Long-term Outcomes After Lung Cancer Resection in Smokers: Analysis of the National Lung Screening Trial

BACKGROUND

Smoking is a known risk factor for perioperative complications after lung resection; however, little data exists looking at the impact of smoking status (current versus former) on long-term oncologic outcomes after lung cancer surgery. We sought to compare overall survival (OS), progression-free survival (PFS), and cancer-specific mortality (CSM) in current and former smokers using data from the National Lung Screening Trial (NLST). Additionally, we performed subset analysis in current smokers in order to evaluate the effect of modern surgical techniques on long-term outcomes.

METHODS

Patients with clinical stage IA or IB NSCLC who underwent upfront resection within 180 days of diagnosis were identified in the NLST database. Cox proportional hazard regression models were used to assess differences in patient and treatment characteristics with respect to OS and PFS, with a cause-specific hazard model used for CSM.

RESULTS

A total of 593 patients were included in the study (269 former smokers, 324 current smokers). Lobar resection (LR) was performed more often than sublobar resection (SLR) (481 vs. 112), and thoracotomy was performed more often than thoracoscopy (482 vs. 86). Comparison of current versus former smokers showed no difference in OS or PFS after resection. Higher CSM was seen in current smokers (p = 0.049). Subset analysis of current smokers revealed no difference in OS or PFS between sub-lobar and lobar resection or thoracotomy and thoracoscopy. Although higher CSM was associated with thoracoscopy versus thoracotomy in this group, this finding was limited by a relatively small thoracoscopy sample size of 44 patients (p = 0.026).

CONCLUSION

Our analysis of the NLST database shows no significant difference in OS and PFS when comparing current and former smokers undergoing resection for stage I NSCLC. Active smoking status was associated with higher CSM. Subset analysis of current smokers showed no difference in OS or PFS between sub-lobar and lobar resection or thoracotomy and thoracoscopy. Higher CSM was seen in current smokers who underwent thoracoscopy compared to thoracotomy; however, this finding was limited by a small sample size.

Prognostic Impact of Smoking Period in Patients with Surgically Resected Non-small Cell Lung Cancer

BACKGROUND

The pack-year index, which is calculated by multiplying a smoking period by the number of cigarette packs smoked per day, is frequently used to investigate the risk of developing lung cancer. Notably, however, whether the smoking period or the number of packs per day is more predictive of postoperative prognosis remains unclear in non-small cell lung cancer (NSCLC) patients who receive curative lung resection.

PATIENTS AND METHODS

Initial screening included 2055 consecutive lung cancer patients who had underwent curative lung resection between 2000 and 2016 at a single center in Japan. Data from 1134 NSCLC patients with smoking history were ultimately analyzed. Time-dependent areas under the curve (AUCs) were used to compare diagnostic accuracy.

RESULTS

On univariate analysis, the number of packs smoked per day was not a significant predictor of disease-free survival (DFS; p = 0.2387) or overall survival (OS; p = 0.1357). On multivariable analysis, smoking period was an independent predictor of DFS and OS (both p < 0.0001). Time-dependent smoking period AUCs were superior to those of number of packs smoked per day. On subgroup analyses, patients with a smoking period ≥ 40 years had significantly shorter DFS and OS than those with a smoking period of < 40 years, independent of sex, clinical stage, and histological type.

CONCLUSIONS

Smoking period was a significant prognostic indicator in NSCLC patients who underwent curative lung resection, which should be validated in further prospective and/or multicenter studies with large sample sizes.

Cost-effectiveness of a low-dose computed tomography screening programme for lung cancer in New Zealand

OBJECTIVES

The cost-effectiveness of low-dose computed tomography (LDCT) screening for lung cancer is uncertain. This study estimated the health gains, costs (net health system, and including 'unrelated') and cost-effectiveness of biennial LDCT screening among 55-74 years olds with a smoking history of at least 30 pack years, and (if a former smoker) having quit within last 15 years, in New Zealand.

METHODS

We used a macrosimulation stage shift model with New Zealand-specific lung cancer incidence rates and intervention parameters from the National Lung Screening Trial, a health system perspective, and a lifetime horizon for quality-adjusted life-years (QALYs) and costs discounted at 3% per annum. We also examined heterogeneity by gender, ethnicity (Māori (indigenous population) versus non-Māori), age and smoking status.

RESULTS AND CONCLUSION

We estimated 0.067 QALYs gained (95 % uncertainty interval (UI) 0.044 to 0.095) per eligible participant, at a cost of US$2843 ($2067-3797; 2011 $US). The overall incremental cost effectiveness ratio (ICER) was US$44,000 per QALY gained (95 % UI US$27,000 to US$70,000). The ICER was substantially lower for Māori, at US$26,000 per QALY gained (95 % UI US$17,000 to US$39,000). The cost-effectiveness varied by socio-demographics, from US$21,000 for 70-74 year old Māori females to US$60,000 for 55-59 year old non-Māori males. The two scenarios that lowered the ICER the most were halving the screening costs (ICER = US$33,000 per QALY), and improving the sensitivity (from 93.8% to 98%) and specificity (from 73.4% to 95%) of the screening test (ICER = US$23,000 per QALY). Based on a threshold of GDP per capita per QALY gained (i.e. US$30,000), LDCT screening for lung cancer is unlikely to be cost-effective in New Zealand for the proposed target population under our modelling assumptions. However, it is likely to be cost-effective for Māori, a population group which carries a disproportionately high disease burden from lung cancer.

Cost-effectiveness of a low-dose computed tomography screening programme for lung cancer in New Zealand

OBJECTIVES

The cost-effectiveness of low-dose computed tomography (LDCT) screening for lung cancer is uncertain. This study estimated the health gains, costs (net health system, and including 'unrelated') and cost-effectiveness of biennial LDCT screening among 55-74 years olds with a smoking history of at least 30 pack years, and (if a former smoker) having quit within last 15 years, in New Zealand.

METHODS

We used a macrosimulation stage shift model with New Zealand-specific lung cancer incidence rates and intervention parameters from the National Lung Screening Trial, a health system perspective, and a lifetime horizon for quality-adjusted life-years (QALYs) and costs discounted at 3% per annum. We also examined heterogeneity by gender, ethnicity (Māori (indigenous population) versus non-Māori), age and current versus ex-smoking status.

RESULTS AND CONCLUSION

We estimated 0.037 QALYs gained (95% uncertainty interval (UI) 0.024-0.053) per eligible participant, at a cost of US$3606 ($2689-4681). The overall incremental cost effectiveness ratio (ICER) was US$104,000 per QALY gained (95% UI US$59,000-US$175,000). The cost-effectiveness varied moderately by socio-demographics, with the 'best' ICER being US$52,000 for 70-74 year old Māori females and the 'worst' ICER being US$142,000 for 55-59 year old non-Māori females. The ICER varied little by current smoking status, due to higher competing mortality risk limiting QALY gains for current smokers. The two scenarios that lowered the ICER the most were increasing the screening uptake to 100% (ICER = US$50,000 per QALY), and improving the sensitivity (from 93.8%-98%) and specificity (from 73.4%-95%) of the screening test (ICER = US$42,000 per QALY). Based on a threshold of GDP per capita per QALY gained (i.e. US$30,000), LDCT screening for lung cancer is unlikely to be cost-effective in New Zealand for any sociodemographic group.

Is mitochondrial dysfunction a driving mechanism linking COPD to nonsmall cell lung carcinoma?

Chronic obstructive pulmonary disease (COPD) patients are at increased risk of developing nonsmall cell lung carcinoma, irrespective of their smoking history. Although the mechanisms behind this observation are not clear, established drivers of carcinogenesis in COPD include oxidative stress and sustained chronic inflammation. Mitochondria are critical in these two processes and recent evidence links increased oxidative stress in COPD patients to mitochondrial damage. We therefore postulate that mitochondrial damage in COPD patients leads to increased oxidative stress and chronic inflammation, thereby increasing the risk of carcinogenesis.

The functional state of the mitochondrion is dependent on the balance between its biogenesis and degradation (mitophagy). Dysfunctional mitochondria are a source of oxidative stress and inflammasome activation. In COPD, there is impaired translocation of the ubiquitin-related degradation molecule Parkin following activation of the Pink1 mitophagy pathway, resulting in excessive dysfunctional mitochondria. We hypothesise that deranged pathways in mitochondrial biogenesis and mitophagy in COPD can account for the increased risk in carcinogenesis. To test this hypothesis, animal models exposed to cigarette smoke and developing emphysema and lung cancer should be developed. In the future, the use of mitochondria-based antioxidants should be studied as an adjunct with the aim of reducing the risk of COPD-associated cancer.

Body mass index and mortality in lung cancer patients: a systematic review and meta-analysis

Studies examining the relation of body mass index (BMI) and mortality in patients with lung cancer have shown diverse results. We conducted a meta-analysis to investigate the association using all available studies from January 1982 to October 2016. PubMed and EMBASE were searched to identify relevant studies. We calculated the summary hazard ratio (HR) and 95% confidence interval (CI) using random effects model. The dose-response relationship was assessed by random effects meta-regression model. Fifty-five articles from 51 studies involving 3 152 552 subjects (males, 54.8%) were included. The pooled results suggested that on average a high BMI decreased risk of death from lung cancer or all-cause. Each 5 kg/m² increase in BMI had a 12% lower risk of lung cancer-specific mortality (HR=0.88, 95% CI: 0.75-1.02, P=0.09) and a 14% lower risk of all-cause mortality (HR=0.86, 95% CI: 0.77-0.96, P<0.01). When stratifying by ethnicity, each 5 kg/m² increase in BMI was associated with 22% and 28% reduction, respectively, in the risk of lung cancer-specific mortality (P<0.01) and all-cause mortality (P<0.01) in Asians, but no association was found in Westerners (P=0.51 and P=0.53, respectively). In conclusion, lung cancer patients with a higher BMI have a longer survival than those with a lower BMI. Considering the significant heterogeneity between included studies, future studies are needed to confirm these findings.

[Systematizing support in cessation smoking to improve care for cancer patients]

Approximately 20% of cancer patients smoke at diagnosis (all localizations included), and over two thirds continue despite the therapeutic management of their cancer, especially when cancer is not associated with tobacco. The impact of smoking on quality of care for patients is actually not enough considered. A literature review conducted by the French National Cancer Institute emphasizes the importance of tobacco cessation to improve the prognosis (decreased mortality from all causes and specific); to reduce the risk of second primary cancers; to reduce per- and post-surgical risks as long as some toxicities related to treatments and to improve the quality of physical and mental life of patients. It is important that a communication with the patient takes place at the beginning of the treatment to impact the smoking behavior. All oncology health professionals should deliver a clearly and personalized cessation advice in the light of scientific data and ensure that smoking cessation help will be offered to the patient.

Systematic Review of Tobacco Use after Lung or Head/Neck Cancer Diagnosis: Results and Recommendations for Future Research

Tobacco use after cancer diagnosis is associated with adverse cancer outcomes, yet reliable prevalence estimates for this behavior are lacking. We conducted a systematic literature review of the prevalence of current tobacco use among individuals with a history of lung or head/neck cancer (CRD #42012002625). An extensive search of electronic databases (MEDLINE, EMBASE, Cochrane Library, CINAHL, PsycINFO, and Web of Science) identified 7,777 potentially relevant articles published between 1980 and 2014 and 131 of these yielded pertinent information. Aggregating results across heterogeneous study designs and diverse patient samples, the overall mean prevalence rate of current tobacco use (mostly cigarette smoking) was 33.0% (median, 31.0%). Among current tobacco users at cancer diagnosis, the mean prevalence rate of current tobacco use (mostly cigarette smoking) was 53.8% (median, 50.3%). In many cases, an operational definition of "current" tobacco use was absent, and biochemical verification of self-reported smoking status was infrequent. These and other observed methodologic limitations in the assessment and reporting of cancer patients' tobacco use underscore the necessity of uniform tobacco use assessment in future clinical research and cancer care.

Recurrence Risk Factors Analysis for Stage I Non-small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related death worldwide. Even early-stage patients might encounter disease recurrence with relative high risk. Effective postoperative therapy is based on an accurate assessment of treatment failure after surgery. The aim of this study is to construct a disease-free survival (DFS) prediction model and stratify patients into different risk score groups.A total of 356 pathological stage I patients (7th American Joint Committee on Cancer) who underwent lung resection from January 2005 through June 2011 were retrospectively reviewed. Of these patients, 63 patients were eliminated for this study. A total of 293 p-stage I patients were included for further univariate and multivariate analysis. Clinical, surgical, and pathological factors associated with high risk of recurrence were analyzed, including age, gender, smoking status, additional primary malignancy (APM), operation method, histology, visceral pleural invasion, angiolymphatic invasion, tumor necrosis, and tumor size.Of the 293 p-stage I non-small cell lung cancer (NSCLC) patients examined, 143 were female and 150 were male, with a mean age of 62.8-years old (range: 25-83-years old). The 5-year DFS and overall survival rates after surgery were 58.9% and 75.3%, respectively. On multivariate analysis, current smoker (hazards ratio [HR]: 1.63), APM (HR: 1.86), tumor size (HR: 1.54, 2.03), nonanatomic resections (HR: 1.81), adenocarcinoma histology (HR: 2.07), visceral pleural invasion (HR: 1.54), and angiolymphatic invasion (HR: 1.53) were found to be associated with a higher risk of tumor recurrence. The final model showed a fair discrimination ability (C-statistic = 0.68). According to the difference risk group, we found patients with intermediate or higher risk group had a higher distal relapse tendency as compared with low risk group (P = 0.016, odds ratio: 3.31, 95% confidence interval: 1.21-9.03).Greater than 30% of disease recurrences occurred after surgery for stage I NSCLC patients. That is why we try to establish an effective DFS predicting model based on clinical, pathological, and surgical covariates. However, our initial results still need to be validated and refined into greater population for better application in clinical use.

Effect of smoking on survival from non-small cell lung cancer: a retrospective Veterans' Affairs Central Cancer Registry (VACCR) cohort analysis

Although a well-established risk factor for lung cancer, the impact of smoking on the survival of non-small cell lung cancer (NSCLC) is not well known. We performed a retrospective analysis of the Veteran's Affairs Comprehensive Cancer Registry of NSCLC patients. Smoking status was categorized as never smoker, past smoker and current smoker based on self-reported history. Multivariate analysis was performed to evaluate the impact of smoking on overall survival (OS) from NSCLC. The study population (n = 61,440) comprised predominantly of males (98 %) and Caucasians (81 %). The median age at diagnosis was 68 years (range 22-108 years). Current smokers were diagnosed with NSCLC at a younger age (65 years) compared to never smokers (71 years) and past smokers (72 years) (p < 0.001). On multivariate analysis, current smokers (n = 34,613) [Hazard ratio (HR) 1.059; 95 % confidence interval (CI) 1.012-1.108], but not past smokers (n = 23,864) (HR 1.008; 95 % CI 0.962-1.056), had worse OS for Stage III and IV NSCLC, compared to never smokers (n = 2,963). Smoking status was not prognostic in stages I and II NSCLC. Current smokers were diagnosed with NSCLC at a younger age than never smokers. Although current smoking was associated with worse prognosis, especially in stages III and IV, the impact of smoking status on OS was modest.

The effect of gender on health-related quality of life and related factors in post-lobectomy lung-cancer patients

PURPOSE

While studies have documented gender differences by histologic type among lung cancer patients, the effect of these differences on the health-related quality of life (HRQoL) of post-lobectomy lungcancer patients and related factors remain uncertain. This study examines gender-specific HRQoL and related factors in post-lobectomy lung-cancer patients.

METHODS

A cross-sectional study design was applied. A convenience sample of 231 post-lobectomy lungcancer patients was recruited from the thoracic surgery outpatient departments of two teaching hospitals in Taipei, Taiwan from March to December 2012. Patients performed a spirometry test and completed instruments that included a Beck Depression Inventory-II, an Interpersonal Support Evaluation List, and the symptom and function scales of the Quality of Life Questionnaire. Data analysis used descriptive statistics, including mean and standard deviations, frequency, and percentage values. Independent-sample Student's t-tests and multivariate analyses were used for comparative purposes.

RESULTS

This study confirmed a significant gender effect on HRQoL and HRQoL-related factors such as marital status, religious affiliation, smoking status, histologic type, symptoms, pulmonary function, depression, and family support. Moreover, multivariate analysis found gender to be a significant determinant of the HRQoL aspects of physical functioning, emotional functioning, and cognitive functioning. Finally, results indicated that factors other than gender were also significant determinants of HRQoL.

CONCLUSION

Gender impacts the HRQoL and related factors of postoperative lung-cancer patients. Therefore, gender should be considered in assessing and addressing the individual care needs of these patients in order to attain optimal treatment outcomes.

Metastatic cancer mimicking mechanical low back pain: a case report

OBJECTIVE AND IMPORTANCE

The purpose of this report is to describe the clinical course of a patient referred to physiotherapy (PT) for the treatment of low back pain who was subsequently diagnosed with metastatic non-small cell carcinoma of the lung.

CLINICAL PRESENTATION

A 48-year old woman was referred to PT for the evaluation and treatment of an insidious onset of low back pain of 2 month duration. The patient did not have a history of cancer, recent weight changes, or general health concerns. The patient's history and physical examination were consistent with a mechanical neuromusculoskeletal dysfunction and no red flag findings were present that warranted immediate medical referral.

INTERVENTION

Short-term symptomatic improvements were achieved using the treatment-based classification approach. However, despite five PT sessions over the course of 5 weeks, the patient did not experience long-term symptomatic improvement. On the sixth session, the patient reported a 2-day history of left hand weakness and headaches. This prompted the physiotherapist to refer the patient to the emergency department where she was diagnosed with lung cancer.

CONCLUSION

Differential diagnosis is a key component of PT practice. The ability to reproduce symptoms or achieve short-term symptomatic gains is not sufficient to rule out sinister pathology. This case demonstrates how extra caution should be taken in patients who are smokers with thoracolumbar region pain of unknown origin. The need for caution is magnified when one can achieve no more than short-term improvements in the patient's symptoms.

Metastatic index of non-small-cell lung cancer and long-term survival

Aim

We aimed to determine whether metastatic index is a factor determining long-term survival in patients undergoing curative resection for non-small-cell lung cancer.

Methods

There were 2695 consecutive pulmonary resections performed between October 2001 and September 2011 in our institution; 1795 were potentially curative resections for non-small-cell lung cancer with bronchial margin length data available. Benchmarking against the International Association for the Study of Lung Cancer data set was performed. Cox multivariate analysis was undertaken. Metastatic index was defined as N stage× bronchial resection margin length.

Results

Benchmarking failed to reveal any significant differences between our data and the International Association for the Study of Lung Cancer data set. Univariate analysis identified metastatic index as a significant factor determining long-term survival ( p = 0.04). Cox regression demonstrated that metastatic index (hazard ratio 1.29, p = 0.0002), age (hazard ratio 1.02, p < 0.0001), body mass index (hazard ratio 0.98, p = 0.006), female sex (hazard ratio 0.65, p < 0.0001), T1 stage (hazard ratio 0.67, p < 0.0001), T2 stage (hazard ratio 2.13, p < 0.0001), T3 stage (hazard ratio 1.59, p = 0.03), forced expiratory volume in 1 s (hazard ratio 0.70, p < 0.0001), pneumonectomy (hazard ratio 1.43, p = 0.001), histology subtype adenosquamous (hazard ratio 3.77, p = 0.01) and squamous (hazard ratio 0.83, p = 0.03) were all significant determinants of long-term survival.

Conclusion

Metastatic index is a significant factor determining long-term survival in patents with adenocarcinoma undergoing potentially curative surgery with a lobectomy.

Modeling the overall survival of patients with advanced-stage non-small cell lung cancer using data of routine laboratory tests

Cancer patients undergo routine clinical monitoring with an array of blood tests that may carry long-term prognostic information. We aimed to develop a new prognostic model predicting survival for patients with advanced non-small cell lung cancer (NSCLC), based on laboratory tests commonly performed in clinical practice. A cohort of 1,161 stage IIIB or IV NSCLC patients was divided into training (n = 773) and testing (n = 388) cohorts. We analyzed the associations of 32 commonly tested laboratory variables with patient survival in the training cohort. We developed a model based on those significant laboratory variables, together with important clinical variables. The model was then evaluated in the testing cohort. Five variables, including albumin, total protein, alkaline phosphatase, blood urea nitrogen and international normalized ratio, were significantly associated with patient survival after stepwise selection. A model incorporating these variables classified patients into low-, medium- and high-risk groups with median survival of 16.9, 7.2 and 2.1 months, respectively (p < 0.0001). Compared with low-risk group, patients in the medium- and high-risk groups had a significantly higher risk of death at 1 year, with hazard ratio (HR) of 1.95 (95% CI 1.62-2.36) and 5.22 (4.30-6.34), respectively. These results were validated in the testing cohort. Overall, we developed a prognostic model relying entirely on readily available variables, with similar predictive power to those which depend on more specialized and expensive molecular assays. Further study is necessary to validate and further refine this model, and compare its performance to models based on more specialized and expensive testing.

[Consequences of pneumonectomy in the early and late phases]

Pneumonectomy can represent the appropriate surgical treatment option in advanced or centrally localized non-small cell lung cancer (NSCLC). A satisfactory oncologic tumor surgery can be reached in these cases although pneumonectomy is associated with a significantly higher mortality and morbidity than less extensive resection of the lung parenchyma.The aim of this article is a systematic review and the presentation of possible postoperative consequences of pneumonectomy in the early and late phases, which depend not only on the underlying disease but are also primarily affected by the state and function of the remaining contralateral lung parenchyma. Cardiopulmonary complications, especially pneumonia, pulmonary embolism, cardiac arrhythmia or myocardial infarction lead to increased 30-day mortality in the early postoperative period. Moreover, advanced ages over 70 years can be identified as a significant risk factor for poor quality of life after pneumonectomy.

Characterizing gender differences in treatment seekers

BACKGROUND

Available evidence suggests women may be more vulnerable to the effects of chronic alcohol consumption than men. The few investigations of gender differences in treatment-seeking populations have often involved study samples restricted by selection criteria (e.g., age, education). The current study examined gender differences in a heterogeneous sample of individuals seeking treatment for a substance use disorder. We examined alcohol drinking levels, age at drinking milestones (e.g., first drink, first intoxication), and progression from milestones to alcohol problems or treatment. Additionally, family history, spousal alcoholism, and nicotine use were analyzed.

METHODS

Participants included men (n = 274) and women (n = 257) in substance abuse treatment facilities. Participants completed inventories quantifying affect, intellectual ability, and drinking consequences. A family tree for substance use and personal histories for alcohol and nicotine use, including chronicity, frequency, and regularity, were collected.

RESULTS

Telescoping was not observed when progression from drinking milestones to alcoholism or alcohol problems was compared between men and women. In contrast, when considered as progression to treatment, marked telescoping effects were detected, with women entering treatment more rapidly by approximately 4 years. Familial differences included a greater proportion of women reporting alcoholic parents (73% women; 61% men) and alcoholic spouses (58% women; 38% men). Smoking behaviors were similar between genders; however, men reporting higher levels of alcohol consumption reported greater intensity of chronic smoking. Smoking and drinking behaviors were correlated among men, but not women. Rates of pretreatment drug problems were equivalent between genders.

CONCLUSIONS

When contrasted with the available literature, our data were only partially supportive of gender-contingent telescoping. While women did not experience alcohol problems or alcoholism earlier than men, they progressed to treatment more quickly. These results highlight the importance of carefully considering the sample and specific outcome variables when interpreting gender differences.

Female sex and long-term survival post curative resection for non-small-cell lung cancer

OBJECTIVES

To determine whether patient sex has a significant effect on long-term outcomes post curative resection of non-small-cell lung cancer.

METHODS

We retrospectively analysed a prospectively validated thoracic surgery database (n = 4212), from a single institution, from September 2001 to October 2012. Univariate, Cox multivariate and propensity analysis was performed. Long-term follow-up was carried out via the National Strategic Tracing Service that operates in the United Kingdom.

RESULTS

One hundred per cent follow-up was achieved. Overall institutional in-hospital mortality was 2.0% for all thoracic resections. Median survival was 2.78 years (range 0-13 years). Two thousand two hundred and thirty-three males and 1979 females were included. Kaplan-Meier survival of all the patients demonstrated superior survival of females for all stages, P = 0.0003, and stage I, P = 0.0006. Female sex conferred no survival advantage in stage II, P = 0.7, and IIIa, P = 0.1. Sub-analysis by histological type demonstrated that females had superior survival with adenocarcinoma compared with males, P < 0.001, but no sex difference existed with squamous carcinomas, P = 0.2. Cox analyses demonstrated that female sex was an advantageous prognostic factor for the entire study group [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.69-0.96] and Stage I only (HR 0.70, 95% CI 0.57-0.63). Sex was of no significance in Stage II and IIIa disease with regard to survival. Sub-analysis demonstrated that female sex was not a significant factor determining survival in patients with squamous carcinoma; however, it was significantly associated with increased survival in patients with adenocarcinoma (HR 0.63, 95% CI 0.51-0.78). A 1:1 propensity analysis confirmed the above findings.

CONCLUSION

Propensity matching and Cox multivariate regression analysis confirmed the univariate finding that female sex is only associated with improved survival in patients with Stage I adenocarcinoma. Patient sex does not affect survival of patients with squamous carcinoma.

KRAS mutation in patients with lung cancer: a predictor for poor prognosis but not for EGFR-TKIs or chemotherapy

BACKGROUND

The prognostic and predictive value of KRAS mutations in patients with lung cancer is controversial. Biases in disease stage, treatment regimen, small-scale patient studies, and biomarker status have led to inconsistent results in previous reports.

METHODS

The KRAS and EGFR genes were examined in 1935 consecutive patients with non-small cell lung cancer. All patients were divided into KRAS mutation (KRAS group), EGFR mutation (EGFR group), and KRAS/EGFR wild type (WT group) groups. Randomly selected cases were paired with patients with the KRAS mutation, the EGFR mutation, and KRAS/EGFR wild type patients according to tumor, node, metastasis stage, time of first visit within 1 year, and pathology. Progression-free survival (PFS) and overall survival were evaluated by Kaplan-Meier and Cox models.

RESULTS

The KRAS mutation rate for lung adenocarcinoma was 5.90 %. The overall survival was 14.47, 20.57, and 42.73 months for the KRAS group, WT group, and EGFR group, respectively (P < 0.001). Multivariate analysis indicated that KRAS mutation status was an independent prognostic factor (hazard ratio 2.69, 95 % confidence interval 1.91-3.80, P < 0.001). No difference was found in PFS and tumor responsiveness between patients with a KRAS mutation and those with wild type KRAS/EGFR for chemotherapy and EGFR tyrosine kinase inhibitors (TKI). PFS did not significantly differ for chemotherapy among the three groups (P = 0.270).

CONCLUSIONS

KRAS mutation is a poor prognosis factor, but it is not an independent predictor of response to EGFR-TKI or chemotherapy in patients with lung cancer.