Chambers Mark S, Tomsett Kelley L, Artopoulou Ioli I, Garden Adam S, El-Naggar Adel K, Martin Jack W, Keene Harris J
Department of Head and Neck Surgery, Department of Radiation Oncology, M.D. Anderson Cancer Center, Houston, TX 77030-4009, USA.
J Prosthet Dent. 2008 Aug;100(2):142-6. doi: 10.1016/S0022-3913(08)60160-2.
Xerostomia often occurs in patients being managed for head and neck cancer who receive radiation therapy. Although accurate salivary sampling can be therapeutically important to measure during radiation, sampling errors can occur because of salivary sediments. Determining the impact that salivary sediments have on measured salivary flow rates during radiation is important for management of patients.
The purpose of this study was to assess the magnitude of error associated with the inclusion of nonsalivary components (sediment) in the calculation of whole stimulated saliva flow rates prior to and during radiation therapy (SS and SSR) in patients with head and neck cancer.
Whole paraffin-stimulated saliva was collected in large-mouth centrifuge tubes from 20 patients with head and neck cancer prior to and during the third week of radiation therapy. Gravimetric methods were used to calculate the flow rates at g/5 min. After centrifugation, supernatant saliva was removed and the sediment was oven-dried to remove residual moisture. Sediment weight was subtracted from the original weight of saliva specimens and flow rates were recalculated. Means and standard deviations were determined and flow rate differences before (BC) and after (AC) sediment correction were evaluated statistically with the paired t test (alpha=.05). A nonparametric analysis of the flow rate data with the Wilcoxon matched-pairs signed-ranks test was also used to examine the magnitude and direction of the intrapair (BC-AC) differences (alpha=.05).
On average, salivary sediment contributed less than 1% of the total uncorrected weight of saliva prior to radiation therapy. In specimens collected during radiation therapy, sediment contributed an average of 14% of the total uncorrected weight and as high as 95.4% in 1 patient. Sediment percentages were 20% and higher in 4 patients. In the Wilcoxon analysis, 19 out of 20 paired BC and AC flow rates were higher in the BC group in the SS and SSR samples.
The error associated with the inclusion of salivary sediment in the calculation of saliva flow rates prior to radiation treatment was small, but statistically significant. The magnitude of the sediment effect was more pronounced in specimens taken during radiotherapy and was significant, as determined by the Wilcoxon test, but the mean paired differences were not significantly different according to the t test.
口干症常发生于接受放射治疗的头颈癌患者。尽管在放疗期间准确采集唾液样本对于测量具有重要的治疗意义，但由于唾液沉积物的存在，可能会出现采样误差。确定唾液沉积物对放疗期间测量的唾液流速的影响对于患者的管理至关重要。
本研究的目的是评估头颈癌患者在放疗前和放疗期间（SS和SSR）计算全刺激唾液流速时，因包含非唾液成分（沉积物）而产生的误差大小。
在放疗第三周前和期间，从20名头颈癌患者口中收集全石蜡刺激唾液，置于大口离心管中。采用重量法计算每5分钟的流速（单位：g）。离心后，去除上清液唾液，将沉积物置于烘箱中干燥以去除残留水分。从唾液标本的原始重量中减去沉积物重量，并重新计算流速。确定平均值和标准差，并使用配对t检验（α = 0.05）对沉积物校正前后（BC和AC）的流速差异进行统计学评估。还使用Wilcoxon配对符号秩检验对流速数据进行非参数分析，以检验配对内（BC - AC）差异的大小和方向（α = 0.05）。
平均而言，放疗前唾液沉积物占未校正唾液总重量的比例不到1%。在放疗期间采集的样本中，沉积物平均占未校正总重量的14%，1例患者中高达95.4%。4例患者的沉积物百分比达到20%及以上。在Wilcoxon分析中，20对BC和AC流速中，有19对在SS和SSR样本中BC组的值更高。
放疗前计算唾液流速时因包含唾液沉积物而产生的误差较小，但具有统计学意义。沉积物的影响在放疗期间采集的样本中更为明显，并且通过Wilcoxon检验确定具有显著性，但根据t检验，平均配对差异无显著差异。
