以放疗的前列腺癌患者淋巴细胞微核率评价生物照射剂量(英文)

Micronuclei in lymphocytes of prostate cancer patients undergoing radiation therapy

目的 进一步验证微核率作为测量生物照射剂量的可行性。方法 8例未经放疗 (xRT)和化疗的前列腺癌 ,经标准分区骨盆xRT治疗方案 ,收集前列腺癌患者xRT前和xRT中外周血 ,测定阻滞胞质分裂的外周血淋巴细胞 (PBL)微核率。检测项目包括 :(1)检查微核率和估计的等效全身吸收剂量之间的关系 ;(2 )评价xRT前PBL微核率的辐射剂量效应关系的个体差异。结果 (1)患者PBL微核率随估算的全身吸收射线量 [y =1.46 + 9.2D (R2 =0 .7,P =0 .0 72 ) ]增加而呈线性增加 ;微核呈广泛分布 ;每10 0 0个双核PBL微核率相应增加的比例分别高于基线水平 0 .9～ 8.2倍 (中位数 4.1)。 (2 )xRT前 ,微核率也随体外照射剂量增加而增加 ,每 1照射剂量下 ,大多数患者微核率呈高度离散分布。 3例因xRT引起的早期副反应患者中 ,2例的PBL微核率明显高于无xRT引起副反应者。结论 PBL微核率可用来测定体外生物照射剂量。因xRT前PBL微核率与体外辐射剂量效应关系存在着显著的个体差异 ,开始应用xRT前可用PBL微核率判定患者个体固有的放射敏感性。

Objective To further verify the applicability of the micronucleus (MN) assay in biodosimetry. Methods The MN yield in cytokinesis-blocked peripheral blood lymphocytes(PBL) of eight prostate cancer patients were measured . These patients had no previous chemotherapy or radiotherapy(xRT).They were treated with standardized schemes of fractionated pelvic xRT.Before xRT and at one random time-point during the course of xRT, blood samples were collected from each patient for the following purposes: (1) to verify the relationship between the MN yield in PBL and the estimated equivalent (EQ) total-body absorbed dose;and (2) to evaluate the individual differences of ex vivo radiation dose-response(1-4Gy) relationship of MN yield in PBL before xPT.The number of xRT fractions,cumulative tumor dose,and EQ total-body absorbed doses of these patients represented a wide range . Results In PBL of these patients,MN yield (Y) increased linearly with the estimated EQ total-body absorbed dose as Y=14.6+9.2D (R 2=0.7,P=0.007) ; the distributions of MN yield were overdispersed , and the ratio of relative increment of MN yield per 1 000 binucleated PBL ranged from 0.9～8.2(median:4.1) folds above that of the respective baseline levels. Before xRT,the MN yields also increased linearly with the ex vivo radiation dose, at each radiation dose level,the distributions of MN yield were overdispersed in most patients. In two of the three patients with xRT-induced early side effects(cystitis, diarrhea), the MN yield in PBL induced by ex vivo irradiation before xRT was significantly higher than in the other patients without xRT-induced side effects. Conclusions These findings suggest that MN yields in cytokinesis-blocked PBL can be used as an in vivo biodosimeter.Since the differences in individual ex vivo radiation dose-response relationship of MN yield in PBL before xRT appeared to be significant, our preliminary results also suggest that it may be possible to identify individual intrinsic radiosensitivity before the start of xRT.