van der Planken H J, Hermens A F
Reinier de Graaf Gasthuis, Department of Radiotherapy, Delft, The Netherlands.
Strahlenther Onkol. 1999 Jan;175(1):32-8. doi: 10.1007/BF02743459.
In the literature there is some evidence that the incidence of metastases may increase after radiation treatment.
In order to investigate whether radiation-induced changes in the lymphatic drainage may alter the rate of lymph node metastasis, the center part of the left hind foot of rats was irradiated with a dose of 1 x 55 Gy before inoculation of tumor cells into the irradiated part of the footpad at different time intervals. Cells of 2 different tumor lines were employed. A rarely metastasising rhabdomyosarcoma, R-1, to look for a possible enhancement of lymphatic metastases, and a readily metastasising mammary carcinoma, Cl-2, in case of a possible decrease in the rate of lymphatic metastasis from tumors growing in pre-irradiated footpads.
The incidence of regional lymph node metastasis decreased for R-1 tumors growing in pre-irradiated footpads, but not for Cl-2 tumors. Furthermore, the average time required for lymph node metastasis to attain a reference volume of 100 mm3 is not significantly influenced by pre-irradiation of the footpad. No difference was observed in average times for doubling in volume of lymph node metastases originating from primary tumors in pre-irradiated footpads. Abscopal effects after footpad irradiation may cause a 50-fold increase in size of regional lymph nodes and, therefore, histological examination is essential for verification of lymph node metastases.
Damage to the lymphatic system to be expected in the irradiated footpad did not enhance the incidence of regional metastasis of R-1 tumors. A reduced rate of lymphatic metastasis contradicts earlier findings of enhanced lymphatic metastasis development of R-1 tumors, growing in pre-irradiated gastrocnemius muscles. The influence of irradiation on regional metastasis formation seems to be "tumor bed" dependent for R-1 tumors.
文献中有一些证据表明放射治疗后转移发生率可能会增加。
为了研究放射诱导的淋巴引流变化是否会改变淋巴结转移率，在不同时间间隔将肿瘤细胞接种到足垫的受照射部位之前，对大鼠左后足的中心部分给予1×55 Gy的剂量照射。使用了2种不同肿瘤系的细胞。一种转移罕见的横纹肌肉瘤R-1，用于寻找淋巴转移可能的增强情况；还有一种易于转移的乳腺癌Cl-2，用于观察在预先照射的足垫中生长的肿瘤淋巴转移率可能降低的情况。
在预先照射的足垫中生长的R-1肿瘤区域淋巴结转移发生率降低，但Cl-2肿瘤未降低。此外，淋巴结转移达到100 mm³参考体积所需的平均时间不受足垫预先照射的显著影响。预先照射足垫后出现的远隔效应可能导致区域淋巴结大小增加50倍，因此，组织学检查对于核实淋巴结转移至关重要。
预期受照射足垫中的淋巴系统损伤并未增加R-1肿瘤区域转移的发生率。淋巴转移率降低与之前在预先照射的腓肠肌中生长的R-1肿瘤淋巴转移增强的研究结果相矛盾。对于R-1肿瘤，照射对区域转移形成的影响似乎取决于“肿瘤床”。
