Pollack A, Zagars G K, Smith L G, Lee J J, von Eschenbach A C, Antolak J A, Starkschall G, Rosen I
Departments of Radiation Oncology, Biostatistics, Urology, and Radiation Physics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
J Clin Oncol. 2000 Dec 1;18(23):3904-11. doi: 10.1200/JCO.2000.18.23.3904.
To determine the effect of radiotherapy dose on prostate cancer patient outcome and biopsy positivity in a phase III trial.
A total of 305 stage T1 through T3 patients were randomized to receive 70 Gy or 78 Gy of external-beam radiotherapy between 1993 and 1998. Of these, 301 were assessable; stratification was based on pretreatment prostate-specific antigen level (PSA). Dose was prescribed to the isocenter at 2 Gy per fraction. All patients underwent planning pelvic computed tomography scan to confirm prostate position. Treatment failure was defined as an increasing PSA on three consecutive follow-up visits or the initiation of salvage treatment. Median follow-up was 40 months.
One hundred fifty patients were randomized to the 70-Gy arm and 151 to the 78-Gy arm. The difference in freedom from biochemical and/or disease failure (FFF) rates of 69% and 79% for the 70-Gy and 78-Gy groups, respectively, at 5 years was marginally significant (log-rank P: =.058). Multiple-covariate Cox proportional hazards regression showed that the study randomization was an independent correlate of FFF, along with pretreatment PSA, Gleason score, and stage. The patients who benefited most from the 8-Gy dose escalation were those with a pretreatment PSA of more than 10 ng/mL; 5-year FFF rates were 48% and 75% (P: =.011) for the 70-Gy and 78-Gy arms, respectively. There was no difference between the arms ( approximately 80% 5-year FFF) when the pretreatment PSA was < or = 10 ng/mL.
A modest dose increase of 8 Gy using conformal radiotherapy resulted in a substantial improvement in prostate cancer FFF rates for patients with a pretreatment PSA of more than 10 ng/mL. These findings document that local persistence of prostate cancer in intermediate- to high-risk patients is a major problem when doses of 70 Gy or less are used.
在一项III期试验中确定放疗剂量对前列腺癌患者预后及活检阳性率的影响。
1993年至1998年间，共305例T1至T3期患者被随机分为两组，分别接受70 Gy或78 Gy的外照射放疗。其中301例可评估；分层依据为治疗前前列腺特异性抗原水平（PSA）。剂量按每分次2 Gy规定至等中心。所有患者均接受盆腔计划计算机断层扫描以确认前列腺位置。治疗失败定义为连续三次随访时PSA升高或开始挽救治疗。中位随访时间为40个月。
150例患者被随机分入70 Gy组，151例分入78 Gy组。5年时，70 Gy组和78 Gy组生化和/或疾病无进展（FFF）率分别为69%和79%，差异接近显著（对数秩检验P = 0.058）。多协变量Cox比例风险回归显示，研究随机分组是FFF的独立相关因素，同时还有治疗前PSA、Gleason评分和分期。从8 Gy剂量增加中获益最大的患者是治疗前PSA大于10 ng/mL者；70 Gy组和78 Gy组5年FFF率分别为48%和75%（P = 0.011）。当治疗前PSA≤10 ng/mL时，两组间无差异（5年FFF率约80%）。
采用适形放疗适度增加8 Gy剂量可使治疗前PSA大于10 ng/mL的前列腺癌患者的FFF率显著提高。这些结果表明，对于中高危患者，当使用70 Gy或更低剂量时，前列腺癌局部残留是一个主要问题。
