Discussion
BLOOD, SECONDARY
No significant differences were found in the histological features of the samples when the endometrial sample was obtained before or after the SCSH. In the sub analysis of only sufficient samples, also no significant differences were found in the histological features apart form a higher amount of blood which was found in the SCSH-Sampling group.Therefore, we can conclude the SCSH does not affect the histological features, and thus the quality, of the endometrial samples.This study also shows that a higher amount of blood, endometrial epithelium, intact endometrial glands, stroma and tissue context were found in the sufficient samples compared to the insufficient samples. Oppositely, a significantly higher amount of mucus was found in the insufficient samples.These results are in line with the results of the primary analysis of the ESPRESSO RCT, which concluded that the quality of the endometrial sample was not affected by whether SCSH was performed before or after endometrial sampling. However, this primary analysis only focused on general adequacy of the sampling and did not assess specific histological features of the endometrial sample such as amount of epithelium, intact glands and stroma. As we were still interested in our predefined hypothesis, we aimed to analyze whether the effect of the SCSH would be seen in the specific histological features of the endometrial sample [In addition, we wanted to determine which histological features have impact on the quality of the endometrial sample. This is of clinical interest, as insufficient endometrial samples have been a common problem in the diagnostic pathway in women with PMB with a reported rate of 7–78% of insufficient samples [Our study suggests that multiple factors determine the quality of the endometrial samples as higher amounts of blood, endometrial epithelium, intact endometrial glands, stroma and tissue context were found in the sufficient samples compared to the insufficient samples. Based on these results, further research to develop a more extensive structured assessment of the endometrial samples in women with PMB, is interesting.Also, the amount of tissue is an important factor and very little material in the sample could lead to diagnostic errors. For this reason, it would be advisable for a gynecologist to macroscopically check the amount of tissue in the container after sampling and consider to reinsert the device to take another sample if only very little tissue, or only mucus, has been sampled.Furthermore, It also has to be noted that the clinical patient characteristics, such as hormonal replacement therapy and the thickness of the endometrium on ultrasound, are valuable details for the pathologist in the assessment of the aspiration sample [It is remarkable that the amount of blood was significantly higher in the group of sufficient samples. Blood and mucus are seen as staining of the endometrial sample by the pathologist, and some would define an inadequate sample if consisting only of blood or cervical mucus with fragments of benign endocervix, or a large amount of blood with only small fragments of endometrial glands and stroma [Bij de Vaate performed a randomized controlled trial to compare the quality and histological features of an endometrial sample obtained before or after the SCSH in predominantly pre-menopausal women [This is a secondary analysis of the randomized controlled trial to investigate the histological features of the endometrial sample obtained before or after the SCSH in women with PMB. The samples were analyzed thoroughly and structurally by dedicated gyneco-pathologists. A limitation of the current study was that there was no sample size calculation performed, as this was a secondary analysis.