CT检查在鼻咽癌放疗后原发灶近期疗效评价中的意义

Significance of CT scan in the early follow-up after definitive radiotherapy of nasopharyngeal cancer

背景与目的：在鼻咽癌根治性放疗后的随访中，往往常规以CT检查结果来评价其近期疗效。本研究进一步探讨CT检查在原发灶近期疗效评价中的意义。方法：1999年3月-2003年10月间连续132例的新诊断的鼻咽癌患者入组研究。有61例是早期鼻咽癌（AJCC Ⅰ／Ⅱ期），接受了根治性放疗；71例是无远处转移的局部晚期鼻咽癌（AJCC Ⅲ／Ⅳ期），接受了同期放化疗。132例均在放疗结束后4～6个月进行头颈部的CT扫描，鼻咽镜检查和鼻咽原发灶的活检。比较治疗前后的CT检查结果来评价临床疗效，并与病理结果相比较。结果：全组中位随访时间29个月（9～40个月）。影像学上疾病进展的有5例，无变化有18例，部分退缩的67例，完全消退的42例。有6例鼻咽活检阳性，其中影像学达CR的患者中有2例活检阳性（4．8％），4例有残留病灶的患者（影像上部分退缩，无变化和进展）活检阳性。CT扫描评价鼻咽癌放疗后早期随访的阳性和阴性预测值为4．4％，95．2％，其敏感性和特异性为66．7％和31．8％：结论：鼻咽癌根治性放疗后病理上完全消退在治疗后4～6个月已很充分，但病理上和影像学上的改变并无明确的相关性。本研究资料显示鼻咽癌放疗后4～6个月的CT扫描对疗效的评价敏感性和特异性均欠佳，也许需要更长的随访期来进一步明确其对原发灶疗效评价的意义，而对于影像学有残留的病灶是否应给予加量也需进一步研究：

Background and purpose： The early efficacy of definitive radiotherapy for patients with nasopharyngeal carcinoma （NPC） is conventionally evaluated by CT scan ＇after treatment. We investigated the role of post-treatment CT scans in assessing response to definitive radiotherapy. Methods： Between March 1999 and October 2003, a total of 132 consecutive patients with newly diagnosed NPC were studied in this IRB approved protocol. Sixty-one patients with early stage disease （ AJCC stage Ⅰ / Ⅱ ） were treated with radiation only; 71 patients with locally advanced disease （ stage Ⅲ/ Ⅳ） but no evidence of distant metastasis （DM） were treated with concurrent chemoradiotherapy. All patients received CT scans of the head and neck, nasopharyngoscopy, and biopsies of primary sites at 4-6 months after completion of radiotherapy. Clinical response of the prima,y tumor as determined by comparison of pre- and post-treatment CT scans was correlated to pathology results. Results： The median follow-up time for all patients was 25 months （ range 9 to 40 months）. Radiological progression was seen in 5 patients, stable disease in 18 patients, and radiographic partial （rPR） and complete responses （rCR） were seen in 67 and 42 patients respectively at 4-6 months of follow-up. Biopsies of the nasopharynx were positive in 6 patients. For patients with rCR, 2 patients （4.8%） had positive biopsies. Four patients with residual disease （ rPR, stable, or progressive disease） following treatment had positive biopsies. The positive and negative predictive values, sensitivity, and specificity of CT scans in evaluating the NPC response to radiotherapy were 4.4%, 95.2%, 66.7%, and 31.8% respectively. Conclusions： Pathologic CR for nasopharyngeal carcinoma is usually evident at 4-6 months after definitive radiotherapy; however, there is no correlation between pathologic and radiographic response. Although longer follow-up is required to define the relationship between radiographic and pathologic responses with respect to disease control, we find CT scan at 4-6 months after radiation treatment to be neither sensitive nor specific in predicting the response of primary NPC to radiation treatment.