ControversyPrognosis of pregnancy-associated breast cancer: A meta-analysis of 30 studies
Introduction
Pregnancy-associated breast cancer (PABC) is commonly defined as breast cancer diagnosed during the course of pregnancy or the one-year following delivery.1 The exact incidence is unknown; however, it is estimated to constitute around 10% of breast cancer cases diagnosed below the age of 40 in Western nations.2, 3 This incidence is currently on the rise as more women are delaying childbearing.4
Prognosis of PABC has been addressed in several studies with inconsistent results.5, 6, 7, 8 The relative rarity of the disease precludes the conduction of large powered controlled studies to address this question. Some studies have found that PABC is more commonly diagnosed at an advanced stage5, 6 suggesting that the poor prognosis is secondary to diagnostic delay rather than an inherent effect of pregnancy or lactation on breast cancer prognosis. However, other studies have shown an independent effect of pregnancy on outcome.9, 10, 11 Nevertheless, the small number of patients examined in each of the individual studies has hindered the proper interpretation of these data. This is of great clinical relevance as it could guide treatment strategies for these highly challenging cases.
In this study, we aimed to perform a comprehensive analysis of all published studies that addressed the prognosis of PABC. We specifically wanted to clarify whether diagnosis during pregnancy or 1-year afterwards has an impact on long-term patient outcome.
Section snippets
Methods
The study design was a quantitative synthesis of retrospective control-matched, population-based and hospital-based studies that evaluated the impact of breast cancer diagnosis during or one year following pregnancy on survival. The primary end-point was overall survival (OS), which was defined as time from breast cancer diagnosis to death or last follow-up. Secondary end-points included disease-free survival (DFS), defined as time from breast cancer diagnosis to local or systemic relapse,
Eligible studies
A total of 6449 articles were initially screened. After applying eligibility criteria, a total of 30 studies were deemed to be eligible5, 6, 7, 8, 9, 10, 11, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 (PRISMA chart, Fig. 1). We were able to obtain original data from only three of the included studies.8, 11, 34
A total of 3,628 patients were diagnosed with PABC and were compared with a control group of 37,100 breast cancer patients (Table 1). PABC
Discussion
To the best of our knowledge, this is the largest work to investigate the prognosis of PABC. Notably, we found that PABC is associated with poor prognosis, even after adjustment for confounding factors. We also found that PABC has a higher risk of recurrence compared to controls. We did not find any impact on the type, time and size of the study on survival outcome.
It is known that pregnancy exert a bi-directional effect on breast cancer development with a short-term increase in risk (up to 5
Conflict of interest
The authors have declared no conflicts of interest.
Acknowledgments
Part of this work was presented as a poster presentation in the 2011 San Antonio Breast Cancer Symposium. Hatem A. Azim Jr. and Luigi Santoro contributed equally to this work. Hatem A. Azim Jr. is supported by an ESMO research grant. Fedro Peccatori is supported by the IEO and Avon foundations. We would like to thank Dr. Sayed A. Aziz for providing original patient information for his study.34
References (47)
- et al.
Breast cancer before age 40 years
Semin Oncol
(2009) - et al.
The Western Australian gestational breast cancer project: a population-based study of the incidence, management and outcomes
Breast
(2005) - et al.
Maternal and fetal outcome after breast cancer in pregnancy
Am J Obstet Gynecol
(1992) - et al.
Impact of pregnancy on non-metastatic breast cancer: a case control study
Clin Oncol (R Coll Radiol)
(1996) - et al.
Case control study of novel prognostic markers and disease outcome in pregnancy/lactation-associated breast carcinoma
Pathol Res Pract
(2003) - et al.
The GH-IGF-I axis and breast cancer
Trends Endocrinol Metab
(2003) - et al.
Pregnancy-associated breast cancer
Cancer J
(2005) - et al.
Increasing incidence of pregnancy-associated breast cancer in Sweden
Obstet Gynecol
(2009) - et al.
Clinicopathologic characteristics and prognosis of breast cancer patients associated with pregnancy and lactation: analysis of case-control study in Japan
Jpn J Cancer Res
(1992) - et al.
Effect of pregnancy on prognosis for young women with breast cancer
Lancet
(1994)
Cause-specific survival for women diagnosed with cancer during pregnancy or lactation: a registry-based cohort study
J Clin Oncol
Presentation, management and outcome of 32 patients with pregnancy-associated breast cancer: a matched controlled study
Breast J
Evidence of poorer survival in pregnancy-associated breast cancer
Obstet Gynecol
Prognosis for patients diagnosed with pregnancy-associated breast cancer: a paired case-control study
Sao Paulo Med J
The biological features and prognosis of breast cancer diagnosed during pregnancy: a case-control study
Acta Oncol
Quantitative methods in the review of epidemiologic literature
Epidemiol Rev
On estimating the relation between blood group and disease
Ann Hum Genet
Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints
Stat Med
Quantifying heterogeneity in a meta-analysis
Stat Med
A comparison of methods to detect publication bias in meta-analysis
Stat Med
Cancer of the breast in Philadelphia hospitals 1951–1964
Cancer
Carcinoma of the breast in women under 30 years of age: a clinical and histopathological study of all cases reported as carcinoma to the Swedish Cancer Registry, 1958–1968
Cancer
Breast cancer and pregnancy
Arch Surg
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