The phosphatidylinositol-3-kinase (PI3-K)/protein kinase B (AKT) pathway is associated with all three major radiation resistance mechanisms: intrinsic radiosensitivity, tumor cell proliferation, and hypoxia. In cell signaling cascades, the PI3-K/AKT signaling pathway is a key regulator of normal and cancerous growth and cell fate decisions by processes such as proliferation, invasion, apoptosis, and induction of hypoxia-related proteins. Activation of this pathway can be the result of stimulation of receptor tyrosine kinases such as epidermal growth factor receptor or vascular endothelial growth factor receptor or from mutations or amplification of PI3-K or AKT itself which are frequently found in non-small cell lung cancer (NSCLC). Furthermore, several treatment modalities such as radiotherapy can stimulate this survival pathway. Monitoring and manipulation of this signal transduction pathway may have important implications for the management of NSCLC. Strong and independent associations were found between expression of activated AKT (pAKT) and treatment outcome in clinical trials. Direct targeting and inhibition of this pathway may increase radiosensitivity by antagonizing the radiation induced cellular defense mechanisms especially in tumors that have activated the PI3-K/AKT cascade. To successfully implement these treatments in daily practice, there is a need for molecular predictors of sensitivity to inhibitors of PI3-K/AKT activation. In conclusion, the PI3-K/AKT pathway plays a crucial role in cellular defense mechanisms. Therefore, quantification of the activation status is a potential parameter for predicting treatment outcome. More importantly, specific targeting of this pathway in combination with radiotherapy or chemotherapy may enhance tumor control in NSCLC by antagonizing cellular defense in response to treatment.

No abstract

Our findings suggest that the adenocarcinomas exhibit glycolysis under normoxic conditions, whereas squamous cell carcinomas are exposed to diffusion-limited hypoxia resulting in a very high anaerobic glycolytic rate. Although squamous cell carcinomas have a higher FDG-uptake, in general regarded as a poor prognostic factor, adenocarcinomas have a higher metastatic potential and a worse DFS. These findings show that FDG-PET should be interpreted in relation to histology. This may improve the prognostic potential of FDG-PET and may aid in exploiting FDG-PET in treatment strategies allied to histology.

ClinicalTrials.gov; No.: NCT01456429; URL: www.clinicaltrials.gov.

Molecular analysis for KRAS and EGFR mutations can be performed routinely in cytologic specimens from EUS- and EBUS-guided FNA.

The potential of 18 F-FDG PET changes was evaluated for prediction of response to concomitant chemoradiotherapy in patients with locally advanced non-small cell lung cancer (NSCLC). Methods: For 28 patients, 18 F-FDG PET was performed before treatment, at the end of the second week of treatment, and at 2 wk and 3 mo after the completion of treatment. Standardized uptake value (SUV), maximum SUV, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained. Early metabolic changes were defined as fractional change (DTLG) when 18 F-FDG PET at the end of the second week was compared with pretreatment 18 F-FDG PET. In-treatment metabolic changes, as measured by serial 18 F-FDG PET, were correlated with standard criteria of response evaluation of solid tumors by means of CT imaging (Response Evaluation Criteria In Solid Tumors 1.1). Parameters were analyzed for stratification in progression-free survival (PFS). Results: When compared with early metabolic nonresponders, a DTLG decrease of 38% or more was associated with a significantly longer PFS (1-y PFS 80% vs. 36%, P 5 0.02). Pretreatment TLG was found to be a prognostic factor for PFS. Conclusion: The degree of change in TLG was predictive for response to concomitant chemoradiotherapy as early as the end of the second week into treatment for patients with locally advanced NSCLC. Pretreatment TLG was prognostic for PFS.

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Guidelines recommend endosonography for mediastinal nodal staging in patients with resectable nonsmall cell lung cancer (NSCLC). We hypothesise that a systematic endobronchial ultrasound (EBUS) evaluation combined with an oesophageal investigation using the same EBUS bronchoscope (EUS-B) improves mediastinal nodal stagingversusthe current practice of targeted positron emission tomography (PET)-computed tomography (CT)-guided EBUS staging alone.A prospective, multicentre, international study (NCT02014324) was conducted in consecutive patients with (suspected) resectable NSCLC. After PET-CT, patients underwent systematic EBUS and EUS-B. Node(s) suspicious on CT, PET, EBUS and/or EUS-B imaging and station 4R, 4L and 7 (short axis ≥8 mm) were sampled. For patients without N2/N3 disease determined on endosonography, surgical-pathological staging was the reference standard.229 patients were included in this study. The prevalence of N2/N3 disease was 103 out of 229 patients (45%). A PET-CT-guided targeted approach by EBUS identified 75 patients with N2/N3 disease (sensitivity 73%, 95% CI 63–81%; negative predictive value (NPV) 81%, 95% CI 74–87%). Four additional patients with N2/N3 disease were found by systematic EBUS (sensitivity 77%, 95% CI 67–84%; NPV 84%, 95% CI 76–89%) and five more by EUS-B (84 patients total; sensitivity 82%, 95% CI 72–88%; NPV 87%, 95% CI 80–91%). Additional clinical relevant staging information was obtained in 23 out of 229 patients (10%).Systematic EBUS followed by EUS-B increased sensitivity for the detection of N2/N3 disease by 9% compared to PET-CT-targeted EBUS alone.