Thorstad Wade L, Haughey Bruce, Chao K S Clifford
Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO 63110, USA.
Semin Oncol. 2003 Dec;30(6 Suppl 18):96-100. doi: 10.1053/j.seminoncol.2003.11.020.
The major salivary glands produce about 90% of salivary secretions; the minor salivary glands produce the remainder. Standard conventional radiation therapy for advanced oropharyngeal tumors typically involves administering high radiation dose to the major salivary glands bilaterally. In most cases, this causes a marked reduction in oral saliva output. Xerostomia is the most prevalent late side effect of radiation for head and neck malignancies and is cited by patients as the major cause of decreased quality of life. The degree of xerostomia has been reported to depend on the radiation dose and salivary gland volume irradiated. Several studies show dose volume response relationships in the salivary glands, suggesting the possibility of significant improvement in saliva production post radiation as well as quality of life if radiation techniques can spare the salivary glands. In recent years, conformal radiation techniques have evolved, which may allow radiation of tumor targets in the head and neck area while sparing substantial portions of salivary glands. It has been shown that in using these techniques, adequate irradiation of the targets while sparing major salivary glands is feasible. Early clinical experience showed substantial sparing of salivary flow following radiation and suggested an improvement of tumor control and of xerostomia over that achieved with standard radiation techniques. We hypothesize that the addition of a radioprotector may further improve salivary function over that obtained with intensity modulated radiation therapy alone. To test this hypothesis, we initiated a pilot clinical trial whose principal objective is to compare measurements of unstimulated and stimulated salivary flow rates 6 months after intensity modulated radiation therapy plus amifostine (Ethyol; MedImmune, Inc, Gaithersburg, MD) (study patients) with those obtained in historical controls treated with intensity modulated radiation therapy alone.
大唾液腺分泌约90%的唾液；小唾液腺分泌其余部分。晚期口咽肿瘤的标准传统放射治疗通常包括双侧对大唾液腺给予高辐射剂量。在大多数情况下，这会导致口腔唾液分泌显著减少。口干是头颈部恶性肿瘤放射治疗最常见的晚期副作用，患者将其视为生活质量下降的主要原因。据报道，口干的程度取决于辐射剂量和受照射的唾液腺体积。多项研究显示了唾液腺的剂量体积反应关系，表明如果放射技术能够保护唾液腺，那么放疗后唾液分泌以及生活质量可能会显著改善。近年来，适形放射技术不断发展，这可能使头颈部区域的肿瘤靶区得到照射，同时保护大部分唾液腺。已经表明，使用这些技术时，在保护大唾液腺的同时对靶区进行充分照射是可行的。早期临床经验表明，放疗后唾液流量得到了显著保护，并且与标准放射技术相比，肿瘤控制和口干情况有所改善。我们假设，添加一种放射保护剂可能会比单纯调强放射治疗进一步改善唾液功能。为了验证这一假设，我们启动了一项初步临床试验，其主要目的是比较调强放射治疗加氨磷汀（依硫磷；MedImmune公司，马里兰州盖瑟斯堡）治疗6个月后的无刺激和刺激唾液流速测量值（研究患者）与仅接受调强放射治疗的历史对照患者的测量值。
