Prognosis of Pregnancy-associated Breast Cancer: A Meta-analysis

Abstract

Background Pregnancy-associated breast cancer (PABC) is defined as breast cancer that is diagnosed during pregnancy and/or the postpartum period. Definitions of the duration of the postpartum period have been controversial, and this variability may lead to diverse results regarding prognosis. Moreover, evidence on the dose-response association between the time from the last pregnancy to breast cancer diagnosis and overall mortality has not been synthesized. Methods We systematically searched PubMed, Embase, and the Cochrane Library for observational studies on the prognosis of PABC published up to June 1, 2019. We estimated summary-adjusted hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs). Subgroup analyses based on diagnosis time, PABC definition, geographic region, year of publication and estimation procedure for HR were performed. Additionally, dose-response analysis was conducted by using the variance weighted least-squares regression (VWLS) trend estimation. Results A total of 54 articles (76 studies) were included in our study. PABC was associated with poor prognosis for overall survival (OS), disease-free survival (DFS) and cause-specific survival (CSS), and the pooled HRs with 95% CIs were 1.45 (1.30-1.63), 1.39 (1.25-1.54) and 1.40 (1.17-1.68), respectively. The corresponding reference category was non-PABC patients. According to subgroup analyses, the varied definition of PABC led to diverse results. The dose-response analysis indicated a nonlinear association between the time from the last delivery to breast cancer diagnosis and the HR of overall mortality ( P <0.001). Compared to nulliparous women, the mortality was almost 60% higher in women with PABC diagnosed at 30 months after the last delivery (HR=1.58, 95% CI 1.39-1.74), and the mortality was not significantly different at 68 months after the last delivery (HR=1.11, 95% CI 0.99-1.24). This finding suggests that the definition of PABC should be extended to include patients diagnosed up to approximately six years postpartum (68 months after the last delivery) to capture this ongoing increased risk. Conclusion This meta-analysis suggests that PABC is associated with poor prognosis, and the definition of PABC should be extended to include patients diagnosed up to approximately six years postpartum.

Cancer and Pregnancy: A Comprehensive Review

“…Nevertheless, some subgroups, such as patients with HER2+ breast cancer diagnosed in pregnancy seemed to have a poorer prognosis compared to the non-pregnant control-group [ 65 ]. Moreover, women diagnosed during lactation or during the first year’s post-partum [ 66 , 67 ] seemed to have a poorer prognosis compared to the non-pregnant control group or those diagnosed during pregnancy. However, pregnant women with malignant melanoma displayed an increased risk of cause-specific death (HR 1.52), while cervical-, thyroid- and ovarian cancer, lymphoma or leukemia did not show a significantly altered cause-specific risk of death (HR 1.23; HR 0.89; HR1.15; HR 4.58; and HR 0.46, respectively) [ 64 ].…”

“…However, the risk of cause-specific death was significantly increased, if breast or ovarian cancer were diagnosed during lactation (HR 1.59–1.95; HR, 2.23, respectively) [ 64 , 67 ].…”

Non‐invasive prenatal testing suggesting a maternal malignancy: What do we tell the prospective parents in Belgium?

“…Regarding the outcome of pregnancy‐associated breast cancer and malignant melanoma, which mainly include women with postpartum cancer diagnoses, conflicting results have been reported. The poorer prognosis described in some studies appears to be largely explained by more adverse tumor characteristics, stage at diagnosis, and treatment 38‐42 …”