Protection of organs at risk during neoadjuvant chemoradiotherapy for gastric cancer based on a comparison between conformal and intensity-modulated radiation therapy

Abstract

Abstract. The aim of the present study was to compare the techniques of dynamic intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in patients with gastric cancer. Implementation of the IMRT technique does not significantly affect the minimum and maximum dose levels in the planning target volume (PTV), but more effectively protects the critical organs. The study group consisted of 25 patients. The results of the analysis of the conformity index (CI) and the homogeneity index (HI) showed that the doses in the PTV regions were at a comparable level. The CI for the PTV was 0.95 for the 2-field technique, 0.95 for the 3-field technique, 0.96 for the 4-field technique and 0.94 for the IMRT technique. The CIs for these techniques for the clinical target volume (CTV) were 0.96, 0.96, 0.97 and 0.96, respectively, and the CIs for the gross tumor volume (GTV) were 0.99, 0.99, 0.99 and 0.98, respectively. The HI values for the PTV were 1.12 for the 2-field technique, 1.12 for the 3-field technique, 1.09 for the 4-field technique and 1.09 for the IMRT technique, and the HI values for the CTV were 1.12, 1.12, 1.09 and 1.08 for the same techniques, respectively. The HI values for the GTV were 1.09, 1.09, 1.07 and 1.06, respectively, which indicated significantly superior performance in the regions of healthy tissue. Statistical study was based on Friedman's rank analysis of variance to determine the level of reliability of the tested groups of variables (P<0.001). The present study demonstrated that the IMRT technique in the pre-operative radiotherapy of gastric cancer patients results in superior treatment tolerance and reduces the risk of damage to healthy tissue that is in close proximity to the irradiated area.

Comparisons between the Dosimetric and Clinical Outcomes of Tomotherapy and 3D Conformal Radiotherapy in Gastric Cancer Treatment

“…The radiation dose distribution can be improved in targeted areas while reducing the radiation dose in normal organs in IMRT (Ringash et al, 2005). Although IMRT provides superior treatment tolerance and reduces the risk of damage to healthy tissues, its advantageous effects on survival have not been reported in the literature (Hawrylewicz et al, 2016). In the present study, although the number of patients in stage IIIC were higher in the TOMO treated group, the survival rate was significantly better in those treated with TOMO.…”

Efficacy and safety of intensity-modulated radiation therapy versus three-dimensional conformal radiation treatment for patients with gastric cancer: a systematic review and meta-analysis

“…A previous study showed significant grade 3 toxicity in patients with resected gastric or gastroesophageal junction cancers treated with 3D-planned CRT [20]. In recent years, several clinical trials have been performed to evaluate clinical outcomes and toxicity in patients with resected gastric cancer treated with IMRT versus 3D-CRT [21–28]. Minn et al [29] compared the clinical efficacy and adverse events in patients with gastric cancer who received IMRT versus 3D-CRT.…”

S3-Leitlinie Magenkarzinom – Diagnostik und Therapie der Adenokarzinome des Magens und des ösophagogastralen Übergangs – Langversion 2.0 – August 2019. AWMF-Registernummer: 032/009OL

“…Die Chemotherapie parallel zur Bestrahlung ist zumeist platinbasiert und orientiert sich an den etablierten Standard-Protokollen der S3-Leitlinie Ösophagus-Karzinom in der jeweils aktuell gültigen Version, derzeit Version 1.0 -September 2015 AWMF-Register-Nummer: 021/023OL[524]. Aufgrund der sehr komplexen anatomischen Verhältnisse und der Lagevariabilität der Organe sind moderne Bestrahlungsverfahren wie intensitätsmodulierte Radiotherapie IMRT und Nachfolgetechniken (VMAT, volumenmodulierte Arc-Therapie) in Kombination mit einer bildgeführten Bestrahlung (IGRT, Image-guided Radiotherapy) und eine Bestrahlungsplanung in 4D-Technik zu bevorzugen, da sie eine bessere Schonung benachbarter Organe und eine sicherere Erfassung der zu behandelnden Region ermöglichen[524,[527][528][529][530]. Die Dosierung der Strahlentherapie erfolgt ebenfalls analog zur definitiven Radiochemotherapie des Ösophaguskarzinoms.11.…”