BARCELONA (EGMN)—If women who have been successfully treated for breast cancer become pregnant, the findings of a large meta-analysis suggest they are not putting their lives at risk. Indeed, investigators found some evidence that pregnancy in breast cancer survivors may confer a protective effect on overall survival.

“There is a wide perception in the oncology community that women with a history of breast cancer should not get pregnant,” said the first author, Dr. Hatem A. Azim Jr. at the European Breast Cancer Conference. “This meta-analysis strongly argues against this notion.”

A total of 14 trials published between 1970 and 2009 were included in the meta-analysis. Together these trials involved more than 19,000 women with a history of breast cancer, of whom 1,417 were pregnant and 18,059 were not pregnant at the time of study (EJC Supplements 2010;8(3):207).

Women who became pregnant after being treated for breast cancer had a 42% decreased risk of dying when compared to women who did not get pregnant (hazard ratio 0.58). Tests for publication bias and heterogeneity did not reach statistical significance.

“Our findings clearly show that pregnancy is safe in women with a history of successfully treated breast cancer,” said Dr. Azim of the Institut Jules Bordet in Brussels, Belgium.

He described three hypotheses as to why pregnancy might have a protective effect in breast cancer survivors:

– First, there could be a ‘healthy mother effect,’ meaning that the women with breast cancer who later became pregnant were more likely to be healthy and less likely to experience recurrences. Dr. Azim noted, however, that data from at least three studies controlled for women who relapsed at the time of pregnancy, and a protective effect of pregnancy was still observed.

– Hormonal effects could also be involved, with some evidence that beyond a certain threshold, estrogen has an inhibitory effect on hormone receptor-positive tumor cells. Other hormones may also be involved, he noted, and high prolactin levels have been linked to a lower risk of breast cancer recurrence.

– Finally, there is the concept of alloimmunization, with the possibility that fetal antigens shared by tumor cells stimulate an immune response in the mother.

Further analyses of the data are planned, and will use individual patient data where available. Dr. Azim and associates plan to look at how age at diagnosis (less than 35 years vs. at least 35 years), the time interval between diagnosis and pregnancy (less than 2 years vs. at least 2 years), lymph node status, and type of study performed (population/hospital-based vs. case-control) could affect findings.

“For the time being, the take-home message is that women who want to get pregnant following breast cancer can do so—it’s safe,” Dr. Azim said.

“There are many guidelines but not much guidance,” commented Dr. Mike Dixon, Clinical Director of the Breakthrough Breast Cancer Research Unit in Edinburgh, UK. “The meta-analysis is very interesting, as it does show better survival in women who become pregnant,” but he expressed concern that there was a selection bias in the trials and said further information was necessary.

Dr. Azim and Dr. Dixon reported no relevant conflicts of interest.

Copyright (c) 2009 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

巴塞罗那(EGMN)——一项大型荟萃分析发现，乳腺癌治疗成功的女性怀孕不会对其生命造成危险。实际上，研究者发现，有些证据显示乳腺癌幸存者妊娠可能对总体生存状况还具有保护效应。

 

第一作者Hatem A. Azim Jr.博士在欧洲乳腺癌会议上说，“肿瘤界人士普遍认为，有乳腺癌病史的女性不应受孕，而这项荟萃分析与此观点极不一致。”

 

这项荟萃分析共纳入14项于1970~2009年间发表的研究。这些研究的受试者共计逾19,000例，均有乳腺癌病史，其中有1,417例为孕妇，18,059例在研究之时未受孕(EJC Supplements 2010;8(3):207)。

 

接受乳腺癌治疗后受孕的女性死亡风险较未受孕者降低42%(危险比 0.58)。发表偏倚和异质性检验均未达到统计学意义。

 

比利时布鲁塞尔朱尔斯•博尔代学院(Institut Jules Bordet )Azim博士称：“我们的研究结果明确显示，有乳腺癌成功治疗史的女性受孕是安全的。”针对妊娠为何对乳腺癌幸存者有保护效应，他提出以下3种假设：

 

·         第一，可能存在“健康母亲效应”，意为乳腺癌女性在后来受孕后健康的可能性更大，而复发的可能性更小。Azim博士指出，至少有3项研究在针对妊娠时复发的女性进行控制后仍观察到妊娠对患者的保护效应。

 

·         可能亦与激素效应有关；有些证据表明，雌激素超过一定阈值后会对激素受体阳性的肿瘤细胞产生抑制效应。他指出，这可能也涉及到其他激素，而高催乳素水平一直与乳腺癌复发风险较低有关。

 

·         最后，与异体免疫有关：胎儿抗原可能与肿瘤细胞相同，激发了母体体内的免疫反应。

 

研究者计划对数据进行进一步分析，而且在分析中将尽可能纳入更多的个体患者数据。Azim博士及其同事计划观察诊断时年龄(>35岁 对 ≥35岁)、诊断与妊娠之间的间隔时间(<2年 对 ≥2年)、淋巴结受累情况以及研究类型(以人群或住院患者为基础的研究 对 病例对照研究)对结果的影响。

 

Azim博士说：“目前，一个重要的信息为，患者在诊断为乳腺癌后若想受孕的话就可以这样做——这是安全的。”

 

英国爱丁堡突破乳腺癌研究所(Breakthrough Breast Cancer Research Unit)临床主任Mike Dixon博士评论道，“现在的指南有很多，但指导却为数不多。这项荟萃分析非常值得关注，因为它确实表明，受孕女性生存状况获得好转。”但他也表达了相关顾虑——试验中存在选择偏倚，有必要收集更多的资料。

 

Azim博士和Dixon博士均报告无相关利益冲突。

 

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