Successful treatment of a free-moving abdominal mass with radiation therapy guided by cone-beam computed tomography: a case report

Abstract

IntroductionBecause tumors in the abdomen can change position, targeting these tumors for radiation therapy should be done with caution; use of daily image-guided radiation therapy is advised.Case presentationWe report the case of a 72-year-old Caucasian man with recurrent mantle cell lymphoma who was referred for palliative radiation therapy for an abdominopelvic tumor. Computed tomography was used to generate images for radiation treatment planning. Comparison of those planning images with a positron emission tomography/computed tomography scan ordered during the planning period revealed that the tumor had moved from one side of the abdomen to the other during the three-day interval between scans. To account for this unusual tumor movement, we obtained a second set of planning computed tomography scans and used a Varian cone-beam computed tomography scanner with on-board imaging capability to target the tumor before each daily treatment session, leading to successful treatment and complete resolution of the mass.ConclusionAbdominal masses associated with the mesentery should be considered highly mobile; thus, radiation therapy for such masses should be used with the utmost caution. Modern radiation therapy techniques offer the ability to verify the tumor location in real time and shift the treatment ports accordingly over the course of treatment.

Daily CT guidance improves target coverage during definitive radiation therapy for gastric MALT lymphoma

“…1–5 In the case of gastric mucosa–associated lymphoid tissue (MALT) lymphoma, challenges include (1) respiratory-induced movement of the stomach by up to 3 cm 6,7 ; (2) variation in the shape, size, and location of the stomach because of intrinsic organ motion 4,6–8 ; and (3) differences in stomach filling and distension. These uncertainties can greatly affect target localization and the accuracy of treatment delivery.…”

Hitting a Moving Target: Successful Management of Diffuse Large B-cell Lymphoma Involving the Mesentery With Volumetric Image-guided Intensity Modulated Radiation Therapy

“…CT-based imaging is commonly utilized for radiation treatment of gastrointestinal malignancies and can provide information regarding daily internal anatomy to inform treatment delivery. Although all abdominal organs demonstrate internal motion due to breathing and peristalsis, masses within the mesentery have been notorious for marked daily changes in location, which can complicate radiation treatment planning and delivery [25]. Given these technical challenges, many are reticent to refer for or to offer radiation therapy to disease in the mesentery, as there is some uncertainty as to whether a planned treatment is effectively delivered.…”

“…However, the use of IMRT for a moving target is yet another obstacle. Using specialized software and CT imaging, physicians are able to provide sub-millimeter accuracy to localize and target a specific mass prior to each treatment [25, 35], making CT-guidance for treatment of a moving mesenteric target possible. In our study daily CT on rails imaging was utilized, which is known to have image quality comparable to a diagnostic CT scan.…”

“…There was one case in this series in which the shift was so significant than re-simulation using a breath hold technique was recommended. We have also previously reported on mobile mesenteric masses requiring adaptable treatment plans[25]. The need for adaptive planning is more common when the target lies was in close proximity to the kidneys or other normal structures.…”

“…The use of daily cone-beam computed tomography (CT) has become routine when treating mobile masses such as lung tumors to ensure reproducibility of radiation treatment [24]. There have been reports of using cone beam CT to treat mobile abdominal masses, though this is not currently a common practice [25, 26]. …”