Darzy Ken H, Shalet Stephen M
Department of Endocrinology, Christie Hospital NHS Trust, Wilmslow Road, Withington, Manchester M20 4BX, United Kingdom.
Growth Horm IGF Res. 2006 Jul;16 Suppl A:S30-40. doi: 10.1016/j.ghir.2006.03.002. Epub 2006 Apr 18.
Radiation-induced growth hormone deficiency (GHD) is primarily due to hypothalamic damage. GH secretion by the pituitary may be affected either secondary to some degree of quantitative deprivation of hypothalamic input or, if the radiation dose is high enough, by direct pituitary damage. As a consequence, the neurosecretory profile of GH secretion in an irradiated patient remains pulsatile and qualitatively intact. The frequency of pulse generation is unaffected, but the amplitude of the GH pulses is markedly reduced. Over the last 25 years, the final heights achieved by children receiving GH replacement for radiation-induced GHD have improved; these improvements are attributable to refinements in GH dosing schedules, increased use of GnRH analogues for radiation-induced precocious puberty, and a reduced time interval between completion of irradiation and initiation of GH therapy. When retested at the completion of growth, 80-90% of these teenagers are likely to prove severely GH deficient and, therefore, will potentially benefit from GH replacement in adult life. Such long-term GH treatment in patients treated previously for a brain tumor means that critical and continuous surveillance must be devoted to the risk of tumor recurrence and the possibility of second neoplasms.
辐射诱导的生长激素缺乏症（GHD）主要是由于下丘脑损伤所致。垂体分泌生长激素可能会受到影响，这要么是下丘脑输入在一定程度上定量减少的继发结果，要么是如果辐射剂量足够高，则是垂体直接受损所致。因此，接受辐射的患者生长激素分泌的神经分泌模式仍保持脉冲式且性质完整。脉冲产生的频率未受影响，但生长激素脉冲的幅度明显降低。在过去25年中，接受生长激素替代治疗辐射诱导的GHD的儿童所达到的最终身高有所改善；这些改善归因于生长激素给药方案的优化、用于辐射诱导性早熟的促性腺激素释放激素类似物使用增加，以及放疗结束至开始生长激素治疗的时间间隔缩短。在生长结束时重新检测时，这些青少年中有80 - 90%可能被证明严重缺乏生长激素，因此，在成年后可能会从生长激素替代治疗中受益。对先前接受过脑肿瘤治疗的患者进行这种长期生长激素治疗意味着必须密切且持续监测肿瘤复发风险和发生第二肿瘤的可能性。
