Hemoglobin level significantly impacts the tumor cell survival fraction in humans after internal radiotherapy

Abstract

BackgroundAnemia is usually not taken into account in internal radiotherapy. We investigated whether the hemoglobin (Hb) level could have an impact on the tumor response, as observed in external beam radiotherapy (EBRT).MethodsAbsorbed doses of 25 hepatic metastatic sites in eight patients who underwent a liver selective internal radiotherapy (SIRT) were computed by a 3D convolution of a dose deposition kernel with the 90Y time-of-flight positron emission tomography (TOF-PET) images acquired following therapy. Early tumor response was assessed by comparing a follow-up FDG TOF-PET scan with a baseline scan. Hb level was measured on the day of the SIRT procedure.ResultsAll patients displayed early tumor response increasing with the tumor-absorbed dose. Significant differences between patients were noted, the response slope correlating with the Hb level. After applying a global fit on all metastases using a tumor radiosensitivity modulated by a Hb enhancement factor (HEF) linearly dependent on the Hb level, a strong correlation (R = 0.96) was observed between the early response and the absorbed dose. Hb level had a major impact on tumor response by modulating HEF by a factor 6.ConclusionsThese results prove the significant impact of Hb level on the tumor response and support the study of methods for correcting tumor hypoxia, such as intensively performed in EBRT. The quantitative analysis of the relationship between tumor doses and early response has the power to allow fast screening of such correction methods in limited patient series. Internal radiotherapy could be more efficient if performed earlier in the therapy line, when the disease- and treatment-related anemia remains limited.

Radioembolization of hepatocarcinoma with 90Y glass microspheres: development of an individualized treatment planning strategy based on dosimetry and radiobiology

“…Dose-toxicity and dose-efficacy analysis was therefore repeated for 4 dosimetric variables, 2 sets of radiobiological parameters and 2 contouring methods (16 different ways) in order to find the methodology in better agreement with clinical outcome. While several dose-response correlation studies are available for 90 Y-microspheres [7,[13][14][15][16][17], only one dose-toxicity curve was published, for resin spheres [7], though important indications about glass sphere toxicity were reported by Garin et al [18]. Results presented here are the first dosimetric analysis of efficacy and toxicity of 90 Y glass microspheres based on radiobiological modelling.…”

Baseline hemoglobin and liver function predict tolerability and overall survival of patients receiving radioembolization for chemotherapy-refractory metastatic colorectal cancer

“…A strategy of reducing anemia prior to radiotherapy with external beam radiation therapy (EBRT) or brachytherapy including RE (30)(31)(32)(33)(34), is supported by wealth of published evidence indicating that a low HGB level before or during radiation therapy is an important risk factor for poor survival and/or locoregional disease control. The more hypoxic environment of solid tumors is associated with decreased radiosensitivity thereby enabling malignant cells to remain viable, especially in patients with anemia (35).…”

Quantitative Monte Carlo–Based 90Y SPECT Reconstruction

“…For enabling the evaluation of radiation absorbed doses in tumorous and healthy liver tissues, posttreatment imaging of the 90 Y microsphere distribution has recently gained interest (3)(4)(5).…”