A comparative planning study on the treatment of gastric cancer patients with tomotherapy, coplanar and non-coplanar three-dimensional conformal radiotherapy (3D-CRT)

Background: The main purpose of this study is to investigate different methods of radiotherapy (RT) using coplanar three-dimensional conformal RT (3D-CRT (cp)), non-coplanar 3D-CRT RT (3D-CRT (ncp)) and helical tomotherapy (HT) techniques to find the optimal method to treat gastric cancer patients. Materials and Methods: Twenty patients with gastric cancer were retrospectively enrolled. Three different treatment plans including HT, 3D-CRT (cp) and 3D-CRT (ncp) were generated and optimized for each patient. All plans were then evaluated with respect to dosimetric parameters exported from dose-volume histogram curves of target and organ-at-risk (OAR). SPSS software was used for statistical analysis. Results: The conformity index in the target was similar for all plans (p > 0.05), but HT showed significantly better homogeneity compared to the two 3D-CRT methods (p-value < 0.05). Compared to the 3D-CRT (cp) and 3D-CRT (ncp) plans, the HT plans significantly reduced the mean dose, V13 and V20 values of the kidneys (p-Value < 0.05); V5 values of both kidneys were lower in the 3D-CRT (ncp) plan compared to 3D-CRT (cp) and HT. The difference was statistically significant. Moreover, the results proved that the 3D-CRT (ncp) could better preserve kidneys rather than 3D-CRT (cp). Dmean of the liver for HT plans (20.03) was significantly higher than those for both coplanar and non-coplanar 3D-CRT plans (17.86 and 17.7, respectively). Conclusion: Generally, HT plans appear to be the best, but in the case of selecting an optimum method, it is necessary to pay attention to the location of tumors compared to OARs.