Intracavitary brachytherapy significantly enhances local control of early T-stage nasopharyngeal carcinoma: The existence of a dose-tumor-control relationship above conventional tumoricidal dose
Intracavitary brachytherapy significantly enhances local control of early T-stage nasopharyngeal carcinoma: The existence of a dose-tumor-control relationship above conventional tumoricidal dose
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DOI：
10.1016/s0360-3016(99)00326-0
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发表时间：
2000-01-15
影响因子：
7
通讯作者：
Zee, B
中科院分区：
文献类型：
--
作者：
Teo, PML;Leung, SF;Zee, B
目的：为探讨腔内后装治疗早期T期鼻咽癌的疗效，对1984 ~ 1996年收治的509例T1期和T2期（鼻腔浸润）鼻咽癌患者进行分析，其中163例（A组）在根治性外照射后行腔内后装治疗。与346例单纯ERT治疗的患者（B组）进行比较，ERT对原发肿瘤的杀伤剂量（未校正的BED-10大于或等于75戈伊）在技术或剂量方面两组之间没有差异。ICT在15天内分3次将18-24戈伊的剂量输送到垂直于源平面中点1 cm的点，ICT用于治疗ERT后4-6周诊断的局部持久性（n = 101）或作为ERT完全应答者的辅助治疗（n = 62）。两组在患者年龄或性别、远处转移率、区域失败率、总生存期或随访时间方面没有差异。然而，A组有更多的T2病变，B组有更多的晚期N分期，局部失败明显较少（粗比率6.75%对13.0%; 5年精算比率5.40%对10.3%），疾病特异性死亡率显著降低（粗利率14.1%对21.7%; A组与B组相比，5年精算率分别为11.9%和16.4%。多变量分析显示，ICT是预测局部失败较少的唯一显著预后因素（考克斯回归p = 0.0328，风险比= 0.49，95%置信区间（95% CI）= 0.256-0.957）。然而，当ICT被排除在考克斯回归模型，总的物理剂量或总的BED-10未校正的肿瘤再增殖在放疗期间成为显着的预测最终的局部失败率。除A组10例患者和B组1例患者发生慢性放射性鼻咽溃疡/坏死外，两组的慢性放射性并发症发生率和慢性放射性并发症的精算累积率相当。溃疡/坏死导致的头痛（n = 4）和恶臭（n = 8）为轻度，可通过保守方法进行管理。当研究局部失效作为总物理剂量或总生物等效剂量的函数时，存在显著的剂量-肿瘤-控制关系（线性二次方程，α/β = 10）在放射治疗的时间过程中未校正肿瘤再增殖。补充递送杀肿瘤剂量的ERT（未校正的BED-10大于或等于75戈伊），ICT显著增强了最终的局部控制，并避免了在早期T阶段进行病态挽救治疗的必要性（T1/T2鼻腔浸润），ICT术后慢性放射性溃疡/坏死轻度增加，症状轻，可控制，其他晚期并发症无增加。在常规杀肿瘤剂量水平以上，存在显著的剂量-肿瘤-控制关系。(C)2000 Elsevier Science Inc.
Purpose: To study the efficacy of intracavitary brachytherapy (ICT) in early T-stage nasopharyngeal carcinoma (NPC).Methods and Materials: All T1 and T2 (nasal infiltration) NPC treated with a curative intent from 1984 to 1996 were analyzed (n = 509), One hundred sixty-three patients were given ICT after radical external radiotherapy (ERT) (Group A). They were compared with 346 patients treated by ERT alone (Group B), The ERT delivered the tumoricidal dose (uncorrected BED-10 greater than or equal to 75 Gy) to the primary tumor and did not differ between the two groups in technique or dosage. The ICT delivered a dose of 18-24 Gy in 3 fractions over 15 days to a point 1 cm perpendicular to the midpoint of the plane of the sources, ICT was used to treat local persistence diagnosed at 4-6 weeks after ERT (n = 101) or as an adjuvant for the complete responders to ERT (n = 62).Results: The two groups did not differ in patients' age or sex, rate of distant metastasis, rate of regional failure, overall survival, or the follow-up duration. However, Group A had significantly more T2 lesions and Group B had significantly more advanced N-stages, Local failure was significantly less (crude rates 6.75% vs. 13.0%; 5-year actuarial rates 5.40% vs. 10.3%) and the disease-specific mortality was significantly lower (crude rates 14.1% vs. 21.7%; 5-year actuarial rates 11.9% vs. 16.4%) in Group A compared to Group B, Multivariate analysis showed that the ICT was the only significant prognostic factor predictive for fewer local failures (Cox regression p = 0.0328, risk ratio = 0.49, 95% confidence interval (95% CI) = 0.256-0.957). However, when ICT was excluded from the Cox regression model, the total physical dose or the total BED-10 uncorrected for tumor repopulation during the period of radiotherapy became significant in predicting ultimate local failure rate. The two groups were comparable in the incidence rates of each individual chronic radiation complication and the actuarial cumulative rate of the chronic radiation complications, with the exception of chronic radiation nasopharyngeal ulceration/necrosis which occurred in 10 patients in Group A and 1 patient in Group B, Headache (n = 4) and foul smell (n = 8) consequential to ulceration/necrosis were mild and manageable by conservative means. A significant dose-tumor-control relationship existed when local failure was studied as a function of the total physical dose or the total biological equivalent dose (linear quadratic equation, alpha/beta = 10) uncorrected for tumor repopulation during the time course of the radiotherapy.Conclusions: Supplementing ERT which delivered tumoricidal dose (uncorrected BED-10 greater than or equal to 75 Gy), ICT significantly enhanced ultimate local control and avoided the necessity for morbid salvage treatments in early T-stage (T1/T2 nasal infiltration) NPC, The slight increase in chronic radiation ulceration/necrosis after ICT was acceptable with mild and manageable symptoms, Other late complications were not increased. A significant dose-tumor-control relationship exists above the conventional tumoricidal dose level. (C) 2000 Elsevier Science Inc.