Page 78 - The diagnostic work-up of women with postmenopausal bleeding

Chapter 4
Based on these two statistical models, three different diagnostic strategies were explored:
1. The ‘patient characteristics’ rule, i.e. probability estimates based on characteristics of the women, and invasive diagnostics in case the probability of (pre)cancer exceeded 4%. In this rule,TVS was not performed.
2. The ‘sequential’ rule, i.e. probability estimates based on characteristics of the women, with TVS in case the probability for cancer exceeded 4%, and subsequent histological analyses when the endometrial thickness exceeds 4 mm.
3. The ‘integrated’ rule, i.e. TVS in all women, with a probability estimate based on both characteristics of the women and TVS results, completed by endometrial sampling when the probability of cancer exceeded 4%.
To estimate the clinical consequences of applying these three different management strategies proposed by Opmeer et al on the validation datasets,16 we calculated for each of the three strategies, the percentage of women in whom TVS would be performed, the percentage of women in whom an invasive procedure would be performed to obtain material for histology, the number of endometrial (pre) cancers identified by the different strategies and specificity (the amount of patients without cancer who fell below the threshold of the specific strategy).We compared all these clinical consequences with the current strategy used in clinical practice: selecting women for further diagnostic work-up by the measurement of endometrial thickness (TVS only). We performed all analyses for the external validation in ‘R’, version 2.15.0 (2012).
Results
Patient characteristics
The two databases available for external validation consisted of 559 Dutch and 433 Swedish women with PMB not using HRT.Table 1 shows the characteristics of women in the two databases and the percentage of missing data per database. Age, time since menopause, anticoagulants use, body mass index (BMI), endometrial thickness and the prevalence of endometrial cancer differed significantly between the two validation populations, women in the Swedish database being older, having
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