Using Geospatial Analysis to Evaluate Access to Lung Cancer Screening in the United States

Abstract

BackgroundScreening current and former heavy smokers 55 to 80 years of age for lung cancer (LC) with low-dose chest CT scanning has been recommended by the United States Preventive Services Task Force since 2013. Although the number of screening facilities in the United States has increased, screening uptake has been slow.Research QuestionTo what extent is geographic access to screening facilities a barrier for screening uptake nationally?Study Design and MethodsScreening facilities were defined as American College of Radiology (ACR) Lung Cancer Screening Registry (LCSR) facilities. Analysis was performed at different geographic levels using a road network to calculate travel distances for the recommended age groups. Full access to screening was defined as the entire 55- to 79-year-old population being within 40 miles of an ACR LCSR facility. No access was defined as lack of access by the entire target population. Partial access was expressed in intervening quartiles. A geospatial approach then was used to integrate accessibility with smoking prevalence and LC mortality rates to identify potential focus areas visually.ResultsScreening facilities addresses were geocoded to identify 3,592 unique locations. Analysis of census tracts and aggregation to counties revealed that among 3,142 counties, adults 55 to 79 years of age have full access to an LC screening registry facility in 1,988 (63%) counties, partial access in 587 (19%) counties, and no access in 567 (18%) counties. Overall, less than 6% of those 55 to 79 years of age do not have access to registry screening facilities. Variation in screening facility access was noted across the United States, between states, and within some states.InterpretationIt is recommended to calculate accessibility using subcounty geographies and to examine variation regionally and within states. A foundation geographic accessibility layer can be integrated with other variables to identify geographic disparities in access to screening and to focus on areas for interventions. Identifying areas of greatest need can inform state and local officials and healthcare organizations when planning and implementing LC screening programs. Screening current and former heavy smokers 55 to 80 years of age for lung cancer (LC) with low-dose chest CT scanning has been recommended by the United States Preventive Services Task Force since 2013. Although the number of screening facilities in the United States has increased, screening uptake has been slow. To what extent is geographic access to screening facilities a barrier for screening uptake nationally? Screening facilities were defined as American College of Radiology (ACR) Lung Cancer Screening Registry (LCSR) facilities. Analysis was performed at different geographic levels using a road network to calculate travel distances for the recommended age groups. Full access to screening was defined as the entire 55- to 79-year-old population being within 40 miles of an ACR LCSR facility. No access was defined as lack of access by the entire target population. Partial access was expressed in intervening quartiles. A geospatial approach then was used to integrate accessibility with smoking prevalence and LC mortality rates to identify potential focus areas visually. Screening facilities addresses were geocoded to identify 3,592 unique locations. Analysis of census tracts and aggregation to counties revealed that among 3,142 counties, adults 55 to 79 years of age have full access to an LC screening registry facility in 1,988 (63%) counties, partial access in 587 (19%) counties, and no access in 567 (18%) counties. Overall, less than 6% of those 55 to 79 years of age do not have access to registry screening facilities. Variation in screening facility access was noted across the United States, between states, and within some states. It is recommended to calculate accessibility using subcounty geographies and to examine variation regionally and within states. A foundation geographic accessibility layer can be integrated with other variables to identify geographic disparities in access to screening and to focus on areas for interventions. Identifying areas of greatest need can inform state and local officials and healthcare organizations when planning and implementing LC screening programs. Take-home PointAlthough variation exists in the geographic distribution of screening facilities and disparities in access between states, the greater majority of the population 55 to 79 years of age has access (within 40 miles) to lung cancer screening (LCS). Although the rate of LCS seems to be increasing, current use is low. Geographic access should be evaluated in conjunction with other barriers, such as financial, cultural, educational, insurance coverage, and local transportation, to be able to tailor interventions to communities. Although variation exists in the geographic distribution of screening facilities and disparities in access between states, the greater majority of the population 55 to 79 years of age has access (within 40 miles) to lung cancer screening (LCS). Although the rate of LCS seems to be increasing, current use is low. Geographic access should be evaluated in conjunction with other barriers, such as financial, cultural, educational, insurance coverage, and local transportation, to be able to tailor interventions to communities. Lung cancer (LC) has been the leading cause of cancer deaths in the United States, contributing to more deaths in 2017 than breast, prostate, colorectal, and brain cancers combined.1Siegel R.L. Miller K.D. Jemal A. Cancer statistics, 2020.CA Cancer J Clin. 2020; 70: 7-30Crossref PubMed Scopus (9382) Google Scholar The poor 5-year survival rate (19%) is attributable to the high proportion of advanced-stage diagnoses.2American Cancer SocietyCancer Facts & Figures 2020. American Cancer Society, Atlanta, GA2020Google Scholar A more favorable stage distribution and reduction in mortality could be achieved if more high-risk adults underwent regular lung cancer screening (LCS). After the results of the National Lung Screening Trial were published in 2011, demonstrating a 20% relative reduction in mortality using annual low-dose CT (LDCT) screening compared with chest radiograph,3The National Lung Screening Trial Research TeamReduced lung-cancer mortality with low-dose computed tomographic screening.N Engl J Med. 2011; 365: 395-409Crossref PubMed Scopus (6156) Google Scholar professional organizations issued guidelines recommending LCS. In 2013, the United States Preventive Services Task Force (USPSTF) recommended LDCT screening in “adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years.”4United States Preventive Services Task ForceFinal recommendation statement: lung cancer: screening. December 2016.https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/lung-cancer-screeningDate accessed: December 28, 2018Google Scholar The recommendations paved the way for insurance coverage under the Affordable Care Act through private payors and subsequent coverage for Medicare beneficiaries in 2015.5Centers for Medicare & Medicaid Services. Decision memo for screening for lung cancer with low dose computed tomography (LDCT) (CAG-00439N). https://www.cms.gov/medicare-coverage-database/details/nca-decision-memo.aspx?NCAId=274#Top. Accessed December 28, 2018.Google Scholar The Centers for Medicare and Medicaid Services (CMS) made reimbursement contingent on facilities meeting eligibility requirements, including screening data submission to a CMS-approved LCS registry.5Centers for Medicare & Medicaid Services. Decision memo for screening for lung cancer with low dose computed tomography (LDCT) (CAG-00439N). https://www.cms.gov/medicare-coverage-database/details/nca-decision-memo.aspx?NCAId=274#Top. Accessed December 28, 2018.Google Scholar Currently, the only CMS-approved registry is the American College of Radiology (ACR) Lung Cancer Screening Registry (LCSR).6Centers for Medicare & Medicaid ServicesLung cancer screening registries. 2016.https://www.cms.gov/Medicare/Medicare-General-Information/MedicareApprovedFacilitie/Lung-Cancer-Screening-Registries.htmlDate accessed: December 27, 2018Google Scholar Despite recommendations for screening by the USPSTF,7United States Preventive Services Task ForceLung cancer: screening. 2013.https://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/lung-cancer-screeningDate accessed: January 15, 2020Google Scholar American Cancer Society,8Smith R.A. Andrews K.S. Brooks D. et al.Cancer screening in the United States, 2017: a review of current American Cancer Society guidelines and current issues in cancer screening.CA Cancer J Clin. 2017; 67: 100-121Crossref PubMed Scopus (280) Google Scholar National Comprehensive Cancer Network,9National Comprehensive Cancer Network Clinical Practice Guidelines in OncologyLung cancer screening. 2020.www.nccn.orgDate accessed: January 15, 2020Google Scholar and other organizations,10Division of Cancer Prevention and Control, Centers for Disease Control and PreventionLung cancer screening guidelines and recommendations. 2018.https://www.cdc.gov/cancer/lung/basic_info/screening.htmDate accessed: September 5, 2019Google Scholar LCS uptake remains low. A recent report estimated that in 2015, approximately 4% of the estimated 6.8 million eligible adults underwent an LDCT scan,11Jemal A. Fedewa S.A. Lung cancer screening with low-dose computed tomography in the united states—2010 to 2015.JAMA Oncol. 2017; 3: 1278-1281Crossref PubMed Scopus (292) Google Scholar and a state-level survey conducted in 2015 also reported low uptake of LCS examinations in ACR screening facilities.12Henderson L.M. Jones L.M. Marsh M.W. Benefield T. Rivera M.P. Molina P.L. Lung cancer screening practices in North Carolina CT facilities.J Am Coll Radiol. 2017; 14: 166-170Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar Data from 10 states representing 17.2% of the US population in the Behavioral Risk Factor Surveillance Survey, completing an optional module in 2017, indicated that 14.4% of eligible individuals reported undergoing LCS within the past year.13Zahnd W.E. Eberth J.M. Lung cancer screening utilization: a behavioral risk factor surveillance system analysis.Am J Prev Med. 2019; 57: 250-255Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar The implementation and adoption of new cancer screening tests typically is slow, evident by the adoption of mammography,14National Cancer InstituteCancer trends progress report. 2019.https://progressreport.cancer.gov/detection/breast_cancer#field_measureDate accessed: October 11, 2019Google Scholar and we expect an even more challenging implementation of LDCT screening programs. Compared with other tests, LCS requires a complex assessment of risk to determine eligibility, and although LCS is covered at no cost under the Affordable Care Act, many eligible adults face significant financial and insurance barriers,11Jemal A. Fedewa S.A. Lung cancer screening with low-dose computed tomography in the united states—2010 to 2015.JAMA Oncol. 2017; 3: 1278-1281Crossref PubMed Scopus (292) Google Scholar and evident variation exists in affordability, access to care, and the rate of uninsured patients associated with Medicaid expansion.15Takvorian S.U. Oganisian A. Mamtani R. et al.Association of Medicaid expansion under the Affordable Care Act with insurance status, cancer stage, and timely treatment among patients with breast, colon, and lung cancer.JAMA Netw Open. 2020; 3 (:e1921653.)Crossref PubMed Scopus (45) Google Scholar Additional unique requirements for reimbursement by CMS include a shared decision-making visit before a first screening.5Centers for Medicare & Medicaid Services. Decision memo for screening for lung cancer with low dose computed tomography (LDCT) (CAG-00439N). https://www.cms.gov/medicare-coverage-database/details/nca-decision-memo.aspx?NCAId=274#Top. Accessed December 28, 2018.Google Scholar The stigma and nihilism surrounding LC and smoking have been identified as barriers to seeking preventive care.16Hamann H.A. Ver Hoeve E.S. Carter-Harris L. Studts J.L. Ostroff J.S. Multilevel opportunities to address lung cancer stigma across the cancer control continuum.J Thorac Oncol. 2018; 13: 1062-1075Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar Finally, geographic access, smoking prevalence, and the burden of disease vary in urban and rural areas and should be considered when planning and implementing screening programs.17Drope J. Liber A.C. Cahn Z. et al.Who’s still smoking? Disparities in adult cigarette smoking prevalence in the United States.CA Cancer J Clin. 2018; 68: 106-115Crossref PubMed Scopus (150) Google Scholar,18Tailor T.D. Choudhury K.R. Tong B.C. Christensen J.D. Sosa J.A. Rubin G.D. Geographic access to CT for lung cancer screening: a census tract-level analysis of cigarette smoking in the United States and driving distance to a CT facility.J Am Coll Radiol. 2019; 16: 15-23Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar reported state-level access to LCS favorable with facility and eligible also reported disparities in access in rural to lung cancer screening analysis of geographic distribution using the ACR Lung Cancer Screening Am Coll Radiol. 2017; 14: Full Text Full Text PDF PubMed Scopus Google J.M. L.M. et of low-dose computed tomography for lung cancer screening in the United States, 2018; PubMed Scopus Google Scholar et R. Miller Jemal A. Cancer statistics, Cancer J Clin. 2019; PubMed Scopus Google Scholar that although in cancer mortality rates a burden of cancers exists among of the counties. state-level data significant disparities in we evaluated and reported accessibility at the state and the is for and A geospatial approach was used to accessibility to LCS facilities by distances between population and facilities. used geographic to and of facilities to potential to identify in to and to inform and T.D. Choudhury K.R. Tong B.C. Christensen J.D. Sosa J.A. Rubin G.D. Geographic access to CT for lung cancer screening: a census tract-level analysis of cigarette smoking in the United States and driving distance to a CT facility.J Am Coll Radiol. 2019; 16: 15-23Abstract Full Text Full Text PDF PubMed Scopus (18) Google R. et and distance barriers to facilities in the 2011; PubMed Scopus Google D. distance to facilities and stage at of cancer in PubMed Scopus Google Scholar analysis was using were evaluated for using Screening facilities used those in some of have as ACR Lung Cancer Screening Centers a of the CT screening College of lung cancer screening accessed: January 15, 2020Google Scholar Although we also and identify ACR the results focus on ACR LCSR facilities that access to screening. ACR LCSR facilities was by the ACR and an ACR was from the ACR College of facility Scholar and census population were from the US States 5-year age and accessed: 2018Google Scholar The through for age from 55 to 79 years were used to the eligible population identified by the on of the Preventive Services Task for lung cancer: US Preventive Services Task Force recommendation Med. PubMed Google Scholar and for Medicare & Medicaid Services. Decision memo for screening for lung cancer with low dose computed tomography (LDCT) (CAG-00439N). https://www.cms.gov/medicare-coverage-database/details/nca-decision-memo.aspx?NCAId=274#Top. Accessed December 28, 2018.Google Scholar used for analysis and of of subcounty tracts subcounty geographic that more analysis and have been used to examine access to A of driving distance distance to PubMed Google Scholar access to facilities using counties and census tracts and compared the results to inform US 3,142 counties and census US population data and Behavioral Risk Factor Surveillance adult smoking prevalence data were used to the population. The of adults years of age and smoking by was from the & for Disease Control and risk factor accessed: December 2018Google & accessed: December 2018Google Scholar smoking is of the adult population in a who report that currently smoke or and have at in and of & more adult accessed: December 2018Google Scholar The of smokers eligible for screening is to address smoking prevalence as a for with adults who for LCS under the The through 2015 LC rates for those years of age and were in December from the National Cancer Cancer cancer Scholar is the of addresses M.P. J. et in cancer a J Prev Med. Full Text Full Text PDF PubMed Scopus Google Scholar Screening facilities were geocoded and used to calculate access on The from facilities areas screening facility. The from population distances from of counties and census tracts to facilities. distances and can be estimated using distance or the road network distance is a more of R. et and distance barriers to facilities in the 2011; PubMed Scopus Google D. distance to facilities and stage at of cancer in PubMed Scopus Google Scholar The of to network distance to determine eligibility for the of distance eligibility for the Google Scholar distance used the road network and a to distance was by the of for distance to the of distance eligibility for the Google Scholar and with the American Cancer eligibility for and considered the age 55 to 79 of the distance to as A distance was used for A by the is in by facility on the proportion of the population of the or census within the It distribution of population within the that not be The of the for can or no access within the Full access that the entire population 55 to 79 years of age has access to at facility within 40 of the population within 40 miles from a facility that proportion can be to the partial access of the population within the travel distances from a to facilities by the between and facilities in or the is within the defined the analysis include the entire population of the that not within the access when of the is within the the is The of the is full or no access for the the for from census tracts to counties, partial access can be by the population within the census that has access to the and by the entire population 55 to 79 years of age within the distances and also were and were reported for counties, census and census tracts to counties. of and distance to facilities and facility were by the and the distance and at the and levels and then for census tracts to counties were first from census and distance or then census results by associated distance or and then counties also to the geographies on the number of 55 to 79 years of age with To address geographic we identified geographic focus areas first by accessibility with smoking prevalence and then with LC mortality areas with high smoking prevalence and low access to screening were identified using accessibility as a foundation Although of the population used to inform population is to identify focus areas for implementing programs. In the United States, the of current smokers has more than the number of current smokers of population J. Liber A.C. Cahn Z. et al.Who’s still smoking? Disparities in adult cigarette smoking prevalence in the United States.CA Cancer J Clin. 2018; 68: 106-115Crossref PubMed Scopus (150) Google Scholar smoking prevalence was used to the number of access of estimated smokers is integrated with mortality to identify areas of low high smoking prevalence, and high mortality The on of the from low to high and with a of in the of the the to identify areas of on the we a of 3,592 unique ACR LCSR and ACR a of LCS facilities in the United States and coverage of ACR compared with ACR across the accessibility to ACR LCSR facilities was as the of the population 55 to 79 years of age who have access and treatment the and state accessibility at the and levels and compared the results with census results an in accessibility for ACR LCSR facilities using the and a of less than using the analysis to the number of not were within 40 miles from compared with more results using compared with counties and focus areas on the results of the at the then and reported by counties. The results of the with the at the in A of and results is and can be in of counties and of census tracts have access to ACR LCSR attributable to counties with more census tracts in urban areas with The travel distances to facilities and to the facility is when at the and compared with census tracts and and is for and for counties and and for census with a number of with access considered in is when using population with access as census tracts to counties, the distances to be to the results as at the results to the travel distance to facilities is miles miles for and miles miles for census travel to the and the number of facilities within 40 miles a for planning can vary for the distance of of and other evaluated access across urban and rural geographies and to a report the that of in access across rural geographies in a report. 3 in access between states and within some states. In states and counties full access and areas no were for partial access full and no A of greater access in the is at and state with the of screening facilities a between states and of the and have access to screening compared with other states is in the still have high access of more than with noted within the states that need to be evaluated at the and North and have the rates than of access to screening. variation is in the of the including the of states from North to that have counties with full variation exists in the of the for and A of accessibility that 1,988 counties (63%) have full access to ACR LCSR 587 counties (19%) have partial access, and 567 counties (18%) have no Overall, of 55 to 79 years of age do not have access to ACR LCSR screening facilities. is not for smoking history and other recommendations for screening smoking prevalence for Disease Control and and accessed: 2019Google Scholar and smoking rates from more than to and of & more adult accessed: December 2018Google Scholar is a accessibility as the estimated number of with no access to a screening facility and smoking prevalence The of the number of of to access and The in smoking the layer the estimated number of smokers 55 to 79 years of age with no access to ACR LCSR facilities. In counties with the access and the of adult and counties with the access or no access to facilities and the of adult with no access and counties with no or low access and high smoking prevalence geographic in states including counties in and in and and the of the in and and counties in and counties with low or no access identified in 3 not identified as focus areas low smoking prevalence and in states of the trends in the in and the Compared with the rates in new areas in in and Although and have the state smoking prevalence rates and for Disease Control and and accessed: 2019Google Scholar more counties in as focus areas in of the number of smokers with no of using rates to identify and focus areas be on the mortality the estimated number of smokers 55 to 79 years of age with no access to an ACR LCSR facility and mortality rates counties with the access and the mortality and counties with the access or no access to facilities and the mortality and areas as areas of high mortality rates and high of estimated smokers with no access to screening. geographic areas across the variables and can be considered focus areas for include counties in and the and counties across the interventions should be considered for areas with high access and high mortality rates such as a screening to stage on access to screening facilities as a first a screening a and is recommended to use subcounty geographies for analysis to subcounty T.D. Choudhury K.R. Tong B.C. Christensen J.D. Sosa J.A. Rubin G.D. Geographic access to CT for lung cancer screening: a census tract-level analysis of cigarette smoking in the United States and driving distance to a CT facility.J Am Coll Radiol. 2019; 16: 15-23Abstract Full Text Full Text PDF PubMed Scopus (18) Google L. R. A. to and a for in and of 2018; Scopus Google Scholar analysis that more than of 55 to 79 years of age do not have access to an ACR LCSR facility. A exists of access in states and greater variation in access in the and of access in some states in the and interventions should be analysis of accessibility within miles revealed that to of 55 to 79 years of age do not have access to ACR LCSR screening facilities. analysis across geographies at different distances areas of those with of estimated smokers who do not have access to screening and areas with high mortality rates as and of geographic areas as potential focus areas and when and should be with high mortality rates and high of estimated with access to screening a potential for areas with screening from such as and access for adults analysis could integrate variables or in areas to focus planning in facilities LDCT screening not in the ACR of facilities more than million States of accessed: January 2020Google Scholar many of current or former States of and accessed: Scholar and facilities that do not Medicare patients not to data in the ACR the number of LCS facilities is access be ACR LCSR facilities still screening and the geographic distribution of screening locations. No exists of the number of cigarette a of smoking across age or the number of who we used estimated population data and adult smoking prevalence to the eligible not include former as a for current and former rates in some counties The geospatial analysis has associated with representing by of population as as potential from those to facilities. that patients the and facilities within 40 miles were considered of of access to that patients used facilities within a of the distance to the facility is for accessibility and J. J.M. R.A. et the facility the assessment of travel on J PubMed Scopus Google Scholar also not address screening and other barriers such as financial, cultural, educational, insurance coverage, and local geographic access not insurance coverage or a facility screening to uninsured is variation in the geographic distribution of screening facilities and disparities in access between states. should examine accessibility regionally and within states to focus interventions on communities. issues not LCSR and rural access in some states.

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