Impact of changes to the interscreening interval and faecal immunochemical test threshold in the national bowel cancer screening programme in England: results from the FIT pilot study

INTRODUCTION

The NHS Bowel Cancer Screening Programme (BCSP) faces endoscopy capacity challenges from the COVID-19 pandemic and plans to lower the screening starting age. This may necessitate modifying the interscreening interval or threshold.

METHODS

We analysed data from the English Faecal Immunochemical Testing (FIT) pilot, comprising 27,238 individuals aged 59-75, screened for colorectal cancer (CRC) using FIT. We estimated screening sensitivity to CRC, adenomas, advanced adenomas (AA) and mean sojourn time of each pathology by faecal haemoglobin (f-Hb) thresholds, then predicted the detection of these abnormalities by interscreening interval and f-Hb threshold.

RESULTS

Current 2-yearly screening with a f-Hb threshold of 120 μg/g was estimated to generate 16,092 colonoscopies, prevent 186 CRCs, detect 1142 CRCs, 7086 adenomas and 4259 AAs per 100,000 screened over 15 years. A higher threshold at 180 μg/g would reduce required colonoscopies to 11,500, prevent 131 CRCs, detect 1077 CRCs, 4961 adenomas and 3184 AAs. A longer interscreening interval of 3 years would reduce required colonoscopies to 10,283, prevent 126 and detect 909 CRCs, 4796 adenomas and 2986 AAs.

CONCLUSION

Increasing the f-Hb threshold was estimated to be more efficient than increasing the interscreening interval regarding overall colonoscopies per screen-benefited cancer. Increasing the interval was more efficient regarding colonoscopies per cancer prevented.

Classifying interval cancers as false negatives or newly occurring in fecal immunochemical testing

OBJECTIVE

To classify interval colorectal cancers as false negatives or newly occurring cases in a biennial Fecal immunochemical test (FIT) screening program and by various interscreening intervals.

SETTING

Data from the Taiwanese biennial colorectal cancer screening program involving FIT from 2004 to 2014 were used to estimate the incidence rate of asymptomatic colorectal cancer and the rate of its subsequent progression to clinical mode.

METHODS

The sensitivity of detecting asymptomatic colorectal cancers excluding newly developed colorectal cancers was compared to the conventional estimate of sensitivity, the complementary FIT interval cancer rate as a percentage of the expected incidence rate ((1-I/E)%). The relative contribution of newly developed or false-negative cases to FIT interval colorectal cancers was estimated by age and interscreening intervals.

RESULTS

The Taiwanese biennial fecal immunochemical test screening program had a conventional sensitivity estimate of 70.2%. After newly developed colorectal cancers were separated from FIT interval cancers, the ability to detect asymptomatic colorectal cancers increased to 75.5%. FIT interval colorectal cancers from the biennial program mainly resulted from newly developed colorectal cancers (68.8%). The corresponding figures decreased to 61.1% for the annual program but increased to 74.7% for the triennial program. The preponderance of newly developed colorectal cancers among FIT interval cancers was more prominent in screenees aged 50-59  than in those aged 60-69.

CONCLUSIONS

Newly developed colorectal cancers showed a predominance among the FIT interval colorectal cancers in particular in the younger population screened. It is desirable to identify high-risk individuals to offer them a short interscreening interval or advanced detection methods to reduce their odds of developing interval cancer.

Simulation modeling validity and utility in colorectal cancer screening delivery: A systematic review

OBJECTIVE

This study sought to assess the impact and validity of simulation modeling in informing decision making in a complex area of healthcare delivery: colorectal cancer (CRC) screening.

MATERIALS AND METHODS

We searched 10 electronic databases for English-language articles published between January 1, 2008, and March 1, 2019, that described the development of a simulation model with a focus on average-risk CRC screening delivery. Included articles were reviewed for evidence that the model was validated, and provided real or potential contribution to informed decision making using the GRADE EtD (Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision) framework.

RESULTS

A total of 43 studies met criteria. The majority used Markov modeling (n = 31 [72%]) and sought to determine cost-effectiveness, compare screening modalities, or assess effectiveness of screening. No study reported full model validation and only (58%) reported conducting any validation. Majority of models were developed to address a specific health systems or policy question; few articles report the model's impact on this decision (n = 39 [91%] vs. n = 5 [12%]). Overall, models provided evidence relevant to every element important to decision makers as outlined in the GRADE EtD framework.

DISCUSSION AND CONCLUSION

Simulation modeling contributes evidence that is considered valuable to decision making in CRC screening delivery, particularly in assessing cost-effectiveness and comparing screening modalities. However, the actual impact on decisions and validity of models is lacking in the literature. Greater validity testing, impact assessment, and standardized reporting of both is needed to understand and demonstrate the reliability and utility of simulation modeling.

The Association between Cancer Screening and Cancer History among Korean Adults: The 2010–2012 Korea National Health and Nutrition Examination Survey

Background

Cancer survivors are at a higher risk of primary cancer recurrence and development of second primary cancer. In both cases, early disease detection is crucial. This cross-sectional study assessed cancer screening participation rates according to cancer history.

Methods

Data were obtained from the 2010–2012 Korea National Health and Nutrition Examination Survey for 12,500 participants. Of these, 624 cancer survivors were enrolled in this study. Sampling weights were applied to maintain the representativeness of the Korean adult population.

Results

Overall 2-year cancer screening rates prior to the survey in male and female cancer survivors were 59.9% and 73.7%, respectively, while opportunistic cancer screening rates were 33.5% and 52.1%, respectively. The odds ratios (95% confidence interval) of the overall cancer screening among the cancer survivors, compared to others, were 1.16 (0.79–1.72) in male and 1.78 (1.20–2.63) in female participants, after the adjustment for confounding variables. The odds ratios (95% confidence interval) for opportunistic cancer screening and National Cancer Screening Program among cancer survivors were 1.56 (1.07–2.27) and 0.80 (0.53–1.21) in males and 2.05 (1.46–2.88) and 0.66 (0.46–0.95) in females.

Conclusion

Female cancer survivors showed a higher rate of overall and opportunistic cancer screening than did the male cancer survivors. Further efforts are required to improve cancer screening among male cancer survivors.

Bias-corrected estimates of effects of PSA screening decisions on the risk of prostate cancer diagnosis and death: Analysis of the Finnish randomized study of screening for prostate cancer

More information is needed about effects of prostate-specific antigen (PSA) screening for informed decision making. The objective of our study is to evaluate the effects of an implemented screening decision on the risk of prostate cancer (PC) diagnosis and PC death. In a randomized trial, 31,867 Finnish men aged 55-67 years were allocated to the screening arm and 48,282 to the control arm during 1996-1999. Two to three screening rounds were offered to the screening arm with a PSA cut-off of 4.0 ng/ml. A counterfactual exclusion method was used to adjust for the effects of screening noncompliance and PSA contamination on risk of PC death and PC incidence by prognostic group at 15 years of follow up. After correcting for noncompliance and contamination, PSA screening led to 32.4 (95% CI 26.4, 38.6) more PC diagnoses per 1,000 men after 15 years and 1.4 (95% CI 0.0, 2.8) fewer PC deaths compared to the control arm. The corresponding results of an intention-to-screen analysis were 16.5 (95% CI 12.3, 20.7) and 0.8 (95% CI 0.5, 2.0), respectively. These results can be used for patient counseling in informed decision making about PC screening. A limitation of the study was the lack of comprehensive data on contamination.

Estimating age group-dependent sensitivity and mean sojourn time in colorectal cancer screening

OBJECTIVE

In evaluating the efficacy of cancer screening programmes, sojourn time (duration of the preclinical detectable phase) and sensitivity of the screening test are the two key parameters. Studies suggest that in breast cancer screening, both parameters may vary depending on age at the time of screening, but few studies have examined other cancers. We expanded an existing probability model for periodic screening by performing simultaneous estimation of age group-dependent and sensitivity at preclinical onset time, and tested the expanded model using data from the Korean National Colorectal Cancer Screening Programme.

METHODS

Simulation studies were conducted to assess the performance of the proposed probability model. The method was then applied to the analysis of 376,542 participants aged 50 or over who underwent fecal occult blood testing (FOBT) as part of the National Colorectal Cancer Screening Programme between 2004 and 2007. Age group-dependent mean sojourn time and screening sensitivity of FOBT for colorectal cancer were derived using maximum likelihood estimation.

RESULTS

The method performed well in terms of bias, standard deviation, and coverage probability. National Colorectal Cancer Screening Programme data results indicated that the sensitivity of FOBT to detect colorectal cancer increases with age, while mean sojourn time decreases with age (approximately 4.3 years for participants aged 50-54, 3.9 years at age 55-59, 3.4 years at age 60-64, and 3.6 years at age 65-69, with corresponding sensitivity estimates around 41%, 47%, 45%, and 51%, respectively).

CONCLUSION

Simulation studies showed that the proposed stochastic model considering both mean sojourn time and sensitivity yields highly accurate results.