Abstract
BACKGROUND: Pregnancy-Associated Breast Cancer (PABC) is a special type of breast cancer that either occurs during pregnancy or one year postpartum. The aim of this systematic review and meta-analysis is to investigate the global incidence of PABC. METHODS: In this meta-analysis, to find related studies, three international databases including PubMed (Medline), Scopus and Web of Science (Clarivate analytics) were explored. An additional search was also carried out using Google Scholar in December 2023 looking for any new relevant article, and the list of references for all new supposedly relevant papers were manually searched for and investigated as well. The required data were extracted from retrieved studies and the quality of the studies was evaluated using the Newcastle-Ottawa scale checklist. Heterogeneity among studies was assessed by I-square statistic and chi-square test and due to presence of a significant heterogeneity among studies, a random-effects model was used to pool the data. RESULTS: Twenty-two studies were included in this meta-analysis. Among 51,944,490 number of female individuals included in the study, a total number of 7,267 cases of PABC were identified. Based on these results, the global incidence of PABC was estimated 19.2 cases per 100,000 pregnancies (95%CI: 16.1-22.2, I-square = 98.9%). The results of cumulative analysis showed that the incidence rate of PABC has risen over decades, as it increased from 13.3 cases (in 1969) to 19.2 cases (in 2022) per 100,000 pregnancies. The lowest incidence rate belonged to the American continent with 14.4 (95%CI: 9.8-19) cases per 100,000 pregnancies. CONCLUSIONS: The results obtained from this study demonstrates that the global incidence of PABC amounts to 19.2 cases per 100,000 pregnancies and it has been increasing slowly during the last few decades as time went by. The incidence rate in developing countries seem to be higher than in the developed countries. However, more studies are required in order to reach a better conclusion on this issue.