Involved field irradiation compared with prophylactic nodal irradiation to unresectable esophageal carcinoma: A retrospective study.

Abstract

e15180 Background: We retrospectively observed the failure patterns in patients of local advanced esophageal squamous cell carcinoma (ESCC) with involved field irradiation (IFI) or with intentional prophylactic nodal irradiation (PNI). Methods: The ESCC patients with unresectable lesion (length >6 cm or T4 or obvious node metastasis) were retrospectively analyzed between 2003 and 2009. All the reviewed patients received 3D-CRT with cisplatin based chemotherapy. For the IFI cases, the GTV was defined as any visible esophageal lesion(GTVe) and clinical involved node(GTVn). The CTVe was defined as the GTVe plus a 3-4cm margin superior and inferior to the primary tumor and a 1.0 cm radial margin. CTVn was defined as the GTVn plus a 0.5cm radial margin. The PTV was defined as CTV plus a 1.0cm margin. For the PNI cases, the same margins outside the primary tumor as that in IFI, and the adjacent regional lymphatics was included in the CTV according to the different location of primary tumor. The prescribed dose to PTV in IFI group was 60-64 Gy in 6-7 weeks and to PNI group was 40-50GY in 4-5weeks followed by 10-20Gy to PTVe+n. Results: Thirty-six cases received IFI and 49 cases underwent PNI. There were no difference between IFI and PNI group in tumor length and nodal status. The clinical response rates were 94.4% and 97.9% in IFI and PNI group, respectively, and no statistical difference was found ( P=0.785).The patterns of first failure in IFI and PNI group were listed as follows:(1) involved field failure, 17/36 vs 34/49 , P=0.046; (2) prophylactic nodal failure, 10/36 vs 4/49 P=0.02; (3) out field of regional nodal failure, 8/36 vs 15/49 , P=0.464; (4) distant metastasis, 17/36 vs 26/49, P=0.663. The medium PFS were 8.5m vs 12.0m( P=0.602), and the median OS were 14.0m vs 16.0m ( P=0.924)in IFI and in PNI group, respectively, and no statistical difference was found. Conclusions: Chemo-radiotherapy with PNI for unresectable ESCC showed better prophylactic field control, but had no advantage over the IFI in LC, PFS and OS.The involved field failure and distant metastasis were the main causes of failure in both groups, which suggests that the prophylactic irradiation may be not necessary for this sub-group patients.