Background

Several studies have investigated an association between organochlorine-concentrations and breast cancer incidence, whereas few have investigated an association with breast cancer mortality.

Methods

We used Cox Proportional Hazards Models to estimate the association between adipose organochlorine-concentrations and mortality after breast cancer in a survivor-cohort of 399 postmenopausal women. During a median follow-up of 16.1 years, 177 women died; 119 from breast cancer.

Results

There was a general inverse association with PCB-concentration (e.g. ΣPCBs: Mortality Rate Ratio (MRR) 0.79, 95% confidence interval (CI) (0.64–0.98) per inter-quartile range (IQR)), and for all pesticides, except β-Hexachlorocyclohexane, which was not associated with mortality (MRR 1.02(0.87–1.18) per IQR), and dieldrin, which was associated with a significantly increased risk of death (MRR 1.22(1.05–1.41) per IQR). We found an interaction with prognostic factors for all PCBs, confining the inverse association to those with adverse prognostic factors. Results for pesticides suggested a similar, but mostly non-significant interaction. Dieldrin diverged from the general picture by being associated with increased mortality across all strata.

Conclusion

A higher concentration of PCBs and several organochlorine pesticides may be inversely associated with breast cancer mortality among women with adverse prognostic factors. Further studies are required to investigate if this is a causal association. Dieldrin was associated with a higher mortality, regardless of prognostic factors.

Impact

This is the first study to investigate an association between organochlorine concentrations in adipose tissue and breast cancer mortality. A prominent finding is a strong interaction with prognostic factors. The unexpected direction of association for most organochlorines encourages further studies of the role of individual metabolism of the organochlorines and a potentially stronger effect of the metabolites on mortality.

中文翻译：

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丹麦绝经后乳腺癌患者脂肪组织中的有机氯浓度和存活率

背景

几项研究调查了有机氯浓度与乳腺癌发病率之间的关系，而很少研究调查与乳腺癌死亡率的关系。

方法

在399名绝经后妇女的幸存者队列中，我们使用Cox比例危害模型估算了脂肪有机氯浓度与乳腺癌死亡率之间的关系。在中位随访期16.1年中，有177名妇女死亡。119来自乳腺癌。

结果

与PCB浓度呈反比关系（例如ΣPCB：死亡率比（MRR）0.79，每个四分位间距（IQR）的95％置信区间（CI）（0.64-0.98）），以及除其他农药外的所有农药β-六氯环己烷与死亡率（每IQR的MRR 1.02（0.87-1.18）不相关）和狄氏剂与死亡风险显着增加（每IQR的MRR 1.22（1.05-1.41）相关）。我们发现所有PCB均与预后因素存在相互作用，从而将反向关联限制于具有不良预后因素的患者。农药的结果表明存在相似但几乎不显着的相互作用。狄氏剂与所有阶层的死亡率增加相关，因此与一般情况有所不同。

结论

预后不良的女性中，PCBs和几种有机氯农药的浓度较高可能与乳腺癌的死亡率呈负相关。需要进一步的研究以调查这是否是因果关系。不论预后因素如何，狄氏剂都与较高的死亡率相关。

影响

这是第一项研究脂肪组织中有机氯浓度与乳腺癌死亡率之间关系的研究。一个突出的发现是与预后因素的强烈相互作用。大多数有机氯的意外的缔合方向鼓励进一步研究有机氯的个体代谢作用以及代谢物对死亡率的潜在更强作用。