Eric A Miller

Contrasts in colorectal cancer incidence and mortality in screening trials of sigmoidoscopy vs the Nordic-European Initiative on Colorectal Cancer colonoscopy trial

Abstract Background Interim 10-year results from the Nordic-European Initiative on Colorectal Cancer (NordICC), a randomized controlled trial (RCT) of screening colonoscopy, demonstrated a statistically significant reduction in colorectal cancer (CRC) incidence but not mortality, contrary to results from 4 flexible sigmoidoscopy RCTs. Methods We constructed CRC incidence and mortality Kaplan–Meier curves through 10 years to standardize comparisons across RCTs and examined CRC screen detection and stage. Novel analyses of 1 flexible sigmoidoscopy RCT (Prostate, Lung, Colorectal, and Ovarian cancer screening trial [PLCO]) assessed year-by-year mortality in screen-detected CRCs. Results At 10 years, all RCTs demonstrated statistically significant CRC incidence reductions with screening (ratio = 0.77, 95% confidence interval [CI] = 0.70 to 0.84, to ratio = 0.82, 95% CI = 0.69 to 0.97, vs control arm; P ≤ .011). Two flexible sigmoidoscopy RCTs and NordICC showed no statistically significant CRC mortality reduction (ratio = 0.84, 95% CI = 0.64 to 1.10, to ratio = 0.90, 95% CI = 0.69 to 1.18; P = .10-0.23). In 3 flexible sigmoidoscopy RCTs and NordICC, relative reductions were greater in CRC incidence than CRC mortality, but only NordICC reported higher CRC mortality with screening vs the control arm for the first 7 years. In contrast, PLCO observed fewer CRC deaths with screening by year 2 (ratio = 0.59; P = .03), and screen-detected CRCs were less often advanced (odds ratio = 0.26; P < .001) or fatal (ratio = 0.50; P < .001). Conclusions After 10 years, NordICC is similar to 2 flexible sigmoidoscopy RCTs in observing statistically significant reductions in CRC incidence but not CRC mortality. However, only NordICC observed greater CRC mortality with screening vs the control arm for 7 years. Granular analyses of CRC cases and deaths in NordICC, paralleling our PLCO analyses, could provide insight into why CRC mortality results differ in NordICC vs flexible sigmoidoscopy RCTs.

Healthcare Access, Utilization, and Preventive Health Behaviors by Eligibility for Lung Cancer Screening

In 2013, the US Preventive Services Task Force recommended low-dose computed tomography screening for smokers at high risk of lung cancer; however, use remains low. Efforts to promote lung cancer screening need to consider how receptive this population is to preventive healthcare and cancer screening. In addition, because of demonstrated heterogeneity in behaviors by smoking status, interventions may need to differ among eligible high-risk subgroups. To assess the engagement of high-risk smokers in other preventive healthcare behaviors, we examined healthcare use, including non-lung cancer screening, and healthcare provider discussions regarding screening by eligibility for lung cancer screening. We used the 2015 National Health Interview Survey to assess smoking history, healthcare use, cancer screening, vaccinations, and healthcare provider discussions regarding non-lung cancer screening. We calculated weighted prevalence estimates and prevalence ratios comparing eligible and ineligible current and former smokers to never smokers. Eligible current and former smokers had significantly different healthcare utilization and screening concordance compared to never smokers and to each other. Compared to never smokers, eligible current smokers were significantly less likely to be concordant with breast, colorectal, and cervical cancer screening while eligible former smokers were only less likely to be concordant with breast cancer screening. Eligible current smokers were less likely to report physician discussions about non-lung screening tests. Provider discussions about screening and engagement in preventive healthcare differed among current and former smokers eligible for lung cancer screening. Intervention efforts to increase lung cancer screening levels will likely need to differ as well.

Cervical cancer screening and predictors of screening by diabetes status

Women with diabetes have lower survival rates after a cervical cancer diagnosis compared to women without diabetes. Pap smears and human papilloma virus (HPV) testing are highly effective screening tests for cervical cancer, therefore, it is important to know the prevalence of guideline-concordant screening among women with diabetes and understand if their predictors of screening differ. The purpose of this analysis was to assess guideline-concordant cervical cancer screening and predictors by diabetes status. We used the 2019 National Health Interview Survey data, limited to women aged 21-65 years without a previous diagnosis of cancer, a hysterectomy, or diagnosed with diabetes in the year prior to the survey. We considered the Pap and HPV tests together and concordance as being tested within the past 3 years as part of a routine exam. We calculated weighted, adjusted prevalence, and prevalence ratios (PRs) of screening concordance comparing women with diabetes to those without. The unadjusted prevalence of concordant screening was 66.5% for women with diabetes compared to 73.3% for women without diabetes (PR = 0.91 95% CI 0.84-0.98). In the fully adjusted model adjusting for factors known to be associated with diabetes and access to healthcare, the association was attenuated and no longer statistically significant (PR = 0.96 95% CI 0.89-1.04). Cervical cancer screening concordance was lower in women with diabetes compared to those without overall but the deficit appears to be due primarily to underlying differences in sociodemographic characteristics and access to healthcare and not diabetes independently.