Postmenopausal bleeding (PMB) accounts for 5% of all
gynecological consultations out of whom nearly 10% will be diagnosed with
endometrial cancer as the cause of bleeding making it to be the most common
malignancy of female genital tract.
Endometrial cancer is the fourth most common cancer in
females in the UK
(2012), accounting for 5% of all new cases of cancer in females.
The liberal use of Transvaginal Ultrasound (TVS) as the
first line of investigation in patients with PMB has decreased the use of more
invasive procedures like endometrial sampling and hysteroscopy.
Based on the very high negative predictive value of TVS,
ACOG recommended a cutoff of 4 mm for endometrial thickness: That is,
endometrial stripes 4 mm or thinner require no endometrial sampling; only those
thicker than 4 mm require a biopsy.
RCOG guidelines for investigation of PMB have also set the
arbitrary cutoff at 4-5 mm by TVS at which the women can be reassured.
However, the endometrial thickness cutoff and the need for
further investigation are being debated since very long.
A literature review showed that 4 different meta-analysis
have been published on this subject showing varying conclusions. All 4 Meta analyses suffered from various biases like
verification bias because the endometrial biopsy was conditioned upon the
endometrial thickness by TVS.
A recent study by Wong et al published in the February issue
of BJOG:An International Journal of Obstetrics & Gynaecology and the Mini Commentary
is unique because it constituted the largest cohort of women (4383 women) with
PMB, in whom endometrial biopsy was performed independent of the endometrial
thickness by TVS. Endometrial histology results were used as the reference
standard to calculate accuracy estimates.
Endometrial cancer was diagnosed in 3.8% of all the women,
with a median endometrial thickness of 15.7 mm which was much higher than that
found in benign conditions (3.2mm).
The sensitivity for the diagnosis of endometrial cancer at
3, 4 and 5mm cutoff were 97%, 94.1% and 93.5% respectively with corresponding
estimates for specificity 45.3% ,66.8% and 74.0% respectively.
According to this study the optimal threshold that combines
the perfect sensitivity with an acceptable specificity appears to be 3 mm.
At this cut-off point, positive and negative predictive
values were 6.5 and 0.26%.
Although the strategies to diagnose endometrial cancer by
TVS are well documented, further improvement can be achieved by adding
patient’s characteristics and individual risk factors to decide the need and
type of testing required.
This study and the resulting data can further validate and
add to the existing prediction models to maximize the probabilities of pre and
post test diagnosis of endometrial cancer!
This will in turn be able to pinpoint women who are least
likely to have endometrial cancer based on TVS screening, avoiding unnecessary invasive surgeries.
References:
, , , , , ,
, . Reappraisal
of endometrial thickness for the detection of endometrial cancer in
postmenopausal bleeding: a retrospective cohort study. BJOG 2016;123:439–446.
Breijer, M. and Mol, B. (2016), Transvaginal ultrasound
measurement of the endometrium remains the first line test for investigating
postmenopausal bleeding but integration of patient characteristics into testing
may further improve diagnostic algorithms. BJOG: An International Journal of
Obstetrics & Gynaecology, 123: 447. doi: 10.1111/1471-0528.13438
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