Importance Patients with schizophrenia are considered to have many risk factors for the development of cancer. However, the incidence of breast cancer in women with schizophrenia compared with the general population remains uncertain.

Objective To perform an updated meta-analysis to evaluate the association between schizophrenia and the risk of breast cancer.

Data Sources A systematic search of the PubMed and EMBASE databases was conducted using the search terms schizophrenia, schizophrenic, psychosis, combined with breast and cancer, tumor, neoplasm, or carcinoma. The final literature search was performed on August 15, 2017.

Study Selection Cohort studies reporting the standardized incidence ratio (SIR) for the risk of breast cancer in women with schizophrenia compared with the general population.

Data Extraction and Synthesis The meta-analysis adhered to Meta-analysis of Observational Studies in Epidemiology and the Cochrane Handbook for Systematic Reviews of Interventions. Data extraction was performed independently. A random-effects model was used to pool the results, and a recently proposed prediction interval was calculated to describe the heterogeneity.

Main Outcomes and Measures The SIR for the risk of breast cancer in women with schizophrenia compared with the general population or those without schizophrenia.

Results Twelve cohorts including 125 760 women were included in this meta-analysis. The results of the meta-analysis showed that schizophrenia was associated with a significantly increased risk of breast cancer incidence in women (SIR, 1.31; 95% CI, 1.14-1.50; P < .001), with significant heterogeneity (P < .001; I² = 89%). Substantial between-study variance was also suggested by the wide prediction interval (0.81-2.10), which indicated that it is possible that a future study will show a decreased breast cancer risk in women with schizophrenia compared with the general population. The subgroup analysis results showed that the association was not significantly affected by whether breast cancer cases were excluded at baseline or the sample size of the included studies.

Conclusions and Relevance The incidence of breast cancer in women with schizophrenia is higher than that of the general female population. However, significant heterogeneity exists among the included studies. Women with schizophrenia deserve intensive prevention and treatment of breast cancer.

重要性精神分裂症患者被认为有许多发展为癌症的危险因素。然而，与一般人群相比，精神分裂症女性乳腺癌的发病率仍不确定。

目的进行更新的荟萃分析，以评估精神分裂症与乳腺癌风险之间的关联。

数据来源使用检索词精神分裂症、精神分裂症、精神病以及乳腺癌和癌症、肿瘤、赘生物或癌对 PubMed 和 EMBASE 数据库进行了系统检索。最终文献检索于2017年8月15日进行。

研究选择队列研究报告了精神分裂症女性与普通人群相比乳腺癌风险的标准化发病率 (SIR)。

数据提取和综合荟萃分析遵循流行病学观察研究荟萃分析和干预系统评价科克伦手册。数据提取是独立进行的。使用随机效应模型来汇总结果，并计算最近提出的预测区间来描述异质性。

主要结果和措施与一般人群或非精神分裂症患者相比，患有精神分裂症的女性患乳腺癌的风险 SIR。

结果本荟萃分析纳入了 12 个队列，包括 125 760 名女性。荟萃分析结果显示，精神分裂症与女性乳腺癌发病风险显着增加相关（SIR，1.31；95% CI，1.14-1.50；P < .001），具有显着异质性（P <） .001；I2 = 89%）。较宽的预测区间（0.81-2.10）也表明研究间存在显着差异，这表明未来的研究可能会显示，与一般人群相比，精神分裂症女性患乳腺癌的风险较低。亚组分析结果显示，该关联并未受到基线时是否排除乳腺癌病例或纳入研究的样本量的显着影响。

结论和相关性精神分裂症女性乳腺癌的发病率高于一般女性人群。然而，纳入的研究之间存在显着的异质性。患有精神分裂症的女性应该加强乳腺癌的预防和治疗。