal cut-off value: +6%, sensitivity: 82%, specificity: 74%, PPV: 64%, NPV: 88%).

CONCLUSIONS

Dynamic lung volumes and radiological changes after chemotherapy seem directly related. Lung function changes could be an additional tool to better evaluate the response to chemotherapy in MPM.

Folylpoly-glutamate synthetase expression is associated with tumor response and outcome from pemetrexed-based chemotherapy in malignant pleural mesothelioma

BACKGROUND

Pemetrexed-based chemotherapy represents the standard of care in first-line treatment of advanced malignant pleural mesothelioma (MPM). However, there are no established predictors of clinical benefit. Pemetrexed inhibits multiple enzymes involved in pyrimidine and purine synthesis, but the main target is thymidylate synthase (TS). After cellular uptake pemetrexed is converted into more effective polyglutamated forms by folylpoly-γ-glutamate synthetase (FPGS). We hypothesized that FPGS and TS protein expressions are associated with clinical outcome after pemetrexed-based chemotherapy.

METHODS

Pretreatment tumor samples from 84 patients with histologically confirmed MPM, who received pemetrexed combined with platinum (79 of 84) or single-agent pemetrexed (5 of 84) as first-line treatment, were retrospectively analyzed. FPGS and TS protein expressions were semiquantitatively assessed by using the Hybrid (H)-scoring system (range, 0-300). H-scores were correlated with radiological response according to modified Response Evaluation Criteria in Solid Tumors, progression-free survival (PFS) and overall survival (OS).

RESULTS

Median H-score of the entire cohort was 230 for FPGS (range, 100-300), and 210 for TS (range, 100-300). High FPGS protein expression was significantly associated with longer PFS (pCOX = 0.0337), better objective tumor response (partial response versus stable disease + progressive disease; pKW = 0.003), and improved disease-control rate (partial response + stable disease versus progressive disease; pKW = 0.0208), but not with OS. In addition, high TS protein expression was associated with progressive disease under pemetrexed-based therapy (p = 0.0383), and shorter OS (pCOX = 0.0071), but no association with PFS was observed.

CONCLUSION

FPGS and TS expressions were associated with clinical response and outcome to pemetrexed-based first-line chemotherapy in MPM. Prospective evaluation of FPGS and TS expressions and their prognostic/predictive power in MPM patients is warranted.

Clinical characteristics and treatment outcomes in 132 patients with malignant mesothelioma

Purpose:

Our objective is to scrutinize clinical, laboratory, radiological characteristics, treatment regimens, and treatment outcomes of malignant mesothelioma (MM) cases in our hospital.

Materials and Methods:

We investigated, retrospectively, the clinical characteristics and treatment outcomes of all 132 MM patients at Dicle University Hospital between January 2006 and April 2010.

Results:

A total of 82 (62.1%) patients were male, and 50 (37.9%) female. Median age was 56.0 years. Mean survival time was 9.6±6.9 months. Mean survival time of patients who had received best supportive care was 7.5 months, chemotherapy 10.4 months, and multimodality treatment regimen 12.6 months. Patients in the multimodality treatment group survived longer than did those in the other two groups (P=0.042). A total of 76 patients received chemotherapy, of whom 17 (22.3%) were administered Cisplatin/Carboplatin and Gemcitabine, 58 (76.4%) Cisplatin/Carboplatin and Pemetrexed, and one (1.3%) Cisplatin + Docetaxel. Complete and partial response to treatment in patients receiving Cisplatin/Carboplatin and Gemcitabine was found 47.1% and Cisplatin/Carboplatin and Pemetrexed was found 50.0% (P>0.05).

Conclusions:

MM related to asbestos exposure is seen frequently in Turkey. Patients present with the typical clinical features of dyspnea, weight loss, and chest pain. Survival analysis shows that patients receiving multimodality treatment may be better.

Intensity-modulated radiotherapy after extrapleural pneumonectomy in the combined-modality treatment of malignant pleural mesothelioma

INTRODUCTION

Local therapy is becoming increasingly important as a part of the definitive treatment for malignant pleural mesothelioma after extrapleural pneumonectomy (EPP) because of the emergence of trimodality therapy consisted of chemotherapy, EPP, and adjuvant radiotherapy. Herein, we explore the current evidence and indications for adjuvant intensity-modulated radiotherapy (IMRT), as well as how to further improve this technique and adapt new technology in the delivering adjuvant radiotherapy in the setting of trimodality therapy.

METHODS

A systematic review of relevant studies identified through PubMed, ISI Web of Knowledge (Web of Science), the Cochrane Library, and the National Guideline Clearinghouse search engines was performed.

RESULTS

Local control remains poor despite the inclusion of conventional adjuvant radiation therapy in trimodality therapy. This can be improved by the delivery of adjuvant IMRT. However, IMRT can be associated with severe pulmonary toxicity if the radiation dose to the remaining lung is not kept to a very low level. This is especially true when patients are receiving chemotherapy. New advances in technology can allow for lower doses to the contralateral lung, decreased treatment delivery time, and improved target dose coverage.

CONCLUSION

Excellent local control can be achieved through adjuvant IMRT after EPP for malignant pleural mesothelioma. Severe pulmonary toxicity may be avoided by setting stringent dose constraints for the contralateral lung. This can be aided by the advances in technology. Post-treatment surveillance may be reliably conducted by periodical [18F]-fluorodeoxyglucose-positron emission tomography imaging.

Early stages of mesothelioma, screening and biomarkers

The early diagnosis of mesothelioma is notoriously difficult, both from a clinical and pathological perspective. Patients often undergo several medical investigations without definitive diagnosis. The discovery of biomarkers that can be assessed in pleural effusions, histological samples, and serum may assist with the difficult early diagnosis of mesothelioma. In this chapter we focus on those markers that have been examined in the setting of either early diagnosis of mesothelioma in symptomatic individuals or that have been proposed as suitable for screening of asbestos-exposed individuals, with an emphasis on cytology and histology.

A practical guide of the Southwest Oncology Group to measure malignant pleural mesothelioma tumors by RECIST and modified RECIST criteria

Malignant pleural mesothelioma (MPM) is difficult to measure radiographically due to the nonradial and variable pattern of growth and response to therapy. Inaccurate and inconsistent tumor measurements often compromise results from clinical trials that are dependent on identifying response rate and progression-free survival. In this article, we sought to provide a practical guide through the Southwest Oncology Group on how to measure MPM by the updated RECIST version 1.1 and by modified RECIST. We hope that these steps will provide a simple means by which computed tomography measurements can be consistently performed, minimizing intra- and interobserver variability. With this consistency, we may be able to better estimate the prognosis and response to therapy. With greater utilization, we will be able to better understand the biology of MPM.

Sarcoma

Sarcomas are a diverse group of malignancies originating in the connective tissue. The approach of a patient with a mass suspect for sarcoma starts with performing a biopsy to obtain tissue for evaluation by pathology. The main role of the current imaging modalities, in general, is to recognize patients with typically benign disease, in whom further invasive staging can be omitted, and select patients with a suspected malignancy, who should be referred for biopsy. Since soft tissue sarcoma tends to be large and heterogeneous, there is growing interest in using imaging modalities to guide these biopsies. Together with pathology, imaging modalities are the basis for accurate staging, evaluation of locoregional extent of the primary lesion, screening for occult metastases, evaluation of response to cancer treatment, and the detection of tumor recurrence. In this chapter, an overview is given of the use of 18F-FDG PET in these settings, its strengths as well as its limitations.

Assessment of therapy responses and prediction of survival in malignant pleural mesothelioma through computer-aided volumetric measurement on computed tomography scans

PURPOSE

The purposes of this study were (1) to calculate the tumor volume in patients with malignant pleural mesothelioma using computed tomography (CT) scan images and a computer-aided measurement technique and (2) to investigate whether the baseline volume, or volume change after chemotherapy, predicts patient survival.

METHODS

We compiled the clinical characteristics and outcome from 30 patients enrolled in two clinical trials at our cancer center in which the patients were treated with induction chemotherapy followed by surgery and radiation. CT scans of 30 patients were obtained at baseline and after two cycles of chemotherapy. Tumor volumes were calculated using a semiautomated computer algorithm. Overall survival was measured using a landmark time at 3 months post-treatment start date such that all patients had already received two cycles of chemotherapy and a follow-up scan. Association of volume changes with overall survival were determined by a Cox Proportional Hazards Model or log-rank test. The relationship between both pre and postoperative clinical stage and baseline tumor volume was analyzed using the rank sum test.

RESULTS

The median baseline tumor volume was 473 cm(3) (range, 61 cm(3)-2108 cm(3)). Patients with high preoperative stages (III and IV) had larger baseline tumor volume than those with low preoperative stages (I and II) (p = 0.05). Patients with baseline volumes smaller than 619 cm(3) tended to survive longer than those with baseline volumes larger than or equal to 619 cm(3) (p = 0.07). Percentage change of tumor volume from baseline to first follow-up CT after two cycles of chemotherapy was significantly associated with overall survival (hazard ratio: 1.94 [95% confidence interval, 1.05-3.60], p = 0.04). Whereas the relative change in modified RECIST measurements was not significantly associated with overall survival (hazard ratio: 1.06 [95% confidence interval, 0.96-1.16], p = 0.25). By classifying changes of tumor volumes between two scans into two groups, i.e., "increase" and "decrease," a significant difference in survival was found between those who increased and decreased after two cycles of chemotherapy (p = 0.03).

CONCLUSIONS

Changes in tumor volume after two cycles of chemotherapy predicted overall survival in patients with malignant pleural mesothelioma. Tumor volume at baseline was shown to be associated with preoperative clinical stage and survival. Computer-aided volumetric measurements may enable more reliable therapeutic response assessment and could provide additional prognostic information.

[What is the role of FDG-PET in thoracic oncology in 2010?]

18F-Fluorodeoxyglucose-Positron Emission Tomography (FGD-PET) has been considered to have a major impact on the management of lung malignancies since the beginning of this century. Its value has been demonstrated by many publications, meta-analysis and European/American/Japanese recommendations. PET combined with computed tomography has provided useful information regarding the diagnosis and staging of lung cancer and allows for the delivery of adaptive radiotherapy. In its more common uses, PET has been shown to be cost-effective. With the widespread use of new radiotracers, PET will play an increasing role in the evaluation of response to treatment.

Analysis of the effect of radiotherapy on malignant pleural mesothelioma when given on adjuvant or palliative basis

Background and objective

This retrospective study was designed to evaluate the response and survival of malignant pleural mesothelioma to radiotherapy when delivered with surgery and chemotherapy and when delivered alone or with chemotherapy.

Methods

A study for 110 patients with malignant pleural mesothelioma who presented to radiotherapy department, National Cancer Institute, Cairo and received radiation therapy in the period from January 1999 to July 2007.

Results

Forty-six patients (41.8%) received trimodality therapy (surgery & adjuvant or neoadjuvant chemotherapy & adjuvant radiotherapy), while bimodality therapy (chemotherapy & radiotherapy) in 38 patients (34.5%), while 26 patients (23.6%) received single modality therapy (palliative radiotherapy), 22 patients (20%) developed local recurrence, 22 patients (20%) developed distant metastases months, 14 patients (12.7%) developed local disease progression, 25 patients (22.7%) are still alive and free of disease at time of reporting. The median survival for all patients was 16 months, while 12 and 18 months overall survival were 63.6% & 31.8% respectively while median survival for stage Ⅱ, Ⅲ, Ⅳ patients was 16.5, 12.5 and 8 months respectively.

Conclusion

Multimodality approach involving surgery, chemotherapy and radiotherapy have been evaluated and proved its superiority in improving survival, especially in stages Ⅱ.

Malignant pleural mesothelioma

Malignant pleural mesothelioma continues to be a challenge. The diagnosis and treatment of patients with malignant pleural mesothelioma requires a multidisciplinary approach. The diagnosis is best made by thoracoscopic biopsy and the aid of immunohistochemistry. Molecular studies identified inactivation of the neurofibromatosis-2 gene and INK4alpha/ARF to be key events in tumorigenesis. Based on the results of a Phase III trial, the combination of cisplatin with pemetrexed has become the preferred choice for chemotherapy, although there is suggestive evidence for the activity of other platin combinations based on Phase II studies. The optimal second-line chemotherapy remains to be defined. Surgical interventions ranging from pleurectomy/decortication to extrapleural pneumonectomy are increasingly offered in specialized centers, and the results of multimodality approaches with neoadjuvant or adjuvant chemotherapy and extrapleural pneumonectomy are encouraging. Ongoing investigations are defining the role of postoperative radiotherapy and the clinical activity of tyrosine kinase inhibitors targeting VEGFR2, histone deacetylase inhibitors and proteosome inhibitors.

From RECIST to PERCIST: Evolving Considerations for PET response criteria in solid tumors

The purpose of this article is to review the status and limitations of anatomic tumor response metrics including the World Health Organization (WHO) criteria, the Response Evaluation Criteria in Solid Tumors (RECIST), and RECIST 1.1. This article also reviews qualitative and quantitative approaches to metabolic tumor response assessment with (18)F-FDG PET and proposes a draft framework for PET Response Criteria in Solid Tumors (PERCIST), version 1.0.

METHODS

PubMed searches, including searches for the terms RECIST, positron, WHO, FDG, cancer (including specific types), treatment response, region of interest, and derivative references, were performed. Abstracts and articles judged most relevant to the goals of this report were reviewed with emphasis on limitations and strengths of the anatomic and PET approaches to treatment response assessment. On the basis of these data and the authors' experience, draft criteria were formulated for PET tumor response to treatment.

RESULTS

Approximately 3,000 potentially relevant references were screened. Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria is widely applied but still has limitations in response assessments. For example, despite effective treatment, changes in tumor size can be minimal in tumors such as lymphomas, sarcoma, hepatomas, mesothelioma, and gastrointestinal stromal tumor. CT tumor density, contrast enhancement, or MRI characteristics appear more informative than size but are not yet routinely applied. RECIST criteria may show progression of tumor more slowly than WHO criteria. RECIST 1.1 criteria (assessing a maximum of 5 tumor foci, vs. 10 in RECIST) result in a higher complete response rate than the original RECIST criteria, at least in lymph nodes. Variability appears greater in assessing progression than in assessing response. Qualitative and quantitative approaches to (18)F-FDG PET response assessment have been applied and require a consistent PET methodology to allow quantitative assessments. Statistically significant changes in tumor standardized uptake value (SUV) occur in careful test-retest studies of high-SUV tumors, with a change of 20% in SUV of a region 1 cm or larger in diameter; however, medically relevant beneficial changes are often associated with a 30% or greater decline. The more extensive the therapy, the greater the decline in SUV with most effective treatments. Important components of the proposed PERCIST criteria include assessing normal reference tissue values in a 3-cm-diameter region of interest in the liver, using a consistent PET protocol, using a fixed small region of interest about 1 cm(3) in volume (1.2-cm diameter) in the most active region of metabolically active tumors to minimize statistical variability, assessing tumor size, treating SUV lean measurements in the 1 (up to 5 optional) most metabolically active tumor focus as a continuous variable, requiring a 30% decline in SUV for "response," and deferring to RECIST 1.1 in cases that do not have (18)F-FDG avidity or are technically unsuitable. Criteria to define progression of tumor-absent new lesions are uncertain but are proposed.

CONCLUSION

Anatomic imaging alone using standard WHO, RECIST, and RECIST 1.1 criteria have limitations, particularly in assessing the activity of newer cancer therapies that stabilize disease, whereas (18)F-FDG PET appears particularly valuable in such cases. The proposed PERCIST 1.0 criteria should serve as a starting point for use in clinical trials and in structured quantitative clinical reporting. Undoubtedly, subsequent revisions and enhancements will be required as validation studies are undertaken in varying diseases and treatments.

[First-line treatment with pemetrexed in association with cisplatin in patients with non-operable malignant pleural mesothelioma]

Malignant pleural mesothelioma (MPM) is an aggressive disease with a poor prognosis. The optimal treatment of MPM was not clearly defined, until the publication of the multicentre, controlled and randomized phase III trial by Vogelzang et al. in 2003, which made the pemetrexed-cisplatin association the gold standard for the non-operable stages. Eleven patients with histologically proven pleural mesothelioma, not candidates for curative surgery, were assessed for eligibility and treated in our hospital. The response rate was similar to the reference study and the toxicity was acceptable. The median survival time was 12.7 months with an objective response rate of 45.5%. The median time to progression was 7.7 months. Neutropenia (all grades included) was the most common haematological toxicity (42.1%) although only one grade 3/4 was noted. Grade 3/4 anaemia and thrombocytopenia were not reported. Nausea and vomiting were the most commonly reported clinical toxicities with 81.8% reported (all grades included). One cutaneous allergic reaction was reported. The combination of pemetrexed and cisplatin chemotherapy provided the best objectives responses, but new therapeutic regimens are still warranted for these patients with a poor prognosis. The results were similar to those obtained in the Vogelzang et al.'s trial despite a selection bias because they correspond to 36.7% of the total recruitment in the unit.

Tumor cavitation: impact on objective response evaluation in trials of angiogenesis inhibitors in non-small-cell lung cancer

PURPOSE

We have observed cavitation of lesions in clinical trials of an angiogenesis inhibitor combined with chemotherapy for non-small-cell lung cancer (NSCLC). We hypothesized that cavitation might alter response assessment in such clinical trials.

PATIENTS AND METHODS

We performed a retrospective radiologic review of patients with NSCLC enrolled onto three National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) trials of platinum-based chemotherapy with or without a small-molecule angiogenesis inhibitor (vascular endothelial growth factor receptor inhibitor [VEGFRI]). Response was assessed both by Response Evaluation Criteria in Solid Tumors (RECIST) guidelines and a novel alternate method in which the longest diameter of any cavity was subtracted from the overall longest diameter of that lesion to measure target lesions. Rates of cavitation were documented.

RESULTS

Marked cavitation of pulmonary lesions was seen in 24% of 33 patients treated with VEGFRI combined with platinum-based chemotherapy but in none of 18 patients treated with platinum-based chemotherapy alone. Use of the alternate method for response assessment resulted in an alteration of response assessment, time to best response, duration of response, and time of disease progression in a minority of patients compared with RECIST.

CONCLUSION

Cavitation of target and nontarget lesions is common in NSCLC patients treated with VEGFRIs and platinum-based chemotherapy. Impact on response and time to event outcomes occurred but seems to be less common. Response assessment might be improved by incorporating cavitation into volume assessment for target lesions, potentially altering outcomes of key efficacy parameters in clinical trials. This should be prospectively assessed in clinical trials of angiogenesis inhibitors.

Combined assessment of metabolic and volumetric changes for assessment of tumor response in patients with soft-tissue sarcomas

By allowing simultaneous measurements of tumor volume and metabolic activity, integrated PET/CT opens up new approaches for assessing tumor response to therapy. The aim of this study was to determine whether combined assessment of tumor volume and metabolic activity improves the accuracy of (18)F-FDG PET for predicting histopathologic tumor response in patients with soft-tissue sarcomas.

METHODS

Twenty patients with locally advanced high-grade soft-tissue sarcoma (10 men and 10 women; mean age, 49 +/- 17 y) were studied by (18)F-FDG PET/CT before and after preoperative therapy. CT tumor volume (CTvol) was measured by delineating tumor borders on consecutive slices of the CT scan. Mean and maximum (18)F-FDG standardized uptake value within this volume (SUVmean and SUVmax, respectively) were determined. Two indices of total lesion glycolysis (TLG) were calculated by multiplying tumor volume by SUVmean (TLGmean) and SUVmax (TLGmax). Changes in CTvol, SUVmean, SUVmax, TLGmean, and TLGmax after chemotherapy were correlated with histopathologic tumor response (> or =95% treatment-induced tumor necrosis). Accuracy for predicting histopathologic response was compared by receiver-operating-characteristic (ROC) curve analysis.

RESULTS

Baseline SUVmax, SUVmean, CTvol, TLGmean, and TLGmax were 11.22 g/mL, 2.84 g/mL, 544.1 mL, 1,619.8 g, and 8852.9 g, respectively. After neoadjuvant therapy, all parameters except CTvol showed a significant decline (DeltaSUVmax = -51%, P < 0.001; DeltaSUVmean = -40%, P < 0.001; DeltaCTvol = -14%, P = 0.37; DeltaTLGmean = -44%, P = 0.006; and DeltaTLGmax = -54%, P = 0.001). SUV changes in histopathologic responders (n = 6) were significantly more pronounced than those in nonresponders (n = 14) (P = 0.001). Histopathologic response was well predicted by changes in SUVmean and SUVmax (area under ROC curve [AUC] = 1.0 and 0.98, respectively) followed by TLGmean (AUC = 0.77) and TLGmax (AUC = 0.74). In contrast, changes in CTvol did not allow prediction of treatment response (AUC = 0.48).

CONCLUSION

In this population of patients with sarcoma, TLG was less accurate in predicting tumor response than were measurements of the intratumoral (18)F-FDG concentration (SUVmax, SUVmean). Further evaluation of TLG in larger patient populations and other tumor types is necessary to determine the value of this conceptually attractive parameter for assessing tumor response.

Pemetrexed plus carboplatin in elderly patients with malignant pleural mesothelioma: combined analysis of two phase II trials

The incidence of malignant pleural mesothelioma (MPM) in elderly patients is increasing. In this study, pooled data from two phase II trials of pemetrexed and carboplatin (PC) as first-line therapy were retrospectively analysed for comparisons between age groups. Patients received pemetrexed 500 mg m(-2) and carboplatin AUC 5 mg ml(-1) min(-1) intravenously every 21 days with standard vitamin supplementation. Elderly patients were defined as those >or=70 years old. A total of 178 patients with an ECOG performance status of or=70 years (27%). Grade 3-4 haematological toxicity was slightly worse in >or=70 vs <70-year-old patients, with neutropenia observed in 25.0 vs 13.8% (P=0.11), anaemia in 20.8 vs 6.9% (P=0.01) and thrombocytopenia in 14.6 vs 8.5% (P=0.26). Non-haematological toxicity was mild and similar in the two groups. No significant difference was observed in terms of overall disease control (60.4 vs 66.9%, P=0.47), time to progression (7.2 vs 7.5 months, P=0.42) and survival (10.7 vs 13.9 months, P=0.12). Apart from slightly worse haematological toxicity, there was no significant difference in outcome or toxicity between age groups. The PC regimen is effective and well tolerated in selected elderly patients with MPM.

Cisplatin and vinorelbine first-line chemotherapy in non-resectable malignant pleural mesothelioma

The aim was to evaluate the activity of cisplatin and vinorelbine in previously untreated, inoperable patients having histologically verified malignant pleural mesothelioma (MPM), normal organ function, and performance status 0-2. Treatment was vinorelbine 25 mg m(-2) i.v. weekly and cisplatin 100 mg m(-2) i.v. every 4 weeks with hydration and standard prophylactic antiemetic treatment. Patients gave written informed consent. Characteristics of 54 consecutive patients were: males 85%, epithelial subtype 74%, IMIG stages III and IV 35 and 46%, performance status 0, 1, and 2, 26, 69, and 6%, and median age 63 years (31-78 years). CTC grade 3 or 4 toxicity occurred with respect to leukocytopenia (48% of patients, grade 4 in 13%), nausea (13%), neurotoxicity (11%), nephrotoxicity (4%), and other toxicities (9%). There were no toxic deaths. The median number of cycles was four. The fraction of patients alive at 1-, 2-, and 3-years were 61, 31, and 4%, respectively, and median survival and median time to progression were 16.8 months (0.5 to 46.4 +months) and 7.2 months (1.6 to 40.6 + months). There were two CRs and 14 PRs (response rate 29.6%). Cisplatin and intravenous vinorelbine is a highly active regimen in MPM with a response rate and survival comparable to the most active regimens so far reported.

Therapy response in malignant pleural mesothelioma-role of MRI using RECIST, modified RECIST and volumetric approaches in comparison with CT

To evaluate and compare early therapy response according to RECIST (response evaluation criteria in solid tumours) and modified RECIST criteria using MRI techniques in patients with malignant pleural mesothelioma (MPM) in comparison with CT. Fifty patients with MPM (32 male/18 female) were included in this study. Early therapy response was evaluated after 9 weeks [three of six chemotherapy (CHT)] cycles. Additionally patients were examined before chemotherapy, 4 weeks after early therapy response evaluation and after six cycles to evaluate diagnostic follow-up. RECIST and modified RECIST criteria were applied using CT and MRI (HASTE, VIBE, T2-TSE sequences). In MRI additionally a volumetric approach measuring tumour weight (overall segmented tumour volume) was applied. Additionally vital capacity (VC) was measured for correlation. Image interpretation was performed by three independent readers independently and in consensus. The 'gold standard' was follow-up examination. Twenty-eight patients showed partial response, 12 patients stable disease and 10 patients progressive disease at early therapy response evaluation. In the follow-up these results remained. For MRI, in 46 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as gold standards in all cases, whereas using RECIST criteria in four cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.7-1.0). For CT, in 44 cases patients were identically classified using RECIST and modified RECIST criteria. Modified RECIST criteria were identically classified as in gold standards in 48 out of 50 patients, whereas using RECIST criteria in 6 cases there was a mismatch (partial response vs. stable disease). Modified RECIST kappa values showed better interobserver variability compared with RECIST criteria (kappa=0.9-1.0 vs. 0.6-1.0). Modified RECIST criteria especially in combination with high-resolution MRI is a very accurate and reproducible technique to correctly evaluate early therapy response in MPM.