## 4 Brachotherapy in the Palliative Treatment of Esophageal Cancer  
The palliative treatment of patients with esophageal cancer is based on both local therapy and systemic treatment. This very heterogeneous group includes patients in good general condition with a small tumor mass and single metastases as well as patients with a large local extension or massive spread in multiple organs. For this reason, the effect of local treatment on overall survival is difficult to demonstrate and local treatment is primarily important for symptom relief. Intraesophageal brachytherapy has a major role in relieving dysphagia. It results in a reduction in dysphagia in 70-90% of cases and achieves a complete endoscopic response in 50% of cases, which, depending on the study, lasts between 2 and 9 months [53]. Studies indicate that both fractional and total dose should be adjusted according to the patient's general condition and life expectancy, as well as any previously administered dose of external beam irradiation. The most common irradiation schedules range from a single dose of 10-12 Gy through two fractions of 8 Gy to three fractions of 6-7.5 Gy. This allows for an EQD2 of alpha/beta 10 ranging from 16.6 to 32.8 Gy [13]. A comparative analysis between intraesophageal brachytherapy and other palliative techniques indicates a benefit of brachytherapy in relieving dysphagia. This was demonstrated both in a review paper with a meta-analysis of prospective studies by [PERSON] et al. [7] and in an Italian literature review by [PERSON] et al. [54]. These studies also highlight the relatively low toxicity of the treatment, which was 8-12% in grades 3 and 4. Studies comparing brachytherapy with other palliative techniques have also been conducted. In 2002, the first randomized study comparing stenting and endobronchial brachytherapy (one fraction--12 Gy) was published. It showed an advantage of brachytherapy over stenting in terms of dysphagia-free time, weight loss, and improved quality of life [55]. There are no randomized trials directly comparing brachytherapy with EBRT. The results of the NTR7397 trial comparing three palliative treatment regimens--brachotherapy 12 Gy once and EBRT five times of 4 Gy up to 20 Gy--have still not been published. Only an indirect comparison is possible. Based on a comparison of the POLER 1 study in which EBRT (20 Gy/5 fr/4 Gy) was used to relieve dysphagia and the SIREC study in which a single dose of 10 Gy was used, it was shown that both therapies offered similar results in terms of relieving dysphagia at 3 months after treatment, but EBRT was more effective in controlling pain, nausea, vomiting, and loss of appetite [56]. The standard of first-line treatment for patients with advanced or metastatic esophageal cancer is chemotherapy. Various chemotherapy regimens based on platinum derivatives, fluoropyrimidine, and taxanes are used in the treatment of metastatic esophageal cancer. In the first line, mainly a combination of platinum with fluoropyrimidine derivatives, in subsequent lines, taxanes or irinotecan. In the case of the overexpression of the HER 2 receptor in adenocarcinoma, the use of trastuzumab is possible. Since the prognosis after such treatment remains poor, attempts are made to use immunotherapy alone or in combination with chemotherapy. The indications for its use vary depending on histology. In squamous cell carcinomas, the CheckMate 648 study, in which patients were randomized to three cohorts of nivolumab with ipilimumab, nivolumab with cisplatin-fluorouracil chemotherapy and chemotherapy alone, showed that, in patients with PD-L1 positive status, prolonged survival was achieved in both the immunotherapy alone and chemotherapy with immunotherapy groups compared to chemotherapy alone [57]. Similarly, the benefit of adding immunotherapy to chemotherapy was shown in the PD-L1 CPS 10 or above group after pembrolizumab in the Keynote 590 trial and in the overall patient group after Camrelizumab in the ESCORT first trial [58; 59].