Radiotherapy of 180 cases of operable esophageal carcinoma

Applying the technique of volume-modulated arc radiotherapy to upper esophageal carcinoma

This study aims to evaluate the possibility of using the technique of volume-modulated arc therapy (VMAT) to combine the advantages of simplified intensity-modulated radiation therapy (sIMRT) with that of regular intensity-modulated radiation therapy (IMRT) in upper esophageal cancer. Ten patients with upper esophageal carcinoma were randomly chosen in this retrospective study. sIMRT, IMRT, and VMAT plans were generated to deliver 60 Gy in 30 fractions to the planning target volume (PTV). For each patient, with the same clinical requirements (target dose prescription, and dose/dose-volume constraints to organs at risk (OARs)), three plans were designed for sIMRT (five equispaced coplanar beams), IMRT (seven equispaced coplanar beams), and VMAT (two complete arcs). Comparisons were performed for dosimetric parameters of PTV and of OARs (lungs, spinal cord PRV, heart and normal tissue (NT)). All the plans were delivered to a phantom to evaluate the treatment time. The Wilcoxon matched-pairs, signed-rank test was used for intragroup comparison. For all patients, compared to sIMRT plans, VMAT plans statistically provide: a) significant improvement in HI and CI for PTV; b) significant decrease in delivery time, lung V20, MLD, heart V30 and spinal cord PRV D1cc; c) significant increase in NT V5; and d) no significant reduction in lung V5, V10, and heart MD. For all patients, compared to IMRT plans, VMAT plans statistically provide: a) significant improvement in CI for PTV; b) significant decrease in delivery time, lung V20, MLD, NT and spinal cord PRV D1cc; c) significant increase in NT V5; and d) no significant reduction in HI for PTV, lung V5, V10, heart V30 and heart MD. For patients with upper esophageal carcinoma, using VMAT significantly reduces the delivery time and the dose to the lungs compared with IMRT, and consequently saves as much treatment time as sIMRT. Considering those significant advantages, compared to sIMRT and IMRT, VMAT is the first choice of radiotherapy techniques for upper esophageal carcinoma.

VEGF165 antisense RNA suppresses oncogenic properties of human esophageal squamous cell carcinoma

AIM: To investigate the effect of antisense RNA to vascular endothelial growth factor165 (VEGF₁₆₅) on human esophageal squamous cell carcinoma cell line EC109 and the feasibility of gene therapy for esophageal carcinoma.

METHODS: By using subclone technique, the full length of VEGF₁₆₅ amino acid cDNA, which was cut from pGEM-3Zf(+), was cloned inversely into the eukaryotic expression vector pCEP4.The recombinant plasmid pCEP-AVEGF₁₆₅ was transfected into EC109 cell with lipofectamine. After a stable transfection, dot blot, enzyme-linked immunosorbent assay (ELISA), laser confocal imaging system analysis, transmission electron microscopy and flow cytometry were performed to determine the biological characteristics of EC109 cell line before and after transfection in vitro and whether there was a reversion in the tumorigenic properties of the EC109 cell in vivo.

RESULTS: The eukaryotic expression vector pCEP-AVEGF₁₆₅ was successfully constructed and transfected into EC109 cells. The expression of VEGF₁₆₅ was significantly decreased in the transfected cells while the biological characteristics of the cells were not influenced by the expression of antisense gene. The tumorigenic and angiogenic capabilities were greatly reduced in nude mice, as demonstrated by reduced tumor end volume (820 ± 112.5) mm³vs (7930 ± 1035) mm³ and (7850 ± 950) mm³,P£¼0.01£½ and microvessel density(8.5 ± 1.2) mm^-2vs (44.3 ± 9.4) mm^-2 and (46.4 ± 12.6) mm^-2,P < 0.01) in comparison between experimental groups empty vector transfected group and control group.

CONCLUSION: The angiogenesis and tumorigenicity of human esophageal squamous cell carcinoma were effectively inhibited by VEGF₁₆₅ antisense RNA. Antisense RNA to VEGF₁₆₅ can potentially be used as an adjuvant therapy for solid tumors.