EGFR mutations are more frequent in well-differentiated than in poor-differentiated lung adenocarcinomas

High SUVmax Is an Independent Predictor of Higher Diagnostic Accuracy of ROSE in EBUS-TBNA for Patients with NSCLC

Introduction: This study aimed to verify the predictors of the diagnostic accuracy of rapid on-site evaluation (ROSE) in endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) among patients with non-small cell lung cancer (NSCLC). Methods: We retrospectively reviewed consecutive patients with NSCLC who underwent EBUS-TBNA for staging or diagnosis at our hospital from June 2016 to June 2018. The patients were divided into two groups—those with a correct diagnosis and an incorrect diagnosis after ROSE. Kaplan−Meier plots and log-rank tests were used to estimate outcomes. Results: A total of 84 patients underwent EBUS-TBNA for staging and diagnosis. Sixty patients with demonstrated malignant mediastinal lymph nodes were enrolled. In the univariate analysis, lymph nodes < 1.5 cm (HR = 3.667, p = 0.031) and a SUVmax > 5 (HR = 41, p = 0.001) were statistically significant for diagnostic accuracy of ROSE. In the multivariate Cox regression analysis, only a SUVmax > 5 (HR = 20.258, p = 0.016) was statistically significant. Conclusions: A SUVmax > 5 is an independent predictor of higher diagnostic accuracy of ROSE in EBUS-TBNA in patients with NSCLC with malignant mediastinal lymph nodes. Therefore, ROSE in patients with a SUVmax < 5 might not be reliable and requires further prudent assessment (more shots or repeated biopsies at mediastinal LNs) in clinical practice.

Genomic Profiling and Prognostic Value Analysis of Genetic Alterations in Chinese Resected Lung Cancer With Invasive Mucinous Adenocarcinoma

Background

Invasive mucinous adenocarcinoma (IMA) of the lung is a distinct histological subtype with unique clinical and pathological features. Despite previous genomic studies on lung IMA, the genetic characteristics and the prognosis-related biomarkers in Chinese surgically resected lung IMA remain unclear.

Methods

We collected 76 surgically resected primary tumors of invasive lung adenocarcinoma, including 51 IMA and 25 non-mucinous adenocarcinomas (non-IMA). IMA was further divided into pure-IMA (mucinous features≥90%) and mixed-IMA subgroups. Comprehensive genomic profiling based on targeted next-generation sequencing (NGS) of 425 genes was explored and genomic characteristics were evaluated for the correlation with postoperative disease-free survival (DFS).

Results

IMA had a unique genetic profile, with more diverse driver mutations and more tumor drivers/suppressors co-occurrence than that of non-IMA. The frequency of EGFR (72.0% vs. 40.0% vs. 23.1%, p=0.002) and ALK (undetected vs. 20.0% vs. 26.9%, p=0.015) alterations showed a trend of gradual decrease and increase from non-IMA to mixed-IMA to pure-IMA, respectively. The frequency of KRAS mutations in pure-IMA was higher than that in mixed-IMA, albeit statistically insignificant (23.1% vs. 4.0%, p=0.10). TP53 mutation was significantly less in pure-IMA compared to mixed-IMA and non-IMA (23.1% vs. 52.0% vs. 56.0%, p=0.03). Besides, IMA exhibited less arm-level amplifications (p=0.04) and more arm-level deletions (p=0.004) than non-IMA, and the frequency of amplification and deletion also showed a trend of gradual decrease and increase from non-IMA to mixed-IMA to pure-IMA, respectively. Furthermore, prognosis analysis in stage III IMA patients showed that patients harboring alterations in EGFR (mDFS=30.3 vs. 16.0 months, HR=0.19, P=0.027) and PI3K pathway (mDFS=36.0 vs. 16.0 months, HR=0.12, P=0.023) achieved prolonged DFS, while patients with poorly differentiated tumors (mDFS=14.1 vs. 28.0 months, HR=3.75, p=0.037) or with KRAS mutations (mDFS=13.0 vs. 20.0 months, HR=6.95, p=0.027) had shorter DFS. Multivariate analysis showed that KRAS mutations, PI3K pathway alterations, and tumor differentiation status were independent factors that have statistically significant influences on clinical outcomes of IMA patients.

Conclusion

Our study provided genomic insights into Chinese surgically resected lung IMA. We also identified several genomic features that may serve as potential biomarkers on postoperative recurrence in IMA patients with stage III disease.

Assessment of EGFR mutation status in Tunisian patients with pulmonary adenocarcinoma

BACKGROUND

Despite recent advances, non-small cell lung cancer carries a grim prognosis. For appropriate treatment selection, the updated guidelines recommend broad molecular profiling for all patients with pulmonary adenocarcinoma. Precise histological subtyping and targeted epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) testing are mandatory.

METHODS

Herein, we assessed the EGFR mutation status of 26 formalin fixed-paraffin embedded (FFPE) samples of lung adenocarcinoma. Mutational analysis concerned exons 18-21 of EGFR by real-time polymerase chain reaction (Real time-PCR) using the Therascreen EGFR RGQ PCR mutation kit. ALK status was established on 22 among 26 patients using D5F3 antibody with a fully automated Ventana CDx technique.

RESULTS

Activating EGFR mutations were found in 3 men among 26 patients (11.5%). Positive ALK expression was found in 2 cases among 22 patients (9.09%).

CONCLUSION

Frequency of EGFR mutations in pulmonary adenocarcinomas of our series is similar to that found in the European ones with some particularities. The mutations detected are uncommon. Whereas, we found a high frequency of positive ALK expression in our series compared to frequency reported in literature. Further studies with larger Tunisian series are required to obtain more conclusive results.

Radiological and pathological analysis of LDCT screen detected and surgically resected sub-centimetre lung nodules in 44 asymptomatic patients

PURPOSE

Once lung cancer is detected due to clinical symptoms or by being visible on chest X-ray, it is usually high stage and non-operable. In order to improve mortality rates in lung cancer, low-dose CT (LDCT) screening of "high risk" individuals is gaining popularity. However, the rate of malignancy in LDCT detected sub-centimetre lung nodules is not clear. We aimed to analyze surgically resected specimens in this patient group to explore cost effectiveness and recommendations for clinical management of these nodules.

MATERIAL & METHODS

Our hospital pathology database was searched for sub-centimeter lung nodules detected by LDCT screening which were resected. The patient demographics were collected and the radiologic and pathologic characteristics of those nodules were analyzed.

RESULTS

From the records, 44 patients with 46 resected subcentimetre nodules were identified. Patients were selected for surgery based on an irregular shape, growth in size during follow up, family history of lung cancer or personal history of cancer of other sites, previous lung disease, smoking and personal anxiety. Of the 44 patients, 33 were women and the ages ranged from 43 to 76 years (56.75 ± 8.44). All nodules were equal to, or less than 10 mm with a mean diameter of 7.81 ± 1.80 mm (SD). Out of 46 nodules, the pathological diagnoses were: invasive adenocarcinoma (ACa) in 4 (8.7%); adenocarcinoma in situ (AIS) or atypical adenomatous hyperplasia (AAH) in 29 (63%); benign fibrosis/fibrotic scar with inflammation or calcification in 12 (26.1%); an intrapulmonary benign lymph node in 1 (2.2%). Of the ACa, AIS and AAH groups (a total of 31 patients), 77% were women (24 vs. 7). The cancer or pre-cancer nodules (ACa, AIS and AAH) tended to be larger than benign fibrotic scars (P = 0.039). Amongst all characteristics, significant statistical differences were found when the following radiological features were considered: reconstructed nodule shape (P = 0.011), margin (P = 0.003) and ground glass pattern (P = 0.000). The patient's age, the axial morphology of the lesion, relationship to major vessels or visceral pleura and location within the lung parenchyma were not predictive of the pathologic diagnosis. Only one of the 31 patients with a cancer or pre-cancer nodule was a smoker.

CONCLUSION

ACa, AIS and AAH nodules detected on LDCT included more women (77%) than men in our cohort. Smoking as inclusive criteria for LDCT screening of lung cancer needs to be further evaluated in the Chinese population. The reconstructed nodule shape, density and margin may help radiologists to identify small cancer and pre-cancer nodules from benign conditions.

Transformation from non-small-cell lung cancer to small-cell lung cancer: molecular drivers and cells of origin

Lung cancer is the most common cause of cancer deaths worldwide. The two broad histological subtypes of lung cancer are small-cell lung cancer (SCLC), which is the cause of 15% of cases, and non-small-cell lung cancer (NSCLC), which accounts for 85% of cases and includes adenocarcinoma, squamous-cell carcinoma, and large-cell carcinoma. Although NSCLC and SCLC are commonly thought to be different diseases owing to their distinct biology and genomic abnormalities, the idea that these malignant disorders might share common cells of origin has been gaining support. This idea has been supported by the unexpected findings that a subset of NSCLCs with mutated EGFR return as SCLC when resistance to EGFR tyrosine kinase inhibitors develops. Additionally, other case reports have described the coexistence of NSCLC and SCLC, further challenging the commonly accepted view of their distinct lineages. Here, we summarise the published clinical observations and biology underlying tumours with combined SCLC and NSCLC histology and cancers that transform from adenocarcinoma to SCLC. We also discuss pre-clinical studies pointing to common potential cells of origin, and speculate how the distinct paths of differentiation are determined by the genomics of each disease.

EGFR immunoexpression, RAS immunoexpression and their effects on survival in lung adenocarcinoma cases

BACKGROUND

The impacts of epidermal growth factor receptor (EGFR) immunoexpression and RAS immunoexpression on the survival and prognosis of lung adenocarcinoma patients are debated in the literature.

METHODS

Twenty-six patients, who underwent pulmonary resections between 2002 and 2007 in our clinic, and whose pathologic examinations yielded adenocarcinoma, were included in the study. EGFR and RAS expression levels were examined by immunohistochemical methods. The results were compared with the survival, stage of the disease, nodal involvement, lymphovascular invasion, and pleural invasion. Nonparametric bivariate analyses were used for statistical analyses.

RESULTS

A significant link between EGFR immunoexpression and survival has been identified while RAS immunoexpression and survival have been proven to be irrelevant. Neither EGFR, nor RAS has displayed a significant link with the stage of the disease, nodal involvement, lymphovascular invasion, or pleural invasion.

CONCLUSIONS

Positive EGFR immunoexpression affects survival negatively, while RAS immunoexpression has no effect on survival in lung adenocarcinoma patients.

Axitinib affects cell viability and migration of a primary foetal lung adenocarcinoma culture

Fetal lung adenocarcinoma (FLAC) is a rare variant of lung adenocarcinoma. Studies regarding FLAC have been based only on histopathological observations, thus representative in vitro models of FLAC cultures are unavailable. We have established and characterized a human primary FLAC cell culture, exploring its biology, chemosensitivity, and migration. FLAC cells and specimen showed significant upregulation of VEGF165 and HIF-1α mRNA levels. This observation was confirmed by in vitro chemosensitivity and migration assay, showing that only Axitinib was comparable to Cisplatin treatment. We provide a suitable in vitro model to further investigate the nature of this rare type of cancer.

Association between SOD2 C47T polymorphism and lung cancer susceptibility: a meta-analysis

Lung cancer is one of the most common cancers worldwide, but its etiology is still unclear. Superoxide dismutase 2 (SOD2) plays an essential role in oxidative stress and may be involved in the development of lung cancer. The association between SOD2 C47T polymorphism and lung cancer risk has been widely investigated, but the results of previous studies are contradictory. We conducted a meta-analysis to comprehensively assess the association between SOD2 C47T polymorphism and lung cancer. The association was estimated by odds ratio (OR) with 95 % confidence interval (95 % CI). A total of 10 studies with 5,146 cases and 6,173 controls were identified. The results showed that SOD2 C47T polymorphism was significantly associated with lung cancer (T versus C: OR = 0.88, 95 % CI = 0.83-0.93, P < 0.001; TT versus CC: OR = 0.74, 95 % CI = 0.66-0.83, P < 0.001; TT versus

CC/CT

OR = 0.81, 95 % CI = 0.73-0.89, P < 0.001). Subgroup analysis by ethnicity suggested that SOD2 C47T polymorphism was significantly associated with lung cancer in both East Asians and Caucasians. Conclusively, this meta-analysis strongly suggests that SOD2 C47T polymorphism is significantly associated with lung cancer.

EGFR mutations in US Hispanic versus non-Hispanic white patients with lung adenocarcinoma

CONTEXT

Lung cancer is the leading cause of cancer deaths worldwide. First-generation tyrosine kinase inhibitors improve progression-free survival in lung cancers with epidermal growth factor receptor (EGFR) mutations. EGFR mutations occur predominantly in exons 19 and 21 in lung adenocarcinomas of Asians (∼30%), whites (∼15%), and African Americans (∼19%). However, minimal information exists on the prevalence or type of genetic changes that occur in lung cancers in US Hispanic patients. We investigated the EGFR mutation frequency in primary lung adenocarcinomas in US Hispanics compared with non-Hispanic whites.

OBJECTIVE

To evaluate EGFR mutations in lung adenocarcinomas from US Hispanic patients compared with those from non-Hispanic white patients.

DESIGN

DNA samples were extracted from paraffin-embedded tissue of consecutive lung adenocarcinomas from 83 patients. Samples were collected from 40 Hispanics and 43 non-Hispanic whites. Mutations in EGFR were analyzed using a custom assay. Results.-Fourteen of 83 patients (16.9%) had EGFR mutations in their tumor DNA, including 6 of 40 Hispanics (15.0%) and 8 of 43 non-Hispanic whites (18.6%). No association with age, sex, or tumor stage was identified. Smoking history could not be obtained for most of the 83 patients, although 8 of the 11 patients with EGFR mutations for whom smoking history was obtained were nonsmokers. Most of the tumors with EGFR mutations (12 of 14; 85.7%) were acinar with lepidic or papillary subtypes. EGFR mutations occurred in exon 19 (42.8%), exon 18 (28.6%), exon 20 (28.6%), and exon 21 (14.3%). Two cases had 2 mutations identified in different exons.

CONCLUSION

The frequency of EGFR mutations is similar in US Hispanics compared with non-Hispanic whites.

Classification and regression tree analysis of patients with non-small-cell lung cancer treated with gefitinib after chemotherapy

BACKGROUND

Many randomized studies have shown that epidermal growth factor receptor (EGFR-) tyrosine kinase inhibitors (TKIs) are apparently advantageous over standard chemotherapy in non-small-cell lung cancer (NSCLC) patients with EGFR active mutation in front-line treatment. But which subgroup of advanced NSCLC could benefit from EGFR-TKIs in the second-or third-line setting remains elusive. To explore predictive factors of advanced NSCLC patients with the unknown status of EGFR mutation treated by gefitinib in the second-or third-line setting, we used classification and regression tree (CART) analysis to screen which patients would benefit more.

METHODS

One hundred and fifty-five patients with advanced NSCLC previously unsuccessfully treated with platinum-based chemotherapy were included in this study. Patients received gefitinib as part of the Expanded Access Program of the China Charity Federation between 2 March 2005 and 11 May 2011. Multivariate analysis of progression-free survival (PFS) was performed using CART analysis. This method uses recursive partitioning to assess the effect of specific variables on PFS, thereby ultimately generating groups of patients with similar clinical features on PFS.

RESULTS

The median PFS in patients with NSCLC who were treated with gefitinib after prior chemotherapy was 16 months (95% confidence interval [CI] 13.44-18.56). CART was performed with an initial split on adenocarcinoma differentiation, and four terminal subgroups were formed. The median PFS of the four subsets ranged from 12 to 42 months.

CONCLUSIONS

Adenocarcinoma differentiation, brain metastasis and prior thoracic radiotherapy are predictors of PFS in previously treated NSCLC patients. CART can be used to identify homogeneous patient populations in clinical practice and future clinical trials.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture published articles from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. EVIDENCE was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Serum detection of epidermal growth factor receptor gene mutations using mutant-enriched sequencing in Chinese patients with advanced non-small cell lung cancer

Epidermal growth factor receptor gene (EGFR) mutations are among the best predictive markers of the efficacy of EGFR tyrosine kinase inhibitor (EGFR-TKI) treatment. Mutations in the EGFR gene confer sensitivity to EGFR-TKIs in patients with advanced non-small cell lung cancer (NSCLC). This study determined the concordance rate of EGFR mutations in serum samples and tumour tissue from Chinese patients with advanced NSCLC and compared two detection methods: mutant-enriched polymerase chain reaction-based DNA sequencing and non-enriched sequencing. The EGFR mutation status in serum was consistent with that in paired tumour samples, with a concordance rate of 93.1% for mutant-enriched sequencing. In serum samples, mutant-enriched sequencing demonstrated sensitivity and specificity of 77.8% and 100%, respectively, and was more sensitive than the non-enriched assay. Mutant-enriched sequencing in serum may provide a non-invasive and sensitive method for detecting EGFR mutation status in patients with unresectable NSCLC.

Targeting tumors that lack methylthioadenosine phosphorylase (MTAP) activity: current strategies

Many solid tumors and hematologic malignancies lack expression of the enzyme methylthioadenosine phosphorylase (MTAP), due either to deletion of the MTAP gene or to methylation of the MTAP promoter. In cells that have MTAP, its natural substrate, methylthioadenosine (MTA), generated during polyamine biosynthesis, is cleaved to adenine and 5-methylthioribose-1-phosphate. The latter compound is further metabolized to methionine. Adenine and methionine are further metabolized and hence salvaged. In MTAP-deficient cells, however, MTA is not cleaved and the salvage pathway for adenine and methionine is absent. As a result, MTAP-deficient cells are more sensitive than MTAP-positive cells to inhibitors of de novo purine synthesis and to methionine deprivation. The challenge has been to take advantage of MTAP deficiency, and the changes in metabolism that follow, to design a strategy for targeted treatment. In this review, the frequency of MTAP-deficiency is presented and past and recent strategies to target such deficient cells are discussed, including one in which MTA is administered, followed by very high doses of a toxic purine or pyrimidine analog. In normal host cells, adenine, generated from MTA, blocks conversion of the analog to its toxic nucleotide. In MTAP-deficient tumor cells, conversion proceeds and the tumor cells are selectively killed. Successful mouse studies using this novel strategy were recently reported.

Clinicopathological predictors of EGFR/KRAS mutational status in primary lung adenocarcinomas

Screening for EGFR and KRAS mutations in patients with lung adenocarcinomas can be used to predict the patient's response to EGFR tyrosine kinase inhibitors, but there is a lack of guidelines for testing in clinical practice. We analyzed the morphological and clinicopathological characteristics, including tumor stage, size, presence of scar, inflammatory response, angiolymphatic and pleural invasion, of 345 surgically treated primary lung adenocarcinomas with respect to their EGFR and KRAS mutational profile and EGFR FISH. EGFR and KRAS mutations were found in 33 (10%) and 78 (23%) of lung adenocarcinomas, respectively, whereas 226 (67%) cases were negative for both mutations. There was a large overlap in the analyzed clinicopathological characteristics among the three study groups. Statistically significant predictors for the presence of EGFR mutations included history of never smoking (OR 5.939; 95% Wald confidence limit 1.662-21.223, P=0.0149), mild lymphocytic host response (OR 4.724; 95% Wald confidence limit 1.33-1.776; P=0.0163), female gender (OR 2.571; 95% Wald confidence limit 1.015-6.511, P=0.0463) and absence of solid growth pattern. Statistically significant predictors for the presence of KRAS mutations included older age (OR 1.034; 95% Wald confidence limit 1.007-1.062, P=0.0132), history of smoking (OR 0.617, 95% Wald confidence limit 0.357-1.066, P=0.0412) and mucinous differentiation. EGFR FISH positivity as defined by the Colorado criteria was a significant predictor of EGFR mutations, with high polysomy as the strongest predictive criteria. Despite statistically significant differences among the study groups and because of the large overlap in the analyzed clinicopathological criteria, none of these could be implemented as the selection criteria for molecular testing in clinical practice. The cost-effectiveness of lung carcinoma mutational testing would be improved by initial determination of KRAS mutational status as negative predictor of the patient's response to EGFR tyrosine kinase inhibitors, followed by EGFR mutational analysis, if necessary.

Clinical outcomes in non-small-cell lung cancer patients with EGFR mutations: pooled analysis

Non-small-cell lung cancer (NSCLC) with mutations in the epidermal growth factor receptor (EGFR) is a distinct subgroup of NSCLCs that is particularly responsive to EGFR tyrosine-kinase inhibitors (TKIs). A weighted pooled analysis of available studies was performed to evaluate clinical outcome in patients with EGFR-mutated NSCLC who were treated with chemotherapy or EGFR TKIs. Median progression-free survival (PFS) times were pooled from prospective or retrospective studies that evaluated chemotherapy or single-agent EGFR TKIs (erlotinib or gefitinib) in patients with NSCLC and EGFR mutations. Among the studies identified for inclusion in the analysis, 12 evaluated erlotinib (365 patients), 39 evaluated gefitinib (1069 patients) and 9 evaluated chemotherapy (375 patients). Across all studies, the most common EGFR mutations were deletions in exon 19 and the L858R substitution in exon 21. In the weighted pooled analysis, the overall median PFS was 13.2 months with erlotinib, 9.8 months with gefitinib and 5.9 months with chemotherapy. Using a two-sided permutation, erlotinib and gefitinib produced a longer median PFS versus chemotherapy, both individually (P= 0.000 and P= 0.002, respectively) and as a combined group (EGFR TKI versus chemotherapy, P= 0.000). EGFR TKIs appear to be the most effective treatment for patients with advanced EGFR-mutant NSCLC. Ongoing prospective trials comparing the efficacy of first-line chemotherapy and EGFR TKIs in EGFR-mutant disease should provide further insight into the most appropriate way to treat this specific group of patients.