Preliminary Evaluation of Postoperative Radiotherapy between Small T-Shaped Field and All Regional Lymph Nodes Field in Thoracic Esophageal Squamous Cell Carcinoma

Abstract

<h3>Purpose/Objective(s)</h3> The optimal extent of clinical target volume (CTV) for postoperative radiotherapy in complete resection thoracic esophageal squamous cell carcinoma (ESCC) patients remains controversial. This study aimed to evaluate the preliminary results of postoperative radiotherapy with standard all regional lymph nodes field and adjusted small T-shaped field. <h3>Materials/Methods</h3> A total of 75 thoracic ESCC patients were enrolled from April 2017 to March 2021, retrospectively. Among them were 63 males and 12 females, with an average age of 64.28 (range, 49-82) years. All patients received intensity-modulated radiotherapy (IMRT) at a dose of 45-50.4Gy/25-28F after radical resection of esophageal carcinoma, of which 39 cases were small T-shaped field (including bilateral supraclavicular lymph nodes, upper and middle mediastinal lymph nodes, small T group),36 cases were all regional lymph nodes field (including tumor bed, bilateral supraclavicular lymph nodes, all mediastinal lymph nodes, left gastric lymph nodes and celiac lymph nodes, control group). 24 cases (32%) received concurrent chemotherapy and 57 cases (76%) received adjuvant chemotherapy. The median follow-up period was 31(range, 15-57) months. <h3>Results</h3> At the end of follow-up period, 7 (17.9%) cases had locoregional recurrence (LRR) and 8(20.5%) had distant metastasis (DM) in small T group, while 9 (25%) cases had LRR and 9 (25%) had DM in control group. There was no significant difference in LRR rate (p=0.456) and DM rate (p=0.643) between the two groups. There was also no significant difference in the total OS rate between the two groups (p=0.146). In terms of radiotherapy parameters, in small T group, the median values of V5, V20 and average dose of the lungs were 37.31%, 16.43% and 8.11Gy, respectively. The median value of the maximum dose of spinal cord was 29.95Gy. For the heart, the median value of the average dose and V30 were 5.13Gy and 2.64%. And the median value of V40 of the stomach was 34.32%. In control group, the median values of V5, V20 and average dose of the lungs were 53.49%, 22.08% and 11.41Gy. The median value of the maximum dose of spinal cord was 36Gy. For the heart, the median value of the average dose and V30 were 27.52Gy and 37.39%. And the median value of V40 of the stomach was 63%. All of the above parameters in small T group were significantly lower than those in control group (p<0.05). In addition, we observed grade 2 radiation pneumonitis and grade 2 radiation esophagitis in both groups:9 cases of radiation pneumonia with grade 2 or above in control group and only 1 case in small T group (p<0.001). There were 15 cases of radiation esophagitis with grade 2 or above in control group and 6 cases in small T group (p=0.024). <h3>Conclusion</h3> In conclusion, radiotherapy with small T-shaped field might be a feasible and efficacious postoperative approach for ESCC patients.