Some people have precancerous or early-stage esophageal cancer found during a physical examination, and when they seek further medical attention, their doctor may recommend endoscopic treatment. It includes endoscopic resection surgery and endoscopic non-resectional treatment. In this article, we will focus on the endoscopic non-excisional treatment methods.
The main treatments in this category include radiofrequency ablation (RFA), photodynamic therapy (PDT), argon plasma coagulation (APC), multipolar electrocoagulation ( multipolar electrocoagulation, MPEC), laser therapy, thermal probe therapy, cryotherapy and so on. They can be used either alone or in combination with endoscopic resection.
Photodynamic therapy
Photodynamic therapy is indicated for patients who do not want to undergo surgery, cannot tolerate surgery (e.g., advanced age, more underlying disease, organ insufficiency), or for whom surgery does not guarantee a clean cut.
It is one of the more commonly used endoscopic non-excisional treatments for esophageal cancer. The first indication for PDT, approved by the US Food and Drug Administration (FDA), was for intermediate to advanced esophageal cancer and obstructive esophageal cancer. It is also a “specialty” for early-stage esophageal cancer. The complete response rate for PDT in early and progressive esophageal cancer has been reported in the foreign literature to be 16% to 97%, with most around 70%.
Before PDT treatment, doctors inject light-sensitive drugs into the patient. These drugs “like” to cluster around tissues that have abnormal growth and metabolism, such as tumors. After a few days, the doctor then shines a specific wavelength of light through the endoscope at the tumor site, where the photosensitized drugs have already collected and activated, triggering a photochemical reaction that destroys the tumor.
Radiofrequency ablation
Radiofrequency ablation uses the thermal effect of electromagnetic waves to “heat” cancer cells by irradiating the diseased tissue with an internal lens that emits electromagnetic waves, which dehydrates, dries, coagulates, and necroses the tissue.
It is commonly used to treat Barrett’s esophagus and early esophageal adenocarcinoma, and is particularly good at treating multiple, long lesions or cancers that involve the entire perimeter of the esophagus.
Barrett’s esophagus is a precancerous lesion of esophageal adenocarcinoma, but it can be difficult for doctors to determine whether it will progress to cancer or not. There is clear evidence from studies that treating Barrett’s esophagus with radiofrequency ablation significantly reduces the risk of lesion progression with very few side effects and a low incidence of adverse events such as postoperative perforation and stricture.
A study published in the Journal of the American Medical Association (JAMA) showed that treatment of Barrett’s esophagus with radiofrequency ablation reduced the risk of progression to adenocarcinoma by 7.4%, and only 11.8% of patients experienced adverse effects of esophageal stricture.
However, the possibility of recurrence of the lesion remains after radiofrequency ablation treatment, so it is generally used in combination with endoscopic resection. The National Comprehensive Cancer Network (NCCN) guidelines recommend that treatment with endoscopic mucosal resection (EMR) in conjunction with radiofrequency ablation in the early stages of esophageal cancer is associated with better outcomes, reduced mortality, and fewer complications.
Cryotherapy
Cryotherapy induces an inflammatory response and apoptosis in cancer cells by rapidly cooling the tissue with some cold-causing substance, such as liquid nitrogen spray or carbon dioxide, which can be simply interpreted as “freezing” the cancer cells.
If you are not physically able to tolerate surgery and are not a candidate for endoscopic resection, then cryotherapy can be tried. It is important to note that it is not the primary curative treatment for early-stage esophageal cancer, but it can provide relief.
Also, cryotherapy can be used to treat Barrett’s esophagus with highly abnormal development with an efficiency of 97%, with complications mainly stricture and chest pain, but the incidence is only 2% to 3%.
Multipolar electrocoagulation
Multipolar electrocoagulation was one of the first thermal ablation methods used for Barrett’s esophagus. It is indicated for lesions without severe atypical hyperplasia (ie, relatively low risk of cancer) and has a treatment response rate (ie, some remission) of 78% to 88%. However, electrocoagulation is cumbersome to perform and only a small amount of mucosa can be removed at a time. Common complications are chest pain, swallowing pain, and stenosis, which can be significantly relieved by balloon dilation.
Endoscopic argon ion beam coagulation
Ionized argon ions generate heat that can be used to kill cancer cells and are commonly used in the treatment of precancerous lesions and early esophageal cancer. It was first used to stop bleeding in surgical wounds and has slowly been used to treat small, flat GI lesions, as well as Barrett’s esophagus, precancerous lesions, and early esophageal cancer. Common complications include painful swallowing, dysphagia, and chest pain. aPC does not obtain a valid sample of cancer tissue and has a high recurrence rate and is now used less and less.
Co-written by:
Dr. Yuan Peng, Department of Gastrointestinal Oncology, Peking University Cancer Hospital