Radiat Oncol J.  2018 Dec;36(4):332-340. 10.3857/roj.2018.00402.

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

• Chung JH
• Na K
• Kim IH

• KMID: 2434322
• DOI: http://doi.org/10.3857/roj.2018.00402

Abstract

PURPOSE
To retrospectively analyze dosimetric parameters of volumetric-modulated arc therapy (VMAT) and three-dimensional conformal radiotherapy (3D-CRT) delivered to extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue in the stomach (gastric MALT lymphoma) to find out advantages of VMAT and conditions for definite benefits of VMAT.
MATERIALS AND METHODS
Fifty patients with stage I-II gastric MALT lymphoma received VMAT (n = 14) or 3D-CRT (n = 36) between December 2005 and April 2018. Twenty-seven patients were categorized according to whether the planning target volume (PTV) overlaps kidney(s). Dosimetric parameters were analyzed by dose-volume histogram.
RESULTS
Radiation dose to the liver was definitely lower with VMAT in terms of mean dose (p = 0.026) and V15 (p = 0.008). The V15 of the left kidney was lower with VMAT (p = 0.065). For those with PTV overlapping kidney(s), the left kidney V15 was significantly lower with VMAT. Furthermore, the closer the distance between the PTV and kidneys, the less the left kidney V15 with VMAT (p = 0.037). Delineation of kidney(s) by integrating all respiratory phases had no additional benefit.
CONCLUSIONS
VMAT significantly increased monitor units, reduced treatment time and radiation dose to the liver and kidneys. The benefit of VMAT was definite in reducing the left kidney V15, especially in geometrically challenging conditions of overlap or close separation between PTV and kidney(s).

Keyword

Volumetric-modulated arc therapy; 3-D conformal radiotherapy; Gastric MALT lymphoma; Organs at risk; Kidney dose; Liver dose

MeSH Terms

Humans
Kidney
Liver
Lymphoid Tissue*
Lymphoma, B-Cell, Marginal Zone*
Organs at Risk
Radiotherapy, Conformal*
Radiotherapy, Intensity-Modulated*
Retrospective Studies
Stomach*