Endometrial biopsy in women with abnormal uterine bleeding: inadequate and unassessable categorisation is not clinically relevant

Current challenges and emerging tools in endometrial cancer diagnosis

The diagnostic process of endometrial cancer includes imaging methods such as trans-vaginal ultrasound, along with procedures to obtain endometrial tissue for histologic evaluation. Common techniques for tissue sampling include Pipelle endometrial biopsy, hysteroscopy, and dilation and curettage, which are used to confirm the diagnosis, determine tumor histology, grade, and molecular profile. However, diagnostic algorithms for endometrial cancer differ significantly across countries, influenced by local resources, protocols, and the availability of diagnostic methods. These variations include differences in the endometrial thickness threshold for recommending a biopsy and the choice of the initial diagnostic test. Moreover, patients often have multiple tests and appointments before a definitive diagnosis, although only 5%-10% of women with post-menopausal bleeding are diagnosed with endometrial cancer. Current diagnostic techniques have limitations. Pipelle endometrial biopsy has a significant false-negative rate (10%-20%) and may fail to provide adequate diagnostic material in up to 30% of cases. Hysteroscopy, while useful, is associated with pain in up to 65% of patients and can delay diagnosis because of limited availability. Dilation and curettage is an invasive procedure requiring general anesthesia and has a higher complication rate. In response to these challenges, there is growing interest in developing new diagnostic tools that are less invasive and provide 1-step diagnoses, including liquid biopsies from urine, blood, cervico-vaginal and endometrial fluid samples by means of genomics and proteomics. This review will examine the current diagnostic algorithms in European and American guidelines, evaluate the sensitivity, specificity, and accuracy of current techniques, and explore new diagnostic tools under development.

Insufficient and Scant Endometrial Samples: Determining Clinicopathologic Outcomes and Consistency in Reporting

There are no widely accepted pathologic criteria for reporting endometrial samples with limited tissue and no consensus on the clinical follow-up of patients with these samples. Our study compares clinicopathologic outcomes and determines reporting consistency for these samples. This was done in 3 parts: (1) retrospective chart review of all patients with reported insufficient or scant endometrial samples from 2010 to 2013 at our center to determine repeat sampling and final pathologic diagnosis; (2) survey of gynecologists about their practice for managing patients with these samples; (3) blind review of 99 cases of previously reported scant or insufficient samples in which 4 reviewers separately reassigned cases as scant, insufficient, or diagnostic. Agreement was determined across reviewers. For part (1): 1149 patients had insufficient (49%) or scant (51%) samples with no significant difference in repeat biopsy rate (33% vs. 31%; P=0.33). Final diagnosis of uterine malignancy was higher in patients with a previous insufficient sample than with scant (19% and 9%, respectively), but this was not statistically significant. For part (2): among gynecologists surveyed, 4 of 5 reported managing patients with insufficient or scant samples similarly. For part (3): complete consensus across raters occurred in 57% of cases (Fleiss κ, 0.4891). Similar repeat biopsy rates between scant and insufficient samples suggest that our clinicians choose similar management for both terminologies. As such, distinction between insufficient and scant samples may not be necessary in pathologic reporting. Given the malignancy outcomes, both groups merit repeat sampling in the appropriate context.

Endophytic-Type Endometrial Cancer with Adenomyosis Successfully Diagnosed with Hysteroscopic Endometrial Biopsy Using an 8.3-mm Operative Resectoscope: A Case Report

In order to diagnose endometrial cancer preoperatively, outpatient endometrial biopsy with a curette is frequently performed owing to its convenience. However, in some cases, gynecologists fail to diagnose endometrial cancer via outpatient endometrial biopsy because of the cancer's distribution in the uterus and its consistency. A 57-year-old Japanese woman (gravida 4 para 4) presented with a 6-month history of light but intermittent postmenopausal vaginal bleeding. A malignant uterine tumor was strongly suspected after imaging using ultrasound examination and magnetic resonance imaging; however, a precise pathological diagnosis was not achieved despite multiple outpatient endometrial biopsies with the aid of office hysteroscopy. Based on an endometrial biopsy obtained using a cutting loop electrode on an 8.3-mm operative resectoscope, we reached a diagnosis of endophytic-type endometrial cancer, which is in accordance with the final pathological diagnosis after abdominal hysterectomy. Three months after her first visit to our hospital, total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic/para-aortic lymph node dissection were performed. Macroscopically, the endometrium was atrophic, and there was no obvious mass in the uterine cavity; however, microscopically, the cancer cells mainly existed in the deep myometrium and the final diagnosis was International Federation of Gynecology and Obstetrics (FIGO) stage IB endometrial cancer. Operative biopsy of the uterine endometrium and deep myometrium using hysteroscopy confirmed an accurate preoperative diagnosis of uterine endometrial cancer specifically of the endophytic type.

Endometrial Samples From Postmenopausal Women: A Proposal for Adequacy Criteria

Approximately 75% of endometrial cancer occurs in women older than 55 yr of age. Postmenopausal bleeding is often considered endometrial cancer until proven otherwise. One diagnostic challenge is that endometrial biopsy or curettage generally yields limited samples from elderly patients. There are no well-defined and unified diagnostic criteria for adequacy of endometrial samples. Pathologists who consider any sample including those lacking endometrial tissue as "adequate" run the risk of rendering false-negative reports; on the contrary, pathologists requiring ample endometrial glands along with stroma tend to designate a greater number of samples as "inadequate," leading to unnecessary follow-up. We undertook a quantitative study of 1768 endometrial samples from women aged 60 yr and older aiming to propose validated adequacy criteria for diagnosing or excluding malignancy. Using repeat-procedure outcomes as reference, we found that samples exceeding 10 endometrial strips demonstrated high negative predictive value close to 100%. Such samples can be scant, yet appear to be sufficient in excluding malignant conditions. When tissue diminished to <10 strips, negative predictive value dropped significantly to 81%. The risk of undersampled malignancy rose to 19%. Among 274 malignant cases, only 4 cases yielded limited tissue yet >10 strips. In conclusion, we propose 10 endometrial strips as the minimum for adequate samples from postmenopausal women. Applying such validated adequacy criteria will greatly reduce false-negative errors and avoid unnecessary procedures while ultimately improving diagnostic accuracy. Our criteria may serve as a reference point in unifying the pathology community on this important and challenging topic.

Patient and provider factors associated with endometrial Pipelle sampling failure

OBJECTIVE

To explore risk factors associated with sampling failure in women who underwent Pipelle biopsy.

METHODS

A consecutive sample of 201 patient records was selected from women who underwent Pipelle biopsy procedures for suspected uterine pathology in a large healthcare system over a 6-month period (January 2013 through June 2013). Personal and medical data including age, BMI, gravidity and parity, and previous history of Pipelle biopsy were abstracted from medical records for each patient. Logistic regression analyses were used to determine factors associated with biopsy sampling failure.

RESULTS

Pipelle biopsy sampling failed in 46 out 201 women (22.89%), where 8 (17.39%) were due to inability to access the endometrium, 37 (80.43%) were inadequate samples, and 1 (2.18%) was due to unknown reasons. Personal and medical factors found to be related to sampling failure included: postmenopausal bleeding as biopsy indication (OR 7.41, 95% CI 2.27-24.14); history of prior biopsy failure (OR 23.87, 95% CI 3.76-151.61); and provider type (physician vs. midlevel provider) (OR 9.152, 95% CI 2.49-33.69).

CONCLUSION

We identified several risk factors for biopsy failure that suggest the need for particular care with Pipelle sampling procedures among women with certain characteristics, including postmenopausal bleeding and a history of prior failed Pipelle biopsy. Our finding of a significantly higher risk of sampling failure based on personal and clinical data suggests that providers must take into account additional considerations to improve sampling success.