Imaging in the diagnosis and treatment of non-small cell lung cancer

Current treatments for non-small cell lung cancer

Despite improved methods of diagnosis and the development of different treatments, mortality from lung cancer remains surprisingly high. Non-small cell lung cancer (NSCLC) accounts for the large majority of lung cancer cases. Therefore, it is important to review current methods of diagnosis and treatments of NSCLC in the clinic and preclinic. In this review, we describe, as a guide for clinicians, current diagnostic methods and therapies (such as chemotherapy, chemoradiotherapy, targeted therapy, antiangiogenic therapy, immunotherapy, and combination therapy) for NSCLC.

Associations between radiologist-defined semantic and automatically computed radiomic features in non-small cell lung cancer

Tumor phenotypes captured in computed tomography (CT) images can be described qualitatively and quantitatively using radiologist-defined "semantic" and computer-derived "radiomic" features, respectively. While both types of features have shown to be promising predictors of prognosis, the association between these groups of features remains unclear. We investigated the associations between semantic and radiomic features in CT images of 258 non-small cell lung adenocarcinomas. The tumor imaging phenotypes were described using 9 qualitative semantic features that were scored by radiologists, and 57 quantitative radiomic features that were automatically calculated using mathematical algorithms. Of the 9 semantic features, 3 were rated on a binary scale (cavitation, air bronchogram, and calcification) and 6 were rated on a categorical scale (texture, border definition, contour, lobulation, spiculation, and concavity). 32-41 radiomic features were associated with the binary semantic features (AUC = 0.56-0.76). The relationship between all radiomic features and the categorical semantic features ranged from weak to moderate (|Spearmen's correlation| = 0.002-0.65). There are associations between semantic and radiomic features, however the associations were not strong despite being significant. Our results indicate that radiomic features may capture distinct tumor phenotypes that fail to be perceived by naked eye that semantic features do not describe and vice versa.

Preparation and biological evaluation of 99mTc-HYNIC-(Ser)3-D4 peptide for targeting and imaging of non-small-cell lung cancer

Aim: In this study, radiolabeled D4 peptide conjugate was studied as a radiotracer for imaging of non-small-cell lung cancer with overexpression of EGFR. Methods: HYNIC-(Ser)3-D4 peptide was labeled with 99mTc using tricine as a co-ligand. Cellular specific binding and internalization as well as in vivo tumor targeting were assessed. Results: The in vitro experiments showed good cellular specific binding. Tumor uptake values as %ID/g were 7.55 and 6.82% at 1 and 4 h after injection, respectively. The presaturation of EGFR in xenografted nude mice reduced 36% tumor uptake of radioactivity at 1 h after injection that confirmed in vivo specificity. Conclusion: Findings showed this radiolabeled peptide is a promising candidate for tumor targeting and molecular imaging of non-small-cell lung cancer.

Outcome of incidentally detected airway nodules

Low-dose chest computed tomography (LDCT) screening increased detection of airway nodules. Most nodules appear to be secretions, but pathological lesions may show similar findings. The National Comprehensive Cancer Network (NCCN) recommends repeating LDCT after 1 month and proceeding to bronchoscopy if the nodules persist. However, no reports exist about incidentally detected airway nodules. We investigated the significance of airway nodules detected by LDCT screening.We screened patients with incidental airway nodules detected by LDCT in the Seoul National University Hospital group. The characteristics of computed tomography, bronchoscopy, pathology and clinical findings were analysed.Among 53 036 individuals who underwent LDCT screening, 313 (0.6%) had airway nodules. Of these, 186 (59.4%) were followed-up with chest computed tomography and/or bronchoscopy. Seven (3.8%) cases had significant lesions, including leiomyoma (n=2), endobronchial tuberculosis (n=2), chronic inflammation (n=1), hamartoma (n=1) and benign granuloma (n=1). The remaining 179 lesions were transient, suggesting that they were secretions.The use of LDCT for lung cancer screening demonstrated the low incidence of airway lesions. Most lesions were transient secretions. True pathological lesions were rare, and no malignant lesion was found. The current recommendation of the NCCN guideline is a reasonable approach that can avoid unnecessary bronchoscopy.

Effect of PET/CT on management of patients with non-small cell lung cancer: results of a prospective study with 5-year survival data

We investigated the incremental management impact and prognostic value of staging with (18)F-FDG PET/CT in patients with non-small cell lung cancer (NSCLC) being considered for potentially curative therapies.

METHODS

Information on 168 consecutive patients with NSCLC being considered for surgery or definitive radiotherapy with curative intent before PET/CT was entered into a prospective database. The pre-PET/CT management plan, based on conventional imaging (conventional CT, appropriately supplemented by bone scintigraphy or other modalities), was defined prospectively by referring clinicians before PET/CT results became available. After PET/CT, actual clinical management was recorded, and patients were followed up until 5 y or death. The appropriateness of PET/CT management plans was assessed by biopsy when available, clinical follow-up, and survival analysis.

RESULTS

Stage was discordant on PET/CT and conventional imaging in 50.6% of patients (41.1% upstaged, 9.5% downstaged), with high management impact (change in treatment modality or curative intent) in 42.3% of patients. Both conventional imaging stage and PET/CT stage were strongly predictive of overall survival (OS) but there were greater differences between hazard rates and separations in the OS curves for stage groupings determined using PET/CT. OS was also strongly predicted by PET/CT-directed choice of therapy (P < 0.0001).

CONCLUSION

PET/CT frequently affects patient management and strongly predicts OS in NSCLC, supporting the appropriateness of such changes.

Use of Positron Emission Tomography in Initial Staging of Nonsmall Cell Lung Carcinoma: A Regional Teaching Hospital Experience

The ability to accurately diagnose mediastinal lymph node involvement is significantly important in patients with nonsmall cell lung cancer (NSCLC). Positron emission tomography (PET) imaging has become a standard technique to assess lymph node involvement in patients with NSCLC. The purpose of this study is to evaluate the accuracy of PET scan imaging as a mediastinal staging tool in patients with NSCLC at our regional teaching institution. We performed a single-institution, retrospective review of patients diagnosed with NSCLC from January 1, 2006, through December 31, 2007. We included only those patients who underwent computed tomography (CT), PET, and pathologic assessment of mediastinal lymph nodes. Using pathologic assessment as the criterion standard, the overall accuracy, sensitivity, specificity, and positive and negative predictive values of CT and PET were calculated. One hundred seventeen patients were identified for inclusion in the study. The overall accuracy was 81.2 per cent for CT and 91.5 per cent for PET. Sensitivity was 42.1 per cent for CT and 52.6 per cent for PET. Specificity was 88.8 per cent for CT and 99.0 per cent for PET. Positive predictive values were 42.1 per cent for CT and 90.9 per cent for PET; negative predictive values were 88.8 per cent for CT and 91.5 per cent for PET. False-negative result rates were 9.4 per cent for CT and 7.7 per cent for PET; false-positive result rates were 9.4 per cent for CT and 0.9 per cent for PET. Our analysis confirms the use of PET scan imaging in the staging of patients with NSCLC at a regional teaching institution.

Quantifying and reducing the effect of calibration error on variability of PET/CT standardized uptake value measurements

The purpose of this study was to measure the errors introduced by regular calibration of PET/CT scanners and to minimize the effect of calibration error on standardized uptake value measurements.

METHODS

Global calibration factors from 2 PET/CT scanners were recorded for 3.5 and 1.8 y, comparing manufacturer-recommended protocols with modified protocols to evaluate error contributions due to operator-influenced procedures. Dose calibrator measurements were evaluated using National Institute of Standards and Technology-traceable sources.

RESULTS

Dose calibrator variability was less than 1%, although there was a consistent bias. Global scaling variability was reduced from 6% to 4% for scanner 1 and from 11% to 4% for scanner 2 when quality assurance and quality control procedures were applied to the calibration protocol. When calibrations were done using a (68)Ge/(68)Ga phantom, the variability for both scanners was reduced to approximately 3%.

CONCLUSION

Applying quality assurance and quality control procedures to scanner calibration reduces variability, but there is a still a residual longitudinal scanner variability of 3%-4%. The procedures proposed here reduce the impact of operator error on scanner calibration and thereby minimize longitudinal variability in standardized uptake value measurements.

PET/CT Assessment of Response to Therapy: Tumor Change Measurement, Truth Data, and Error

We describe methods and issues that are relevant to the measurement of change in tumor uptake of (18)F-fluorodeoxyglucose (FDG) or other radiotracers, as measured from positron emission tomography/computed tomography (PET/CT) images, and how this would relate to the establishment of PET/CT tumor imaging as a biomarker of patient response to therapy. The primary focus is on the uptake of FDG by lung tumors, but the approach can be applied to diseases other than lung cancer and to tracers other than FDG. The first issue addressed is the sources of bias and variance in the measurement of tumor uptake of FDG, and where there are still gaps in our knowledge. These are discussed in the context of measurement variation and how these would relate to the early detection of response to therapy. Some of the research efforts currently underway to identify the magnitude of some of these sources of error are described. In addition, we describe resources for these investigations that are being made available through the Reference Image Database for the Evaluation of Response project. Measures derived from PET image data that might be predictive of patient response as well as the additional issues that each of these metrics may encounter are described briefly. The relationship between individual patient response to therapy and utility for multicenter trials is discussed. We conclude with a discussion of moving from assessing measurement variation to the steps necessary to establish the efficacy of PET/CT imaging as a biomarker for response.

Identification of lung cancer patients by serum protein profiling using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry

OBJECTIVE

Diagnosis of lung cancer at an early disease stage is important for successful treatment and improving the outcome of patients. To improve its prognosis, we attempted to explore novel tools for screening serum biomarkers to distinguish lung cancer from healthy individuals by serum protein profiles and a classification tree algorithm.

METHODS

Serum samples were applied to metal affinity protein chips to generate mass spectra by surface-enhanced laser desorption/ionization (SELDI) time-of-flight mass spectrometry. Protein peak identification and clustering were performed using the Biomarker Wizard software. Proteomic spectra of serum samples from 89 lung cancer patients and age- and sex-matched 68 healthy individuals were used as a training set and a classification tree with 3 distinct protein masses was generated by using Biomarker Pattern software. The validity of the classification tree was then challenged with a blind test set including another 62 lung cancer patients and 34 healthy individuals. We additionally determined Cyfra21-1 and carcinoembryonic antigen in all the serum samples included in this study using an electrochemiluminescent immunoassay.

RESULTS

The software identified an average of 48 mass peaks/spectrum and 3 of the identified peaks at 5808, 5971, and 7779 d were used to construct the classification tree. The classification tree separated effectively lung cancer from healthy individuals, achieving a sensitivity of 91% (81 of 89) and a specificity of 97% (66 of 68). The blind test challenged the model with a sensitivity of 89% (55 of 62) and a specificity of 91% (31 of 34), and a positive predictive value of 90% (86 of 96), respectively. The specificity of Cyfra21-1 and the sensitivity provided by Cyfra21-1 and carcinoembryonic antigen used individually or in combination were significantly lower than that of the SELDI marker pattern (P < 0.05 or P < 0.005, respectively).

CONCLUSION

The results suggest that SELDI time-of-flight mass spectrometry technique can correctly distinguish lung cancer patients from healthy individuals and shows great potential for the development of a screening test for the detection of lung cancer.

Nanoparticulate carrier containing water-insoluble iodinated oil as a multifunctional contrast agent for computed tomography imaging

Contrast-enhanced computed tomography (CT) imaging is a valuable and routine strategy for the clinical diagnosis of various diseases. However, all current CT contrast agents are liquids, so they flow through the blood vessels and disappear very quickly by extravasation. If it were possible to make a blood-compatible particulate contrast agent, we could highlight a particular tissue by either passive or active targeting. In this work, Pluronic F127 and a naturally iodinated compound, Lipiodol, were used to form radiopaque nanoreservoir structures. The resultant nanoparticles have a stable structure at high concentrations, sufficient X-ray absorption, a safety profile similar to or better than that of Iopromide, and a longer circulation time than commercial iodinated preparations. The utility of the resultant radiopaque nanoparticles as a contrast agent was tested using micro-SPECT/CT imaging in vivo. Together with the very good solubility of hydrophobic drugs (e.g., Taxol) in Lipiodol, these results suggest the possibility that these particulate structures and their bioconjugates could become functional CT contrast agents that could deliver therapeutic agents to a particular tissue.