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

Seo Hee Choi,Jin Sung Kim,So Hyun Park,Jong Geol Baek,Jason Joon Bock Lee,Hong In Yoon

doi:10.1186/s13014-019-1263-7

Seo Hee Choi, Jin Sung Kim + Show 4 more

Open Access

https://doi.org/10.1186/s13014-019-1263-7

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Abstract

BackgroundAlthough there have been many attempts to increase the therapeutic ratio of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), only a few planning studies have reported the efficacy of the modern radiotherapy technique till date. Therefore, we performed the dosimetric comparison among 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) plans, using deep-inspiration breath hold (DIBH) or free-breathing (FB) techniques, to determine the most optimal plan for gastric MALToma.MethodsWe evaluated 9 patients with gastric MALToma for whom 3D-CRT, step-and-shoot IMRT (SIMRT), volumetric-modulated arc therapy (VMAT), and tomotherapy plans with identical prescribed doses were generated using DIBH or FB computed tomography (CT). Planning target volume (PTV) coverage and non-target doses were calculated for each plan and compared with plan quality metric (PQM) scores.ResultsAll 72 plans of 9 patients satisfied our dosimetric goals, and the IMRT plans and 3D-CRT plans had similarly good conformity index values with no differences related to respiratory movement. IMRT plans yielded significantly better doses to the organs-at-risk, and DIBH plans yielded significantly lower liver, heart, and lung Dmean and spinal cord Dmax with smaller irradiated volumes compared to FB plans. For the mean PQM scores, VMAT-DIBH and SIMRT-DIBH yielded the best scores, whereas 3D plans provided reduced beam monitor unit values.ConclusionOur findings demonstrate that modern RT technologies (DIBH with VMAT or SIMRT) could potentially provide excellent target coverage for gastric MALToma while reducing doses to organs-at-risk. However, the relevance of the most optimal plan considering clinical outcomes should be confirmed further in a larger patient cohort.

Highlights

There have been many attempts to increase the therapeutic ratio of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), only a few planning studies have reported the efficacy of the modern radiotherapy technique till date
Our findings demonstrate that modern RT technologies (DIBH with volumetric-modulated arc therapy (VMAT) or shoot IMRT (SIMRT)) could potentially provide excellent target coverage for gastric MALToma while reducing doses to organs-at-risk
All D95 values were larger than 95% of the prescribed dose, the tomotherapy plans yielded the best result, followed by SIMRT, VMAT, and 3D-plans, with no differences between the deepinspiration breath hold (DIBH) and FB plans

Summary

Introduction

There have been many attempts to increase the therapeutic ratio of radiotherapy for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), only a few planning studies have reported the efficacy of the modern radiotherapy technique till date. The recent National Comprehensive Cancer Network (NCCN) guidelines recommend 30 Gy involved-site radiation therapy for gastric MALToma [9]; this generally involves the entire stomach and adjacent perigastric lymph nodes (if involved). This involved-site radiation therapy uses low doses, the doses to the organs-at-risk (OARs) near the stomach, such as the kidneys, small bowel, or liver, must be considered.

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