The volume of 99m Tc sulfur colloid SPET-defined active bone marrow can predict grade 3 or higher acute hematologic toxicity in locally advanced cervical cancer patients who receive chemoradiotherapy

Hematologic Toxicity and Bone Marrow-Sparing Strategies in Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review

The standard treatment for locally advanced cervical cancer typically includes concomitant chemoradiation, a regimen known to induce severe hematologic toxicity (HT). Particularly, pelvic bone marrow dose exposure has been identified as a contributing factor to this hematologic toxicity. Chemotherapy further increases bone marrow suppression, often necessitating treatment interruptions or dose reductions. A systematic search for original articles published between 1 January 2006 and 7 January 2024 that reported on chemoradiotherapy for locally advanced cervical cancer and hematologic toxicities was conducted. Twenty-four articles comprising 1539 patients were included in the final analysis. HT of grade 2 and higher was observed across all studies and frequently exceeded 50%. When correlating active pelvic bone marrow and HT, significant correlations were found for volumes between 10 and 45 Gy and HT of grade 3 and higher. Several dose recommendations for pelvic bone and pelvic bone marrow sparing to reduce HT were established, including V10 < 90-95%, V20 < 65-86.6% and V40 < 22.8-40%. Applying dose constraints to the pelvic bone/bone marrow is a promising approach for reducing HT, and thus reliable implementation of therapy. However, prospective randomized controlled trials are needed to define precise dose constraints and optimize clinical strategies.

Effects of bone marrow sparing radiotherapy on acute hematologic toxicity for patients with locoregionally advanced cervical cancer: a prospective phase II randomized controlled study

OBJECTIVE

To evaluate effects of bone marrow sparing (BMS) radiotherapy on decreasing the incidence of acute hematologic toxicity (HT) for locoregionally advanced cervical cancer (LACC) patients treated by pelvic irradiation.

MATERIALS AND METHODS

LACC patients were recruited prospectively from May 2021 to May 2022 at a single center and were evenly randomized into the BMS group and the control group. All patients received pelvic irradiation with concurrent cisplatin (40 mg/m2 weekly), followed by brachytherapy and BM V40 < 25% in the BMS group was additionally prescribed. Acute HT was assessed weekly. Binary logistic regression model and receiver operating characteristic (ROC) curve were used for predictive value analysis. The trial was registered with Chinese clinical trial registry (ChiCTR2200066485).

RESULTS

A total of 242 patients were included in the analysis. Baseline demographic, disease and treatment characteristics were balanced between the two groups. In the intention-to-treat population, BMS was associated with a lower incidence of grade ≥ 2 and grade ≥ 3 acute HT, leukopenia and neutropenia s(72.70% v 90.90%, P < 0.001*; 16.50% vs. 65.30%, P < 0.001*; 66.10% vs. 85.10%, P = 0.001*; 13.20% vs. 54.50%, P < 0.001*; 37.20% vs. 66.10%, P < 0.001*; 10.70% vs. 43.80%, P < 0.001*). BMS also resulted in decreased dose delivered to the organs at risk (OARs) including rectum, bladder and left and right femoral head. Univariate and multivariate analyses showed that BM V40 was an independent risk factor for grade ≥ 3 acute HT (odds ratio [OR] = 2.734, 95% confidence interval [CI] = 1.959-3.815, P < 0.001*). Cutoff value was 25.036% and area under the curve (AUC) was 0.786. The nomogram was constructed, which was rigorously evaluated and internally cross-validated, showing good predictive performance.

CONCLUSIONS

Receiving BMS pelvic irradiation could reduce the incidence of acute HT in LACC patients, and BM V40 < 25% may be a significant factor in reducing the risks of acute HT.

Dose-Volume Parameters of Spared Magnetic Resonance Imaging-Defined Active Bone Marrow Predict Hematologic Toxicity in Pelvic Malignancies Patients Undergoing Radiotherapy: A Cohort Study

Background: The objective of this investigation is to evaluate the superiority of dose-volume parameters relying on magnetic resonance imaging (MRI)-defined active bone marrow (ABM) over those based on total bone marrow (TBM) contoured via CT in the prediction of hematologic toxicity (HT) occurrence among patients with pelvic malignancies undergoing radiotherapy. Methods: The clinical data of 116 patients with pelvic malignancies treated with pelvic radiotherapy were analyzed retrospectively. The ABM areas on T1-weighted MRI were contoured. The statistical significance between TBM and ABM dose-volume measures was assessed through the utilization of either Student's t-test or Wilcoxon signed rank test. Logistic and linear regression models were employed to analyze the correlation between dose-volume parameters (V5-V50) and HT occurrence in pelvic ABM and TBM. Receiver operating characteristic (ROC) curves were used to compare predictors of HT2+. Results: There were significant differences in dosimetric parameters between ABM and TBM. Logistic regression analysis showed that ABM V5, ABM V10, ABM V15, ABM V20, and TBM V5 were significantly associated with the occurrence of HT2+ in pelvic malignancies. Linear regression analysis showed that ABM V5, ABM V10, and ABM V15 were significantly associated with white blood cell (WBC), absolute neutrophil count (ANC), hemoglobin (Hb), and lymphocyte (Lym) nadir. ABM V5, ABM V10, ABM V15, and ABM V30 were predictive of HT2+. Conclusions: More accurate prediction of HT in patients receiving pelvic radiotherapy may be achieved by relying on dose-volume parameters of MRI-based ABM. Further prospective studies are needed to confirm this.

A prospective single-arm study on the relationship between dose-volume parameters of pelvic functional bone marrow and acute hematological toxicities during intensity-modulated radiotherapy with or without concurrent chemotherapy for uterine cervical/endometrial cancer

BACKGROUND

FLT-PET/CT can accurately identify and locate functional bone marrow (FBM) with hematopoietic capability, the FBM were divided into two levels as FBM1 (strongest hemopoietic ability region)and FBM2 (moderate hemopoietic ability region) via FLT-PET/CT. The purpose of this study was to explore the relationship between dose-volume parameters of pelvic FBM and hematologic toxicity (HT) during radiotherapy with or without concurrent chemotherapy for uterine cervical/endometrial cancer.

METHODS

From December 2016 to September 2021, ninety-seven uterine cervical/endometrial cancer patients received intensity-modulated radiation therapy were prospectively recruited in this single-arm, prospective, phase II trial. Blood counts were reviewed weekly during radiotherapy. Single- and multifactor regression methods were used to analyze the relationships between dose-volume parameters of FBM1/2 and grade ≥ 2 HT. ROC curves were used to determine the cutoff values for the dose-volume parameters of FBM1/2.

RESULTS

The incidence of grade ≥ 2 leukopenia, neutropenia, thrombocytopenia and anemia in patients during radiotherapy was 63.9%, 45.4%, 19.6% and 38.8% respectively, and the median occurrence time was the 29th, 42th, 35th and 31th day, respectively. Multivariate regression analysis showed that the Dmax of FBM1 was significantly related to grade ≥ 2 leukopenia (OR = 1.277 95% CI 1.067-1.528, P = 0.008), Dmean of FBM2 was significantly related to grade ≥ 2 thrombocytopenia (OR = 1.262 95% CI 1.066-1.494, P = 0.007), and V10 of FBM1 was significantly related to grade ≥ 2 anemia (OR = 1.198 95% CI 1.003-1.431, P = 0.046). The incidence of grade ≥ 2 leukopenia for patients with FBM1 Dmax < 53 Gy was lower than that for patients with FBM1 Dmax ≥ 53 Gy (53.4% vs. 95.8%, P < 0.001). The incidence of grade ≥ 2 thrombocytopenia in patients with FBM2 Dmean < 33 Gy was lower than that in patients with FBM2 Dmean ≥ 33 Gy (0 vs. 28.4%, P < 0.001). The incidence of grade ≥ 2 anemia for patients with FBM1 V10 < 95% was lower than that in patients with FBM1 V10 ≥ 95% (24.4% vs. 57.1%, P = 0.003).

CONCLUSIONS

Grade ≥ 2 HT usually occurs in the 4th week of radiotherapy for patients with uterine cervical/endometrial cancer. The Dmax and V10 of FBM1 and the Dmean of FBM2 were significantly associated with the occurrence of grade ≥ 2 HT. The recommended optimal dose constraints were FBM1 Dmax < 53 Gy, V10 < 95%, and FBM2 Dmean <33 Gy.

Is it time for bone marrow sparing radiation therapy to be standard of care in cervical cancer?

Evaluating a recent prospective trial of active bone marrow sparing defined by 99mTc‐single‐photon emission computed tomography imaging in the landscape of the existing literature.

Single-photon emission computed tomography-defined active bone marrow-sparing volumetric-modulated arc therapy reduces the incidence of acute hematologic toxicity in locally advanced cervical cancer patients who receive chemoradiotherapy: A single-center prospective randomized controlled trial

BACKGROUND

This study aims to test the efficacy of single-photon emission computed tomography (SPECT)-defined active bone marrow-sparing (ABMS) volumetric-modulated arc therapy (VMAT) in reducing grade 3+ acute hematologic toxicity (HT) in locally advanced cervical cancer patients treated with chemoradiotherapy.

METHODS

This was a prospective, single-center, open label, randomized clinical trial that enrolled locally advanced cervical cancer patients. Participants were randomized to the 99m Tc sulfur colloid SPECT-defined ABMS VMAT (ABMS group) or control group, who received weekly cisplatin concurrently with VMAT followed by high-dose-rate intracavitary brachytherapy. The ABMS group additionally received SPECT-defined ABM dose constraints. The primary end point was the incidence of grade 3+ acute HT.

RESULTS

A total of 192 Federation of Gynaecology and Obstetrics stage IB-IIIB patients were randomly treated (96 each in the ABMS control groups). The median follow-up was 24.0 months. The incidence of grade 3+ acute HT in the ABMS group was significantly lower than that in the control group (32.3% vs. 53.1%, p < .01). The number of patients completing five cycles of cisplatin was 88.5% in the ABMS group and 75% in the control group, and the difference was significant (p = .02). There were no differences in planning target value coverage, organs at risk dosimetric parameters, 2-year progression-free survival, or 2-year overall survival between the two groups. Patients in the control group had nonsignificantly worse 2-year distant metastasis than patients in the ABMS group (17.8% vs. 11.1%, p = .19).

CONCLUSIONS

ABMS VMAT significantly reduced grade 3+ acute HT and improved chemotherapy delivery compared with the control treatment. We found weak evidence of the effect of ABMS VMAT on distant metastasis.

A radiomics approach for predicting acute hematologic toxicity in patients with cervical or endometrial cancer undergoing external-beam radiotherapy

PURPOSE

This study is purposed to establish a predictive model for acute severe hematologic toxicity (HT) during radiotherapy in patients with cervical or endometrial cancer and investigate whether the integration of clinical features and computed tomography (CT) radiomics features of the pelvic bone marrow (BM) could define a more precise model.

METHODS

A total of 207 patients with cervical or endometrial cancer from three cohorts were retrospectively included in this study. Forty-one clinical variables and 2226 pelvic BM radiomic features that were extracted from planning CT scans were included in the model construction. Following feature selection, model training was performed on the clinical and radiomics features via machine learning, respectively. The radiomics score, which was the output of the final radiomics model, was integrated with the variables that were selected by the clinical model to construct a combined model. The performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

The best-performing prediction model comprised two clinical features (FIGO stage and cycles of postoperative chemotherapy) and radiomics score and achieved an AUC of 0.88 (95% CI, 0.81-0.93) in the training set, 0.80 (95% CI, 0.62-0.92) in the internal-test set and 0.85 (95% CI, 0.71-0.94) in the external-test dataset.

CONCLUSION

The proposed model which incorporates radiomics signature and clinical factors outperforms the models based on clinical or radiomics features alone in terms of the AUC. The value of the pelvic BM radiomics in chemoradiotherapy-induced HT is worthy of further investigation.

Role of 18FDG PET/CT metabolic parameters in predicting hematological toxicity during chemoradiotherapy for locally advanced cervical cancer

Purpose

The aim of this study is to evaluate the value of ¹⁸FDG PET/CT metabolic parameters in predicting hematological toxicity (HT) during chemoradiotherapy (CRT) for locally advanced cervical cancer (LACC).

Methods and materials

Forty-one patients with LACC undergoing concurrent CRT were retrospectively analyzed. The correlations among age, body mass index, FIGO stage, differentiation, maximum diameter of primary lesion, parametrial invasion, lymph node metastasis, pelvic active bone marrow volume (BM_ACT), BM_ACT volume percentage (BM_ACT%), maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and HT were analyzed using hypothesis testing and logistic regression. A p-value< 0.05 was considered significant unless otherwise specified.

Results

Among the 41 patients, 19 had grade 3–4 HT and 22 had grade 0–2 HT. Only SUVmax (Z = −1.961, p = 0.050) and BM_ACT% (χ2 = 7.769, p = 0.020) showed statistically significant difference in univariate analysis. In logistic regression, grade 3–4 HT was not associated with SUVmax. The probability of HT occurrence in<30% BM_ACT% was 0.071 times less than in 30%–40% BM_ACT% (p = 0.010, OR = 0.071, 95% CI = 0.010–0.532), and the probability of HT occurrence in >40% BM_ACT% was 0.148 times less than in 30%–40% BM_ACT% (p = 0.037, OR = 0.148, 95% CI = 0.025–0.892).

Conclusion

Baseline ¹⁸FDG PET/CT BM_ACT% could help predict the severity of HT during CRT for LACC.

Pelvic bones ADC could help to predict severe hematologic toxicity in patients undergoing concurrent chemoradiotherapy for cervical cancer

BACKGROUND

Hematologic toxicity (HT) during concurrent chemoradiotherapy (CCRT) for cervical cancer can lead to treatment breaks and compromise efficacy.

PURPOSE

To evaluate the association between severe hematologic toxicity (HT) and clinical factors and pelvic apparent diffusion coefficient (ADC) during CCRT of cervical cancer patients.

METHODS

Data from 120 patients with cervical cancer who were treated with CCRT from January 2016 and December 2018 were retrospectively analyzed. The clinical data (age, menopausal status, clinical stage, body mass index, chemotherapy regimen and chemotherapy cycle) of the patients were collected, and the cohort were divided into two groups based on the HT grade: HT3+ group (HT grade ≥ 3; 66 patients) and HT3- group (HT grade<3; 54 patients). All patients performed MRI before CCRT, and pelvic (ilium, pubis, ischium) ADC value was measured on ADC map. The correlation between severe HT and clinical parameters and pelvic ADC value were analyzed by univariate analysis, and the diagnostic performance was further assessed by receiver operating characteristic (ROC) analysis.

RESULTS

In univariate analysis, the menopausal status (p = 0.012) and chemotherapy regimen (p = 0.011) were significantly correlated with severe HT in overall patients, and menopausal patients or patients receiving paclitaxel plus cisplatin (TP) regimen were more likely to develop severe HT. HT3+ group showed a significantly lower pelvic ADC value than HT3- group. The ADC value cut-offs derived from our study for predicting severe HT was 0.317 × 10^-3 mm²/s in overall patients. Neither clinical parameters or pelvic ADCs were associated with severe HT in menopausal patients when analyzed separately (p > 0.05).

CONCLUSIONS

Severe HT was significantly associated with menopausal status and chemotherapy regimen in patients with cervical cancer treated with CCRT, and HT3+ group showed a lower pelvic ADC value.

Feasibility of bone marrow sparing volumetric modulated arc therapy to spare active bone marrow in cervical and vaginal cancer patients: a retrospective dosimetric analysis

INTRODUCTION

Chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical and vaginal cancer. It is associated with high haematological toxicity (HT) that can lead to treatment interruptions and cancelled chemotherapy cycles, reducing the potential effectiveness of this regimen. Bone marrow sparing (BMS) utilising volumetric modulated arc therapy (VMAT) is one method to reduce dose to the active bone marrow (ABM) so that HT rates are reduced. The aim of this paper was to assess whether BMS-VMAT can effectively spare the ABM whilst maintaining clinically acceptable target and organ-at-risk (OAR) doses.

METHODS

Twenty gynaecological cancer patients treated with definitive CRT at the Liverpool/Macarthur Cancer Therapy centres between 2015 and 2020 were retrospectively included. ABM was delineated based on fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Weekly blood tests and ABM dose parameters at the V10Gy, V20Gy, V30Gy, V40Gy and Dmean were assessed on original plans for any potential correlation with grade 2+ HT. Replanned with VMAT for BMS, various dose parameters were compared with the original plan to assess for any significant differences.

RESULTS

Active bone marrow doses were significantly reduced (P < 0.001 for all parameters) in BMS-VMAT plans, and significant improvements in target and OAR coverage were found compared with the original plans. Compared with VMAT only, target and OARs were comparable. No significant correlations between HT and ABM doses were found.

CONCLUSION

Bone marrow sparing volumetric modulated arc therapy can significantly reduce dose to the active bone marrow whilst maintaining acceptable target and OAR doses. Future prospective trials are needed to evaluate the clinical impact of BMS on toxicity and compliance.

Pelvic bone marrow sparing radiotherapy for cervical cancer: A systematic review and meta-analysis

BACKGROUNDS

Concurrent chemo-radiotherapy in patients with locally advanced cervical cancer has significant hematologic toxicities (HT), leading to treatment disruption and affecting patient prognosis. We performed the meta-analysis to assess the clinical benefit of pelvic (active) bone marrow (BM) sparing radiotherapy.

METHODS

A systematic methodological search of six primary electronic databases was performed. This systematic review mainly assessed the differences in pelvic (active) BM dose-volume parameters (DVP), hematologic toxicity of pelvic (active) BM sparing versus non-sparing radiotherapy plans. The secondary objective was to explore optimal dose limitation regimens and evaluate other radiation-induced toxicities (gastrointestinal and urological toxicity (GT/UT)). Random-effects models were used for meta-analysis.

RESULTS

Final 65 publications that met inclusion criteria were included in the meta-analysis and descriptive tables. Meta-analysis of mean pelvic BM-DVP differences showed that pelvic BM-V_10,20,40,50 (Vx: volume of BM receiving ≥ X Gy) were reduced by -4.6% [95% CI: -6.6, -2.6], -10.9% [-13.2, -8.6], -7.3% [-9.5, -5.2] and -3.4% [-4.3, -2.4] in pelvic BM-sparing plans. Pelvic BM sparing radiotherapy decreased G2/3+ HT [odds ratio (OR) 0.31, (0.23, 0.41)/0.42, (0.28, 0.63)], without increasing GT [G2/3+: OR 0.76, (0.51, 1.14)/0.90, (0.47, 1.74)] and UT [G2/3+: OR 0.91, (0.57, 1.46)/0.54, (0.25, 1.17)]. Pelvic active BM sparing radiotherapy also reduced HT [G2/3+ HT: OR 0.42, (0.23, 0.77)/0.34, (0.16, 0.72)]. There were significant variations between publications in dose restriction regimens.

CONCLUSION

The pelvic BM protection radiotherapy can decrease BM dose and HT. Moreover, it does not increase GT and UT. The clinical benefit of pelvic active BM protection needs to be further validated in randomized controlled trials.

The Impact of Pelvic Nodal Radiotherapy on Hematologic Toxicity: A Systematic Review with Focus on Leukopenia, Lymphopenia and Future Perspectives in Prostate Cancer Treatment

INTRODUCTION

Hematologic toxicity (HT), particularly leukopenia, is a common side-effect of oncologic treatments for pelvic malignancies. Pelvic nodal radiotherapy (PNRT) has been associated with HT development mainly through incidental bone marrow (BM) irradiation; however, several questions remain about the clinical impact of radiotherapy-related HT. Herein, we perform a systematic review of the available evidence on PNRT and HT.

MATERIALS AND METHODS

A comprehensive systematic literature search was performed through EMBASE. Hand searching and clinicaltrials.gov were also used.

RESULTS

While BM-related dose-volume parameters and BM-sparing techniques have been more thoroughly investigated in pelvic malignancies such as cervical, anal, and rectal cancers, the importance of BM as an organ-at-risk has received less attention in prostate cancer treatment.

CONCLUSIONS

We examined the available evidence regarding the impact of PNRT on HT, with a focus on prostate cancer treatment. We suggest that BM should be regarded as an organ-at-risk for patients undergoing PNRT.

Correlations between bone marrow radiation dose and hematologic toxicity in locally advanced cervical cancer patients receiving chemoradiation with cisplatin: a systematic review

Patients with locally advanced cervical cancer (LACC) treated with chemoradiation often experience hematologic toxicity (HT), as chemoradiation can induce bone marrow (BM) suppression. Studies on the relationship between BM dosimetric parameters and clinically significant HT might provide relevant indices for developing BM sparing (BMS) radiotherapy techniques. This systematic review studied the relationship between BM dose and HT in patients with LACC treated with primary cisplatin-based chemoradiation. A systematic search was conducted in Embase, Medline, and Web of Science. Eligibility criteria were treatment of LACC-patients with cisplatin-based chemoradiation and report of HT or complete blood cell count (CBC). The search identified 1346 papers, which were screened on title and abstract before two reviewers independently evaluated the full-text. 17 articles were included and scored according to a selection of the TRIPOD criteria. The mean TRIPOD score was 12.1 out of 29. Fourteen studies defining BM as the whole pelvic bone contour (PB) detected significant associations with V10 (3/14), V20 (6/14), and V40 (4/11). Recommended cut-off values were V10 > 95-75%, V20 > 80-65%, and V40 > 37-28%. The studies using lower density marrow spaces (PBM) or active bone marrow (ABM) as a proxy for BM only found limited associations with HT. Our study was the first literature review providing an overview of articles evaluating the correlation between BM and HT for patients with LACC undergoing cisplatin-based chemoradiation. There is a scarcity of studies independently validating developed prediction models between BM dose and HT. Future studies may use PB contouring to develop normal tissue complication probability models.

Multifunctional Transferrin Encapsulated GdF3 Nanoparticles for Sentinel Lymph Node and Tumor Imaging

The transferrin encapsulated GdF₃ nanoparticles have been fabricated via biomineralization method. The obtained GdF₃@Tf NPs show an attractive T2MRI and CT enhancement effect. Furthermore, PET and NIR imaging capacity are integrated into nanoparticles through conjugating with radionuclide ⁶⁴Cu and fluorescent dye Cy7. ⁶⁴Cu-GdF₃@Tf-Cy7 NPs are developed and applied in small animal multimodal imaging in vivo. Compared with the previous multimodal imaging agents, ⁶⁴Cu-GdF₃@Tf-Cy7 NPs enable not only precise sentinel lymph node (SLN) identification, but specific imaging for transferrin receptor overexpressed colorectal tumor in vivo. The results reveal that ⁶⁴Cu-GdF₃@Tf-Cy7 NPs are potential and efficient multimodal imaging agents for SLN and tumor preclinical imaging.

The volume of 99m Tc sulfur colloid SPET-defined active bone marrow can predict grade 3 or higher acute hematologic toxicity in locally advanced cervical cancer patients who receive chemoradiotherapy

Background

The purpose of the current study was to evaluate whether radiation dose‐volume metrics to technetium‐99m (^99mTc) sulfur colloid single‐photon emission tomography (SPET)‐defined active bone marrow (ABM) subregions can more accurately predict acute hematologic toxicity in locally advanced cervical cancer patients who receive chemoradiotherapy than conventional dosimetric parameters.

Methods and materials

Thirty‐nine patients with stage IB2‐III cervical cancer who underwent ^99mTc sulfur colloid SPET imaging before treatment with cisplatin‐based chemoradiation between January 2017 and March 2018 were analyzed. The total bone marrow (TBM) volume was defined as the external contours of all bones within the vertebral bodies from L4 to the coccyx, the pelvic bones, and the proximal femoral heads. The ABM volume was defined by SPET as the subregion of TBM with a nuclide uptake value greater than or equal to the mean total body nuclide uptake value. Student's t test was used to test for statistical significance between TBM and ABM dose‐volume metrics. Receiver operating characteristic (ROC) curves were generated to compare the predictors of grade 3 or higher (grade 3+) hematologic toxicity.

Results

The mean ABM‐V40 (23.22% ± 7.65%) and ABM‐V30 (45.28% ± 9.20%) were significantly lower than the mean TBM‐V40 (33.06% ± 6.72%) and TBM‐V30 (53.08% ± 7.77%), respectively (t = 5.78, P = .001) (t = 4.13, P = .001). The ABM volume (<387.5 cm³, AUC = 0.928, P = .001), ABM‐V30 (>46.5%, AUC = 0.875, P = .001), and ABM‐V40 (>23.5%, AUC = 0.858, P = .001) can predict the occurrence of grade 3+ hematologic toxicity. Among patients with an ABM volume < 387.5 cm³, 16/19 (84.2%) had grade 3+ hematologic toxicity compared to 3/20 (15%) with an ABM volume > 387.5 cm³.

Conclusions

The ABM volume (<387.5 cm³) may be a better predictor of hematologic toxicity than conventional dose‐volume metrics, but this finding needs to be further evaluated.