Safety of total body irradiation using intensity-modulated radiation therapy by helical tomotherapy in allogeneic hematopoietic stem cell transplantation: a prospective pilot study

Abstract

Total body irradiation using intensity-modulated radiation therapy total body irradiation (IMRT-TBI) by helical tomotherapy in allogeneic hematopoietic stem cell transplantation (allo-HSCT) allows for precise evaluation and adjustment of radiation dosage. We conducted a single-center pilot study to evaluate the safety of IMRT-TBI for allo-HSCT recipients. Patients with hematological malignancies in remission who were scheduled for allo-HSCT with TBI-based myeloablative conditioning were eligible. The primary endpoint was the incidence of adverse events (AEs). Secondary endpoints were engraftment rate, overall survival, relapse rate, non-relapse mortality, and the incidence of acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively). Between July 2018 and November 2018, ten patients were recruited with a median observation duration of 571 days after allo-HSCT (range, 496–614). D80% for planning target volume (PTV) in all patients was 12.01 Gy. Average D80% values for lungs, kidneys and lenses (right/left) were 7.50, 9.03 and 4.41/4.03 Gy, respectively. Any early AEs (within 100 days of allo-HSCT) were reported in all patients. Eight patients experienced oral mucositis and gastrointestinal symptoms. One patient experienced Bearman criteria grade 3 regimen-related toxicity (kidney and liver). All cases achieved neutrophil engraftment. There was no grade III–IV aGVHD or late AE. One patient died of sinusoidal obstruction syndrome 67 days after allo-HSCT. The remaining nine patients were alive and disease-free at final follow-up. Thus, IMRT-TBI was well tolerated in terms of early AEs in adult patients who underwent allo-HSCT; this warrants further study with longer observation times to monitor late AEs and efficacy.

ESTRO ACROP and SIOPE recommendations for myeloablative Total Body Irradiation in children

“…The PTV is adjusted 3-5 mm inside of the body contour For planning ease, PRV of OAR can be excluded from the body PTV [17,18,198,200] PRVs of 3-5 mm inside OAR (e.g. lungs, kidneys) may help to ensure adequate dose on surrounding lymphatic or medullary structures.…”

“…Several centers have implemented these techniques as standard TBI solution. The first reported clinical results are promising [121,196,200], but more reports and longer follow-up results need to establish its base for standard TBI setup. For implementation of optimized TBI, measures need to be taken to ensure robust planning, high reproducibility, safety, and stringent quality control.…”

Fractionated Total Body Irradiation on an Infant Using Tomotherapy

“…Since the patient was only 82 cm in length, it was possible to treat the entire body using a single plan in head first supine (HFS) position in 16.8 minutes [2][3][4]. Another advantage of treatment on the Radixact was that the patient had a more comfortable setup as they lie supine with arms at the side in an immobilization device.…”

“…A third method for total body irradiation treatment was commissioned on the Radixact® (Accuray Incorporated, Sunnyvale, California, United States) unit using a helical tomotherapy approach. This report describes the treatment delivery of fractionated TBI using helical tomotherapy with pediatric anesthesia, which enabled delivery of the prescribed dose with appropriate sparing of the lungs [ 2 ]. This technique may serve as an equivalent technological alternative to consider when patients are young and lung sizes are small for TBI using two-dimensional treatment planning techniques.…”

Total Body Irradiation in Haematopoietic Stem Cell Transplantation for Paediatric Acute Lymphoblastic Leukaemia: Review of the Literature and Future Directions

“…It is a fundamentally different approach to extended SSD TBI because it uses a much higher dose rate and requires field junctioning. Examples of isocentric TBI techniques include TomoTherapy (29,(290)(291)(292)(293) and VMAT (30,125,127,294) (Figure 3). These isocentric techniques are seeing nascent clinical implementation in centres around the world, although outcome data from longterm follow-up are yet to be published.…”