Reinders, Tammo Konstantin and Kieschke, Joachim and Timmer, Antje and Jürgens, Verena
(2018)
Sequential tests for monitoring methods to detect elevated incidence – a simulation study.
BMC Cancer, 18 (1).
ISSN 1471-2407
Abstract
Background: Common cancer monitoring practice is seldom prospective and rather driven by public requests. This
study aims to assess the performance of a recently developed prospective cancer monitoring method and the
statistical tools used, in particular the sequential probability ratio test in regard to specificity, sensitivity, observation
time and heterogeneity of size of the geographical unit.
Methods: A simulation study based on a predefined selection of cancer types, geographical unit and time period
was set up. Based on the population structure of Lower Saxony the mean number of cases of three diagnoses were
randomly assigned to the geographical units during 2008–2012. A two-stage monitoring procedure was then
executed considering the standardized incidence ratio and sequential probability ratio test. Scenarios were constructed
differing by the simulation of clusters, significance level and test parameter indicating a risk to be elevated.
Results: Performance strongly depended on the choice of the test parameter. If the expected numbers of cases were
low, the significance level was not fully exhausted. Hence, the number of false positives was lower than the chosen
significance level suggested, leading to a high specificity. Sensitivity increased with the expected number of cases and
the amount of risk and decreased with the size of the geographical unit.
Conclusions: The procedure showed some desirable properties and is ready to use for a few settings but demands
adjustments for others. Future work might consider refinements of the geographical structure.
Inhomogeneous unit size could be addressed by a flexible choice of the test parameter related to the observation time.
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