Influence of Delayed Gastric Emptying in Radiotherapy after a Subtotal Gastrectomy

Kim, Dong Hyun; Kim, Won Taek; Lee, Mi Ran; Ki, Yong Gan; Nam, Ji Ho; Park, Dal; Jeon, Ho Sang; Jeon, Kye Rok; Kim, Dong Won

Abstract

PURPOSE
This aim of this study was to evaluate changes in gastric volume and organ position as a result of delayed gastric emptying after a subtotal gastrectomy performed as part of the treatment of stomach cancer. MATERIALS AND METHODS: The medical records of 32 patients who underwent concurrent chemoradiotherapy after a subtotal gastrectomy from March 2005 to December 2008 were reviewed. Of these, 5 patients that had more than 50 cc of residual gastric food detected at computed tomography (CT) simulation, were retrospectively enrolled in this study. Gastric volume and organ location was measured from CT images obtained before radiotherapy, twice weekly. In addition, authors evaluated the change of radiation dose distribution to planning the target volume and normal organ in a constant radiation therapy plan regardless of gastric volume variation. RESULTS: A variation in the gastric volume was observed during the radiotherapy period (64.2~340.8 cc; mean, 188.2 cc). According to the change in gastric volume, the location of the left kidney was shifted up to 0.7 - 2.2 cm (mean, 1.2 cm) in the z-axis. Under-dose to planning target volume (V43, 79.5+/-10.4%) and over-dose to left kidney (V20, 34.1+/-12.1%; Mean dose, 23.5+/-8.3 Gy) was expected, given that gastric volume change due to delayed gastric emptying wasn't taken into account. CONCLUSION: This study has shown that a great change in gastric volume and left kidney location may occur during the radiation therapy period following a subtotal gastrectomy, as a result of delayed gastric emptying. Detection of patients who experienced delayed gastric emptying and the application of gastric volume variation to radiation therapy planning will be very important.