## 2 Brachytherapy as Radical Treatment
### Brachotherapy Combined with Teleral radiotherapy in the Treatment of Early Esophageal Cancer  
As the degree of local advancement increases, the risk of lymph node metastases increases, e.g., in stage T1b, it is 20% [2,13]. In the case of local advancement in stages above T1a-T2, the combination of brachytherapy with teleral radiotherapy is justified (Figure 2). However, such treatment is not the standard of care, and surgical treatment remains the basis of treatment in these stages of advancement [6]. Despite this, the results of treatment using teleral radiotherapy with brachytherapy are very good [9,14]. The effectiveness of treatment decreases with an increasing depth of infiltration and is the greatest when the mucous membrane is involved. Studies indicate that the 5-year local control in such cases reaches 100% in patients with mucosa involvement and 75% in those with submuc involvement [15], although some analyses indicate that the 2-year local control rate is only 63% [16]. In the case of submucosal invasion, the local control rate is slightly lower, usually approximately 10%, compared to stage T1a [12,17]. Five-year survival rates vary in different analyses and range from 31 to 66% [14, 18, 19, 20, 21, 22, 23] (Table 1). There are no studies directly comparing the effectiveness of combined EBRT and BT vs. surgical treatment, but the results seem to be slightly worse than those of surgical treatment (5-OS 77-85.5%) [24,25]. The diversity of results is influenced by the retrospective nature of the studies and the variety of treatment regimens. Teleral radiotherapy doses range from 50 to even 70 Gy, conventionally fractionated in the dose range of 1.8-2 Gy [14, 18, 19, 20, 21, 22, 23]. The variety of brachytherapy regimens is even greater when low dose rate (LDR) and high dose rate (HDR) techniques are used. The number of fractions was from 1 to 4, and the fractional dose was from 3 to 7.5 Gy, which gave a different biologically effective dose (EQD2). EQD2 for the alpha/beta = 10 ratio ranged from nearly 10 to even 32 Gy, which gave a total biologically equivalent dose of over 70 Gy. Some studies also used concurrent chemotherapy, mainly based on cisplatin with 5 FU. Current indications for radiochemotherapy alone recommend a dose of 50.4 Gy, conventionally fractionated without the use of brachytherapy, which is a much lower dose than in the above analyses. Late complications were related to BT dose and the number of fractions--17% for 12 Gy compared to 80% for 24 Gy [22]. Ulcers occurred in 3.5-20%, depending on the study. Less common complications included fistula, esophageal stricture, radiation pneumonia, and heart failure [10, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 26]. Neoadjuvant radiochemotherapy according to the CROSS regimen is the cornerstone of treatment for more advanced (T2-T3, N0-1, M0) operable esophageal cancer. Pre-operative radiotherapy up to 41.4 Gy concurrent with paclitaxel and carboplatin significantly improved OS and DFS compared to surgery alone in patients with the resectable (T1N1M0, T2-T3, N0-1.M0) cancer of the esophagus or gastroesophageal junction (GEJ). The median OS in the study group was 5 years, and in the control group, 2 years [27]. Improved OS in patients with gastric adenocarcinoma and GEJ was noted when surgery was combined with subsequent radiochemotherapy in the SWOG/INT 0116 study. The median OS was 36 months in the group treated with chemoradiotherapy compared to 27 months in patients treated with surgery alone [28]. In the CALGB 9781 study, in the group of patients treated with induction radiochemotherapy with cisplatin and 5 FU, the median OS was nearly 4.5 years, and in patients treated solely with surgery, almost 1.8 years [29]. Based on the above studies, induction radiochemotherapy has become the standard in the treatment of early cancer of the esophagus and gastroesophageal junction. The role of surgical treatment in patients who achieve a complete response after radiochemotherapy remains controversial.