Gene expression profile of high PD-L1 non-small cell lung cancers refractory to pembrolizumab.

BACKGROUND: Despite high expression of PD-L1, around half of advanced non-small cell lung cancer (NSCLC) will not experience tumor response with pembrolizumab. There is an need for a better understanding of the resistance mechanisms in this setting. METHODS: This bi-centric retrospective study included all consecutive patients with PDL1 ≥ 50% advanced NSCLC treated with pembrolizumab in first-line treatment between 2016 and 2020. We compared the clinical characteristics of patients with early progression (refractory) vs others. We performed a comprehensive gene expression profile screening by RNAseq capture on tumor samples. RESULTS: We included 46 patients. Twenty-two patients were refractory to pembrolizumab, mainly women, with poor performance status and lower albumin concentration. RNAseq analysis was performed on 19 samples. Hierarchical clustering allowed the identification of 3 clusters with various proportion of refractory tumors: intermediate (C1: 57%), high (C2: 71%) and low proportion (C3: 40%). Comparative analysis between C2 and C3 allowed the identification of overexpressed (n = 137) and underexpressed (n = 40) genes. Among the genes of interest, C2 exhibits higher activation of pathways associated with stemness phenotype (Hedgehog, Notch and Hippo pathways) and pathways associated with loss of PTEN and JAK2. In C2, genes associated with PD-1, toll-like receptor-9 (TLR-9), major histocompatibility complex (MHC) and interferon-γ pathways were underexpressed. CONCLUSION: This study gives an overview of activated and downregulated pathways in high PD-L1 NSCLC refractory to pembrolizumab. These tumors showed activation of pathways associated with cancer stem cells, loss of PTEN and JAK2, and inhibition of both priming and effector phases of the immune response.

Baseline Hedgehog Pathway Activation and Increase of Plasma Wnt1 Protein Are Associated with Resistance to Immune Checkpoint Inhibitors in Advanced Non-Small-Cell Lung Cancer.

Hedgehog (Hh) and Wingless-type (Wnt) pathways are associated with resistance to immune checkpoint inhibitors (ICIs) in preclinical studies. This study aimed to assess the association between expression and activation levels of Wnt and Sonic Hedgehog (Shh) pathways and resistance to ICIs in advanced NSCLC patients treated with ICI. Hh and Wnt pathways activation was assessed by immunohistochemistry (Gli1 and beta-catenin) on corresponding tumor tissues, and by plasma concentrations of Shh and Wnt (Wnt1, Wnt2 and Wnt3) at ICI introduction and at the first clinical evaluation. Sixty-three patients were included, with 36 patients (57.1%) with available tissue. Response rate was lower in Gli1+ NSCLC (20.0%) compared to Gli1 negative (Gli-) NSCLC (55.6%) (p = 0.015). Rate of primary resistance was 69.8%, vs. 31.2%, respectively (p = 0.04), and median progression-free survival (PFS) was 1.9 months (interquartile range (IQR) 1.2-5.7) vs. 6.1 months (1.6-26.0), respectively (p = 0.08). Median PFS and overall survival were shorter in case of increase of Wnt1 concentration during ICI treatment compared to other patients: 3.9 months vs. 11.2 months (p = 0.008), and 15.3 months vs. not reached (p = 0.003). In conclusion, baseline activation of Hh pathway and increase of Wnt1 concentrations during ICI treatment were associated with poor outcome in NSCLC patients treated with ICIs.

Plasma Biomarkers Screening by Multiplex ELISA Assay in Patients with Advanced Non-Small Cell Lung Cancer Treated with Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs) are commonly used in patients with advanced non-small cell lung cancer (NSCLC). An unmet need remains for new biomarkers associated with ICIs. In this study, consecutive patients with advanced NSCLC treated with nivolumab or pembrolizumab were included. Plasma at ICIs initiation was prospectively collected and a multiplex ELISA assay testing 48 cytokines and growth factors was performed. Exploratory endpoints were the association between plasma biomarkers with outcome and grade III-IV immune related adverse events (irAEs). Thirty-five patients were included. Patients without clinical benefit (n = 22) had higher pre-ICI soluble Hepatocyte Growth Factor (sHGF) (210.9 vs. 155.8 pg/mL, p = 0.010), lower pre-ICI soluble Fibroblast Growth Factor (sFGF) (4.0 vs. 4.8 pg/mL, p = 0.043) and lower pre-ICI interleukine-12 (IL-12) (1.3 vs. 2.2 pg/mL, p = 0.043) concentrations. Patients with early progression (n = 23) had higher pre-ICIs sHGF (206.2 vs. 155.8 pg/mL, p = 0.025) concentrations. Patients with low sHGF levels at ICIs initiation had longer progression-free survival and overall survival than those with high sHGF levels: respectively 2.5 vs. 8.0 months (p = 0.002), and 5.5 vs. 35.0 months (p = 0.001). TNF-α, IL-16, IL-12p40 and MCP3 were associated with high grade irAEs. This study shows the potential association between several plasma biomarkers with outcome and grade 3-4 IrAEs in advanced NSCLC treated with ICIs.

Sequential ctDNA whole-exome sequencing in advanced lung adenocarcinoma with initial durable tumor response on immune checkpoint inhibitor and late progression.

BACKGROUND: Despite prolonged tumor response to immune checkpoint inhibitors (ICIs) for a subset of patients with advanced non-small cell lung cancer (NSCLC), a secondary resistance will occur for a majority of these patients. The understanding of late progression mechanisms with ICIs is important to improve future treatment strategies. METHODS: We performed whole-exome sequencing (WES) on circulating tumor DNA and compared molecular profiles between the beginning of ICI treatment and tumor progression in patients with advanced NSCLC treated with ICIs and who had initial and prolonged tumor response with secondary progression, after at least 6 months of treatment. RESULTS: We identified eight patients who experienced initial and durable tumor response, and secondary tumor progression after 6 months of treatment, with available paired blood samples (diagnosis and progression). All had lung adenocarcinoma, three had programmed-death ligand-1 expression ≥50% in immunohistochemistry and all presented low blood tumor mutational burden (bTMB). Seven patients received nivolumab in second-line or more, and one received pembrolizumab as first-line treatment. WES at progression showed clonal selection with molecular alterations of Wnt pathway-related genes, increase of copy number aberrations in cancer-related genes and loss of tumor-suppressor genes (such as PTEN) or of genes associated with immune response (such as B2M). No difference in term of bTMB was observed at progression. CONCLUSIONS: This is the first study describing putative molecular mechanisms associated with late progression under ICI in lung cancer. Studies on treatment strategies adapted to these mechanisms are needed.

Plasma Biomarkers and Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer: New Tools for Better Patient Selection?

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape for patients with non-small cell lung cancer (NSCLC). Although some patients can experience important response rates and improved survival, many others do not benefit from ICIs developing hyper-progressive disease or immune-related adverse events. This underlines the need to select biomarkers for ICIs use in order to better select patients. There is currently no universally validated robust biomarker for daily use of ICIs. Programmed death-ligand 1 (PD-L1) or tumor mutational burden (TMB) are sometimes used but still have several limitations. Plasma biomarkers are a promising approach in ICI treatment. This review will describe the development of novel plasma biomarkers such as soluble proteins, circulating tumor DNA (ctDNA), blood TMB, and blood microbiome in NSCLC patients treated with ICIs and their potential use in predicting response and toxicity.

Role of antibiotic use, plasma citrulline and blood microbiome in advanced non-small cell lung cancer patients treated with nivolumab.

BACKGROUND: Recent data suggested a role of gut microbiota and antibiotic use on immune checkpoint inhibitors efficacy. We aimed to evaluate the impact of early use of antibiotic (EUA), blood microbiome and plasmatic citrulline (marker of the intestinal barrier) on nivolumab efficacy in non-small cell lung cancer (NSCLC). METHODS: We included all consecutive patients with advanced NSCLC treated with nivolumab in our Department between 2014 and 2017. Blood microbiome was analyzed at month (M) M0 and M2. Citrulline rates were evaluated at M0, M2, M4 and M6. RESULTS: Seventy-two patients were included (EUA in 42%). Overall survival (OS) was longer without EUA (median 13.4 months) than with EUA (5.1 months, p = 0.03). Thirty-five patients (49%) had plasma samples available. High citrulline rate (≥20 µM) at M0 was associated with tumor response (p = 0.084) and clinical benefit (nivolumab > 6 months) (p = 0.002). Median progression-free survival (PFS) was 7.9 months (high citrulline) vs 1.6 months (low citrulline) (p < 0.0001), and median OS were respectively non reached vs 2.2 months (p < 0.0001). Patients with EUA had lower median citrulline rates at M0: 21 µM (IQR 15.0-30.8) vs 32 µM (IQR 24.0-42.0) without EUA (p = 0.044). The presence of specific bacterial DNA in blood at M0 was associated with response and clinical benefit (Peptostreptococcae, Paludibaculum, Lewinella) or with tumor progression (Gemmatimonadaceae). Multivariate analyses on PFS and OS confirmed the prognostic role of citrulline and blood microbiome. CONCLUSIONS: EUA is associated with shorter OS with nivolumab and lower citrulline rates. Plasma citrulline and blood microbiome appear to be promising predictive factors of nivolumab efficacy.

Positive plasma cotinine during platinum-based chemotherapy is associated with poor response rate in advanced non-small cell lung cancer patients.

INTRODUCTION: Patients with advanced non-small cell lung cancer (NSCLC) are most of the time treated with a first-line cytotoxic chemotherapy. Tobacco use is responsible for 90% of lung cancer. The aim of this study was to evaluate the impact of smoking continuation during first-line chemotherapy on tumor response in advanced-stage NSCLC. MATERIALS AND METHODS: All patients with an advanced-stage NSCLC (IIIb or IV), treated with first-line platinum-based chemotherapy in our Department between June 2013 and July 2017 were included. Smoking status was assessed at inclusion by self-report, then at the tumor assessment consultation after 2 months of treatment, by both self-report and plasmatic cotinine measurement. Chemotherapy response, progression-free survival (PFS), overall survival (OS) and stage 3-4 toxicity were registered. RESULTS: Ninety-seven patients were included: 8 (8%) declared to be non-smokers, 56 (58%) current smokers and 33 (34%) former smokers at diagnosis. At the first tumor evaluation, 24 (25%) self-reported as active smokers and 73 (75%) as non-smokers; overall response rate (ORR) was respectively 38% and 48% (p = 0.373). Fifty-four patients had a plasmatic cotinine evaluation at the first tumor evaluation. Seventeen patients (32%) had a positive cotinine rate (median 108ng/mL, IQR 31-236). Six patients (35%) had positive cotinine rate whereas declaring to be non-smokers at the first tumor evaluation. ORR was 18% in case of positive cotinine rate, and 57% when negative (p = 0.007). Regardless of the method for smoking status evaluation, PFS, OS and grade 3-4 toxicities were similar between smoker and non-smoker patients at the first tumor evaluation. CONCLUSION: Smoking continuation during platinum-based chemotherapy, reflected by positive plasma cotinine rate, was associated with a poor ORR.

Clinical factors associated with early progression and grade 3-4 toxicity in patients with advanced non-small-cell lung cancers treated with nivolumab.

INTRODUCTION: The prognosis of advanced non-small-cell lung cancer (NSCLC) has been improved by development of immune checkpoint inhibitors (ICIs) such as nivolumab for second-line treatment. As phase III trials include only selected patients, we here investigated the clinical factors associated with efficacy and safety of nivolumab in 'real life' patients with advanced NSCLC. METHODS: Clinical and histological characteristics, therapies and survival data of all consecutive patients with advanced NSCLC included prospectively and treated by nivolumab in two French academic hospitals between February 2015 and December 2016 were examined. RESULTS: Sixty-seven patients were included, mostly male (69%), current or former smokers (87%) with PS <2 (73%). Median age was 68.5 years and 42% were aged ≥70 years. According to uni- and multi-variate analyses, only PS 2 (OR = 0.17, 95% CI 0.03-0.99, p = 0.049) and number of previous treatment lines (OR = 0.33, 95% CI 0.13-0.85, p = 0.022) were significantly negatively associated with tumor control. Worse progression-free survival (PFS) was significantly associated with PS 2 (HR = 5.17, 95% CI 1.99-13.43, p = 0.001) and use of steroids (HR = 3.27, 95% CI 1.39-7.69, p = 0.006). Worse overall survival was associated with symptomatic brain metastasis (HR = 3.15, 95% CI 1.23-8.85, p = 0.029). Treatment-related adverse events occurred in 47 patients (70%), symptomatic brain metastasis being significantly associated with Grade ≥3 toxicity (OR = 8.13, 95% CI 1.21-55.56, p = 0.031). Age and nutritional status were not associated with response, PFS, OS or toxicity. CONCLUSION: Our results suggest that nivolumab is not beneficial or safe for patients with PS 2 and symptomatic brain metastases.

Predictive role of plasmatic biomarkers in advanced non-small cell lung cancer treated by nivolumab.

Immune checkpoint inhibitors, as nivolumab, are used in advanced non-small cell lung cancer (NSCLC). However, no associated biomarker is validated in clinical practice with this drug. We investigated herein immune-related blood markers in patients with advanced NSCLC treated with nivolumab. Plasma of 43 consecutive patients were prospectively collected at time of the diagnosis of cancer, at the initiation of nivolumab and at the first tumour evaluation (2 months). Concentrations of PD-L1 (sPD-L1), soluble PD-L2 (sPD-L2), Interleukine-2 (sIl-2), Interferon-gamma (sIFN-γ), and Granzyme B (sGranB) were quantified by ELISA. Cell free RNA was quantified by Reverse Transcriptase -PCR), and plasmatic microRNAs (miRNAs) were evaluated by targeted sequencing. Expression of PD-L1 on tumour biopsies was performed by immunohistochemistry using E13LN. High sPD-L1 at 2 months and increase of sPD-L1 concentrations were associated with poor response and absence of clinical benefit (nivolumab treatment less than 6 months). The variation of sPD-L1 concentrations were confirmed by RNA quantification. sPD-L1 concentrations were not correlated with PD-L1 expression on corresponding tumour samples. Low sGranB at nivolumab initiation was also associated with poor response. High sPD-L1 and low sGranB were associated with poor progression-free survival (PFS) and overall survival (OS). Low sPD-L2, low sIl-2 and high sIFN-γ were associated with grade 3-4 toxicities. Finally, miRNA screening showed that patients with clinical benefit (n = 9) had down-expression of miRNA-320b and -375 compared to patients with early progression at 2 months (n = 9). In conclusion, our results highlight the interest of circulating biomarkers in patients treated with nivolumab.

Circulating tumor DNA evaluated by Next-Generation Sequencing is predictive of tumor response and prolonged clinical benefit with nivolumab in advanced non-small cell lung cancer.

Nivolumab is an anti-PD1 antibody, given in second-line or later treatment in advanced non-small cell lung cancer (NSCLC). The objective of this study was to describe the predictive value of circulating tumor DNA (ctDNA) on the efficacy of nivolumab in advanced NSCLC. We prospectively included all consecutive patients with advanced NSCLC treated with nivolumab in our Department between June 2015 and October 2016. Plasma samples were obtained before the first injection of nivolumab and at the first tumor evaluation with nivolumab. ctDNA was analyzed by Next-Generation Sequencing (NGS), and the predominant somatic mutation was followed for each patient and correlated with tumor response, clinical benefit (administration of nivolumab for more than 6 months), and progression-free survival (PFS). Of 23 patients, 15 had evaluable NGS results at both times of analysis. ctDNA concentration at the first tumor evaluation and ctDNA change correlated with tumor response, clinical benefit and PFS. ROC curve analyses showed good diagnostic performances for tumor response and clinical benefit, both for ctDNA concentration at the first tumor evaluation (tumor response: positive predictive value (PPV) at 100.0% and negative predictive value (NPV) at 71.0%; clinical benefit: PPV at 83.3% and NPV 77.8%) and the ctDNA change (tumor response: PPV 100.0% and NPV 62.5%; clinical benefit: PPV 100.0% and NPV 80.0%). Patients without ctDNA concentration increase >9% at 2 months had a long-term benefit of nivolumab. In conclusion, NGS analysis of ctDNA allows the early detection of tumor response and long-term clinical benefit with nivolumab in NSCLC.

Epigenetic prediction of response to anti-PD-1 treatment in non-small-cell lung cancer: a multicentre, retrospective analysis.

BACKGROUND: Anti-programmed death-1 (PD-1) treatment for advanced non-small-cell lung cancer (NSCLC) has improved the survival of patients. However, a substantial percentage of patients do not respond to this treatment. We examined the use of DNA methylation profiles to determine the efficacy of anti-PD-1 treatment in patients recruited with current stage IV NSCLC. METHODS: In this multicentre study, we recruited adult patients from 15 hospitals in France, Spain, and Italy who had histologically proven stage IV NSCLC and had been exposed to PD-1 blockade during the course of the disease. The study structure comprised a discovery cohort to assess the correlation between epigenetic features and clinical benefit with PD-1 blockade and two validation cohorts to assess the validity of our assumptions. We first established an epigenomic profile based on a microarray DNA methylation signature (EPIMMUNE) in a discovery set of tumour samples from patients treated with nivolumab or pembrolizumab. The EPIMMUNE signature was validated in an independent set of patients. A derived DNA methylation marker was validated by a single-methylation assay in a validation cohort of patients. The main study outcomes were progression-free survival and overall survival. We used the Kaplan-Meier method to estimate progression-free and overall survival, and calculated the differences between the groups with the log-rank test. We constructed a multivariate Cox model to identify the variables independently associated with progression-free and overall survival. FINDINGS: Between June 23, 2014, and May 18, 2017, we obtained samples from 142 patients: 34 in the discovery cohort, 47 in the EPIMMUNE validation cohort, and 61 in the derived methylation marker cohort (the T-cell differentiation factor forkhead box P1 [FOXP1]). The EPIMMUNE signature in patients with stage IV NSCLC treated with anti-PD-1 agents was associated with improved progression-free survival (hazard ratio [HR] 0·010, 95% CI 3·29 × 10-4-0·0282; p=0·0067) and overall survival (0·080, 0·017-0·373; p=0·0012). The EPIMMUNE-positive signature was not associated with PD-L1 expression, the presence of CD8+ cells, or mutational load. EPIMMUNE-negative tumours were enriched in tumour-associated macrophages and neutrophils, cancer-associated fibroblasts, and senescent endothelial cells. The EPIMMUNE-positive signature was associated with improved progression-free survival in the EPIMMUNE validation cohort (0·330, 0·149-0·727; p=0·0064). The unmethylated status of FOXP1 was associated with improved progression-free survival (0·415, 0·209-0·802; p=0·0063) and overall survival (0·409, 0·220-0·780; p=0·0094) in the FOXP1 validation cohort. The EPIMMUNE signature and unmethylated FOXP1 were not associated with clinical benefit in lung tumours that did not receive immunotherapy. INTERPRETATION: Our study shows that the epigenetic milieu of NSCLC tumours indicates which patients are most likely to benefit from nivolumab or pembrolizumab treatments. The methylation status of FOXP1 could be associated with validated predictive biomarkers such as PD-L1 staining and mutational load to better select patients who will experience clinical benefit with PD-1 blockade, and its predictive value should be evaluated in prospective studies. FUNDING: "Obra Social" La Caixa, Cellex Foundation, and the Health and Science Departments of the Generalitat de Catalunya.

Paradoxical worsening of hypoxemia in a patient treated by noninvasive positive pressure ventilation for obesity hypoventilation syndrome with concomitant obstructive sleep apnea: a case report.

BACKGROUND: Noninvasive positive pressure ventilation is frequently prescribed to obese patients with obstructive sleep apnea syndrome and obesity hypoventilation syndrome. However, mechanical ventilation with a positive end-expiratory pressure can induce or worsen a right-to-left shunt through a patent foramen ovale associated with systemic hypoxemia. Thus, in obese patients treated with noninvasive positive pressure ventilation, a paradoxical worsening of hypoxemia may reveal the existence of a patent foramen ovale. CASE PRESENTATION: A 50-year-old African woman was referred to our sleep center for severe obstructive sleep apnea syndrome and obesity hypoventilation syndrome. Because she had alveolar hypoventilation and had failed previous obstructive sleep apnea syndrome therapy, noninvasive positive pressure ventilation was started. In May 2015, she had a normal residual apnea/hypopnea index calculated by the ventilator software with no hypoventilation. Six months later, severe hypoxemia without hypercapnia was noted. Contrast transthoracic echocardiography showed right-to-left shunt through a patent foramen ovale. This finding prompted a decrease in expiratory and inspiratory positive airway pressures, after which the ventilator software recorded a normal residual apnea/hypopnea index and the blood gas values improved. CONCLUSION: Noninvasive positive pressure ventilation therapy for combined obstructive sleep apnea syndrome and obesity hypoventilation syndrome must be monitored by arterial blood gas measurements, both to reassess the hypercapnia and to look for worsening hypoxemia due to a patent foramen ovale.

Immunotherapy revolutionises non-small-cell lung cancer therapy: Results, perspectives and new challenges.

Immune checkpoint inhibitors (ICIs) are antibodies that target key signalling pathways such as programmed death 1 (PD1)/programmed death-ligands 1 and 2 (PDL1 and PDL2) to improve anti-tumour immune responses. Until recently, nivolumab was the only ICI validated for advanced non-small-cell lung cancer (NSCLC) in a second-line treatment setting. Results from recent phase II and phase III randomised trials testing other ICIs have been presented. In Keynote-024, pembrolizumab, an anti-PD1 antibody, was reported to have great efficacy in the first-line treatment of PDL1 ≥ 50% tumours (30% of screened tumours), with a progression-free survival (PFS, median) of 10.4 months versus 6.0 months with chemotherapy (CT; hazard ratio [HR] = 0.50; 95% confidence interval [95% CI] 0.37-0.68, P < 0.001), overall response rate (ORR) of 45% versus 28% with CT (P = 0.0011), and a 1-year overall survival (OS) of around 70%. In contrast, Checkmate-026 reported that nivolumab failed to show any benefit compared with standard platinum-based CT, with a PFS (median) in the PDL1 ≥ 5% NSCLC group of 4.2 months (nivolumab) versus 5.9 months (CT; HR = 1.15: 95% CI 0.91-1.45, P = 0.25). No benefit was observed in the PDL1 ≥ 50% subgroup. An encouraging report of the efficacy of pembrolizumab in addition to CT in first-line treatment in unselected NSCLC was also presented (Keynote-021) with an ORR of 55% versus 29% with CT alone (P = 0.0016). Atezolizumab, an anti-PDL1 antibody, showed efficacy for second-line treatment compared with docetaxel (OAK phase III study) with an OS (median) of 13.8 months versus 9.6 months with docetaxel. These results suggest a new paradigm for the treatment of advanced NSCLC using pembrolizumab for the first-line treatment of PDL1 ≥ 50% tumours.

Molecular characterization of circulating tumor cells in lung cancer: moving beyond enumeration.

Molecular characterization of tumor cells is a key step in the diagnosis and optimal treatment of lung cancer. However, analysis of tumor samples, often corresponding to small biopsies, can be difficult and does not accurately reflect tumor heterogeneity. Recent studies have shown that isolation of circulating tumor cells (CTCs) is feasible in non-small cell lung cancer patients, even at early disease stages. The amount of CTCs corresponds to the metastatic potential of the tumor and to patient prognosis. Moreover, molecular analyses, even at the single-cell level, can be performed on CTCs. This review describes the technologies currently available for detecting and capturing CTCs, the potential for downstream molecular diagnostics, and the clinical applications of CTCs isolated from lung cancer patients as screening, prognostic, and predictive tools. Main limitations of CTCs are also discussed.

Is there a specific phenotype associated with the different subtypes of KRAS mutations in patients with advanced non-small-cell lung cancers?

OBJECTIVES: KRAS mutations occur in 20 to 25% of non-small-cell lung cancers (NSCLC) and seem to predict a poor prognosis. There is heterogeneousness in the frequency and spectrum of KRAS mutations, which can be categorized in transitions and transversions. We wondered if subtypes of KRAS mutation were associated with specific clinical phenotypes and specific survival. MATERIALS AND METHODS: Between July 2007 and May 2012, patients with advanced NSCLC and KRAS mutation diagnosed in two university hospitals were included. Clinical and histological characteristics, therapeutics and survival data were collected. RESULTS: Among 635 patients screened for KRAS mutations, 90 were found to be mutated and were included. Median age was 59 years (range: 54-69). Most were males (60%), current or former smokers (63% and 33%, respectively) and had an adenocarcinoma (ADC) (80%). Eighty patients were stage IV and 10 were stage IIIB. Eighty percent of the KRAS mutations were transversions and 20% were transitions. In uni- and multivariate analyses, there was a trend for fewer smokers among patients with transitions than among those with transversions (Odds Ratio [OR]=0.28, 95% CI [0.079-0.999], p=0.05). No significant difference was noted between transitions and transversions for other clinical characteristics. Patients with transitions had more frequently squamous-cell carcinoma (SCC) compared to those with transversions, who had more frequently adenocarcinomas (OR=16.7, 95% CI [2.76-100.8], p=0.002). Seventy-nine patients (86%) had received first-line chemotherapy. No significant difference was seen for disease-control rate, median progression-free survival or overall survival between transitions and transversions. CONCLUSION: A higher proportion of non-smokers and SCC subtypes were observed in the transitions compared to transversions. This confirms the heterogeneity of KRAS mutations and could suggest to expand KRAS testing in SCC to assess impact of RAS in SCC, which remains poorly investigated.

Bilateral pneumothorax complicating cystic metastases of bronchial squamous cell carcinoma under erlotinib.

Cystic lung metastases are a rare presentation in non-small cell lung cancer and occurs mainly in squamous cell carcinoma. We present the case of a 57-year-old woman with a lung squamous cell carcinoma and cystic lung metastases, who developed bilateral metachronous pneumothorax while being administered erlotinib in third-line treatment. The apparition of a pneumothorax under chemotherapy is most often the result of tumor necrosis and formation of bronchopleural fistula. However, very few cases have been reported under targeted therapies, and to our knowledge this is the first case under erlotinib. This complication is potentially life-threatening, especially due to the possibility of pneumothorax bilateralization.