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一项关于抗氧化维生素预防头颈癌患者二次原发性癌症的随机试验。

A randomized trial of antioxidant vitamins to prevent second primary cancers in head and neck cancer patients.

作者信息

Bairati Isabelle, Meyer François, Gélinas Michel, Fortin André, Nabid Abdenour, Brochet François, Mercier Jean-Philippe, Têtu Bernard, Harel François, Mâsse Benoît, Vigneault Eric, Vass Sylvie, del Vecchio Pierre, Roy Jean

机构信息

Centre de Recherche en Cancérologie de L'Université Laval, Québec City, Québec, Canada.

出版信息

J Natl Cancer Inst. 2005 Apr 6;97(7):481-8. doi: 10.1093/jnci/dji095.

DOI:10.1093/jnci/dji095

PMID:15812073

Abstract

BACKGROUND

Although low dietary intakes of antioxidant vitamins and minerals have been associated with higher risks of cancer, results of trials testing antioxidant supplementation for cancer chemoprevention have been equivocal. We assessed whether supplementation with antioxidant vitamins could reduce the incidence of second primary cancers among patients with head and neck cancer.

METHODS

We conducted a multicenter, double-blind, placebo-controlled, randomized chemoprevention trial among 540 patients with stage I or II head and neck cancer treated by radiation therapy between October 1, 1994, and June 6, 2000. Supplementation with alpha-tocopherol (400 IU/day) and beta-carotene (30 mg/day) or placebo began on the first day of radiation therapy and continued for 3 years after the end of radiation therapy. In the course of the trial, beta-carotene supplementation was discontinued after 156 patients had enrolled because of ethical concerns. The remaining patients received alpha-tocopherol or placebo only. Survival was evaluated by Kaplan-Meier analysis. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

After a median follow-up of 52 months, second primary cancers and recurrences of the first tumor were diagnosed in 113 and 119 participants, respectively. The effect of supplementation on the incidence of second primary cancers varied over time. Compared with patients receiving placebo, patients receiving alpha-tocopherol supplements had a higher rate of second primary cancers during the supplementation period (HR = 2.88, 95% CI = 1.56 to 5.31) but a lower rate after supplementation was discontinued (HR = 0.41, 95% CI = 0.16 to 1.03). Similarly, the rate of having a recurrence or second primary cancer was higher during (HR = 1.86, 95% CI = 1.27 to 2.72) but lower after (HR = 0.71, 95% CI = 0.33 to 1.53) supplementation with alpha-tocopherol. The proportion of participants free of second primary cancer overall after 8 years of follow-up was similar in both arms.

CONCLUSIONS

alpha-Tocopherol supplementation produced unexpected adverse effects on the occurrence of second primary cancers and on cancer-free survival.

摘要

背景

尽管饮食中抗氧化维生素和矿物质的摄入量较低与患癌风险较高有关，但测试抗氧化剂补充剂用于癌症化学预防的试验结果并不明确。我们评估了补充抗氧化维生素是否能降低头颈癌患者发生第二原发性癌症的发生率。

方法

我们在1994年10月1日至2000年6月6日期间对540例接受放射治疗的I期或II期头颈癌患者进行了一项多中心、双盲、安慰剂对照的随机化学预防试验。从放射治疗的第一天开始补充α-生育酚（400 IU/天）和β-胡萝卜素（30 mg/天）或安慰剂，并在放射治疗结束后持续3年。在试验过程中，由于伦理问题，在156例患者入组后停止了β-胡萝卜素补充。其余患者仅接受α-生育酚或安慰剂。通过Kaplan-Meier分析评估生存率。使用Cox比例风险模型估计风险比（HR）和95%置信区间（CI）。所有统计检验均为双侧检验。

结果

中位随访52个月后，分别有113例和119例参与者被诊断出患有第二原发性癌症和首次肿瘤复发。补充剂对第二原发性癌症发生率的影响随时间而变化。与接受安慰剂的患者相比，接受α-生育酚补充剂的患者在补充期间第二原发性癌症的发生率较高（HR = 2.88，95%CI = 1.56至5.31），但在停止补充后发生率较低（HR = 0.41，95%CI = 0.16至1.03）。同样，补充α-生育酚期间复发或发生第二原发性癌症的发生率较高（HR = 1.86，95%CI = 1.27至2.72），但补充后较低（HR = 0.71，95%CI = 0.33至1.53）。在随访8年后，两组中总体无第二原发性癌症的参与者比例相似。