Comparison of target volume and clinical effects of four radiotherapy plans for acute lymphoblastic leukemia prior to hematopoietic stem cell transplantation

The present study aimed to investigate the variations in target volume, clinical reaction and transplantation effects of helical tomotherapy (HT)-total body irradiation (TBI), HT-total marrow and lymphatic irradiation (TMLI), intensity modulated radiotherapy (IMRT)-TBI and IMRT-TMLI within patients with acute lymphoblastic leukemia (ALL). A total of 18 patients with ALL were treated with the four aforementioned radiotherapy plans prior to hematopoietic stem cell transplantation. A planned prescribed dose of 12 Gy/6 Frequency was administered to determine planning target volume (PTV). Dosimetry evaluation indexes in PTV and organs at risk were analyzed. Comparison of clinical untoward effects and the results of transplantation among the four plans were performed. The conformity index of HT plans was significantly increased compared with those in IMRT plans. The mean dose (D) to the lung and volume ratio of target volume occupied by 5 Gy (V(5)) in TMLI plans were lower compared with TBI plans. Doses to organs were controlled within the normal range. D(max), D(mean) and V(5) of bilateral lungs and D(max) and D(mean) of bilateral crystalline lens in IMRT plans were significantly higher compared with HT plans. There were no significant differences in untoward effects among the four plans. Subsequent to symptomatic treatments with antiemetic, antidiarrheal and fluid infusion, untoward effects improved, and all patients demonstrated tolerance to these therapies. A total of six patients treated with HT-TBI revealed complete and successful transplantation; however, one patient following transplantation suffered from severe rejection and had succumbed to mortality due to severe infection. Patients treated with HT-TMLI, IMRT-TBI and IMRT-TMLI completed successful transplantation and no rejection responses were observed. Conformity of HT plans are higher than that of IMRT plans. The four radiotherapy plans exhibit similar clinical untoward effects and the same transplantation success rate. HT-TMLI is more feasible in dosimetry compared with HT-TBI, IMRT-TBI and IMRT-TMLI, which require further long-term observation.