White Blood Cell Nadir Research Articles

White blood cell count nadir to zero following intensive chemotherapy as a predictive factor for patients with acute myeloid leukemia

Predictors for response to intensive therapy in AML have focused on baseline factors: percent leukemic blasts in marrow, cytogenetic/molecular genetic abnormalities, and presence of secondary AML. Non-baseline dynamic factors, occurring after induction but before response, may be useful for decisions related to salvage chemotherapy. We hypothesized white blood cell (WBC) count nadir after induction may be a real time indicator of treatment efficacy. We also examined whether time to stem cell transplant (SCT) or baseline molecular genetic abnormalities are associated with a low nadir. Data showed WBC nadir = 0 was a negative predictor for response to intensive induction and was correlated with reduced overall survival and progression free survival. Patients with WBC nadir = 0 did not have a significantly longer time to SCT, and none of the mutations increased the likelihood of reaching WBC nadir = 0. WBC nadir may be a useful real-time monitor in AML patients receiving intensive induction chemotherapy.

BIOM-28. PROGNOSTIC BIOMARKERS IN GLIOBLASTOMA PATIENTS TREATED WITH TEMOZOLOMIDE

Abstract OBJECTIVE Identifying blood biomarkers that predict favorable outcomes for patients with glioblastoma treated with temozolomide (TMZ). BACKGROUND Glioblastoma is the most aggressive primary brain tumor. The standard of care is maximum safe resection, then radiation plus oral TMZ, followed by six months of cyclic oral TMZ. Previous studies have revealed that TMZ-induced myelosuppression is associated with improved overall survival. METHODS Adults with glioblastoma who completed radiation therapy and received temozolomide for at least 6-months at Beth Israel Deaconess Medical Center between 2018-2021 were identified. Baseline and nadir white blood cell count, absolute neutrophil count, absolute lymphocyte count, red blood cells, and platelets were collected retrospectively. Additionally, IDH1 R132H, MGMT promoter methylation, progression free survival (PFS), and overall survival (OS) were also collected retrospectively. Data was combined with that of Vaios et al. and Ho et al. Kaplan-Meier analysis and multivariate testing were performed. RESULTS Leukopenia is associated with increased overall survival (p = 0.008) and progression free status (p = 0.02). Grade 3 thrombocytopenia is associated with decreased PFS (p = 0.0005) and OS (p = 0.0006). Grade 1 & 2 lymphopenia is associated with increased progression free survival (p = 0.01 and p = 0.03). Lower baseline absolute lymphocyte count is associated with improved OS (p = 0.007). Higher baseline absolute neutrophil count is associated with worse OS (p = 0.002). CONCLUSION Cytopenia may serve as a prognostic biomarker for OS and PFS. Leukopenia may reflect adequate temozolomide dosing, anti-tumor activity, or changes in the tumor micro-environment. Peripheral biomarker monitoring may improve prognostic stratification and lead to personalized treatment with improved outcomes.

Preoperative chemoradiation-induced hematological toxicity and related vertebral dosimetry evaluations in patients with locally advanced gastric cancer: data from a phase III clinical trial

BackgroundTo explore the hematological toxicity (HT) induced by neoadjuvant chemoradiotherapy (nCRT) compared with neoadjuvant chemotherapy (nCT) and to identify the appropriate vertebral body (VB) dosimetric parameters for predicting HT in patients with locally advanced gastric cancer (GC).MethodsIn the phase III study, 302 patients with GC from an ongoing multi-center randomized clinical trial (NCT 01815853) were included. Patients from two major centers were grouped into training and external validation cohorts. The nCT group received three cycles of XELOX chemotherapy, while the nCRT received the same dose-reduced chemotherapy plus 45 Gy radiotherapy. The complete blood counts at baseline, during neoadjuvant treatment, and in the preoperative period were compared between the nCT and nCRT groups. The VB was retrospectively contoured and the dose-volume parameters were extracted in the nCRT group. Patients’ clinical characteristics, VB dosimetric parameters, and HTs were statistically analyzed. Instances of HT were graded according to the Common Terminology Criteria for Adverse Events v5.0 (CTCAE v5.0). The receiver operating characteristic (ROC) curves were generated to identify the optimal cut-off points for dosimetric variables and verify the prediction efficiency of the dosimetric index in both training and external validation cohorts.ResultsIn the training cohort, 27.4% Grade 3 + HTs were noted in the nCRT group and 16.2% in the nCT group (P = 0.042). A similar result was exhibited in the validation cohort, with 35.0% Grade 3 + HTs in the nCRT group and 13.2% in the nCT group (P = 0.025). The multivariate analysis of the training cohort revealed that V5 was associated with Grade 3 + leukopenia (P = 0.000), Grade 3 + thrombocytopenia (P = 0.001), and Grade 3 + total HTs (P = 0.042). The Spearman correlation analysis identified a significant correlation of V5 with the white blood cell nadir (P = 0.0001) and platelet nadir (P = 0.0002). The ROC curve identified the optimal cut-off points for V5 and showed that V5 < 88.75% could indicate a decreased risk of Grade 3 + leukopenia, thrombocytopenia, and total HTs in the training as well as the external validation cohorts.ConclusionsCompared with nCT, nCRT could increase the risk of Grade 3 + HT in patients with locally advanced GC. Dose constraints of V5 < 88.75% in irradiated VB could reduce the incidence of Grade 3 + HT.

Analysis of Outcome of Patients Treated with Anti PD-1/Pdl-1 Therapy According to the Degree of Lymphopenia

Introduction: Immunotherapy directed against the PD-1/PDL-1 pathway has shown activity across a wide range of malignancies and is currently being investigated in several others. Attia et al. showed that autoimmune toxicity correlates with tumor regression in patients with metastatic melanoma treated with anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4). Grade ¾ lymphopenia has been reported in up to 9% of patients receiving anti PD-1/PDL-1 treatment. The aim of this study was to examine if severe lymphopenia (Grade ¾) correlates with outcome in patients treated with anti PD-1/PDL-1 therapy.Methods: We looked at a sample of 154 patients aged 18 years or older, treated at the University of Oklahoma Health Sciences Center between 2014 and 2016. Total white blood cell (WBC) count at baseline as well as peak and nadir WBC count were examined. Similarly, absolute lymphocyte count (ALC) at nadir was examined as well. We also looked at the hemoglobin at baseline and number of packed red blood cell and platelet transfusions. Simple descriptive statistics were created for all covariates. The primary objective of this study was to examine the association between grade ¾ lymphopenia and progression free survival (PFS),defined as disease progression or death. Our secondary objectives were to examine if the choice of a particular anti PD-1/PDL-1 treatment or the line of treatment correlate with PFS. Kaplan Meier Survival analysis and plots were created for categorical outcomes and cox proportional hazards model was used to assess the association of each continuous covariate with survival.Results: The majority of patients were females (57%). The median age was 63 years. Lung cancer was the most common diagnosis (20.8%) followed by melanoma (20.1%) and ovarian cancer (12.3%). Nivolumab was the most commonly used agent (47.4%) followed by Pembrolizumab (22.7%), other investigational agents (22.7%) and Atezolizumab (7.2%). Median number of treatments received was 5. Median WBC count at baseline was 6.87 K/mm3. Median peak and nadir WBC counts were 10.5 k/mm3 and 5 k/mm3 respectively. Median hemoglobin at baseline was 11.8 g/dL. 19.5% patients required PRBC transfusion with a median number of 3 transfusions. Only 3.3% patients required platelet transfusion with a median number of 4 transfusions. Grade ¾ lymphopenia (less than 500/mm3 ) was observed in 20.3% of patients. Among those patients, lung cancer was the most common diagnosis (23.3%) followed by cervical cancer (20%), urothelial cancer (13.3%) and head and neck cancer (10%). On a univariate analysis, there was a trend towards worse PFS in patients with grade ¾ lymphopenia but it was not statistically significant (p= 0.0829) . Similarly, one anti PD-1/PDL-1 agent was not found to be superior over another (p=0.099). Not surprisingly, patients who received anti PD-1/PDL-1 treatment as first line had a better PFSand overall survival (OS) than those who received it as second line, third line or higher and this was statistically significant (p=0.0001).Conclusion: In our patients treated with anti PD-1/PDL-1 therapy, we noticed a higher incidence of grade ¾ lymphopenia than previously reported in literature. Grade ¾ lymphopenia was associated with a trend towards worse PFS but this was not statistically significant. DisclosuresNo relevant conflicts of interest to declare.

Letermovir for Cytomegalovirus Prophylaxis in Lung Transplant Patients with Valganciclovir-Induced Leukopenia

Cytomegalovirus (CMV) prophylaxis with valganciclovir is the standard of practice in most transplant centers, but treatment-related leukopenia can limit valganciclovir’s use. Therefore, we evaluated letermovir, a novel antiviral agent recently approved for use in hematopoietic cell transplant patients as CMV prophylaxis, in lung transplant recipients unable to tolerate valganciclovir due to severe leukopenia. We performed a retrospective analysis of all lung transplant patients at our center who received letermovir for CMV prophylaxis between 1 December 2018 and 1 January 2020. A repeated measures mixed model was used to analyze white blood cell (WBC) trends, and descriptive statistics were used to analyze secondary endpoints, including CMV DNAemia, renal function, immunosuppression dosing, and allograft function. Seventeen patients were administered letermovir during the study period due to valganciclovir-induced leukopenia (median WBC nadir 1.1 K/uL, range &lt;0.30–2.19 K/uL). Median WBC improvement was noted in 15 (88.2%) patients after starting letermovir. Breakthrough CMV DNAemia necessitating treatment occurred in two patients, with one of the two cases being due to patient noncompliance. CMV resistance to letermovir was detected in two patients, necessitating a change to an alternative agent in one of these patients. No major side effects were reported in any patient. Letermovir is a generally safe and effective alternative for CMV prophylaxis in lung transplant recipients unable to tolerate valganciclovir due to leukopenia.

Model-Based Optimal AML Consolidation Treatment.

Neutropenia is an adverse event commonly arising during intensive chemotherapy of acute myeloid leukemia (AML). It is often associated with infectious complications. Mathematical modeling, simulation, and optimization of the treatment process would be a valuable tool to support clinical decision making, potentially resulting in less severe side effects and deeper remissions. However, until now, there has been no validated mathematical model available to simulate the effect of chemotherapy treatment on white blood cell (WBC) counts and leukemic cells simultaneously. We developed a population pharmacokinetic/pharmacodynamic (PK/PD) model combining a myelosuppression model considering endogenous granulocyte-colony stimulating factor (G-CSF), a PK model for cytarabine (Ara-C), a subcutaneous absorption model for exogenous G-CSF, and a two-compartment model for leukemic blasts. This model was fitted to data of 44 AML patients during consolidation therapy with a novel Ara-C plus G-CSF schedule from a phase II controlled clinical trial. Additionally, we were able to optimize treatment schedules with respect to disease progression, WBC nadirs, and the amount of Ara-C and G-CSF. The developed PK/PD model provided good prediction accuracies and an interpretation of the interaction between WBCs, G-CSF, and blasts. For 14 patients (those with available bone marrow blast counts), we achieved a median 4.2-fold higher WBC count at nadir, which is the most critical time during consolidation therapy. The simulation results showed that relative bone marrow blast counts remained below the clinically important threshold of 5%, with a median of 60% reduction in Ara-C. These in silico findings demonstrate the benefits of optimized treatment schedules for AML patients. Until 2017, no new drug had been approved for the treatment of AML, fostering the optimal use of currently available drugs.

Infection risk in autoimmune hematological disorders with low-dose rituximab treatment.

BackgroundRituximab has been widely used in many autoimmune diseases.AimTo evaluate the infection risk of rituximab in autoimmune hematological disorders.MethodsRetrospectively studied and compared the clinical data of 89 patients in our hospital who used low‐dose rituximab (group R) or pulse cyclophosphamide (group C) for their refractory/relapsed autoimmune hematological diseases from January 2011 to January 2017. The kinds of their diseases included autoimmune hemolytic disease (AIHA), Evans syndrome, and idiopathic thrombocytopenic purpura (ITP). All patients chose either rituximab treatment or cyclophosphamide treatment on their own considerations.FindingsThe median follow‐up time was six months in group R and four months in group C. After treatments, the patients in group R showed higher white blood cell (WBC) count and neutrophil count than group C (P = .020, P = .037). CD20‐positive B cells in group R remained at a very low level after rituximab treatment and need about 15 months to return to normal level, which was longer than group C (six months). The incidence of infection in these two groups has no significant difference, which was 34.7% (17/30) in group R and 32.5% (13/28) in group C (P = .976). Tuberculosis infections after rituximab treatment were found in three patients for the first time.ConclusionThe G‐CSF, nadir WBC count, and IgA level were protective factors of infection during rituximab treatment. Low‐dose rituximab therapy in autoimmune hematological diseases does not increase infection risk compared with cyclophosphamide.

An intronic FTO variant rs16952570 confers protection against thiopurine-induced myelotoxicities in multiethnic Asian IBD patients

Thiopurines are used in the treatment of inflammatory bowel disease (IBD) but remain clinically challenging to manage due to wide interpatient variability in clinical outcomes and adverse events. Apart from genetic variants in thiopurine S-methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15) genes, polymorphisms in FTO alpha-ketoglutarate dependent dioxygenase (FTO) were found predictive of thiopurine-induced leukopenia, albeit with conflicting results. To clarify the role of FTO variants in a multiethnic Asian IBD cohort, we recruited 149 patients on thiopurine-based therapy and genotyped two FTO variants p.Ala134Thr (rs79206939) and rs16952570 T > C using Sanger sequencing. FTO p.Ala134Thr (rs79206939) was non-polymorphic and absent whereas intronic rs16952570 T > C was equally prevalent in Chinese (22%) and Indians (18%) and higher in Malays (28%). Higher nadir white blood cell (WBC) and absolute neutrophil count (ANC) levels were observed in patients harboring FTO rs16952570 CC genotypes compared with TT carriers at 4, 8, and 12 weeks after start of thiopurine therapy (P < 0.05). A similar trend was observed in patients carrying the previously well-characterized NUDT15 rs116855232 wild-type CC genotypes. Further in silico analysis suggests that FTO variants linked to rs16952570, particularly rs74018601, may play a regulatory role in altering the FTO expression. The findings from this study indicate a novel protective association with the FTO variant rs16952570 CC genotype and hematological parameters.

High Endogenous DNA Damage Levels Predict Hematological Toxicity in Testicular Germ Cell Tumor Patients Treated With First-Line Chemotherapy

Testicular germ cell tumors (TGCTs) are an excellent example of chemosensitive disease. However, cisplatin-based chemotherapy has significant side effects, including myelosuppression. Previously, we found endogenous DNA damage level in peripheral blood mononuclear cells (PBMCs) to be an independent prognostic marker. In this study, we tested the hypothesis that patients with high endogenous DNA damage levels in PBMCs have an increased risk of developing hematological toxicity. One hundred twenty chemotherapy-naive TGCT patients treated in the National Cancer Institute and the St Elisabeth Cancer Institute in Bratislava, Slovakia, from 2012 to 2018 were enrolled. All patients received platinum-based chemotherapy with granulocyte colony stimulating factor support. On the day of starting treatment, we measured the DNA damage levels in PBMCs using the comet assay. We used the cutoff level of 5.25, a value previously reported to stratify patients on the basis of their prognosis. We monitored hematological toxicity during the first cycle of chemotherapy. The mean and standard error of the mean were calculated for all variables. Patients with high DNA damage levels (>5.25) had more significant hematological toxicity with significantly lower nadir white blood cell count (P= .001), absolute neutrophil count (P= .013) and absolute lymphocyte count (ALC; P< .001). ALCs on day 0 (P= .005) and day 22 (P= .046) were also significantly lower in patients with high DNA damage levels. This study shows that higher endogenous DNA damage levels correlate with increased risk of hematological toxicity in TGCT patients. Hence, the DNA damage levels can be used to select patients for closer monitoring because of a higher risk of acute chemotherapy-related complications.

Clinical experience of craniospinal intensity-modulated spot-scanning proton therapy using large fields for central nervous system medulloblastomas and germ cell tumors in children, adolescents, and young adults.

The outcomes of intensity-modulated proton craniospinal irradiation (ipCSI) are unclear. We evaluated the clinical benefit of our newly developed ipCSI system that incorporates two gantry-mounted orthogonal online X-ray imagers with a robotic six-degrees-of-freedom patient table. Nine patients (7–19 years old) were treated with ipCSI. The prescribed dose for CSI ranged from 23.4 to 36.0 Gy (relative biological effectiveness) in 13–20 fractions. Four adolescent and young adult (AYA) patients (15 years or older) were treated with vertebral-body-sparing ipCSI (VBSipCSI). Myelosuppression following VBSipCSI was compared with that of eight AYA patients treated with photon CSI at the same institution previously. The mean homogeneity index (HI) in the nine patients was 0.056 (95% confidence interval: 0.044–0.068). The mean time from the start to the end of all beam delivery was 37 min 39 s ± 2 min 24 s (minimum to maximum: 22 min 49 s – 42 min 51 s). The nadir white blood cell, hemoglobin, and platelet levels during the 4 weeks following the end of the CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0071, 0.0453, 0.0024, respectively). The levels at 4 weeks after the end of CSI were significantly higher in the VBSipCSI group than in the photon CSI group (P = 0.0023, 0.0414, 0.0061). Image-guided ipCSI was deliverable in a reasonable time with sufficient HI. Using VBSipCSI, AYA patients experienced a lower incidence of serious acute hematological toxicity than AYA patients treated with photon CSI.

High DNA damage levels to predict hematologic toxicity in testicular germ cell tumor (TGCT) patients treated with first-line chemotherapy.

e16055 Background: TGCTs are an excellent example of chemosensitive disease. However, cisplatin-based chemotherapy has significant side effects, including myelosuppression. Previously, we found endogenous DNA damage level in peripheral blood mononuclear cells (PBMCs) to be an independent prognostic marker. We tested the hypothesis that patients with high endogenous DNA damage levels in PBMCs have an increased risk of developing hematologic toxicity. Methods: 120 chemotherapy-naïve patients with TGCTs treated in the National Cancer Institute and the St. Elisabeth Cancer Institute in Bratislava, Slovakia, from 2012 to 2018 were enrolled. All patients received platinum-based chemotherapy with G-CSF support. On the day of starting treatment, we measured the endogenous DNA damage levels in PBMCs using the Comet assay. We used a cut-off level of 5.25, a value previously found to stratify patients based on their prognosis. We monitored hematologic toxicity during the 1st cycle of chemotherapy. The mean and SEM were calculated for all variables. Results: Patients with high DNA damage levels ( &gt; 5.25) had more significant hematologic toxicity with significantly lower nadir white blood cell count (6.0±1.1×109/L vs 9.8±1.0×109/L p = 0.001), absolute neutrophil count (4.1±1.0×109/L vs 7.0±0.9×109/L p = 0.013) and absolute lymphocyte count (ALC, 1.1±0.1×109/L vs 1.5±0.1×109/L p &lt; 0.001). ALCs on day 0 (1.5±0.1×109/L vs 1.8±0.1×109/L p = 0.005) and day 22 (2.0±0.1×109/L vs 2.4±0.1×109/L p = 0.046) were also significantly lower in patients with high DNA damage levels. There were no significant differences in hemoglobin levels or platelet counts between the two groups. Neutrophil to lymphocyte ratio and systemic immune-inflammation index were lower at nadir in patients with high DNA damage levels, however, these differences were not statistically significant (p = 0.08 and p = 0.10, respectively). Conclusions: This study shows that higher endogenous DNA damage levels correlate with an increased risk of hematologic toxicity. The Comet assay data can be used to select patients for closer monitoring due to a higher risk of acute chemotherapy-related complications.

Predictive role of NUDT15 variants on thiopurine-induced myelotoxicity in Asian inflammatory bowel disease patients.

Genetic variants ofTPMTand NUDT15have been reported to predict the inter-patient variability in response and toxicity profiles of patients receiving thiopurine therapy. However, the clinical utility of TPMT genotyping in guiding thiopurine doses has been questionable, in part due to underlying differences in the prevalence of TPMT variants in both Caucasian and Asian populations. Several NUDT15 variants have been associated with thiopurine-induced leukopenia, particularly in Asian cohorts. So far, none have been reported in a multiethnic Asian population. To investigate the associations between TPMT and NUDT15 variants with thiopurine-induced myelotoxicity in 129 Asian inflammatory bowel disease patients. Pyrosequencing was performed to screen for TPMT and NUDT15 variants. Intracellular steady-state metabolite concentrations were quantified using liquid chromatography-tandem mass spectrometry. Significant declines in nadir white blood cell, absolute neutrophil count and platelet counts were observed with increasing copy numbers of the risk T allele at NUDT15 c.415C>T locus (overall p < 0.05) within 4, 8 and 12 weeks and 6 months after thiopurine initiation. Patients with low and intermediate NUDT15 activity, as inferred from haplotype pairs, had significantly higher risks of leukopenia (p = 0.000253) and neutropenia (p = 0.002) compared with patients with normal NUDT15 activity. These findings highlight the critical relevance of NUDT15 pharmacogenetics in predicting for thiopurine-induced myelotoxicity and confirm the lack of significance of TPMT variants in Asian inflammatory bowel disease patients.

The impact of proton beam therapy on blood cell count nadir during neoadjuvant chemoradiation therapy for esophageal cancer.

137 Background: To analyze the blood cell count nadir, particularly grade 4 hematologic toxicities, in patients with esophageal cancer who were treated with neoadjuvant chemoradiation (nCRT) with either Proton Beam Therapy (PBT) or Intensity Modulated Radiation Therapy (IMRT) in a propensity-matched pair analysis. Methods: Esophageal cancer patients (n = 480) treated from 2005-2016 with nCRT with (n = 167) or without (n = 313) induction chemotherapy (ICT) were analyzed. White blood cell, neutrophil, lymphocyte and platelet counts nadir during ICT and CRT were obtained, and graded according to the CTCAE v.4.0. Univariate and multivariable logistic regression models to identify factors associated with increased risk of grade 4 lymphopenia were fitted. By propensity score matching, 136 PBT cases and 136 propensity score matched IMRT controls were selected for comparison. Results: In the entire study cohort during CRT (n = 480), 2 (0.4%), 1 (0.2%), 159 (33%), and 2 (0.4%) patients experienced grade 4 leukopenia, neutropenia, lymphopenia and thrombocytopenia, respectively. This is not seen in patients who received ICT (n = 167), as only 0 (0%), 2 (1.2%), 1 (0.6%) and 0 (0%) patients experienced grade 4 leukopenia, neutropenia, lymphopenia and thrombocytopenia during the ICT phase. Multivariable analyses identified older age (p = 0.0139), larger planning tumor volume (PTV) (p = 0.0213), distal vs upper/mid tumor location (borderline significance, p = 0.0779) and IMRT vs PBT (p &lt; 0.0001) as factors associated with increased risk of grade 4 lymphopenia during CRT. Among the 272 propensity-matched patients treated with either PBT or IMRT, 24 (17.6 %) and 55 (40.4 %) patients experienced grade 4 lymphopenia, respectively (p &lt; 0.001). Grade 4 lymphopenia correlates with poorer survival (p = 0.0587), lower progression free survival (p = 0.0384) and distant metastatic recurrence (p = 0.0185). Conclusions: The use of PBT may be an important modifying factor in altering the incidence of grade 4 lymphopenia during CRT in esophageal cancer. The dosimetric factors that can modulate this risk is a subject of continued investigation.

Correlations Between Radiation Dose in Bone Marrow and Hematological Toxicity in Patients With Cervical Cancer: A Comparison of 3DCRT, IMRT, and RapidARC.

To comparatively evaluate the hematological toxicity (HT) associated with 3 concurrent chemoradiotherapies that are routinely used to treat cervical cancer, including 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT), and RapidARC and to establish a new normal tissue complication probability model of bone marrow (BM) to predict HT in cervical cancer patients undergoing concurrent chemoradiotherapy. Patients with cervical cancer (N = 100) who received concurrent cisplatin and whole-pelvic radiotherapy were enrolled in this study. Dosimetric parameters (including V10, V20, V30, and V40 and mean doses to the pelvic bone) and HT were analyzed. The V20, V30, and V40 and mean doses to the BM were lower in the IMRT and RapidARC groups than in the 3DCRT group, and the RapidARC group had higher V10 and V40 and mean values than the IMRT group. The V20, V30, and V40 and the mean dose to the pelvic bone were positively correlated with HT. Generalized linear normal tissue complication probability models of white blood cell (WBC) and absolute neutrophil cell (ANC) nadirs and BM V20 were established as follows: WBC nadir = 3.382 - 4.056 • V20 + 0.295 • baseline of WBC (adjusted R = 0.246, F = 15.847) and ANC nadir = 2.438 - 2.780 • V20 + 0.233 • baseline of ANC (adjusted R = 0.236, F = 16.282). This study suggests that IMRT results in milder hematological toxicity than either 3DCRT or RapidARC. Dosimetric parameters were associated with the incidence of HT in cervical cancer patients who received concurrent chemoradiotherapies.

Effects of Different Dose of Cyclophosphamide on Peripheral Blood Cells of Normal ICR Mice

To investigate effective doses of cyclophosphamide (CTX) for establishment of leukopenia model in ICR mouse. Normal ICR mice (n = 96) were divided into CTX(80), CTX(100), CTX(120), CTX(150) and CTX(300) groups, of which mice received CTX intraperitoneally at a dose of 80, 100, 120, or 150 mg/kg once a day for 3 consecutive days, or 300 mg/kg with single injection. The peripheral blood cell counts were detected at various times before and after CTX administration. The peripheral white blood cell nadirs in the mice injected with CTX appeared on day 4 after the first dose of CTX. The peripheral white blood cell nadir in group CTX(100) was 26.7% of the value measured in mice before CTX administrated, and that of group CTX(80) was 35.0%. Higher doses of CTX, however, caused too severity in hematopoietic injury. The dose of CTX 100 mg/(kg·d) × 3d is appropriate for leucopenia model of ICR mouse.

Thoracic Vertebral Body Irradiation Contributes to Acute Hematologic Toxicity During Chemoradiation Therapy for Non-Small Cell Lung Cancer.

To determine the relationships between radiation doses to the thoracic bone marrow and declines in blood cell counts in non-small cell lung cancer (NSCLC) patients treated with chemoradiation therapy (CRT). We included 52 patients with NSCLC treated with definitive concurrent carboplatin-paclitaxel and RT. Dose-volume histogram (DVH) parameters for the thoracic vertebrae (TV), sternum, scapulae, clavicles, and ribs were assessed for associations with changes in blood counts during the course of CRT. Linear and logistic regression analyses were performed to identify associations between hematologic nadirs and DVH parameters. A DVH parameter of Vx was the percentage of the total organ volume exceeding x radiation dose. Grade ≥ 3 hematologic toxicity including neutropenia developed in 21% (n=11), leukopenia in 42% (n=22), anemia in 6% (n=3), and throbocytopenia in 2% (n=1) of patients. Greater RT dose to the TV was associated with higher risk of grade ≥ 3 leukopenia across multiple DVH parameters, including TV V20 (TVV) (odds ratio [OR] 1.06; P=.025), TVV30 (OR 1.07; P=.013), and mean vertebral dose (MVD) (OR 1.13; P=.026). On multiple regression analysis, TVV30 (β = -0.004; P=.018) and TVV20 (β = -0.003; P=.048) were associated with white blood cell nadir. Additional bone marrow sites (scapulae, clavicles, and ribs) did not affect hematologic toxicity. A 20% chance of grade ≥ 3 leukopenia was associated with a MVD of 13.5 Gy and a TTV30 of 28%. Cutoff values to avoid grade ≥ 3 leukopenia were MVD ≤ 23.9 Gy, TVV20 ≤ 56.0%, and TVV30 ≤ 52.1%. Hematologic toxicity is associated with greater RT doses to the TV during CRT for NSCLC. Sparing of the TV using advanced radiation techniques may improve tolerance of CRT and result in improved tolerance of concurrent chemotherapy.

Plerixafor Successfully Rescues Poor Mobilizers Resulting in Adequate CD34 Cell Numbers However Stem Cell Products Yield Lower Numbers of CFU/CD34 and Delayed Neutrophil Engraftment

Background: The CXCR4 inhibitor plerixafor was studied as a rescue agent in the setting of poor chemotherapy/filgrastim mobilization in a phase II trial of adults with lymphoma and myeloma who underwent a peripheral hematopoietic stem cell (HSC) mobilization prior to autologous transplant (ASCT) (NCT01037517). Given the wide range of expression of CD34 in myeloid precursors we were interested in the quality of the CD34 positive cells that were collected to proceed to transplant in poor mobilizers. Amongst a population of poor mobilizers would the CD34+ population contain cells of a more differentiated phenotype or express different proportions of homing receptors as CD34 cells collected from patients who mobilized easily?Methods: From 2009 to 2012 sequential adult patients with a diagnosis of lymphoma or multiple myeloma undergoing chemo-mobilization in preparation for autologous stem cell collection were enrolled on a phase II study to examine a strategy of plerixafor rescue in the setting of poor mobilization. Plerixafor (240 mcg/kg sc X 1) was administered on the evening prior to planned apheresis in subjects with a post nadir white blood cell count >1 X109/L and a peripheral blood [CD34] ≤ 10x106/L on the day prior to planned collection. Participants proceeded to stem cell apheresis the next day if their peripheral blood CD34 > 10x106/L. An aliquot from the mobilized product was analyzed for CD34+ cell subsets using markers of stemness ( CD33-, CD90, CD133 , CD166) and homing (CD26, CD49F, CD184) Differences between the groups are reported as means ±standard deviation and compared by two tailed t-tests.Results: 46/48 subjects were successfully mobilized in one day (HSC collection of >2 x 106 CD34+ cells/kg): 38 pts were not administered plerixafor (good mobilizer) and 8 pts were administered plerixafor (plerixafor rescue). The two participants not able to mobilize with plerixafor had evidence of progression of underlying disease within 2 weeks of attempted mobilization. Forty four participants (6/8 plerixafor and 38/38 good mobilizers) underwent ASCT. Median time to platelet engraftment was similar between good mobilizers (12 d, range 9-22d) and the plerixafor rescue group (13 d, range 12-13 d). The median time to neutrophil engraftment was prolonged in the plerixafor rescue group (23 d, range 17-67d) compared to good mobilizers (17 d, range 10-31d). CD34 content/kg of the apheresis product collected was similar between groups (good mobilizer 11.6±7.9 versus the plerixafor rescue group 6.4±4.6 p = 0.1). Subset analysis of CD34 positive cells in the products showed comparable expression of markers associated with more immature HSC progenitors but fewer CFU per CD34 positive cell plated. Homing receptors on the CD34 positive cells were similar despite the use of a CXCR4 inhibitor in the poor mobilizers. (See table) TableGood mobilizer N= 38 (Mean % ± SD)Plerixafor rescue N= 8 (Mean % ± SD)P valueStemmness MarkersCD90+ (Thy-1)24.4±12.730.6±19.30.3CD133+ (prominin1)59.1 ± 12.959.1 ± 16.80.9CD166+ (ALCAM)5.7±3.36.6±5.10.5CD33- (Siglec-3)80.6±3.369.8±13.10.01CFU/105 CD34+ cells1015±799276±3160.02Homing MarkersCD26 (dipeptidyl peptidase-4)5.4±410.4±13.30.05CD49F (VLA4)8.5±7.96.8±9.70.6CD184 (CXCR4)16.2±20.517.7±9.70.8Discussion: Plerixafor used to rescue patients at risk of poor mobilization resulted in collection of adequate numbers of CD34+ cells for transplantation and allowed ASCT in a majority of poor mobilizers in our series. Delayed neutrophil recovery, was seen in the poor mobilizer cohort. We did not see a skewing of the CD34+ cells in the products from poor mobilizers to a more mature phenotype but did find lower clonogenic potency with fewer CFU generated/CD34 cells plated. DisclosuresOff Label Use: Plerixafor used as initial mobilization strategy in autologous stem cell mobilization.

Nadir White Blood Cell, Absolute Neutrophil, and Absolute Lymphocyte Counts During Concurrent Chemoradiation Therapy Are Associated With Worse Outcomes in Patients With Limited-Stage Small Cell Lung Cancer: Small Cell Lung Cancer

Nadir White Blood Cell, Absolute Neutrophil, and Absolute Lymphocyte Counts During Concurrent Chemoradiation Therapy Are Associated With Worse Outcomes in Patients With Limited-Stage Small Cell Lung Cancer: Small Cell Lung Cancer

Nadir White Blood Cell, Absolute Neutrophil, and Absolute Lymphocyte Counts During Concurrent Chemoradiation Therapy Are Associated With Worse Outcomes in Patients With Limited-Stage Small Cell Lung Cancer

Limited-stage small cell lung carcinoma (LSCLC) has a poor prognosis with a 5-year overall survival of < 20%. Studies have suggested that SCLC may affect the immune system. We hypothesis that baseline or nadir white blood cell (WBC), absolute neutrophil count (ANC), absolute lymphocyte count (ALC), platelet (PLT) count and hemoglobin (Hb) levels during the course of concurrent chemoradiation (CCRT) is associated with treatment outcomes for LSCLC.

Evidence for Radiation-Induced Disseminated Intravascular Coagulation as a Major Cause of Radiation-Induced Death in Ferrets

The studies reported here were performed as part of a program in space radiation biology in which proton radiation like that present in solar particle events, as well as conventional gamma radiation, were being evaluated in terms of the ability to affect hemostasis. Ferrets were exposed to 0 to 2 Gy of whole-body proton or gamma radiation and monitored for 30 days. Blood was analyzed for blood cell counts, platelet clumping, thromboelastometry, and fibrin clot formation. The lethal dose of radiation to 50% of the population (LD50) of the ferrets was established at ∼ 1.5 Gy, with 100% mortality at 2 Gy. Hypocoagulability was present as early as day 7 postirradiation, with animals unable to generate a stable clot and exhibiting signs of platelet aggregation, thrombocytopenia, and fibrin clots in blood vessels of organs. Platelet counts were at normal levels during the early time points postirradiation when coagulopathies were present and becoming progressively more severe; platelet counts were greatly reduced at the time of the white blood cell nadir of 13 days. Data presented here provide evidence that death at the LD50 in ferrets is most likely due to disseminated intravascular coagulation (DIC). These data question the current hypothesis that death at relatively low doses of radiation is due solely to the cell-killing effects of hematopoietic cells. The recognition that radiation-induced DIC is the most likely mechanism of death in ferrets raises the question of whether DIC is a contributing mechanism to radiation-induced death at relatively low doses in large mammals.