The Impact of splenic irradiation during chemoradiation for Gastric and Gastroesophageal junctional cancers in the development of acute hematological toxicity

Abstract

Background : Spleen being in close proximity to radiation field in patients of gastric and gastroesophageal carcinomas treated with radiotherapy will inadvertently receive a part of the dose. The purpose of this study was to determine the impact of radiation dose and fractional volume of irradiated spleen in the setting of chemoradiation therapy for gastric and gastroesophageal junctional cancers on haematologic toxicity. Materials and Methods: 40 patients with gastric and gastroesophageal junctional cancers who received concurrent chemoradiation were retrospectively analysed in the Department of Radiation oncology, Father Muller Medical College. Splenic dose-volume histogram (DVH) parameters were calculated as mean splenic dose (MSD) and percentage of splenic volume receiving 10 Gy (V10), 20 Gy (V20), 30 Gy (V30) and 40 Gy (V40) dose and correlated with clinical blood parameters.Mean, percentage, standard deviation and Student paired t-test were used to analyse the results. Results: All the patients experienced haematological toxicities, including 7 patients with grade 3 leukopenia and 3 had grade 4 leukopenia, 19 with grade 2 thrombocytopenia and 4 had grade 3 thrombocytopenia, 28 with both leukopenia and lymphopenia. Mean dose to the spleen was 32 Gy (range 27-37). Higher spleen V10-V40 was correlated with leukopenia, lymphopenia and thrombocytopenia. Conclusion: This dosimetric study demonstrates that splenic radiation was correlated with haematological toxicities, however role of chemotherapy as cause for toxicity could not be assessed as separate variable in this study. Future clinical correlational studies are needed to significantly determine the splenic dose contraints. Key Messages: Radiation therapy for gastric and gastroesophageal carcinoma leads to significant dose to spleen causing an impact in acute haematological toxicities.