Lee A W, Foo W, Law S C, Poon Y F, Sze W M, O S K, Tung S Y, Lau W H
Department of Radiotherapy, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong.
Int J Radiat Oncol Biol Phys. 1997 Apr 1;38(1):43-52. doi: 10.1016/s0360-3016(97)00244-7.
To identify factors for maximizing local salvage and minimizing damages by reirradiation for recurrent nasopharyngeal carcinoma.
654 patients with recurrent nasopharyngeal carcinoma treated by reirradiation during 1976-1992 were retrospectively analyzed. Various fractionation schedules had been used during primary treatment with the total dose ranging from 45.6-70 Gy, fractional dose (at different phases) 1.5-4.2 Gy, and overall time 36-101 days. The gap between the two courses ranged from 0.5-10.6 years. Eighty-two percent of patients were reirradiated with teletherapy, 6% brachytherapy, and 12% with both. For those treated with teletherapy alone, the total dose ranged from 7.5-70 Gy, fractional dose 1.8-5 Gy, and overall time 3-89 days.
The 5-year actuarial local salvage and complication-free rates were 23% and 52%, respectively. Multivariate analyses showed that the extensiveness of local recurrence was the most significant factor affecting local salvage, while T-stage of primary tumor also influenced prognosis. Choice of method for reirradiation and fractional effect during both courses affected the risk of late complications. For patients treated by teletherapy alone, the hazard of local failure decreased by 1.7% per Biological Effective Dose (assuming alpha/beta ratio = 10) of the second course, while radiation factors during primary radiotherapy had no significant effect. On the other hand, the risk of late complications was predominantly affected by the primary treatment: the hazard increased by 4.2% per Biological Effective Dose (assuming alpha/beta ratio = 3) of the first course, while the corresponding impact of reirradiation failed to reach statistical significance. Length of the gap between the two courses did not affect the outcome.
Early detection of local recurrence and adequate total dose by reirradiation are crucial for improving the chance of local salvage. Combination of teletherapy and brachytherapy should be considered whenever feasible and large fractional dose avoided to minimize late complications. Optimization of biological dose during primary treatment is important.
确定使复发性鼻咽癌局部挽救最大化及再程放疗所致损伤最小化的因素。
回顾性分析1976年至1992年间接受再程放疗的654例复发性鼻咽癌患者。初次治疗期间采用了多种分割方案，总剂量范围为45.6 - 70 Gy，分次剂量（在不同阶段）为1.5 - 4.2 Gy，总疗程时间为36 - 101天。两个疗程之间的间隔时间为0.5 - 10.6年。82%的患者接受远距离放疗再程放疗，6%接受近距离放疗，12%两者联合应用。对于仅接受远距离放疗的患者，总剂量范围为7.5 - 70 Gy，分次剂量为1.8 - 5 Gy，总疗程时间为3 - 89天。
5年精算局部挽救率和无并发症率分别为23%和52%。多因素分析显示，局部复发的范围是影响局部挽救的最显著因素，而原发肿瘤的T分期也影响预后。再程放疗方法的选择以及两个疗程中的分次效应影响晚期并发症风险。对于仅接受远距离放疗的患者，第二个疗程每增加1个生物等效剂量（假设α/β比值 = 10），局部失败风险降低1.7%，而初次放疗期间的放疗因素无显著影响。另一方面，晚期并发症风险主要受初次治疗影响：第一个疗程每增加1个生物等效剂量（假设α/β比值 = 3），风险增加4.2%，而再程放疗的相应影响未达到统计学意义。两个疗程之间的间隔时间长度不影响治疗结果。
局部复发的早期发现及再程放疗时给予足够的总剂量对于提高局部挽救机会至关重要。只要可行，应考虑远距离放疗与近距离放疗联合应用，并避免大分次剂量以尽量减少晚期并发症。初次治疗期间生物剂量的优化很重要。
