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 12 months after the last delivery (HR=1.59, 95% CI 1.30-1.82), and the mortality was not significantly different at 70 months after the last delivery (HR=1.14, 95% CI 0.99-1.25). This finding suggests that the definition of PABC should be extended to include patients diagnosed up to approximately six years postpartum (70 months after the last delivery) to capture the 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.

Prognosis of triple-negative breast cancer associated with pregnancy: A propensity score-matched analysis from the French CALG (Cancer Associé à la Grossesse) network

“…Nevertheless, it is important to note that the study period was long and that diagnostic tools and treatment modalities differed widely from country to country. A recent meta-analysis published in 2020 by Shao et al collecting data from 76 studies showed that PABC was associated with poor prognosis for OS, DFS and causespecific survival (CSS) [21]. The pooled HRs with 95% CIs for OS, DFS and CSS were 1.45 (1.30e1.63), 1.39 (1.25e1.54) and 1.40 (1.17e1.68), respectively [21].…”

“…A recent meta-analysis published in 2020 by Shao et al collecting data from 76 studies showed that PABC was associated with poor prognosis for OS, DFS and causespecific survival (CSS) [21]. The pooled HRs with 95% CIs for OS, DFS and CSS were 1.45 (1.30e1.63), 1.39 (1.25e1.54) and 1.40 (1.17e1.68), respectively [21]. However, gestational age was not taken into account in this meta-analysis, and no specific analysis was made between patients with true PABC and patients diagnosed in the postpartum period [21].…”

“…However, gestational age was not taken into account in this meta-analysis, and no specific analysis was made between patients with true PABC and patients diagnosed in the postpartum period [21]. Moreover, Shao et al found a nonlinear association between the time from last delivery to breast cancer diagnosis and the HRs of overall mortality (p < 0.001) [21]. Indeed, they found that mortality was almost 60% higher in women with PABC diagnosed at 12 months after delivery (HR ¼ 1.59, 95% CI 1.30e1.82) but not significantly different at 70 months after delivery (HR ¼ 1.14, 95% CI 0.99e1.25) compared with nulliparous women.…”

“…A recent meta-analysis published in 2020 by Shao et al. collecting data from 76 studies showed that PABC was associated with poor prognosis for OS, DFS and cause-specific survival (CSS) [ 21 ]. The pooled HRs with 95% CIs for OS, DFS and CSS were 1.45 (1.30–1.63), 1.39 (1.25–1.54) and 1.40 (1.17–1.68), respectively [ 21 ].…”

“…Although a meta-analysis of 30 studies concluded that women with PABC had a poorer prognosis than non-PABC patients even after adjustment for confounding factors, national and international guidelines recommend that PABC treatment should be as similar as possible to that in non-PABC patients [ 21 ]. However, few data are available about the management and survival of women with TNBC associated with pregnancy (TN-PABC).…”