Radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma: dosimetric comparison and risk assessment of solid secondary cancer

Abstract

PurposeTo determine the optimal radiotherapy technique for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), we compared the dosimetric parameters and the risk of solid secondary cancer from scattered doses among anterior-posterior/posterior-anterior parallel-opposed fields (AP/PA), anterior, posterior, right, and left lateral fields (4_field), 3-dimensional conformal radiotherapy (3D-CRT) using noncoplanar beams, and intensity-modulated radiotherapy composed of 7 coplanar beams (IMRT_co) and 7 coplanar and noncoplanar beams (IMRT_non).Materials and MethodsWe retrospectively generated 5 planning techniques for 5 patients with gastric MALToma. Homogeneity index (HI), conformity index (CI), and mean doses of the kidney and liver were calculated from the dose-volume histograms. Applied the Biological Effects of Ionizing Radiation VII report to scattered doses, the lifetime attributable risk (LAR) was calculated to estimate the risk of solid secondary cancer.ResultsThe best value of CI was obtained with IMRT, although the HI varied among patients. The mean kidney dose was the highest with AP/PA, followed by 4_field, 3D-CRT, IMRT_co, and IMRT_non. On the other hand, the mean liver dose was the highest with 4_field and the lowest with AP/PA. Compared with 4_field, the LAR for 3D-CRT decreased except the lungs, and the LAR for IMRT_co and IMRT_non increased except the lungs. However, the absolute differences were much lower than <1%.ConclusionTailored RT techniques seem to be beneficial because it could achieve adjacent organ sparing with very small and clinically irrelevant increase of secondary solid cancer risk compared to the conventional techniques.

Combining deep-inspiration breath hold and intensity-modulated radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma: Dosimetric evaluation using comprehensive plan quality indices

“…Previous studies of RT planning techniques for gastric lymphoma have recommended a PTV comprising the CTV plus a 1.5–2-cm margin in all directions [10, 12] for the delivery of radiation in a FB state. Other studies have used respiratory synchronized 4D-CT images to provide information about respiratory-induced organ motion during treatment planning and minimize motion uncertainties [13, 23]. Specifically, Matoma et al [17] compared the usefulness of 4D-CT vs. a uniform margin for the treatment planning of gastric MALToma, and found that the former yielded a significantly smaller mean PTV volume, with significantly lower mean doses to the liver and heart.…”

“…Furthermore, Bae at al. [13] compared 5 planning techniques (AP/PA, 4-field, 3D-CRT, IMRT with only coplanar beams, and IMRT with a few non-coplanar beams). 4D-CT was conducted under a FB status, ITV was defined as the sum total of the entire stomach at every respiratory stage, and CTV was defined as the ITV plus a 1-cm margin.…”

“…Some institutions have implemented the deep-inspiration breath hold (DIBH) technique to address these concerns. However, only a few planning studies have included modern radiotherapy techniques when evaluating the efficacy of this technique [11–13, 17]. Therefore, in the present study, we performed a dosimetric comparison of 3D-CRT and IMRT plans using DIBH or free-breathing (FB) techniques to determine the most optimal treatment plan for gastric MALToma.…”

Progress in the treatment of advanced gastric cancer

“…24 A gastroscopy is required in patients with poor appetite, indigestion, burning sensation, nausea and vomiting, upper abdominal pain, bleeding, and perforation. Radiotherapy may also damage the small intestine.…”

Benefit of volumetric-modulated arc therapy over three-dimensional conformal radiotherapy for stage I-II extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue in the stomach: a dosimetric comparison

“…Both CI and HI were significantly better with the VMAT plan compared to those with a 3D-CRT plan, although the difference was small. Various studies have revealed that IMRT plan yields better value in CI and HI than 3D-CRT [14,20], although other studies have reported that there is no significant difference between the two [12,15]. Most precedent studies used step-and-shoot IMRT rather than VMAT which was utilized in the present study.…”