Clark L C, Dalkin B, Krongrad A, Combs G F, Turnbull B W, Slate E H, Witherington R, Herlong J H, Janosko E, Carpenter D, Borosso C, Falk S, Rounder J
Arizona Cancer Center, College of Medicine, University of Arizona, Tucson 85716, USA.
Br J Urol. 1998 May;81(5):730-4. doi: 10.1046/j.1464-410x.1998.00630.x.
To test if supplemental dietary selenium is associated with changes in the incidence of prostate cancer.
A total of 974 men with a history of either a basal cell or squamous cell carcinoma were randomized to either a daily supplement of 200 microg of selenium or a placebo. Patients were treated for a mean of 4.5 years and followed for a mean of 6.5 years.
Selenium treatment was associated with a significant (63%) reduction in the secondary endpoint of prostate cancer incidence during 1983-93. There were 13 prostate cancer cases in the selenium-treated group and 35 cases in the placebo group (relative risk, RR=0.37, P=0.002). Restricting the analysis to the 843 patients with initially normal levels of prostate-specific antigen (< or = 4 ng/mL), only four cases were diagnosed in the selenium-treated group and 16 cases were diagnosed in the placebo group after a 2 year treatment lag, (RR=0.26 P=0.009). There were significant health benefits also for the other secondary endpoints of total cancer mortality, and the incidence of total, lung and colorectal cancer. There was no significant change in incidence for the primary endpoints of basal and squamous cell carcinoma of the skin. In light of these results, the 'blinded' phase of this trial was stopped early.
Although selenium shows no protective effects against the primary endpoint of squamous and basal cell carcinomas of the skin, the selenium-treated group had substantial reductions in the incidence of prostate cancer, and total cancer incidence and mortality that demand further evaluation in well-controlled prevention trials.
检验膳食补充硒是否与前列腺癌发病率的变化有关。
共有974名有基底细胞癌或鳞状细胞癌病史的男性被随机分为两组，一组每日补充200微克硒，另一组服用安慰剂。患者平均接受治疗4.5年，平均随访6.5年。
在1983 - 1993年期间，硒治疗与前列腺癌发病率这一次要终点显著降低（63%）相关。硒治疗组有13例前列腺癌病例，安慰剂组有35例（相对风险，RR = 0.37，P = 0.002）。将分析局限于最初前列腺特异性抗原水平正常（≤4 ng/mL）的843名患者，经过2年的治疗延迟后，硒治疗组仅诊断出4例，安慰剂组诊断出16例（RR = 0.26，P = 0.009）。对于总癌症死亡率以及总癌、肺癌和结直肠癌发病率等其他次要终点，也有显著的健康益处。皮肤基底细胞癌和鳞状细胞癌这一主要终点的发病率没有显著变化。鉴于这些结果，该试验的“盲法”阶段提前终止。
尽管硒对皮肤鳞状细胞癌和基底细胞癌这一主要终点没有保护作用，但硒治疗组前列腺癌发病率、总癌症发病率和死亡率大幅降低，这需要在严格控制的预防试验中进一步评估。
