Evaluate a given screening program, including the interpretation of measures of diagnostic / screening tests.

1
Breast Cancer: Screening and Critique
Screening Test and Critical Evaluation of Population-based Screening Mammography
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Word Count: 1500
Part A: The Hypothetical Scenario
Test Results
Total number of women = 10000
Women having cancer = 170 (10000-9830)
Women not having cancer = 9830
Women testing positive = 2844 (2837+7)
Women testing negative = 6986 (9830-2844)
Table 1: Test Results
    
    
    Screening
    
    
    Positive
    Negative
    Cancer
    Yes
    2837
    7
    
    No
    0
    6986
Calculations
True positive = a = 170
False Positive = c = 9830
False Negative = b = 2844
True Negative = d = 6986
Sensitivity (Sn) or the true positive rate is the probability that the test result will turn out to be positive in case of the presence of the disease
= a/ (a+b)
= 170/ (170+2844)
= 0.056 or 5.64%
Specificity (Sp) or the true negative rate is the probability test result that is likely to turn out to be negative when the disease is not present
= d/(c+d)
= 6986/ (9830+6986)
= 0.4154 or 41.54%
Positive predictive Value (PPV) is referred to as the probability that the disease is present when the test results come out to be positive.
= sensitivity * prevalence/ sensitivity*prevalence + (1-specifity) * (1-prevalence)
= 0.056*0.152/0.056*0.0152 + (1-0.056) * (1-0.152)
= 1.70%
Negative predictive Value (NPV) is the probability that the test is negative, and the disease is not present in such cases.
= specificity * (1-prevalence)/ (1- sensitivity) * prevalence + specificity * (1-prevalence)
= 0.4154* (1-0.152)/ (1-0.056) * 0.152+0.4154 * (1-0.152)
=71.07%
Outcomes and Implications
    The integration of mammography as a screening tests help in the development of the possible platform of identifying breast cancer at an early stage. The test results brought to light the fact that of the 9830 women who did not have cancer, 2844 tested positive in the screening test. Thus, it can be concluded that the application of the screening tool helped in the establishment of the scenario wherein it is indicated that the women might have breast cancer but without the screening test it cannot be detected and realised unless it reaches a later and more dangerous stage. Seely (2017) highlighted that the integration of screening mammography can be helpful in reducing the untimely detectable progress of breast cancer and the early detection can be useful in increasing mortality. It is therefore recommended that the screening test be used on a regular basis to identify any possible signs of breast cancer risk among women. As mentioned by Rodriguez-Ruiz et al. (2018) the detection of breast cancer with mammography can prove to be beneficial as an enriched and fully crossed report can be obtained highlighting the development of cancer even at its earliest stage. Thus, it can be implied that the results from screening test can be beneficial and therefore should be considered for future proceedings.
Part B – Critical Evaluation of a Population-based Screening Mammography Program
Introduction
    The data published by World Health Organisation [WHO] (2020) on breast cancer reveals that there are as many as 2.1 million women impacted with breast cancer making it the most frequently occurring cancer among women. The improvement of breast cancer outcomes and associated survival is based on its early detection dependent on diagnosis and screening. The discussion presented by Choi et al. (2018) highlights that the introduction of screening tools like mammography can be beneficial in the early...