Divergent epidermal growth factor receptor mutation patterns between smokers and non-smokers with lung adenocarcinoma

Association of smoking status with non-small cell lung cancer patients harboring uncommon epidermal growth factor receptor mutation

INTRODUCTION

Uncommon epidermal growth factor receptor (EGFR) mutations include single and complex mutations. However, the association of the smoking status of patients with uncommon and complex EGFR mutations remains unclear.

METHODS

This retrospective study evaluates the spectrum of uncommon EGFR mutations and investigates the influence of smoking status on the frequency of various uncommon EGFR mutations using a multi-institutional medical database.

RESULTS

Between 2010 and 2019, 5,608 non-small cell lung cancer (NSCLC) patients were analyzed. EGFR mutations were detected in 3,155 (56.3%) patients. Among the 399 (12.6%) patients with uncommon mutations, 198 had single uncommon and 201 complex mutations, including 87 exon 20 insertions, 79 de novo T790M, 70 complex common, and 52 complex uncommon mutations. For comparison, we also included 402 patients with common EGFR mutations. The percentage of ever-smokers was significantly higher in patients with uncommon EGFR mutations than in patients with common EGFR mutations (25.8% vs. 17.4%, p = 0.005). Furthermore, the percentage of ever-smokers was higher in those with a complex mutation than in those with a single uncommon mutation (30.3% vs. 21.2%, p = 0.040). Among patients carrying uncommon EGFR mutations, ever-smokers had significantly more complex uncommon EGFR mutations than never-smokers (22.3% vs. 9.8%, p = 0.002). Among patients carrying G719X, L861Q, and S768I, ever-smokers tended to have complex EGFR mutations more frequently than never-smokers (64.7% vs. 28.7%, 50.0% vs. 18.7%, 88.9% vs. 81.2%, respectively).

CONCLUSIONS

Our study demonstrates not only a comprehensive spectrum of uncommon EGFR mutations, but also a positive relationship between smoking status and uncommon EGFR mutation frequency, especially complex uncommon EGFR mutations. The results suggest that smoking contributes to the development of complex EGFR mutations.

Association of Smoking With Patient Characteristics and Outcomes in Small Cell Lung Carcinoma, 2011-2018

IMPORTANCE

Small cell lung carcinoma (SCLC) is uncommon in individuals who have never smoked (never-smokers). The related epidemiologic factors and prognosis remain unclear.

OBJECTIVE

To assess the epidemiologic factors, clinical characteristics, and outcomes of SCLC in never-smokers.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted using data from the national Taiwan Cancer Registry, which was inaugurated in 1979 and maintains standardized records of patients' characteristics and clinical information for all individuals with cancer. Patients with cytologically or pathologically proven lung cancer were included for analysis. The study obtained data on patients from January 1, 1996, to December 31, 2018; data analysis was conducted from January 1, 1996, to December 31, 2019.

EXPOSURES

Clinical characteristics and outcomes of smokers and never-smokers with SCLC.

MAIN OUTCOMES AND MEASURES

Clinical characteristics for comparison included age at diagnosis, sex, performance status, tumor stage, and treatment. The main outcome parameter was overall survival of patients with SCLC from 2011 to 2018.

RESULTS

From 1996 to 2018, a total of 225 788 patients had diagnosed lung cancer; 141 654 patients (62.7%) were men; mean (SD) age was 67.55 (12.58) years. The numbers of both patients with newly diagnosed lung cancer and those with SCLC increased until 2009 by 111.5% for lung cancer and 118.5% for SCLC. Thereafter, lung cancer cases grew in number, but SCLC cases did not; hence, the percentage of patients with SCLC decreased from 9.3% in 2009 to 6.3% in 2018. From 2011 to 2018, the percentage of never-smokers increased significantly among all patients with lung cancers (from 49.9% in 2011 to 60.2% in 2018) and among those with lung adenocarcinomas (from 64.1% in 2011 to 70.9% in 2018) (both P < .001). However, the percentage of never-smokers appeared to vary little in the SCLC population: 15.5% in 2011 and 16.1% in 2018 (P = .28). The median overall survival was significantly longer in patients with adenocarcinoma vs SCLC (adjusted hazard ratio, 0.32; 95% CI, 0.31-0.33; P < .001). Compared with smokers with SCLC, never-smokers with SCLC tended to include more older patients (age ≥70 years: 492 [57.3%] vs 2242 [44.8%]), more women (274 [31.9%] vs 322 [6.4%]), more individuals with a poor performance status (Eastern Cooperative Oncology Group performance status ≥2: 284 [33.1%] vs 1261 [25.2%]) and stage IV cancer (660 [76.9%] vs 3590 [71.8%]), and more patients without treatment (203 [23.7%] vs 626 [12.5%]). Furthermore, never-smokers, particularly men, experienced a shorter survival rate (adjusted hazard ratio, 1.10; 95% CI, 1.00-1.20; P = .04) compared with the other groups.

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that the decrease in the percentage of patients with SCLC was associated with increased lung cancers of other histologic types, with no substantial decrease in the number of those with SCLC.

The Survival Benefit for Optimal Glycemic Control in Advanced Non-Small Cell Lung Cancer Patients With Preexisting Diabetes Mellitus

Background

Diabetes mellitus (DM) is a frequent comorbidity in patients with cancer. This study aimed to evaluate the prognosis of advanced non-small cell lung cancer (NSCLC) patients with DM and to assess whether an optimal glycemic control improves overall survival (OS).

Methods

A total of 1279 advanced NSCLC patients including 300 (23.5%) with preexisting DM were retrospectively reviewed. The continuous relationship between glycated hemoglobin A1C (HbA1c) level and OS was analyzed by restricted cubic spline (RCS) function. Optimal HbA1c cut-off point was determined using X-tile analysis. Survival was analyzed with the Kaplan–Meier method and compared among groups stratified by diabetes status and HbA1c. Multivariable Cox proportional hazards regression analysis was employed to identify prognostic factors for OS after adjusting for baseline characteristics.

Results

DM and non-DM patients had similar OS (median (95% CI): 22.85 (20.05-26.73) vs. 22.22 (20.35-24.76) months, P=0.950). The multivariate Cox regression analyses showed that DM status was not a prognostic factor for OS (HR: 0.952, 95% CI: 0.808-1.122, P=0.559). However, there existed a non-linear but generally positive relationship between the elevated HbA1c level and increased risk of overall mortality. HbA1c > 6.6% was a negative prognostic factor for OS (HR: 1.593, 95% CI: 1.113-2.280, P=0.011). The median OS (95% CI) for nondiabetic patients, DM patients with HbA1c ≤6.6% and those with HbA1c > 6.6% was 22.22 (20.01-24.43), 25.28 (21.79-28.77) and 15.45 (7.57-23.33) months, respectively. Well-controlled DM patients had a comparable crude OS (HR (95% CI): 0.90 (0.76-1.08), P=0.273] compared to nondiabetic patients while patients with HbA1c>6.6% had a worse crude OS than patients without DM (HR (95% CI): 1.70 (1.24-2.34), P=0.001]. The survival benefit of good HbA1c control was prominent in all subgroups.

Conclusion

Impaired glycemic level negatively affects survival for patients with advanced NSCLC while proper glycemic control with HbA1c ≤6.6% improves the OS.

The effectiveness of afatinib in patients with lung adenocarcinoma harboring complex epidermal growth factor receptor mutation

Background and aims:

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) are effective against classical EGFR mutations in lung cancer. However, their effectiveness and the prognosis of lung cancer patients with complex EGFR mutations are not well delineated. Therefore, we aimed to investigate the treatment effectiveness of different EGFR TKIs in patients with complex EGFR mutations.

Patients and methods:

From 2005 to 2020, we collected lung adenocarcinoma tissue samples for EGFR mutation analysis using direct Sanger sequencing. Patients with EGFR mutations treated with EGFR TKIs as first-line treatment were enrolled. Clinical characteristics, EGFR mutation status, treatment response, progression-free survival (PFS), and overall survival (OS) were analyzed.

Results:

Among 2675 patients with EGFR mutations, 239 (8.9%) had complex EGFR mutations, of whom 125 received EGFR TKI treatment as first-line treatment. Multivariate analysis revealed that afatinib was a more favorable factor for PFS than gefitinib [hazard ratio (HR), 2.01; 95% confidence interval (CI), 1.11–3.62] and erlotinib (HR, 2.61; 95% CI, 1.31–5.22), especially in patients with uncommon mutation patterns. Afatinib treatment as first-line treatment was also associated with longer OS compared with erlotinib (HR, 2.48; 95% CI, 1.20–5.12). Classical mutation pattern was associated with longer PFS (p = 0.001) and OS (p = 0.020). Secondary T790M was detected in 22 of 52 (42.3%) patients who had re-biopsied tissue samples after acquiring resistance to EGFR TKIs. There was no significant difference in secondary T790M formation after acquired resistance to the three EGFR TKIs (p = 0.261). Furthermore, three (5.8%) patients had small-cell lung cancer transformation.

Conclusion:

Afatinib is an effective first-line treatment for patients with lung adenocarcinoma harboring complex EGFR mutations, especially those with uncommon mutation patterns.

Brain metastases: epidemiology

Brain metastases (BM) are the most commonly diagnosed type of central nervous system tumor in the United States. Estimates of the frequency of BM vary significantly, as there is no nationwide reporting system for metastases. BM may be the first sign of a previously undiagnosed cancer, or occur years or decades after the primary cancer was diagnosed. Incidence of BM varies significantly by primary cancer site. Lung, breast, and melanoma continue to be the leading cause of BM. These tumors are increasingly more common as new therapeutics, advanced imaging, and improved screening have led to lengthened survival after primary diagnosis for cancer patients. BM are difficult to treat, and for most individuals the diagnosis of BM generally portends a poor prognosis.

ctDNA assessment of EGFR mutation status in Chinese patients with advanced non-small cell lung cancer in real-world setting

Background

The prevalence of EGFR mutations in circulating free tumor-derived DNA (ctDNA) was still unknown in China. This large-scale study (NCT02623257) aimed to explore the prevalence of epidermal growth factor receptor (EGFR) mutations and determine the correlation of EGFR mutation status with clinical characteristics.

Methods

Plasma DNA samples from 1,001 patients with stage III/IV NSCLC who received ≤1st line chemotherapy were collected from 65 hospitals. EGFR mutations were tested by amplification refractory mutation system (ARMS) method. The EGFR mutation rate was calculated and the associations between EGFR status and patients' demographic data, disease status as well as treatment pattern were explored.

Results

EGFR mutations were detected in 251 of 1,001 (25.1%) patients, 26.8% in adenocarcinoma and 11.7% in squamous carcinoma. A total of 189 harbored sensitizing mutations alone, 28 had resistance mutations alone, 3 had a combination of activating mutations, and 31 had a combination of activating and resistance mutations. Higher detection rate was observed in chemotherapy-naïve patients than those received 1st line chemotherapy (27.0% vs. 18.0%; P=0.006). Of which, the mutation rate of exon 19 deletion was 9.31% for naïve patients and 7.37% for the 1st chemotherapy patients; while the mutation rate of L858R decreased obviously from 10.20% (naïve) to 3.69% (1st line). We also noticed the mutation rate was 37.1% in patients with ≥2 organ metastases. Multivariate analysis showed female, chemotherapy-naïve, or ≥2 metastatic organs patients had higher EGFR mutation rate.

Conclusions

ctDNA based EGFR mutation test is feasible and could be a surrogate when tissue biopsy is not available.

EGFR mutation, smoking, and gender in advanced lung adenocarcinoma

Purpose

In the current targeted therapy era, information on the effect of smoking in epidermal growth factor receptor (EGFR)-mutant lung cancer patients is scarce.

Results

In total, 11,678 adenocarcinoma patients were enrolled. Of these, 33.3% and 91.8% of male and female patients were non-smokers, respectively. An increased amount of smoking (P < 0.001 for trend), fewer smoke-free years (P < 0.001 for trend), and younger age of smoking initiation (P = 0.034 for trend) were all associated with significantly lower EGFR mutation rates. Smokers had a shorter median overall survival (OS) among both EGFR-mutant and EGFR-wild type patients (17.8 vs. 21.1 months, and 7.9 vs. 11.4 months respectively; both P < 0.001). Among patients with EGFR-mutant adenocarcinoma, younger smokers were associated with shorter OS (P = 0.047). In multivariate analysis, female gender was an independent prognostic factor for OS (hazard ratio: 0.86 [95% confidence interval {CI}: 0.80-0.93]; P < 0.001 in the EGFR-mutant group and 0.88 [95% CI: 0.81-0.96]; P = 0.004 in the EGFR-wild type group).

Materials and Methods

We reviewed the National Lung Cancer database (Taiwan) to assess the impact of smoking on the EGFR mutation rate and survival in advanced lung adenocarcinoma patients during 2011 and 2014 retrospectively.

Conclusions

Smoking was associated with lower incidence of EGFR mutation rate and reduced OS of advanced lung adenocarcinoma patients in a dose-dependent manner. In addition to EGFR mutation and smoking, gender also plays an important role in survival among these patients.

Prognostic value of pretreatment inflammatory biomarkers in advanced lung adenocarcinoma patients receiving first-line pemetrexed/platinum doublet

Inflammation is a new hallmark feature of cancer initiation and progression. We aimed to investigate the association between inflammatory response biomarkers and progression-free survival and overall survival in advanced lung adenocarcinoma patients treated with first-line pemetrexed and platinum doublet chemotherapy. Patients hospitalized between April 2012 and March 2015 were enrolled and eliminated according to the inclusion and exclusion criteria. The pretreatment neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, derived neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio were calculated. Besides the well-established clinical prognostic factors, the prognostic values of the four markers were evaluated by the Kaplan-Meier method and Cox's proportional hazards regression model. A total of 78 patients were enrolled in this study. Elevated neutrophil-to-lymphocyte ratio and derived neutrophil-to-lymphocyte ratio were correlated with poor treatment response ( p = 0.014, 0.012, respectively). A high pretreatment neutrophil-to-lymphocyte ratio, derived neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio, as well as low lymphocyte-to-monocyte ratio, were associated with worse progression-free survival and overall survival. Multivariate analysis revealed that high neutrophil-to-lymphocyte ratio (hazard ratio = 2.056; 95% confidence interval, 1.281-3.299; p = 0.003) and ≥3 metastasis organs (hazard ratio = 1.989; 95% confidence interval, 1.069-3.702; p = 0.030) were independent prognostic factors for progression-free survival. Meanwhile, high neutrophil-to-lymphocyte ratio (hazard ratio = 5.540; 95% confidence interval, 2.974-10.321; p < 0.001) and habitual smoking (hazard ratio = 2.806; 95% confidence interval, 1.509-5.221; p = 0.001) were independent prognostic factors for overall survival. In conclusion, Pretreatment neutrophil-to-lymphocyte ratio was an independent prognostic factor for advanced lung adenocarcinoma patients treated with first-line pemetrexed/platinum doublet chemotherapy. Elevated pretreatment derived neutrophil-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio might be potential biomarkers for poorer responses to chemotherapy. To verify these findings, larger well-designed prospective studies are needed.