Low dose computed tomography scan (LDCT) screening versus empiric surveillance in asbestos exposed subjects: an update from the ATOM002 study

Transcription

1 Low dose computed tomography scan (LDCT) screening versus empiric surveillance in asbestos exposed subjects: an update from the ATOM002 study Gianpiero Fasola Dipartimento di Oncologia Azienda Sanitaria Universitaria Integrata di Udine 1

2 Disclosures The authors have no conflicts of interest I am a medical oncologist (not an epidemiologist) 2

3 Background Asbestos-related malignancies are a global health care issue Successful strategies to reduce mortality in asbestos exposed subjects are urgently needed Lung cancer is the most prevalent asbestos related malignancy, followed by pleural mesothelioma Low dose CT scan screening in asbestos exposed workers has been proven effective in detecting early stage lung cancer Fasola et al. 2007; Stayner et al. 2013; LaDou et al. 2013; McCormack et al. 2012; Ollier et al

4 4

5 Aimof the study To evaluate whether LDCT screening, compared with empiric health surveillance program, is effective in reducing mortality for lung cancer and/or malignant pleural mesothelioma in asbestos-exposed former workers 5

6 INTERNAL COMPARISON: P vs NP Relative mortality for all causes, all cancers, lung cancer and MPM by Cox Proportional Hazard Models Asbestos-exposed subjects under surveillance at the Occupational Health Unit in Monfalcone, Italy ATOM002 PARTICIPANTS (P) n = 926 ATOM002 NOT PARTICIPANTS (NP) n = 1507 Final models were adjusted for: smoking hx, age, level of asbestos exposure, comorbidity index EXTERNAL COMPARISON vs regional and national rates Standardized Incidence Rate Ratios (SIRs)* for all cancers, lung cancer, MPM Standardized Mortality Rate Ratios (SMRs)** for all cancers, lung cancer, MPM * To estimante SIRs we used Regional standard rates **To estimante SMRs we used both Regional (FVG) and Italian standard rates Prevalent cases of cancer at start of follow-up were excluded 6

7 Study Population Total ATOM002-P 1 ATOM002-NP 2 N % N % N % Total 2, , Characteristics Age at start of follow-up < median Smoking Habits Never Former Current Abestos exposure level Low Medium 1, Hight Charlson s Comorbidity Index 3 0 2, , Follow-up Total (person-years) 19, , , Mean (years) ATOM002 study participants (P) subcohort 2 ATOM002 study non-participants (NP) subcohort 3 Categorization of Charlsoncomorbidity index updated (Quan, H., et al, 2011) used as adjustment variable in final Cox proportional hazard models. 7

8 Results Incidence Person years (PY), observed (O) and expected (E) incident cases, standardized incidence rate (SIR) for each incident cause and 95% confidence interval among ATOM002-P and ATOM002-NP subjects. Follow Up Period FVG Standard Rates 1 ATOM002-P (n=926) ATOM002-NP (n=1,507) Cause of incidence ICD10 PY O E SIR 95% CI PY O E SIR 95% CI All Cancers C00-C43/ C45-C96 4, , Trachea, bronchus, lung C33-C34 4, , Malignant neoplasm of pleura C45 4, , Standard rate: age-specific incidence rates of FVG by AIRTUM (for years 2008 e 2009 are applied the age-specific incidence rates of

9 Results Standardized mortality ratios Observed (O) and Expected (E) Deaths, Standardized Mortality Ratios (SMR) for causes of death and 95% CI among ATOM002-P and ATOM002-NP subjects Follow Up Period * Italian Standard Rates 1 ATOM002-P (Person-year=8,045.51) ATOM002-NP (Person-year=11,617.75) Cause of Death ICD9 O E SMR_ITA 95% CI O E SMR_ITA 95% CI All Cause All Cancers Trachea, bronchus, lung Malignant neoplasm of pleura *Cohort of study: 2,433 subjects for 19,663,26 total person-years ; We used for standardization available rates of ICD-9 code ( ). 1 Standard rate: age-specific mortality rates of Italy for years and calculated from the data of mortality provided by the National Institute of Statistics (ISTAT) 9

10 Results Multivariate analysis: specific mortality risk reduction HR estimated in Cox Proporzional Hazard Models with CI 95% by cause of death and ATOM002 participation Univariate Multivariate Outcome ATOM002 Participation N. cases (%) HR CI95% HR CI95% All Causes 1 NP 256 (78.53) P 70 (21.47) All Cancers 1 NP 98 (69.01) P 44 (30.99) Lung Cancer 1 NP 50 (86.21) P 8 (13.79) Cancer of pleura 2 NP 11 (64.71) P 6 (35.29) Final multivariate models are adjusted for: a) Level of exposure to asbestos (High, Medium, Low); b)smoking Habits (Current, Former, Never); c) Age at Start of Follow-Up; d) Charlson-Quan Comorbidity Index 2 Final multivariate models are adjusted for: a) Sector of employment (Shipbuilding, Other); b) Age at Start of Follow-Up;c) Charlson-Quan Comorbidity Index 10

11 Open issues false positive findings anxiety unnecessary (invasive) diagnostic procedures overdiagnosis radiation exposure cost-effectiveness evaluation 11

12 Conclusions In our cohort, we register a noticeable 50% reduction in risk of death from lung cancer, compared with national figures Lung cancer mortality reduction is independent from smoking habits, level of asbestos exposure, age and comorbidities in multivariate analysis LDCT deserves to be evaluated in an international prospective randomized trial In the meantime LDCT could reasonably be considered within public surveillance programs for selected, high risk, population 12

13 Thankyoufor yourattention! 13

14 Current LDCT-screening recommendations among patients exposed to asbestos NCCN 2016 Lung Cancer Screening AATS 2012 Lung Cancer NCCN 2016 Malignant Pleural Mesothelioma ASCO 2012 Lung Cancer USPSTF 2014 Lung Cancer Individuals age > 50, with a smoking history > 20 pack-year and an additional risk factor (ex. asbestos exposure). Grade 2 A recommendation. Individuals age > 50, with a smoking history > 20 pack-year and additional comorbidity that produces a cumulative risk of developing lung cancer 5% in 5 year (ex. asbestos exposure). Screening is not recommended. None recommendation for lung cancer screening among asbestos exposed. None recommendation for lung cancer screening among asbestos exposed. 14

15 *29 subjects retrieved by link to the Regional Repository of micro-data ( ). ** Deleting prevalent cases for all cancers, excluded lung and pleura. The latter have already been excluded at start of follow up in ATOM study. BACK 15