Planning comparison between standard and conformal 3D techniques in post-operative radiotherapy of gastric cancer: a systematic review

The objective of this study was to establish the impact of three-dimensional conformal radiotherapy (3D-CRT) technique in post-operative radiotherapy of gastric cancer. A bibliographical research was performed using the PubMed. On the database, Search was carried out using Medical Subject Heading (MeSH) database; the algorithm for search was ''Radiotherapy" (MeSH) AND ''Stomach Neoplasms" (MeSH). Only planning comparative studies on conformal techniques vs standard techniques in post-operative radiotherapy of gastric cancer were included in the review process. We identified 185 papers, five of them fulfilling the inclusion criteria. A great inhomogeneity was observed regarding the analysed dosimetric end points. Three of the five studies reported a benefit in favour of 3D-CRT for target irradiation despite a minimal advantage in most cases. The liver was better spared from irradiation by the traditional technique in all studies. No univocal result was obtained for the right kidney: the traditional technique performed better in two studies, 3D-CRT yielded better results in two others, whereas in the fifth study, each technique was either better or worse according to the different considered end point. 3D-CRT, however, allowed for better sparing of the left kidney in four studies. There is no absolute reason to prefer 3D-CRT with multiple beams in every patient. It may be preferable to choose the technique based on individual patient characteristics. Because there is no proof of superiority for 3D-CRT, there is no absolute reason to exclude patients who are treated in centres equipped with only the two-dimensional technique from the potential benefit of post-operative chemoradiation.