Comparison of two total body irradiation fractionation regimens with respect to acute and late pulmonary toxicity

High dose total marrow irradiation (TMI) does not increase long-term toxicity of myeloablative fludarabine/busulfan (FluBu4) conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT)

OBJECTIVES

Based on a previous phase 1 study, total marrow irradiation (TMI) at 9Gy was added to a myeloablative FluBu4 conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT) for myeloid malignancies. Here, we report on the long-term toxicity of TMI combined with FluBu4 and compare it to patients who received only FluBu4.

METHODS

We retrospectively analyzed 38 consecutive patients conditioned with FluBu4/TMI (n = 15) or FluBu4 (n = 23, control group) who had at least 1 year follow-up post-transplant. The rate of long-term adverse events that have been previously associated with total body irradiation (TBI) was analyzed in the two groups.

RESULTS

The baseline characteristics did not differ between the two groups. The control group had a longer median follow-up (71.2 mo) than the TMI group (38.5 mo) (p = .004). The most common adverse events were xerostomia, dental complications, cataracts, or osteopenia and did not differ between the two groups. Cognitive dysfunction or noninfectious pneumonitis, often detected after high dose TBI, were also not different in the two groups (p = .12 and p = .7, respectively). There was no grade 4 adverse event.

CONCLUSION

Our results suggest that a conditioning regimen with TMI 9Gy and FluBu4 does not increase long-term adverse events after allogeneic HSCT.

Diffuse Alveolar Hemorrhage in Hematopoietic Cell Transplantation

Diffuse alveolar hemorrhage (DAH) is a morbid syndrome that occurs after autologous and allogeneic hematopoietic cell transplantation in children and adults. DAH manifests most often in the first few weeks following transplantation. It presents with pneumonia-like symptoms and acute respiratory failure, often requiring high levels of oxygen supplementation or mechanical ventilatory support. Hemoptysis is variably present. Chest radiographs typically feature widespread alveolar filling, sometimes with peripheral sparing and pleural effusions. The diagnosis is suspected when serial bronchoalveolar lavages return increasingly bloody fluid. DAH is differentiated from infectious causes of alveolar hemorrhage when extensive microbiological testing reveals no pulmonary pathogens. The cause is poorly understood, though preclinical and clinical studies implicate pretransplant conditioning regimens, particularly those using high doses of total-body-irradiation, acute graft-versus-host disease (GVHD), medications used to prevent GVHD, and other factors. Treatment consists of supportive care, systemic corticosteroids, platelet transfusions, and sometimes includes antifibrinolytic drugs and topical procoagulant factors. Therapeutic blockade of tumor necrosis factor-α showed promise in observational studies, but its benefit for DAH remains uncertain after small clinical trials. Even with these treatments, mortality from progression and relapse is high. Future investigational therapies could target the vascular endothelial cell biology theorized to contribute to alveolar bleeding and pathways that contribute to susceptibility, inflammation, cellular resilience, and tissue repair. This review will help clinicians navigate through the limited evidence to diagnose and treat DAH, counsel patients and families, and plan for future research.

Total marrow irradiation reduces organ damage and enhances tissue repair with the potential to increase the targeted dose of bone marrow in both young and old mice

Total body irradiation (TBI) is a commonly used conditioning regimen for hematopoietic stem cell transplant (HCT), but dose heterogeneity and long-term organ toxicity pose significant challenges. Total marrow irradiation (TMI), an evolving radiation conditioning regimen for HCT can overcome the limitations of TBI by delivering the prescribed dose targeted to the bone marrow (BM) while sparing organs at risk. Recently, our group demonstrated that TMI up to 20 Gy in relapsed/refractory AML patients was feasible and efficacious, significantly improving 2-year overall survival compared to the standard treatment. Whether such dose escalation is feasible in elderly patients, and how the organ toxicity profile changes when switching to TMI in patients of all ages are critical questions that need to be addressed. We used our recently developed 3D image-guided preclinical TMI model and evaluated the radiation damage and its repair in key dose-limiting organs in young (~8 weeks) and old (~90 weeks) mice undergoing congenic bone marrow transplant (BMT). Engraftment was similar in both TMI and TBI-treated young and old mice. Dose escalation using TMI (12 to 16 Gy in two fractions) was well tolerated in mice of both age groups (90% survival ~12 Weeks post-BMT). In contrast, TBI at the higher dose of 16 Gy was particularly lethal in younger mice (0% survival ~2 weeks post-BMT) while old mice showed much more tolerance (75% survival ~13 weeks post-BMT) suggesting higher radio-resistance in aged organs. Histopathology confirmed worse acute and chronic organ damage in mice treated with TBI than TMI. As the damage was alleviated, the repair processes were augmented in the TMI-treated mice over TBI as measured by average villus height and a reduced ratio of relative mRNA levels of amphiregulin/epidermal growth factor (areg/egf). These findings suggest that organ sparing using TMI does not limit donor engraftment but significantly reduces normal tissue damage and preserves repair capacity with the potential for dose escalation in elderly patients.

Pulmonary Toxicity After Total Body Irradiation - Critical Review of the Literature and Recommendations for Toxicity Reporting

INTRODUCTION

Total body irradiation is an effective conditioning regimen for allogeneic stem cell transplantation in pediatric and adult patients with high risk or relapsed/refractory leukemia. The most common adverse effect is pulmonary toxicity including idiopathic pneumonia syndrome (IPS). As centers adopt more advanced treatment planning techniques for TBI, total marrow irradiation (TMI), or total marrow and lymphoid irradiation (TMLI) there is a greater need to understand treatment-related risks for IPS for patients treated with conventional TBI. However, definitions of IPS as well as risk factors for IPS remain poorly characterized. In this study, we perform a critical review to further evaluate the literature describing pulmonary outcomes after TBI.

MATERIALS AND METHODS

A search of publications from 1960-2020 was undertaken in PubMed, Embase, and Cochrane Library. Search terms included "total body irradiation", "whole body radiation", "radiation pneumonias", "interstitial pneumonia", and "bone marrow transplantation". Demographic and treatment-related data was abstracted and evidence quality supporting risk factors for pulmonary toxicity was evaluated.

RESULTS

Of an initial 119,686 publications, 118 met inclusion criteria. Forty-six (39%) studies included a definition for pulmonary toxicity. A grading scale was provided in 20 studies (17%). In 42% of studies the lungs were shielded to a set mean dose of 800cGy. Fourteen (12%) reported toxicity outcomes by patient age. Reported pulmonary toxicity ranged from 0-71% of patients treated with TBI, and IPS ranged from 1-60%. The most common risk factors for IPS were receipt of a TBI containing regimen, increasing dose rate, and lack of pulmonary shielding. Four studies found an increasing risk of pulmonary toxicity with increasing age.

CONCLUSIONS

Definitions of IPS as well as demographic and treatment-related risk factors remain poorly characterized in the literature. We recommend routine adoption of the diagnostic workup and the definition of IPS proposed by the American Thoracic Society. Additional study is required to determine differences in clinical and treatment-related risk between pediatric and adult patients. Further study using 3D treatment planning is warranted to enhance dosimetric precision and correlation of dose volume histograms with toxicities.

Adverse Effects of Total Body Irradiation: A Two-Decade, Single Institution Analysis

Purpose

Several adverse effects have been reported in the literature associated with total body irradiation (TBI). Reports of the adverse effects of TBI have been primarily drawn from single-institution retrospective analyses. We report, to our knowledge, one of the largest cohorts of patients treated with TBI using multiple preparative chemotherapy and radiation regimens.

Methods and Materials

A retrospective chart review was performed for all 705 patients treated with TBI at our institution from 1995 to 2017. Based on availability of TBI records, 622 patients (88%) had sufficient evaluable documentation for analysis. Patients received 1 of 4 conditioning regimens: busulfan-fludarabine, 2 Gy (BUFLU); fludarabine-melphalan, 2 Gy (FLUMEL); cyclophosphamide, 12 Gy fractionated (CY); or etoposide, 12 Gy fractionated (VP16). Individual patients were evaluated for 13 specific recognized adverse effects based on the Common Terminology Criteria for Adverse Events, version 5.0.

Results

Mucositis (grade 3) was the most common serious adverse effect and occurred most frequently in the group receiving the VP16 12 Gy regimen (40% vs less than 14% in each of the other groups). Serious febrile neutropenia (grade 3-5) was less frequent (24%) among patients receiving CY than among those receiving the other conditioning regimens (more than 38% in each of the other groups). The incidence of serious lung infection was less common (5%) in patients receiving CY than in those receiving VP16 (18%). There was a higher frequency of grade 3-5 diarrhea among those receiving FLUMEL (5%) and VP16 (4%) than in the other groups (<3%) (P = .034). Otherwise, there were no detectable differences in serious toxicity by regimen for the 13 adverse effects reviewed. Only 2 secondary malignancies were reported, and both were in the BUFLU group. Cataract formation occurred in approximately 16% of patients overall, and the rates were similar across regimens. Median time to cataract formation was 1 to 4 years across regimens, with cataracts occurring earlier in the 2-Gy regimens. The overall rate of grade ≥3 pneumonitis was approximately 2% across the entire cohort.

Conclusions

Our nearly 20-year TBI experience showed relatively low rates of radiation-related toxicities. However, cataracts were common with a relatively short onset time.

Determining the incidence of interstitial pneumonitis and chronic kidney disease following full intensity haemopoetic stem cell transplant conditioned using a forward-planned intensity modulated total body irradiation technique

PURPOSE/OBJECTIVE

Total body irradiation (TBI) remains a key component of conditioning for allogeneic haemopoietic stem cell transplant (HSCT), with interstitial pneumonitis (IP) and chronic kidney disease (CKD) important late sequelae. We undertook a retrospective service evaluation of TBI patients treated with a forward-planned intensity modulated radiotherapy technique (FP IMRT).

MATERIAL/METHODS

74 adult patients were identified; all received step and shoot FP IMRT TBI, 14.4 Gy in 8 fractions over 4 days. Mean doses to the lungs and kidneys were 12-12.5 Gy. Toxicities were defined as per CTCAE v4.0: IP as multilobar infiltrates on CT with symptoms of dyspnoea, and renal dysfunction as an Estimated Glomerular Filtration rate (eGFR) < 60 ml/min/1.73 m2 for > 3 months. Secondary endpoints were overall survival (OS), progression free survival (PFS), cumulative incidence of non-relapse mortality (NRM), relapse risk and of acute and chronic GvHD.

RESULTS

Patients received treatment for the following diagnosis: ALL/LBL (n = 37); AML (n = 33), CML-BC (n = 2) and High grade NHL (n = 2). The rate of IP due to any cause was 30%; positive microbiological evidence in 73% (16 /22). Idiopathic IP was seen in 8%, with only 4% (n = 3) having IP Grade ≥ 3. Two (4%) of 52 long term survivors developed CKD, one with thrombotic microangiopathy. 4 year NRM was 16% (CI 11-32%); no treatment related deaths in matched sibling or umbilical cord blood HSCT.

CONCLUSION

FP IMRT TBI, reducing dose to the lungs and kidneys, has lower rates of idiopathic IP and CKD compared to the literature. This technique is safe and effective conditioning for full intensity HSCT.

Total Body Irradiation for Hematopoietic Stem Cell Transplantation: What Can We Agree on?

Total body irradiation (TBI), used as part of the conditioning regimen prior to allogeneic and autologous hematopoietic cell transplantation, is the delivery of a relatively homogeneous dose of radiation to the entire body. TBI has a dual role, being cytotoxic and immunosuppressive. This allows it to eliminate disease and create “space” in the marrow while also impairing the immune system from rejecting the foreign donor cells being transplanted. Advantages that TBI may have over chemotherapy alone are that it may achieve greater tumour cytotoxicity and better tissue penetration than chemotherapy as its delivery is independent of vascular supply and physiologic barriers such as renal and hepatic function. Therefore, the so-called “sanctuary” sites such as the central nervous system (CNS), testes, and orbits or other sites with limited blood supply are not off-limits to radiation. Nevertheless, TBI is hampered by challenging logistics of administration, coordination between hematology and radiation oncology departments, increased rates of acute treatment-related morbidity and mortality along with late toxicity to other tissues. Newer technologies and a better understanding of the biology and physics of TBI has allowed the field to develop novel delivery systems which may help to deliver radiation more safely while maintaining its efficacy. However, continued research and collaboration are needed to determine the best approaches for the use of TBI in the future.

Organ sparing of linac-based targeted marrow irradiation over total body irradiation

PURPOSE

Targeted marrow irradiation (TMI) is an alternative conditioning regimen to total body irradiation (TBI) before bone marrow transplantation in hematologic malignancies. Intensity-modulation methods of external beam radiation therapy are intended to permit significant organ sparing while maintaining adequate target coverage, improving the therapeutic ratio. This study directly compares the dose distributions to targets and organs at risk from TMI and TBI, both modalities conducted by general-use medical linacs at our institution.

METHODS

TMI treatments were planned for 10 patients using multi-isocentric feathered volumetric arc therapy (VMAT) plans, delivered by 6 MV photon beams of Elekta Synergy linacs. The computed tomography (CT) datasets used to obtain these plans were also used to generate dose distributions of TBI treatments given in the AP/PA extended-field method. We compared dose distributions normalized to the same prescription for both plan types. The generalized equivalent uniform dose (gEUD) of Niemierko for organs and target volumes was used to quantify effective whole structure dose and dose savings.

RESULTS

For the clinical target volume (CTV), no significant differences were found in mean dose or gEUD, although the radical dose homogeneity index (minimum dose divided by maximum dose) was 31.7% lower (P = 0.002) and the standard deviation of dose was 28.0% greater (P = 0.027) in the TMI plans than in the TBI plans. For the TMI plans, gEUD to the lungs, brain, kidneys, and liver was significantly lower (P < 0.001) by 47.8%, 33.3%, 55.4%, and 51.0%, respectively.

CONCLUSION

TMI is capable of maintaining CTV coverage as compared to that achieved in TBI, while significantly sparing organs at risk. Improvement on sparing organs at risk permits a higher prescribed dose to the target or the maximum number of times marrow conditioning may be delivered to a patient while maintaining similar typical tissue complication rates.

Gamma-Tocotrienol Protects the Intestine from Radiation Potentially by Accelerating Mesenchymal Immune Cell Recovery

Natural antioxidant gamma-tocotrienol (GT3), a vitamin E family member, provides intestinal radiation protection. We seek to understand whether this protection is mediated via mucosal epithelial stem cells or sub-mucosal mesenchymal immune cells. Vehicle- or GT3-treated male CD2F1 mice were exposed to total body irradiation (TBI). Cell death was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Villus height and crypt depth were measured with computer-assisted software in tissue sections. Functional activity was determined with an intestinal permeability assay. Immune cell recovery was measured with immunohistochemistry and Western blot, and the regeneration of intestinal crypts was assessed with ex vivo organoid culture. A single dose of GT3 (200 mg/kg body weight (bwt)) administered 24 h before TBI suppressed cell death, prevented a decrease in villus height, increased crypt depth, attenuated intestinal permeability, and upregulated occludin level in the intestine compared to the vehicle treated group. GT3 accelerated mesenchymal immune cell recovery after irradiation, but it did not promote ex vivo organoid formation and failed to enhance the expression of stem cell markers. Finally, GT3 significantly upregulated protein kinase B or AKT phosphorylation after TBI. Pretreatment with GT3 attenuates TBI-induced structural and functional damage to the intestine, potentially by facilitating intestinal immune cell recovery. Thus, GT3 could be used as an intestinal radioprotector.

Preclinical models of radiation-induced lung damage: challenges and opportunities for small animal radiotherapy

Despite a major paradigm shift in radiotherapy planning and delivery over the past three decades with continuing refinements, radiation-induced lung damage (RILD) remains a major dose limiting toxicity in patients receiving thoracic irradiations. Our current understanding of the biological processes involved in RILD which includes DNA damage, inflammation, senescence and fibrosis, is based on clinical observations and experimental studies in mouse models using conventional radiation exposures. Whilst these studies have provided vital information on the pulmonary radiation response, the current implementation of small animal irradiators is enabling refinements in the precision and accuracy of dose delivery to mice which can be applied to studies of RILD. This review presents the current landscape of preclinical studies in RILD using small animal irradiators and highlights the challenges and opportunities for the further development of this emerging technology in the study of normal tissue damage in the lung.

Decline of forced expiratory volume in 1 s after allogeneic hematopoietic cell transplantation is a good indicator for pulmonary damage and is associated with busulfan use

Reduced pulmonary function is commonly observed after allogeneic hematopoietic stem cell transplantation (HSCT); however, its relationship with the development of noninfectious pulmonary complications (NIPCs) is unclear, and the impact of changes in pulmonary function test (PFT) values on HSCT outcome remains controversial. We conducted a retrospective study including 150 patients to investigate changes in PFTs and impact on clinical outcome. PFT data at around 1 year after HSCT were available in 84 patients, and showed a significant time-dependent decline in percentage predicted forced expiratory volume in 1 s and other parameters. We focused on %FEV1, calculated decline of %FEV1 from pretransplant to around 1 year after HSCT (Δ%FEV1), and divided patients into good-Δ%FEV1 or poor-Δ%FEV1 groups, using a cut-off point of 20% decline of Δ%FEV1. In the poor-Δ%FEV1 group, half of the patients developed NIPCs. In the good-Δ%FEV1 group, PFT values were maintained, whereas those of the poor-Δ%FEV1 group declined significantly. Multivariate analysis showed that busulfan use was a risk factor for %FEV1 decline, and poor-Δ%FEV1 was a risk factor for overall survival. These data indicate that decline of %FEV1 may be a useful indicator of pulmonary damage after HSCT, and is strongly associated with busulfan use.

National survey of myeloablative total body irradiation prior to hematopoietic stem cell transplantation in Japan: survey of the Japanese Radiation Oncology Study Group (JROSG)

A myeloablative regimen that includes total-body irradiation (TBI) before hematopoietic stem cell transplantation results in higher patient survival rates than achieved with regimens without TBI. The TBI protocol, however, varies between institutions. In October 2015, the Japanese Radiation Oncology Study Group initiated a national survey of myeloablative TBI (covering 2010-2014). Among the 186 Japanese institutions performing TBI, 90 (48%) responded. The 82 institutions that had performed myeloablative TBI during this period treated 2698 patients with malignant disease [leukemia (2082 patients, 77.2%), malignant lymphoma (378, 14%)] and 37 with non-malignant disease [severe aplastic anemia (20, 54%), inborn errors of metabolism (5, 14%)]. A linear accelerator was used at all institutions. The institutions were divided into 41 large and 41 small institutions based on the median number of patients. The long source-surface distance technique was the method of choice in the 34 institutions (82.9%) and the moving-couch technique in the 7 (17.1%) in the large institutions. The schedules most routinely used by the participating institutions consisted of 12 Gy/6 fractions/3 days (26 institutions, 63.5%) in the large institutions. The dose rate varied from 5 to 26 cGy/min. The lungs and lenses were routinely shielded in 23 large institutions (56.1%), and only the lungs in 9 large institutions (21.9%). At lung-shielding institutions, the most frequent maximum acceptable total dose for the lungs was 8 Gy (19 institutions, 27.5%). Our results reveal considerable differences in the TBI methods used by Japanese institutions and thus the challenges in designing multicenter randomized trials based on TBI.

Craniospinal irradiation prior to stem cell transplant for hematologic malignancies with CNS involvement: Effectiveness and toxicity after photon or proton treatment

PURPOSE/OBJECTIVE(S)

Craniospinal irradiation (CSI) improves local control of leukemia/lymphoma with central nervous system (CNS) involvement; however, for adult patients anticipating stem cell transplant (SCT), cumulative treatment toxicity is a major concern. We evaluated toxicities and outcomes for patients receiving proton or photon CSI before SCT.

METHODS AND MATERIALS

We identified 37 consecutive leukemia/lymphoma patients with CNS involvement who received CSI before SCT at our institution. Photon versus proton toxicities during CSI, transplant, and through 100 days posttransplant were compared using Fisher exact and Wilcoxon rank sum tests. Long-term neurotoxicity, disease response, and overall survival were analyzed.

RESULTS

Thirty-seven patients (23 photon, 14 proton) underwent CSI for CNS involvement of acute lymphoblastic leukemia (49%), acute myeloblastic leukemia (22%), chronic lymphocytic leukemia (3%), chronic myelocytic leukemia (14%), lymphoma (11%), and myeloma (3%). CSI was used for consolidation (30 patients, 81%) and gross disease treatment (7 patients, 19%). Median radiation dose (interquartile range) was 24 Gy (23.4-24) for photons and 21.8 Gy (21.3-23.6) for protons (P = .03). Proton CSI was associated with lower rates of Radiation Therapy Oncology Group grade 1-3 mucositis during CSI (7% vs 44%, P = .03): 1 grade 3 with protons versus 5 grade 1, 3 grade 2, and 2 grade 3 with photons. During CSI, other toxicities (infection, gastrointestinal symptoms) did not differ. Allogeneic stem cell transplant (SCT) was used in 95% of patients, with 53% of patients in remission before SCT. Myeloablative conditioning was used for 76%. During SCT admission and 100 days post-SCT, toxicities did not differ by CSI technique. Successful engraftment occurred in 95% of patients (P = .67). Progression or death occurred for 47% of patients, with only 1 CNS relapse.

CONCLUSION

In our cohort, CSI offered excellent local control for CNS-involved hematologic malignancies in the pre-SCT setting. Acute mucositis occurred less frequently with proton CSI with comparable peritransplant/long-term toxicity profile, suggesting the need to further explore the benefit/toxicity profile of this technique.

Noninfectious Generalized Bronchiolitis in the Setting of Allogeneic Stem Cell Transplantation: A Potential Mimic of Lower Respiratory Tract Infection

RATIONALE AND OBJECTIVES

To describe a little-known therapy-related small-airway phenomenon presumably caused by mucosal irritation in patients undergoing allogeneic stem cell transplantation (allo-SCT).

MATERIALS AND METHODS

Retrospective database search at our institution identified 739 hematologic patients who underwent chemotherapy + allo-SCT between September 2004 and March 2014. After infectious pulmonary complications were excluded, 75 patients (female = 24; male = 51; median age = 47 years) with signs of generalized bronchiolitis (GB) on chest high-resolution computed tomography were identified. Computed tomography (CT) was performed proximate to chemotherapy onset; 92% had follow-up CT (mean, 1.9 weeks). The presence of centrilobular nodules, bronchial wall thickening (BWT), tree-in-bud (distributed diffuse vs. focal), ground-glass opacity, airspace opacification, luminal impactions, and air trapping was correlated with occurrence and duration of oral mucositis and therapy characteristics. Intensity of tree-in-bud and centrilobular nodules was graded absent (grade = 0), moderate (grade = 1), or marked (grade = 2).

RESULTS

Overall incidence of GB among allo-SCT patients was 10.14%. GB was diagnosed at the time point of transplantation with a mean duration of CT findings of 4 weeks (±2.7). Tree-in-bud (17% [grade 2] and 83% [grade 1]) and BWT were present in 100% of the patients. Centrilobular nodules diffusely distributed were found in 45.5% of patients (20% [grade 2], 24% [grade 1], and 56% [none]). Air trapping and mosaic pattern were found in 13% and 16% of the patients, respectively. Resolution of GB was spontaneous. GB and its severity correlated with the temporal course and grade of oral mucositis; frequency and degree were not significantly influenced by the chemotherapy regimen. The incidence of GB in high-resolution computed tomography was statistically and significantly higher in patients with oral mucositis (P < 0.035).

CONCLUSIONS

GB is frequent during chemotherapy for allo-SCT and is characterized by an even distribution of tree-in-bud, BWT, centrilobular nodules, mild clinical symptoms, and spontaneous resolution.

Impact of body mass index on pulmonary complications in patients with non-Hodgkin lymphoma treated with hematopoietic stem cell transplant

The objective of this study was to examine the association between body mass index (BMI) and the incidence of pulmonary complications (PCs) after hematopoietic stem cell transplant (HCT). We reviewed 398 adult patients with non-Hodgkin lymphoma (NHL) who received autologous or allogeneic HCT between 1993 and 1997. BMI was classified as normal (18.5 < BMI ≤ 24.9), overweight (24.9 < BMI ≤ 30) and obese (BMI > 30). Multivariate logistic regression was used to analyze the relationship between BMI and presence of PCs within 100 days post-HCT while adjusting for patient-, disease- and transplant-related variables. The incidence of PCs within 100 days post-HCT was 32% (n = 129). Median BMI was 25.4 (range: 18.6-52.2). Median age was 48.8 years (range: 19.5-73.6 years). Multivariate analysis failed to show significant association between BMI and PCs. However, a total body irradiation (TBI)-based conditioning regimen was associated with lower rate of PCs.

Stable long-term pulmonary function after fludarabine, antithymocyte globulin and i.v. BU for reduced-intensity conditioning allogeneic SCT

Lung function decline is a well-recognized complication following allogeneic SCT (allo-SCT). Reduced-intensity conditioning (RIC) and in vivo T-cell depletion by administration of antithymocyte globulin (ATG) may have a protective role in the occurrence of late pulmonary complications. This retrospective study reported the evolution of lung function parameters within the first 2 years after allo-SCT in a population receiving the same RIC regimen that included fludarabine and i.v. BU in combination with low-dose ATG. The median follow-up was 35.2 months. With a median age of 59 years at the time of transplant, at 2 years, the cumulative incidences of non-relapse mortality was as low as 9.7%. The cumulative incidence of relapse was 33%. At 2 years, the cumulative incidences of extensive chronic GVHD (cGVHD) and of pulmonary cGVHD were 23.1% and 1.9%, respectively. The cumulative incidences of airflow obstruction and restrictive pattern were 3.8% and 9.6%, respectively. Moreover, forced expiratory volume (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio remained stable from baseline up to 2 years post transplantation (P=0.26, P=0.27 and P=0.07, respectively). These results correspond favorably with the results obtained with other RIC regimens not incorporating ATG, and suggest that ATG may have a protective pulmonary role after allo-SCT.

The effect of peritransplant minimal residual disease in adults with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation

BACKGROUND

Allogeneic HSCT is highly effective for treating ALL. However, many ALL patients relapse after HSCT. There has been a continuing effort to improve identification of patients at high risk of relapse, with the goal of early intervention to improve outcome.

PATIENTS AND METHODS

In this retrospective analysis, we examined the effect of MRD on the risk of hematologic relapse in 149 adult patients with ALL in morphologic remission undergoing allogeneic HSCT. MRD was assessed at the time of HSCT and after HSCT.

RESULTS

Patients with pretransplant MRD had a trend for shorter progression-free survival (PFS) at 2 years compared with patients without MRD, nearing statistical significance; 28% versus 47%, P = .08, on univariate analysis. This trend remained on multivariate analysis with better PFS in patients without MRD at the time of HSCT, hazard ratio (HR), 0.62 (95% confidence interval, 0.37-1.04); P = .07. Additionally, emergence of MRD after HSCT was a strong predictor for overt hematologic relapse (HR, 4; P < .001) with a median latency interval of 3.8 months.

CONCLUSION

These findings demonstrate the predictive value of monitoring for MRD around the time of transplant in adult patients with ALL.

Long-term follow-up of allogeneic hematopoietic stem cell transplantation for patients with Philadelphia chromosome-positive acute lymphoblastic leukemia: impact of tyrosine kinase inhibitors on treatment outcomes

The introduction of tyrosine kinase inhibitors (TKI) has revolutionized therapy for patients with acute lymphoblastic leukemia (ALL) who have the Philadelphia (Ph) chromosome. A retrospective analysis was conducted on 102 adults and 11 children who received a first-matched related (n = 60), matched unrelated (n = 40), mismatched cord blood (n = 12), or haploidentical (n = 1) allogeneic hematopoietic stem cell transplantation (HSCT) for Ph-positive (Ph+) ALL in first complete remission (n = 71), second complete remission (n = 11), or with active disease (n = 31) between 1990 and 2009. Sixty-seven patients received TKI with upfront ALL therapy, and 32 patients received TKI maintenance following HSCT. With median follow-up of 5 years among survivors (range: 1.1-20.4 years), overall survival (OS) was significantly better for patients transplanted in first remission compared with HSCT in advanced disease: 43% versus 16%, P = .002. Disease stage and age at time of HSCT, the development of acute graft-versus-host disease (aGVHD), and decade of HSCT were found to significantly impact OS, progression-free survival (PFS), and nonrelapse mortality (NRM) in multivariate analyses. Allogeneic HSCT provides durable remission for patients with Ph+ ALL in first remission. Neither TKI use pre- nor post-HSCT were found to significantly impact transplant outcomes in univariate and multivariate analyses.

Radiobiological effects of total body irradiation on the spinal cord

Total body Irradiation (TBI) is often used for conditioning, prior to bone marrow transplantation. Doses of 8-14 Gy in 1-8 fractions over 1-4 days are administered using low dose rate external beam radiotherapy (EBRT). When necessary, consolidation EBRT using conventional doses, fractionation and dose rate is given. The irradiated volume usually contains critical organs such as spinal cord. The purpose of this study was to assess the biologic effect of TBI on the spinal cord in terms of EQD(2) (equivalent dose given in fractions of 2 Gy). EQD(2) values were calculated using the linear-quadratic generalized incomplete repair (IR) model that incorporates IR between fractions and low dose rate irradiation corrections and accounts for mono and bi-exponential repair. Three fractionation schemes were studied as function of dose rate: 8 Gy in 1 and 2 fractions and 12 Gy in 8 fractions. For the 12 Gy in 8 fractions scheme, the influence of dose rate on EQD(2) was limited because the effect of IR between fractions dominates. For the 8 Gy in 1 fraction scheme, significant sparing of the spinal cord may be achieved for low dose rate (5-20 cGy/min). The extent of effects depends on the parameters used. The IR model provides a useful mathematical framework for examination of the effects of fractionated treatments of varying dose rate. Reliable experimental data are needed for accurate assessment of radiation damage to the spinal cord following fractionated low dose rate TBI.

Vascular injury after whole thoracic x-ray irradiation in the rat

PURPOSE

To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury.

METHODS AND MATERIALS

Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy.

RESULTS

By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung weights, and decreases in total lung angiotensin-converting enzyme activity, as well as pulmonary artery distensibility. In contrast, irradiation with 5 Gy resulted in only a modest increase in right ventricular weight and a reduction in lung angiotensin-converting enzyme activity.

CONCLUSION

In a previous investigation using the same model, we observed that recovery from radiation-induced attenuation of pulmonary vascular reactivity occurred. In the present study, we report that deterioration results in several vascular parameters for </=1 year after 10 Gy, suggesting sustained remodeling of the pulmonary vasculature. Our data support clinically relevant injuries that appear in a time- and dose-related manner after exposure to relatively low radiation doses.

Total marrow irradiation with helical tomotherapy for bone marrow transplantation of multiple myeloma: first experience in Asia

Three Asian patients with plasma cell myeloma stage IIIa with IgG predominant were selected for autologous hematopoietic cell transplantation (HSCT). Total marrow irradiation (TMI) tomotherapy planned with melphalan 140 mg/m2 as a preconditioning regimen of HSCT. Two image sets of computed tomography (CT) were scanned with 2.5 mm and 5 mm for the upper and lower part of the plan, respectively. The junction was determined and marked at 15 cm above knee on both thighs for upper and lower part of the plan. The clinical target volume (CTV) included the entire skeletal system. The planning target volume (PTV) was generated with with 0.8 cm for CTV(extremities) and with 0.5 cm margin for all other bones of CTV. A total dose of 800 cGy (200 cGy/fraction) was delivered to the PTV. Update to presentation, all of three patients post transplant without evidence of active disease were noted. During TMI treatment, one with grade 1 vomiting, two with grade 1 nausea, one with grade 1 mucositis, and three with grade 1 anorexia were noted. Toxicity of treatment was scored according to the Common Terminology Criteria for Adverse Events v3.0 (CTCAE v3.0). The average for upper part versus lower part of PTV (Bone marrow) of CI and H-index were 1.5 and 1.4 versus 1.2 and 1.2, respectively. The dose reduction of TMI tomotherapy to various OARs of head, chest, and abdomen relative to TBI varied from 31% to 74%, 21% to 51%, and 46% to 63%, respectively. The maximum average value of registration for upper torso versus lower extremities in different translation directions were 5.1 mm versus 4.1 mm for pretreatment and 1.5 mm versus 0.7 mm for post-treatment, respectively. The average treatment time for the upper versus lower part in beam-on time, setup time, and MVCT registration time took roughly 49.9, 23.3, and 11.7 min versus 11.5, 10.0, and 7.3 min, respectively. The margin of PTV could be less than 1 cm under good fixation and close position confirmation with MVCT. Antiemetics should be prescribed in the whole course of TMI for emesis prevention. TMI technique replaced TBI technique with 8 Gy as conditioning regiment for multiple myeloma could be acceptable for the Asian and the outcomes were feasible for the Asian.

Pulmonary function following total body irradiation (with or without lung shielding) and allogeneic peripheral blood stem cell transplant

Our purpose was to determine if total body irradiation (TBI) with lung dose reduction protects against subsequent radiation-induced deterioration in pulmonary function. Between July 1997 and August 2004, 181 consecutive patients with hematologic malignancies received fractionated TBI before allogeneic peripheral blood stem cell transplant. The first 89 patients were treated to a total dose of 13.6 Gy. Thereafter, total body dose was decreased to 12 Gy with lung dose reduction to 9 or 6 Gy. All patients underwent pulmonary function test evaluation before treatment, 90 days post-treatment, then annually. Median follow-up was 24.0 months. Eighty-nine patients were treated with lung shielding, and 92 without. At 1-year post transplant, there was a small but significant difference in lung volume measurements between patients with lung shielding and those without. This was not observed at the 2-year time point. When stratified by good (>100% predicted) or poor (</=100% predicted) baseline lung function, patients with poor function demonstrated protection at 1 year with lung shielding, while those with good initial lung function did not. TBI with or without lung dose reduction has a small but statistically significant effect on pulmonary function measured at 1 year but not 2 years post irradiation.

Fludarabine allows dose reduction for total body irradiation in pediatric hematopoietic stem cell transplantation

PURPOSE

To examine, in the setting of total body irradiation (TBI) for the preparation of pediatric hematopoietic stem cell transplantation (HSCT), whether TBI dose can be reduced without compromising the efficacy of a regimen consisting of fludarabine and radiotherapy; and whether there is any increased risk of pulmonary toxicity due to the radiosensitizing effect of fludarabine.

METHODS AND MATERIALS

A total of 52 pediatric patients with hematologic malignancies received TBI-based conditioning regimens in preparation for allogeneic HSCT. Twenty-three patients received 12 Gy in 4 daily fractions in combination with cyclophosphamide, either alone or with other chemotherapeutic and biologic agents. Twenty-nine patients received 9 Gy in 3 fractions in conjunction with fludarabine and melphalan. Clinical and radiation records were reviewed to determine engraftment, pulmonary toxicity (according to Radiation Therapy Oncology Group criteria), transplant-related mortality, recurrence of primary disease, and overall survival.

RESULTS

The two groups of patients had comparable pretransplant clinical characteristics. For the 12-Gy and 9-Gy regimens, the engraftment (89% and 93%; p = 0.82), freedom from life-threatening pulmonary events (65% and 79%; p = 0.33), freedom from relapse (60% and 73%; p = 0.24), and overall survival (26% and 47%; p = 0.09) were not statistically different.

CONCLUSIONS

The addition of fludarabine and melphalan seems to allow the dose of TBI to be lowered to 9 Gy without loss of engraftment or antitumor efficacy.

Chronic GVHD and pretransplantation abnormalities in pulmonary function are the main determinants predicting worsening pulmonary function in long-term survivors after stem cell transplantation

Pulmonary function (PF) was studied in 69 consecutive patients with hematologic diseases, with a minimum 5-year (range, 5-13 years) follow-up after allogeneic stem cell transplantation from an HLA-matched sibling. Fifty-six patients (81%) received total body irradiation based myeloablative stem cell transplantation (MT) and 13 (19%) underwent nonmyeloablative stem cell transplantation (NST). Thirty-one patients (45%) developed a late decrease in PF from baseline, 25 with a restrictive and 6 with an obstructive pattern PF abnormality. Twelve patients (17%) were symptomatic, 8 with a severe restrictive PF defect, but none required supplemental oxygen. The incidence of developing a late PF abnormality was comparable in MT (24 of 56) and NST (5 of 13; P = .51). In multivariate analysis, chronic graft-versus-host disease (relative risk, 16) and pretransplantation diffusion capacity for carbon monoxide or forced expiratory volume in the first second <80% predicted were independently associated with a late decrease in PF from baseline (relative risk, 7). Our results indicate that late PF abnormality is common after MT and NST. Patients with a low pretransplantation diffusion capacity for carbon monoxide of or forced expiratory volume in the first second who developed chronic graft-versus-host disease were most severely affected. Longer follow-up is needed to determine whether PF will continue to decrease or reach a plateau and whether more patients with PF abnormality will eventually become symptomatic.

Allogeneic hematopoietic stem cell transplantation after rituximab-containing myeloablative preparative regimen for acute lymphoblastic leukemia

We explored the safety and efficacy of rituximab administered in combination with the standard transplant conditioning regimen of cyclophosphamide (Cy) 120 mg/kg and total body irradiation (TBI) 12 Gy for adult patients with acute lymphoblastic leukemia (ALL). Patients were eligible if their disease expressed CD20. Rituximab was administered at 375 mg/m2 weekly for four doses beginning on day -7 of the conditioning regimen. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus and methotrexate. Thirty-five patients undergoing matched sibling (n = 23) or unrelated donor (n = 12) transplantation were studied, with a median age of 30 years (range 15-55 years). At 2 years, progression-free survival, treatment-related mortality, and overall survival were 30, 24, and 47%, respectively. There was no delay in engraftment or increased incidence of infection. The cumulative incidence of grade II-IV acute GVHD was 17%, and limited and extensive chronic GVHD was 43% at 2 years. The addition of rituximab to the standard Cy/TBI transplant conditioning regimen in ALL was safe and well tolerated, and there was a suggestion of decreased incidence of acute GVHD when compared to historically reported GVHD rates for this group of patients.

Influence of Radiation Dose Rate and Lung Dose on Interstitial Pneumonitis after Fractionated Total Body Irradiation: Acute Parotitis May Predict Interstitial Pneumonitis

This study evaluated patients for the influence of the dose rate and lung dose of fractionated total body irradiation (TBI) in preparation for allogeneic bone marrow transplantation (BMT) on the subsequent development of interstitial pneumonitis (IP). Sixty-six patients at our institute were treated with TBI followed by BMT. All of the patients received a total TBI dose of 12 Gy given in 6 fractions over 3 days and were divided into 3 groups according to the radiation dose rate and lung dose: group A, lung dose of 8 Gy (n = 18); group B, lung dose of 12 Gy at 8 cGy/min (n = 25); and group C, lung dose of 12 Gy at 19 cGy/min (n = 23). The overall survival rate, the cumulative incidence of relapse, and the cumulative incidence of IP were evaluated in relation to various potential indicators of future IP. There were no significant differences in survival and relapse rates between patient group A and combined groups B and C. Clinically significant IP occurred in 13 patients. The cumulative incidence of IP was significantly higher in patients who developed acute parotitis as indicated by either an elevation in the serum amylase level or parotid pain of grade 1 to 2. There was no difference in IP incidence among groups A, B, and C. There was no significant difference in IP incidence between lung dose values of 8 Gy (with lung shielding) and 12 Gy (without lung shielding) and between dose rate values of 8 cGy/min and 19 cGy/ min, at least when TBI was given in 6 fractions. The presence of acute parotitis during or just after TBI may be a predictor of IP.

Dose response and factors related to interstitial pneumonitis after bone marrow transplant

PURPOSE

Total body irradiation (TBI) and chemotherapy are common components of conditioning regimens for bone marrow transplantation. Interstitial pneumonitis (IP) is a known regimen-related complication. Using published data of IP in a multivariate logistic regression, this study sought to identify the parameters in the bone marrow transplantation conditioning regimen that were significantly associated with IP and to establish a radiation dose-response function.

METHODS AND MATERIALS

A retrospective review was conducted of articles that reported IP incidence along with lung dose, fractionation, dose rate, and chemotherapy regimen. In the final analysis, 20 articles (n = 1090 patients), consisting of 26 distinct TBI/chemotherapy regimens, were included in the analysis. Multivariate logistic regression was performed to determine dosimetric and chemotherapeutic factors that influenced the incidence of IP.

RESULTS

A logistic model was generated from patients receiving daily fractions of radiation. In this model, lung dose, cyclophosphamide dose, and the addition of busulfan were significantly associated with IP. An incidence of 3%-4% with chemotherapy-only conditioning regimens is estimated from the models. The alpha/beta value of the linear-quadratic model was estimated to be 2.8 Gy. The dose eliciting a 50% incidence, D50, for IP after 120 mg/kg of cyclophosphamide was 8.8 Gy; in the absence of chemotherapy, the estimated D50 is 10.6 Gy. No dose rate effect was observed. The use of busulfan as a substitute for radiation is equivalent to treating with 14.8 Gy in 4 fractions with 50% transmission blocks shielding the lung. The logistic regression failed to find a model that adequately fit the multiple-fraction-per-day data.

CONCLUSIONS

Dose responses for both lung radiation dose and cyclophosphamide dose were identified. A conditioning regimen of 12 Gy TBI in 6 daily fractions induces an IP incidence of about 11% in the absence of lung shielding. Shielding the lung to receive 50% of this dose lowers the estimated incidence to about 2.3%. Because the lungs can be adequately shielded, we recommend against using busulfan as a substitute for fractionated TBI with cyclophosphamide.

Very late nonfatal consequences of fractionated TBI in children undergoing bone marrow transplant

PURPOSE

To describe long-term late consequences in children who received total body irradiation (TBI) for hematopoietic stem cell transplantation 10 years earlier.

METHODS AND MATERIALS

A cohort of 42 children treated with TBI between 1985 and 1993, still alive at least 10 years after fractionated TBI (FTBI), was evaluated. Twenty-five patients received FTBI at 330 cGy/day for 3 days (total dose 990 cGy), whereas 17 children were administered fractions of 200 cGy twice daily for 3 days (total dose 1200 cGy). Twenty-seven patients received autologous and 16 allogeneic hematopoietic stem cell transplantation. Median age at TBI was 6.3 years, and 18.4 years at most recent follow-up.

RESULTS

Cataract was diagnosed in 78% of patients after a median of 5.7 years. Hypothyroidism was detected in 12%, whereas thyroid nodules were observed in 60% of our population after a median interval of 10.2 years. Patients treated with 990 cGy developed thyroid nodules more frequently than those treated with 1200 cGy (p = 0.0002). Thyroid carcinoma was diagnosed in 14% of the total population. Females who received FTBI after menarche more frequently developed temporary ovarian dysfunction than those treated before menarche, but cases of persistent ovarian dysfunction did not differ between the two groups. Indirect signs of germinal testicular dysfunction were detected in 87% of males. Restrictive pulmonary disease was observed in 74% of patients. Osteochondroma was found in 29% of patients after a median interval of 9.2 years. This latter complication appeared more frequently in patients irradiated before the age of 3 years (p < 0.001).

CONCLUSIONS

This study shows that late effects that are likely permanent, although not fatal, are frequent in survivors 10 years after TBI. However, some of the side effects observed shortly after TBI either disappeared or remained unchanged without signs of evolution. Monitoring is recommended to pursue secondary prevention strategies and counseling on family planning.

Pulmonary function testing prior to hematopoietic stem cell transplantation

The pretransplant pulmonary function test plays an important role in the management of noninfectious pulmonary complications after hematopoietic stem cell transplantation (HCT). Although these tests are widely used as standard preoperative assessments in the nontransplant population, common conditions associated with the HCT patient requires that particular attention be given to interpretation of pulmonary function testing (PFT) results, such as comparison of serial pulmonary function tests and evaluation of the diffusion capacity. Although their utility in helping to predict the likelihood of developing post transplant pulmonary complications and mortality is not well established, current data indicate that pretransplant PFTs are important as a reference for the interpretation of post transplant PFTs and for identifying patients at high risk for developing pulmonary complications and/or mortality after HCT. Future studies of pretransplant pulmonary function should consider the advances in HCT, so that pretransplant PFTs will become a useful tool in pretransplant risk assessment and help the transplant oncologist to determine the most appropriate conditioning regimen for a patient with compromised lung function.

The protective effect of recombinant human keratinocyte growth factor on radiation-induced pulmonary toxicity in rats

PURPOSE

Radiation-induced lung toxicity is a significant dose-limiting side effect of radiotherapy for thoracic tumors. Recombinant human keratinocyte growth factor (rHuKGF) has been shown to be a mitogen for type II pneumocytes. The purpose of this study was to determine whether rHuKGF prevents or ameliorates the severity of late lung damage from fractionated irradiation in a rat model.

METHODS AND MATERIALS

Female Fisher 344 rats were irradiated to the right hemithorax with a dose of 40 Gy/5 fractions/5 days. rHuKGF at dose of 5 mg/kg or 15 mg/kg was given via a single intravenous injection 10 min after the last fraction of irradiation. Animals were followed for 6 months after irradiation.

RESULTS

The breathing rate increased beginning at 6 weeks and reached a peak at 14 weeks after irradiation. The average breathing frequencies in the irradiated groups with rHuKGF (5 mg/kg and 15 mg/kg) treatment were significantly lower than that in the group receiving radiation without rHuKGF (116.5 +/- 1.0 and 115.2 +/- 0.8 vs 123.5 +/- 1.2 breaths/min, p < 0.01). The severity of lung fibrosis and the level of immunoreactivity of integrin alphavbeta6, TGFbeta1, type II TGFbeta receptor, Smad3, and phosphorylated Smad2/3 were significantly decreased only in the group receiving irradiation plus high-dose rHuKGF treatment compared with irradiation plus vehicle group, suggesting a dose response for the effect of rHuKGF.

CONCLUSIONS

This study is the first to demonstrate that rHuKGF treatment immediately after irradiation protects against late radiation-induced pulmonary toxicity. These results suggest that restoration of the integrity of the pulmonary epithelium via rHuKGF stimulation may downregulate the TGF-beta-mediated fibrosis pathway. These data also support the use of rHuKGF in a clinical trial designed to prevent radiation-induced lung injury.