调强放疗条件下鼻咽癌原发肿瘤体积对预后的影响

目的 探讨调强放疗条件下鼻咽癌原发肿瘤体积(PTV)对患者预后的影响。方法 330例接受调强放疗的鼻咽癌初治患者入组本研究。所有患者治疗前均行CT增强扫描,扫描图像资料输人三维治疗计划系统进行肿瘤轮廓勾画和PTV计算。在国际抗癌联盟2002年T分期框架内借助受试者工作特征曲线,将所有患者按PTV大小分为V₁(<10 cm³)、V₂(10~ 25 cm³)、V₃(>25~50 cm³)、V₄(>50 cm³)组。用 Kaplan Meier 法计算生存率并 Logrank 检验, Cox 回归模型分析原发肿瘤体积与患者预后的关系。结果 随访率100%。330例 鼻咽癌患者所测平均PTV为(34.2±27.1) cm³(0.4~153.7 cm³)。V₁、V₂、V₃、V₄组 3年总生存率分别为88.6%、90.0%、91.2%、74.2%(χ²=12.83, P=0.005)。PTV>50 cm³ (V₄组)和≤50 cm³(V₁+V₂+V₃) 者 3年无远处转移生存率和无瘤生存率及总生存率均明显下降 [77.4%∶89.9%(χ²=7.24, P=0.007)和64.5%∶85.1%(χ²=13.95, P=0.000) 及74.2%∶90.3% (χ²=11.76, P=0.001)]。多因素分析证实PTV同N分期一样,是影响患者生存的预后因素(χ²=0.00, P=2.580)。结论 鼻咽癌PTV可能是影响患者生存的一个重要的预后因素。

Significance of primary tumor volume on prognosis in nasopharyngeal carcinoma treated by Intensity-modulated radiotherapy

Objective To analyze the correlation between primary tumor volume (PTV) and prognosis of nasopharyngeal carcinoma (NPC) treated by intensity-modulated radiotherapy (IMRT). Methods 330 NPC patients treated by IMRT were included. Pretreatment computerized tomography image were input into tree-dimensional treatment-planning system, in which the primary tumor volume were calculated automatically. The receiver operating characteristic curve was used to determine the best cut-off point of PTV. Within the framework of UICC 2002 T stage,The PTV　was divided into four groups:V₁<10 cm³, V₂ 10－25 cm³, V₃>25－50 cm³ and V₄>50 cm³. Kaplan-Meier and Logrank test was used to analyze the survival, Cox proportion risk regression model were used to analysis the correlation between PTV and prognosis. Results The mean PTV for all NPC patients was (34.2±27.1) cm³ with the range of 0.4－153.7 cm³. The 3-year overall survival for V₁, V₂, V₃ and V₄ stage were 88.6%,90.0%,91.2% and 74.2%, respectively (χ²=12.83,P=0.005). There was no significant difference among V₁, V₂ and V₃ in terms of overall survival (χ²=1.96,P=0.376). The 3-year distant metastasis-free survival and diseases-free survival or overall survival were decrease in PTV>50 cm³ and PTV≤50 cm³ (77.4%∶89.9%, χ²=7.24, P=0.007and 64.5%∶85.1%, χ²=13.95,P=0.000 or 74.2%∶90.3%, χ²=11.76,P=0.001). Multivariate analysis revealed that PTV was a adverse prognostic factors for overall survival (χ²=0.00,P=2.580). Conclusion Our data showed that the primary tumor volume had significantly impacted on the prognosis of NPC patients treated by intensity modulated radiotherapy.