Digestive endoscopy has significantly increased the rates of early detection of esophageal cancer or precancerous mucosal lesions [5]. Gastroscopy can allow direct observation of the lesions of the esophageal mucosa, especially for swelling and ulcerative lesions. EB can be performed simultaneously, which is generally accepted as one of the best ways to obtain the sample from esophageal cancer pretreatment, and the accuracy of endoscopic forceps biopsy was 60%-95% in previous literature [6–8]. However, some patients cannot undergo EB due to anesthesia-related risks, age-related factors, severe occlusion, refusal, and other reasons, and appropriate diagnosis in these patients remains a clinical difficult problem. The most ideal condition in forceps biopsy is to obtain the least amount of biopsy tissue from the most typical part to reflect the overall nature of the lesion [9]. For patients with severe esophageal stenosis, the tumor information is hidden across the stenosis area and the approach used for obtaining pathological tissue out of the stenosis area is very important. In the past, Li TF et al have reported that TTFB can be used to diagnose malignant obstructive jaundice; thus, it can hypothetically be used to diagnose esophageal strictures [10]. In addition, some patients don't even have water for several weeks, the general condition is very poor, nutritional support is still the most basic and important treatment for these patients. We can complete forceps biopsy and provide a nutrition tube or esophageal stent placement simultaneously under local anesthesia to improve the efficiency of diagnosis and treatment.
In this pilot study, 35 patients underwent TTFB for esophageal stenosis. The technical success rate was 100% and sufficient histologic specimens were obtained. The final pathological accuracy rate was 88.6%, which was satisfactory, and was within the accuracy range of previous reports [6–8]. The stenoses were relatively narrow, and biopsy forceps were manipulated closely to the beginning of the lesion at the head of the sheath so as to obtain samples out of lesion sidewalls. In terms of complications, two cases showed minor self-limiting hemorrhage, which is reasonable in comparison with that associated with the use of clamp forceps under endoscopy, and the safety was satisfactory [11]. However, TTFB has certain disadvantages such as unclear visualization of the mucosal surface, outline, and scope of the lesion and the incompatibility with narrow-band imaging technology. In addition, it is difficult to sample deeper submucosal lesions with such forceps. Diagnoses were missed in four patients, who were finally confirmed as showing cancer. This is still a practical problem, and a non-specific outcome in this examination cannot rule out the presence of malignant tumors, necessitating further evaluations. The location, method, quantity, forceps times, and specimen preparation may affect the assessment [12]. As for irradiation dose, 7.2 mSv is similar to the radiation dose in a standard CT chest scan (7 mSv) [13], which is reasonable in our opinion, although the irradiation dose can be further reduced by using a small field of view and improving work efficiency.
In order to obtain more samples in patients with esophageal stenosis, our technical experience is as follows: (1) The long sheath must be introduced along a super-stiff guidewire and should be as close to the stenosis as possible. (2) After introducing the forceps through the outer sheath, the forceps can be opened and then pushed forward 5-10 mm into the stenosis so as to obtain more samples. (3) If the stenosis is very severe, forceps biopsy should be performed after dilatation with a small balloon dilator (diameter, 6-8 mm). Larger balloons (diameter ≥ 10 mm) are not recommended. When no stenosis indicates no support platform at the head of the sheath, it is easy to slide to the distal end of the stenosis. In such cases, the opening biopsy forceps cannot touch the sidewall of the lesion, and the forceps cannot get close to the diseased wall leading to sampling failure, or a large balloon can compress the esophageal cells leading to denaturation or necrosis. (4) Multiple biopsies may be required because the obstructive disease is actually caused by the lesion itself and the inflammatory edema around it. The biopsy forceps must be used in a very limited part of the middle of the lesion while obtaining the lesion tissue; otherwise, it may also collect inflammatory tissue. Therefore, it is necessary to forceps the stenosis in different parts and directions, but multiple biopsies do not imply the use of a higher number of clamps, which is also important to reduce complications while diagnosing diseases. (5) The diagnosis of tissue sections should be performed promptly by the pathology department, and the tissue dehydration time should not be too long; otherwise, the specimen will undergo compression, degeneration, and necrosis.
However, this study had its own limitations, such as the small number of patients, biased selection, and the absence of a prospective design and a control group.
In conclusion, TTFB is a safe and effective method for patients with severe esophageal obstruction under fluoroscopy, especially those who cannot undergo EB due to anesthesia-related risks, age-related factors, severe occlusion, or refusal to undergo endoscopy.