Outpatient-based endometrial sampling techniques have largely replaced diagnostic curettage as the method of choice for the diagnosis of endometrial lesions. These techniques offer a minimally invasive option for the diagnosis of endometrial cancer, hyperplasia and other endometrial pathological changes.
The advantages of endometrial sampling are.
Can be performed on an outpatient basis without the need for an operating room (given the current limitations of outpatient care in our hospitals, we still recommend that endometrial sampling be performed in an outpatient procedure).
It can be performed without anesthesia or with only local anesthesia. No or only slight cervical dilatation is required.
Reduced chance of uterine perforation (0.1-0.2% for outpatient endometrial sampling; 0.3-2.6% for curettage).
Short operation time, actual sampling time is only 5-15 seconds. Inexpensive. Endometrial sampling of the ring in situ can also be performed in the case of IUD placement. Sample volume and sampling conditions A large number of studies have shown that endometrial sampling techniques can obtain a sufficient amount of endometrium for diagnostic purposes. Specimens can be obtained by sampling in more than 90% of patients. However, it should be noted that these sampling devices do not allow direct visualization of the uterine cavity and are therefore better for the diagnosis of extensive endometrial lesions than localized lesions, such as endometrial polyps. Endometrial sampling should provide the pathologist with a sufficient number of specimens for pathologic diagnosis. The adequacy of the sample is highly dependent on the skill of the operator. The Gynecologic Oncology Society guidelines do not recommend the use of devices that may cause specimen extrusion (devices with forceps), cautery (thermal rings), or specimens that are too small (devices with forceps).
Indications and Contraindications Indications.
Women with abnormal uterine bleeding or certain abnormal cervical cytology findings to assess for endometrial tumors Women at high risk for endometrial tumors or women with a history of endometrial tumors Endometrial cancer screening Women treated for endometrial cancer with preservation of fertility should undergo periodic endometrial sampling
Women with Lynch syndrome (hereditary nonpolyposis colon cancer) need to be tested for endometrial cancer. There are no routine screening guidelines for women with other risk factors and decisions need to be made on an individual basis.
Endometrial sampling is used by some physicians as a means of infertility evaluation, but its clinical use is limited.
Contraindications The only absolute contraindication to endometrial sampling is intrauterine pregnancy with a viable fetus and a desire to continue the pregnancy.
Bleeding tendency is a relative contraindication, as heavy bleeding may occur in these patients. Overall, endothelial sampling can be performed in patients on anticoagulation therapy if coagulation parameters are stable and within the standard treatment range. If the bleeding tendency is uncontrolled and the patient requires an endothelial biopsy, a specialist dealing with the patient’s coagulation problems should be consulted. These patients may need to reverse their anticoagulant therapy or receive other treatments (e.g., desmopressin). Women with uncontrolled bleeding tendencies should have an endometrial biopsy performed in the operating room, with blood preparation and anesthesia.
In cases of acute vaginal, cervical, or pelvic infection, endometrial biopsy should be postponed until the infection is controlled, if possible.
In rare cases where endometrial sampling is required in patients with cervical cancer, obstructive cervical lesions may be a relative contraindication in a subset of patients and may result in an increased risk of bleeding and uterine perforation.
Endometrial sampling can be performed without complications when the intrauterine device (IUD) is in place. There are no studies on whether endometrial sampling with the IUD in place affects the diagnosis.
Indications for diagnostic curettage based on the results of endometrial aspiration sampling do not require further diagnostic curettage in the following cases.
The pathologic diagnosis of aspirated endometrium is clear, and if the pathologic diagnosis is clear for endometrial cancer, further diagnostic scraping is not required.
If the pathological diagnosis of aspiration endometrium is found to be normal endometrium, and the symptoms of abnormal uterine bleeding are relieved by hemostatic and anti-inflammatory symptomatic treatment or hormonal therapy, and the ultrasound does not suggest abnormal occupancy, no further treatment is needed.
Further diagnostic curettage is required in the following cases (in these cases, hysteroscopically guided diagnostic curettage is recommended rather than blind curettage)
Aspiration of endometrial pathologic diagnosis does not reveal endometrial lesions, but symptoms persist with symptomatic management.
Aspiration of endometrial pathology does not reveal endometrial lesions, but ultrasound still suggests intrauterine occupancy or endometrial heterogeneity.
Endometrial lesions were found by aspiration endopathology diagnosis, and further diagnosis is needed to exclude the possibility of higher grade lesions.
Women at high risk of endometrial cancer whose lesions are not detected by outpatient endometrial biopsy Outpatient endometrial biopsy to take insufficient amount of tissue for pathological diagnosis Those with cervical stenosis who cannot undergo outpatient biopsy must undergo other procedures such as hysteroscopy or laparoscopy Should skip endometrial sampling and undergo direct diagnostic curettage in the following cases
Treatment of incomplete miscarriage, refractory miscarriage, indolent miscarriage, infected miscarriage and induction of labor.
Initial treatment of gravida.
Temporary management of prolonged or heavy vaginal bleeding where hormonal therapy has failed.
Aspiration (without cervical dilatation) can be used to treat postpartum bleeding due to retained pregnancy material Preoperative Preparation Anesthesia —- Outpatient endoscopic sampling usually does not cause severe pain. Patient discomfort can be reduced by means of adequate information; explanation prior to each step of the procedure; and avoidance of mechanical cervical dilation and/or cervical forceps when possible. Most clinicians recommend oral administration of nonsteroidal anti-inflammatory drugs 30-60 min before the operation to reduce the occurrence of cervical spasm, and some institutions use paracentesis block anesthesia or intrauterine instillation with local anesthetic drugs.
Cervical Preparation and Dilation —- Most women do not require cervical preparation and dilation, especially premenopausal women. Some women who cannot have a sampler placed without cervical dilation may have misoprostol (200-400 μg) administered orally or placed vaginally the night before the procedure. Vaginal placement seems to be more effective than oral placement.
Women with cervical stenosis require mechanical dilation of the cervix under general or regional anesthesia or ultrasound guidance to complete endocervical sampling.
Prophylactic antibiotics —- endometrial sampling does not require prophylactic antibiotics to prevent surgical site infection or bacterial endocarditis.
Procedure —- The basic steps common to all endocardial sampling are as follows.
The patient is placed in a truncated bladder position.
Perform a bimanual examination, paying particular attention to the size, shape, and position of the uterus.
A speculum is placed to expose the cervix.
The cervix is cleaned with a disinfectant solution (e.g., povidone-iodine), which is performed by some but not all physicians.
In many women, the sampler is inserted directly into the cervix without the need for cervical forceps to grasp the cervix. The use of a cervical forceps can increase patient discomfort.
If the uterus is not median, cervical forceps should be used. In this case, the anterior lip of the cervix is grasped with a cervical grasper (keeping the teeth horizontal) and pulled towards the operator to flatten the angle of the uterine body of the cervix. Straightening the uterine axis reduces the risk of uterine perforation. If cervical grasping forceps are required and no parametrial block anesthesia is performed, we can use local anesthesia (e.g., 2% benzocaine gel or 20% benzocaine spray) sprayed on the site where the cervical grasping forceps are to be placed. Having the patient cough while placing the cervical grasping forceps may also reduce discomfort.
Using a steady and moderate force, slowly insert the sampling device through the cervical os to the fundus of the uterus. Stop placement when resistance is encountered.
If the sampling device does not pass through the cervical canal, place a cervical grasper (if not already used) and gently dilate the canal using a small Hegar (1-4 mm).
Many sampling devices are marked with a scale so that the depth of the uterine cavity can be measured. The average uterine cavity depth is 6-200 px.
One hand holds the outer sheath of the sampler in place while the other hand draws the inner core as far outward as possible to create suction.
The sampler is withdrawn when the entire pipette is filled with the sample. The sample is pushed out and placed in formalin solution. If not enough tissue is sampled, perform another aspiration operation. This can be repeated for the same patient if the sampler is not contaminated; the sampler must not touch the formalin.
Remove the cervical grasping forceps. If bleeding is present, stop the bleeding by applying pressure with a cotton swab. If bleeding persists, cauterize the bleeding site with an alkaline ferric sulfate solution (Monsel solution) or a silver nitrate rod.
If an aspiration device is used, do not allow the outer sheath of the device to dislodge beyond the ectocervix or you will lose negative pressure. If this occurs, simply drain the contents of the aspiration tube into the formalin solution and then place the sampler back into the uterine cavity. Several operations are usually required to ensure an adequate sample volume.
The endometrial aspiration device The endometrial aspiration sampling device is a cannula with a piston insert and an outer sheath. When the cannula is placed in the uterine cavity, the piston insert is pumped backwards, thereby creating a negative pressure that draws endometrial tissue into the sampling device. Most sampling devices use a low negative pressure. However, some devices have a sampling canister or syringe attached to the end of the sampler, thereby creating a higher negative pressure that allows for more tissue to be obtained.
Low-pressure devices —- low-pressure endocardial aspiration devices (e.g. Pipelle, Endocell) are the most commonly used endocardial sampling devices. It consists of a bendable polypropylene inner core and outer sheath, less than 3 mm in diameter. the distal end of the sampler has a lateral hole of 2.4 mm or less in diameter through which endothelial tissue is drawn into the lumen. The bendability of the sampler allows it to be adapted to the morphology of the uterine cavity and reduces the incidence of spasm.
Typically, endometrial sampling can take 5-15% of the endometrial area. The failure rate for low pressure endoaspiration biopsy is approximately 0-8%.
Increasing the amount of tissue obtained is achieved by using a combination of rotational twisting and diagnostic scraping techniques during the aspiration process. In this method, the sampling device is placed at the base of the uterus and then gradually pulled outward to the lower uterine segment, alternating between rotational twisting and scraping maneuvers. Data on the effectiveness of the combined use of this maneuver are limited. In a retrospective study, based on a consistent pathologic assessment, the combination of rotational twisting and curettage resulted in adequate specimens in 95% of patients, compared with a success rate of 77% with rotational twisting alone.
High-pressure devices —- High-pressure devices (e.g., Vabra suction, Karman cannula) are used less frequently than low-pressure devices because they can cause more discomfort to the patient. These devices should not be bent and often require the use of cervical grasping forceps, cervical canal dilation and paracervical block anesthesia.
The Vabra and Karman systems have the advantage of obtaining a greater volume of tissue comparable to that of a diagnostic curettage. These devices are commonly used in patients with moderate amounts of uterine bleeding because, in the author’s experience, they can be used not only for diagnosis but also for treatment.
The Vabra —- Vabra suction is a 4mm disposable plastic tube or a 2 or 3mm stainless steel device. An external negative pressure pump is connected. Tissue is obtained and stored in a tissue compartment, which is removed and placed in formalin solution.
The Karman —- Karman cannula is 4-6 mm in diameter and is a bendable plastic tube with two side holes at the distal end. A syringe is attached to the cannula to generate negative pressure. An external negative pressure pump can also be used.
Endometrial brushes —- endometrial brushes (such as the Tao Brush) are disposable devices with a brush at the distal end, similar to the commonly used cervical tube brush.
Several observational studies have compared the sampling results of endometrial brushes with those of endometrial aspiration sampling devices. In one of the largest studies, 526 premenopausal and postmenopausal women used both the Tao Brush and Pipelle. regardless of whether they were operated with or without hysteroscopic assistance, the majority of postmenopausal women had significantly higher rates of adequate specimen volume for endometrial brush sampling than for aspiration devices, 83% vs 50% with hysteroscopic assistance and 61% vs 36% without hysteroscopic assistance. In premenopausal women, there was no significant difference in sample adequacy between the two techniques.
An alternative approach is to use the hysteroscopic brush and aspiration device sequentially during the sampling procedure. One study analyzed 101 women with 100% sensitivity and specificity for the combined use to diagnose endometrial cancer or hyperplasia.
Due to the high hormonal influence of endometrial cells and significant cellular morphological atypia, it brings great difficulties and unreliability for morphological diagnosis. Therefore, to date, endothelial cytopathology is still not accepted and used by a wide range of pathologists. Limited data show that endothelial cytology has a high diagnostic yield for endothelial carcinoma. However, for other endothelial lesions, its diagnostic efficiency is doubtful due to the unreliability of cytomorphology. Molecular pathology diagnostic methods have been tried for endothelial cytology examination in China and abroad, and how to find an accurate and effective marker is the biggest problem at present.
Side effects and complications The most common side effect of endothelial sampling is cramping, which resolves rapidly after the operation is completed. High-pressure aspiration devices can cause more severe cramping than low-pressure devices because the former are stiffer and have more suction force to aspirate more endothelial samples. Many women experience a small amount of vaginal bleeding or spotting for several days after the procedure.
Vaso-vagal reactions are not commonly associated with endothelial sampling operations. Allowing the patient to eat and drink appropriately before the procedure and using analgesic medications or local anesthesia to reduce pain can usually prevent such reactions. The risk of uterine perforation is approximately 1-2/1000.
Rare complications include massive uterine bleeding (especially in patients with undiagnosed coagulopathy), uterine perforation (risk 0.1-0.3%), pelvic infection, and bacteremia (including sepsis and endocarditis).
Postoperative care Patients should be kept in a semi-recumbent position for several minutes after surgery to reduce the chance of vasovagal reactions. Thereafter, if the patient has no symptoms of dizziness or heavy bleeding, he/she can leave the clinic. Nonsteroidal anti-inflammatory drugs may be applied to manage spasticity, although sustained spasticity rarely occurs.
Patients should be seen immediately if fever occurs, cramping lasts 48 hours or longer, pain increases, vaginal drainage is offensive, or bleeding is greater than menstrual flow. The operation does not interfere with the patient’s daily activities, including sexual intercourse.
In summary and recommendation, outpatient endometrial sampling has largely replaced curettage for the diagnosis of endometrial tumors. Indications for endometrial sampling include abnormal uterine bleeding or follow-up of patients at high risk for endometrial cancer (e.g., women with a history of endometrial neoplasia).
The primary contraindication to endometrial sampling is pregnancy, with acute cervical or uterine infection and bleeding tendencies being relative contraindications.
Adequate samples can be obtained by endometrial sampling in more than 90% of patients. All endometrial sampling devices perform better when the endometrial lesion is extensive rather than limited.
Endothelial sampling is performed with disposable low-pressure suction devices, a technique that is widely used because of the minimal discomfort. High-pressure devices can be used if more samples are needed.
In postmenopausal women, observational data suggest that the endo-brush provides a more adequate sample volume than the low-pressure aspiration device. The combined use of both devices increases the diagnostic yield.
The most common side effects are cramping and vasovagal reactions. Uterine perforation is the most serious complication