Rusthoven Kyle, Chen Changhu, Raben David, Kavanagh Brian
Department of Radiation Oncology, University of Colorado Health Sciences Center, Aurora, CO 80045-0508, USA.
Int J Radiat Oncol Biol Phys. 2008 May 1;71(1):192-8. doi: 10.1016/j.ijrobp.2007.09.045. Epub 2007 Dec 19.
Patients with head and neck cancer have a significant risk of developing a second primary cancer of the head and neck. We hypothesized that treatment with external beam radiotherapy (RT) might reduce this risk, because RT can eradicate occult foci of second head and neck cancer (HNCA).
The data of patients with Surveillance, Epidemiology, and End Results Historic Stage A localized squamous cell carcinoma of the oral cavity, larynx, and pharynx were queried using the Surveillance, Epidemiology, and End Results database. For patients treated with or without RT, the incidence of second HNCA was determined and compared using the log-rank method. Cox proportional hazards analysis was performed for each site, evaluating the influence of covariates on the risk of second HNCA.
Between 1973 and 1997, 27,985 patients were entered with localized HNCA. Of these patients, 44% had received RT and 56% had not. The 15-year incidence of second HNCA was 7.7% with RT vs. 10.5% without RT (hazard ratio 0.71, p <0.0001). The effect of RT was more profound in patients diagnosed between 1988 and 1997 (hazard ratio 0.53, p <0.0001) and those with pharynx primaries (hazard ratio 0.47, p <0.0001). On multivariate analysis, RT was associated with a reduced risk of second HNCA for pharynx (p <0.0001) and larynx (p = 0.04) tumors. For oral cavity primaries, RT was associated with an increased risk of second HNCA in patients treated before 1988 (p <0.001), but had no influence on patients treated between 1988 and 1997 (p = 0.91).
For localized HNCA, RT is associated with a reduced incidence of second HNCA. These observations are consistent with the eradication of microscopic foci of second HNCA with external beam RT.
头颈癌患者发生第二原发性头颈癌的风险显著。我们假设外照射放疗（RT）可能会降低这种风险，因为放疗可以根除隐匿的第二原发性头颈癌（HNCA）病灶。
利用监测、流行病学和最终结果（SEER）数据库查询SEER历史阶段A的口腔、喉和咽局部鳞状细胞癌患者的数据。对于接受或未接受放疗的患者，确定第二原发性头颈癌的发病率，并使用对数秩检验进行比较。对每个部位进行Cox比例风险分析，评估协变量对第二原发性头颈癌风险的影响。
1973年至1997年间，27985例患者被纳入局部头颈癌研究。其中，44%的患者接受了放疗，56%的患者未接受放疗。接受放疗的患者第二原发性头颈癌的15年发病率为7.7%，未接受放疗的患者为10.5%（风险比0.71，p<0.0001）。放疗的效果在1988年至1997年间诊断的患者（风险比0.53，p<0.0001）和咽原发性肿瘤患者（风险比0.47，p<0.0001）中更为显著。多因素分析显示，放疗与咽（p<0.0001）和喉（p=0.04）肿瘤患者第二原发性头颈癌风险降低相关。对于口腔原发性肿瘤，放疗与1988年前接受治疗的患者第二原发性头颈癌风险增加相关（p<0.001），但对1988年至1997年间接受治疗的患者没有影响（p=0.91）。
对于局部头颈癌，放疗与第二原发性头颈癌发病率降低相关。这些观察结果与外照射放疗根除第二原发性头颈癌微小病灶一致。
