Encheva Elitsa, Deleva Sofia, Hristova Rositsa, Hadjidekova Valeria, Hadjieva Tatiana
Radiotherapy Department, University Hospital "Queen Giovanna-ISUL", Sofia, Bulgaria.
Laboratory of Radiation Genetics, National Center of Radiobiology and Radiation Protection, Sofia, Bulgaria.
Rep Pract Oncol Radiother. 2011 Oct 29;17(1):24-31. doi: 10.1016/j.rpor.2011.10.002. eCollection 2011.
Pelvic organs morbidity after irradiation of cancer patients remains a major problem although new technologies have been developed and implemented. A relatively simple and suitable method for routine clinical practice is needed for preliminary assessment of normal tissue intrinsic radiosensitivity. The micronucleus test (MNT) determines the frequency of the radiation induced micronuclei (MN) in peripheral blood lymphocytes, which could serve as an indicator of intrinsic cell radiosensitivity.
To investigate a possible use of the micronucleus test (MNT) for acute radiation morbidity prediction in gynecological cancer patients.
Forty gynecological cancer patients received 50 Gy conventional external pelvic irradiation after radical surgery. A four-field "box" technique was applied with 2D planning. The control group included 10 healthy females. Acute normal tissue reactions were graded according to NCI CTCAE v.3.0. From all reaction scores, the highest score named "summarized clinical radiosensitivity" was selected for a statistical analysis. MNT was performed before and after in vitro irradiation with 1.5 Gy. The mean radiation induced frequency of micronuclei per 1000 binucleated cells (MN/1000) and lymphocytes containing micronuclei per 1000 binucleated cells (cells with MN/1000) were evaluated for both patients and controls. AN ARBITRARY CUT OFF VALUE WAS CREATED TO PICK UP A RADIOSENSITIVE INDIVIDUAL: the mean value of spontaneous frequency of cells with MN/1000 ± 2SD, found in the control group.
Both mean spontaneous frequency of cells with MN/1000 and MN/1000 were registered to be significantly higher in cancer patients compared to the control group (t = 2.46, p = 0.02 and t = 2.51, p = 0.02). No statistical difference was registered when comparing radiation induced MN frequencies between those groups. Eighty percent (32) of patients developed grade 2 summarized clinical radiosensitivity, with great variations in MNT parameters. Only three patients with grade 2 "summarized clinical radiosensitivity" had values of cells with MN/1000 above the chosen radiosensitivity threshold.
The present study was not able to confirm in vitro MNT applicability for radiosensitivity prediction in pelvic irradiation.
尽管已开发并应用了新技术，但癌症患者放疗后的盆腔器官并发症仍然是一个主要问题。需要一种相对简单且适用于常规临床实践的方法来初步评估正常组织的固有放射敏感性。微核试验（MNT）可测定外周血淋巴细胞中辐射诱导的微核（MN）频率，其可作为细胞固有放射敏感性的指标。
探讨微核试验（MNT）在预测妇科癌症患者急性放射并发症方面的可能应用。
40例妇科癌症患者在根治性手术后接受50 Gy的常规盆腔外照射。采用四野“盒式”技术进行二维计划。对照组包括10名健康女性。根据美国国立癌症研究所（NCI）的《常见不良反应事件评价标准》第3.0版对急性正常组织反应进行分级。从所有反应评分中，选取最高评分即“综合临床放射敏感性评分”进行统计分析。在体外照射1.5 Gy前后进行微核试验（MNT）。评估患者和对照组每1000个双核细胞中微核的平均辐射诱导频率（MN/1000）以及每1000个双核细胞中含微核的淋巴细胞频率（含MN的细胞/1000）。设定一个任意临界值来筛选放射敏感个体：即对照组中含MN的细胞/1000的自发频率平均值±2个标准差。
与对照组相比（t = 2.46，p = 0.02；t = 2.51，p = 0.02），癌症患者中含MN的细胞/1000以及MN/1000的平均自发频率均显著更高。比较两组之间辐射诱导的微核频率时未发现统计学差异。80%（32例）的患者出现2级综合临床放射敏感性，微核试验（MNT）参数差异很大。只有3例2级“综合临床放射敏感性”患者的含MN的细胞/1000值高于所选的放射敏感性阈值。
本研究未能证实体外微核试验（MNT）在盆腔照射放射敏感性预测中的适用性。
