Lung cancer and socio-economic status: inextricably linked to place of residence

Smoking status and the association between patient-level factors and survival among lung cancer patients

BACKGROUND

Declines in the prevalence of cigarette smoking, advances in targeted therapies, and implementation of lung cancer screening have changed the clinical landscape for lung cancer. The proportion of lung cancer deaths is increasing in those who have never smoked cigarettes. To better understand contemporary patterns in survival among patients with lung cancer, a comprehensive evaluation of factors associated with survival, including differential associations by smoking status, is needed.

METHODS

Patients diagnosed with lung cancer between January 1, 2010, and September 30, 2019, were identified. We estimated all-cause and lung cancer-specific median, 5-year, and multivariable restricted mean survival time (RMST) to identify demographic, socioeconomic, and clinical factors associated with survival, overall and stratified by smoking status (never, former, and current).

RESULTS

Analyses included 6813 patients with lung cancer: 13.9% never smoked, 54.2% formerly smoked, and 31.9% currently smoked. All-cause RMST through 5 years for those who never, formerly, and currently smoked was 32.1, 25.9, and 23.3 months, respectively. Lung cancer-specific RMST was 36.3 months, 30.3 months, and 26.0 months, respectively. Across most models, female sex, younger age, higher socioeconomic measures, first-course surgery, histology, and body mass index were positively associated, and higher stage was inversely associated with survival. Relative to White patients, Black patients had increased survival among those who formerly smoked.

CONCLUSIONS

We identify actionable factors associated with survival between those who never, formerly, and currently smoked cigarettes. These findings illuminate opportunities to address underlying mechanisms driving lung cancer progression, including use of first-course treatment, and enhanced implementation of tailored smoking cessation interventions for individuals diagnosed with cancer.

Association between socioeconomic status and net survival after primary lung cancer surgery: a tertiary university hospital retrospective observational study in Japan

BACKGROUND

Inequalities in opportunities for primary lung cancer surgery due to socioeconomic status exist. We investigated whether socioeconomic inequalities exist in net survival after curative intent surgery at a tertiary university hospital, in Japan.

METHODS

Data from the hospital-based cancer registry on primary lung cancer patients who received lung resection between 2010 and 2018 were linked to the surgical dataset. An area deprivation index, calculated from small area statistics and ranked into tertiles based on Japan-wide distribution, was linked with the patient's address as a proxy measure for individual socioeconomic status. We estimated net survival of up to 5 years by deprivation tertiles. Socioeconomic inequalities in cancer survival were analyzed using an excess hazard model.

RESULTS

Of the 1039 patient-sample, advanced stage (Stage IIIA+) was more prevalent in the most deprived group (28.1%) than the least deprived group (18.0%). The 5-year net survival rates (95% confidence interval) from the least to the most deprived tertiles were 82.1% (76.2-86.6), 77.6% (70.8-83.0) and 71.4% (62.7-78.4), respectively. The sex- and age-adjusted excess hazard ratio of 5-year death was significantly higher in the most deprived group than the least deprived (excess hazard ratio = 1.64, 95% confidence interval: 1.09-2.47). The hazard ratio reduced toward null after additionally accounting for disease stage, suggesting that the advanced stage may explain the poor prognosis among the deprived group.

CONCLUSION

There was socioeconomic inequality in the net survival of patients who received curative intent surgery for primary lung cancer. The lower socioeconomic status group might be less likely to receive early curative surgery.

Mendelian randomization to explore the direct or mediating associations between socioeconomic status and lung cancer

Objective

The purpose of this study was to verify whether there are direct or mediated causal associations between socioeconomic status and lung cancer.

Methods

Pooled statistics were obtained from corresponding genome-wide association studies. The inverse-variance weighted, weighted median, MR-Egger, MR-PRESSO and contamination-mixture methods were used as supplements to Mendelian randomization (MR) statistical analysis. Cochrane's Q value and the MR-Egger intercept were used for sensitivity analysis.

Results

In the univariate MR analysis, household income and education had protective effects on overall lung cancer (income: P = 5.46×10^-4; education: P = 4.79×10^-7) and squamous cell lung cancer (income: P = 2.67×10^-3; education: P = 1.42×10^-10). Smoking and BMI had adverse effects on overall lung cancer (smoking: P = 2.10×10^-7; BMI: P = 5.67×10^-4) and squamous cell lung cancer (smoking: P = 5.02×10^-6; BMI: P = 2.03×10^-7). Multivariate MR analysis found that smoking and education were independent risk factors for overall lung cancer (smoking: P = 1.96×10^-7; education: P = 3.11×10^-3), while smoking was an independent risk factor for squamous cell lung cancer (P = 2.35×10^-6). Smoking, education, and household income mediate the effect of BMI on overall lung cancer (smoking 50.0%, education 49.2%, income 25.3%) and squamous cell lung cancer (smoking 34.8%, education 30.8%, income 21.2%). Smoking, education, and BMI mediate the effect of income on overall lung cancer (smoking 13.9%, education 54.8%, BMI 9.4%) and squamous cell lung cancer (smoking 12.6%, education 63.3%, BMI 11.6%). Smoking, BMI, and income mediate the effect of education on squamous cell lung cancer (smoking 24.0%, BMI 6.2%, income 19.4%).

Conclusion

Income, education, BMI, and smoking are causally associated with both overall lung cancer and squamous cell lung cancer. Smoking and education are independent association factors for overall lung cancer, while smoking is an independent association factor for squamous cell lung cancer. Smoking and education also play important mediating roles in overall lung cancer and squamous cell lung cancer. No causal relationship was found between multiple risk factors associated with socioeconomic status and lung adenocarcinoma.

Impact of socioeconomic status on cancer staging, survival in non-small cell lung cancer

Purpose

We performed this study to evaluate the association of socioeconomic status (SES) factors with cancer-specific survival (CSS) of patients with non-small cell lung cancer (NSCLC). We further assessed the predictive value of a novel Tumor Node Metastasis (TNM)-SES staging system, combining the TNM stage with the SES stage.

Methods

Using the Surveillance, Epidemiology, and End Results (SEER) database, we selected 40,378 patients diagnosed with NSCLC from 2012 to 2016. Cox regression method and Harrell's concordance index (C-index) were performed to select the SES factors related to CSS and evaluate the predictive ability of the novel TNM-SES stage. We used Kaplan-Meier curves and a log-rank test to conduct a survival analysis.

Results

We identified four SES factors (marriage, insurance, education, and household income) associated with CSS and constructed the SES stage (SES-1 and SES-2). NSCLC patients with SES-2 stage (low SES) was associated with young adult, black race, male, squamous carcinoma, upper lobe site, and advanced stage. SES-2 stage patients were significantly associated with a dismal prognosis of patients with NSCLC, with a 21.0% increased risk (HR = 1.21, 95%CI (1.18-1.24), p < 0.001). The C-index of our novel TNM-SES stage was 0.732 [95% CI (0.728-0.736)], higher than the traditional TNM stage [0.717, 95% CI (0.715-0.719)], indicating superior predictive value.

Conclusion

Our population-based study indicated that SES was significantly associated with cancer staging and SCC in patients with NSCLC. Our novel TNM-SES staging system showed a superior predictive value to the traditional TNM stage. The impact of SES on patients with NSCLC should receive more concern in clinical management.

Socioeconomic Differences and Lung Cancer Survival-Systematic Review and Meta-Analysis

Background: The impact of socioeconomic differences on cancer survival has been investigated for several cancer types showing lower cancer survival in patients from lower socioeconomic groups. However, little is known about the relation between the strength of association and the level of adjustment and level of aggregation of the socioeconomic status measure. Here, we conduct the first systematic review and meta-analysis on the association of individual and area-based measures of socioeconomic status with lung cancer survival.

Methods: In accordance with PRISMA guidelines, we searched for studies on socioeconomic differences in lung cancer survival in four electronic databases. A study was included if it reported a measure of survival in relation to education, income, occupation, or composite measures (indices). If possible, meta-analyses were conducted for studies reporting on individual and area-based socioeconomic measures.

Results: We included 94 studies in the review, of which 23 measured socioeconomic status on an individual level and 71 on an area-based level. Seventeen studies were eligible to be included in the meta-analyses. The meta-analyses revealed a poorer prognosis for patients with low individual income (pooled hazard ratio: 1.13, 95 % confidence interval: 1.08–1.19, reference: high income), but not for individual education. Group comparisons for hazard ratios of area-based studies indicated a poorer prognosis for lower socioeconomic groups, irrespective of the socioeconomic measure. In most studies, reported 1-, 3-, and 5-year survival rates across socioeconomic status groups showed decreasing rates with decreasing socioeconomic status for both individual and area-based measures. We cannot confirm a consistent relationship between level of aggregation and effect size, however, comparability across studies was hampered by heterogeneous reporting of socioeconomic status and survival measures. Only eight studies considered smoking status in the analysis.

Conclusions: Our findings suggest a weak positive association between individual income and lung cancer survival. Studies reporting on socioeconomic differences in lung cancer survival should consider including smoking status of the patients in their analysis and to stratify by relevant prognostic factors to further explore the reasons for socioeconomic differences. A common definition for socioeconomic status measures is desirable to further enhance comparisons between nations and across different levels of aggregation.

Achieving Thoracic Oncology data collection in Europe: a precursor study in 35 Countries

BACKGROUND

A minority of European countries have participated in international comparisons with high level data on lung cancer. However, the nature and extent of data collection across the continent is simply unknown, and without accurate data collection it is not possible to compare practice and set benchmarks to which lung cancer services can aspire.

METHODS

Using an established network of lung cancer specialists in 37 European countries, a survey was distributed in December 2014. The results relate to current practice in each country at the time, early 2015. The results were compiled and then verified with co-authors over the following months.

RESULTS

Thirty-five completed surveys were received which describe a range of current practice for lung cancer data collection. Thirty countries have data collection at the national level, but this is not so in Albania, Bosnia-Herzegovina, Italy, Spain and Switzerland. Data collection varied from paper records with no survival analysis, to well-established electronic databases with links to census data and survival analyses.

CONCLUSION

Using a network of committed clinicians, we have gathered validated comparative data reporting an observed difference in data collection mechanisms across Europe. We have identified the need to develop a well-designed dataset, whilst acknowledging what is feasible within each country, and aspiring to collect high quality data for clinical research.

ERS statement on harmonised standards for lung cancer registration and lung cancer services in Europe

The European Respiratory Society (ERS) task force for harmonised standards for lung cancer registration and lung cancer services in Europe recognised the need to create a single dataset for use in pan-European data collection and a manual of standards for European lung cancer services.

The multidisciplinary task force considered evidence from two different sources, reviewing existing national and international datasets alongside the results of a survey of clinical data collection on lung cancer in 35 European countries. A similar process was followed for the manual of lung cancer services, with the task force using existing guidelines and national or international recommendations for lung cancer services to develop a manual of standards for services in Europe.

The task force developed essential and minimum datasets for lung cancer registration to enable all countries to collect the same essential data and some to collect data with greater detail. The task force also developed a manual specifying standards for lung cancer services in Europe.

Despite the wide variation in the sociopolitical landscape across Europe, the ERS is determined to encourage the delivery of high-quality lung cancer care. Both the manual of lung cancer services and the minimum dataset for lung cancer registration will support this aspiration.

Rural dwellers are less likely to survive cancer - An international review and meta-analysis

BACKGROUND

Existing research from several countries has suggested that rural-dwellers may have poorer cancer survival than urban-dwellers. However, to date, the global literature has not been systematically reviewed to determine whether a rural cancer survival disadvantage is a global phenomenon.

METHODS

Medline, CINAHL, and EMBASE were searched for studies comparing rural and urban cancer survival. At least two authors independently screened and selected studies. We included epidemiological studies comparing cancer survival between urban and rural residents (however defined) that also took socioeconomic status into account. A meta-analysis was conducted using 11 studies with binary rural:urban classifications to determine the magnitude and direction of the association between rurality and differences in cancer survival. The mechanisms for urban-rural cancer survival differences reported were narratively synthesised in all 39 studies.

FINDINGS

39 studies were included in this review. All were retrospective observational studies conducted in developed countries. Rural-dwellers were significantly more likely to die when they developed cancer compared to urban-dwellers (HR 1.05 (95% CI 1.02 - 1.07). Potential mechanisms were aggregated into an ecological model under the following themes: Patient Level Characteristics; Institutions; Community, Culture and Environment; Policy and Service Organization.

INTERPRETATION

Rural residents were 5% less likely to survive cancer. This effect was consistently observed across studies conducted in various geographical regions and using multiple definitions of rurality. High quality mixed-methods research is required to comprehensively evaluate the underlying factors. We have proposed an ecological model to provide a coherent framework for future explanatory research.

FUNDING

None.

Does presentation at multidisciplinary team meetings improve lung cancer survival? Findings from a consecutive cohort study

BACKGROUND

Multidisciplinary team (MDT) presentation in lung cancer has the potential to improve longterm outcomes, although this varies between studies. This study aims to evaluate outcomes including survival, according to MDT presentation and to explore the utility of data obtained from local clinical sources.

PATIENTS AND METHODS

Prospective cases of lung cancer recorded in our institution's cancer registry were analyzed according to MDT presentation for patient and tumour characteristics, adjusted survival and referral to palliative care.

RESULTS

1197 cases were included, 295 (24.6%) with MDT presentation and 902 (75.4%) without. 60% of patients were male with median (IQR) age at diagnosis of 70 years (62-78). Histopathology distribution (non-small cell lung cancer and small-cell lung cancer) was similar between the two groups. Compared with the non-MDT group, the MDT group had (1) ECOG score recorded more often (71.9% vs. 47.6%), (2) higher proportion of ECOG 0 cases (31.2% vs. 11.9%) and ECOG 1 cases (28.8% vs. 20.3%), (3) higher proportion of early stage disease (stage I - 23.1% vs. 9.7% stage II - 10.2% vs. 4.8%, stage IIIA - 14.6% vs 6.3%) and (4) lower proportion of metastatic disease (stage IV - 39.3% vs. 56.1%). Referral to palliative care was incompletely recorded in both groups (MDT: n = 116/295, 39.3%; non-MDT: n = 430, 47.7%) but did not differ significantly for stage IV cases. Survival analyzed by stage was greater in the MDT group at 1, 2 and 5 years for all stages except stage IIIB at 1 year post-diagnosis. Adjusted survival analysis for the entire cohort showed improved survival at 5 years for the MDT group (HR 0.7 (0.58-0.85), p < 0.001).

CONCLUSION

MDT presentation is associated with improved adjusted survival for lung cancer in this single institutional cohort in an analysis of local clinical cancer registry data.