Jacob Rojymon, Hanlon Alexandra L, Horwitz Eric M, Movsas Benjamin, Uzzo Robert G, Pollack Alan
Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111-2497, USA.
Cancer. 2004 Feb 1;100(3):538-43. doi: 10.1002/cncr.11927.
The association of increasing radiotherapy (RT) dose with reduced biochemical failure (BF) is accepted widely. However, there is little direct evidence that dose escalation has an impact on distant metastasis (DM) or overall mortality (OM). These associations were examined in the current study.
The outcome of 835 patients who were treated at the Fox Chase Cancer Center (Philadelphia, PA) between 1989 and 1997 using 3-dimensional, conformal RT alone (median dose, 74 Gray [Gy]) was analyzed. Stepwise multivariate Cox proportional hazards regression analyses (MVAs) were performed with RT dose included as a covariate along with log-transformed initial pretreatment PSA level, Gleason score, palpation T status, age, and year of treatment (YOT), where indicated. To minimize the effect of YOT, an analysis was performed on a subgroup of 363 patients who were treated prior to 1994.
With a median follow-up of 64 months, there were 220 PSA failures, 44 distant metastases, and 162 deaths. In MVA, RT dose (as a continuous variable) was a significant predictor for BF, DM, and OM. When YOT was included as a covariate, it was related strongly to all endpoints, and the correlations of RT dose with DM and OM were lost. When the effect of YOT was minimized by limiting the MVA to patients who were treated prior to 1994, RT dose again emerged as a significant predictor of DM.
Escalation of RT dose reduced the rates of BF, DM, and OM significantly in patients with prostate cancer. The inclusion of YOT had a pronounced effect on these correlations that may confound interpretation.
放疗（RT）剂量增加与生化失败（BF）减少之间的关联已被广泛认可。然而，几乎没有直接证据表明剂量递增对远处转移（DM）或总死亡率（OM）有影响。本研究对这些关联进行了探讨。
分析了1989年至1997年间在福克斯蔡斯癌症中心（宾夕法尼亚州费城）接受单纯三维适形放疗（中位剂量，74戈瑞[Gy]）的835例患者的结局。进行逐步多变量Cox比例风险回归分析（MVAs），视情况将RT剂量作为协变量纳入，同时纳入对数转换后的初始治疗前前列腺特异性抗原（PSA）水平、Gleason评分、触诊T分期、年龄和治疗年份（YOT）。为尽量减少YOT的影响，对1994年前接受治疗的363例患者亚组进行了分析。
中位随访64个月，有220例PSA失败、44例远处转移和162例死亡。在多变量分析中，RT剂量（作为连续变量）是BF、DM和OM的显著预测因素。当将YOT作为协变量纳入时，它与所有终点均密切相关，且RT剂量与DM和OM的相关性消失。当通过将多变量分析限制在1994年前接受治疗的患者中来尽量减少YOT的影响时，RT剂量再次成为DM的显著预测因素。
放疗剂量递增显著降低了前列腺癌患者的BF、DM和OM发生率。纳入YOT对这些相关性有显著影响，可能会混淆解释。
