[excerpt] A large Swedish study shows that neither induced nor spontaneous abortions are associated with increased risk of breast cancer.Primary Source: “Abortions and Breast Cancer: Record-Based Case-Control Study.” International Journal of Cancer 2003; 103:676-679.
Expert Commentary by Raquel D. Arias, MD Associate Professor
Obstetrics and Gynecology
Keck School of Medicine
University of Southern California
Los Angeles, CABREASTLINK ANALYSIS By Mary Batten
This is a large, well-designed prospective study from the highly respected Karolinska Institute in Stockholm, Sweden (Ref. 1). There are several factors in its favor. First, the study was conducted in a country where abortion is an accepted part of women’s health services and not a political issue as it is in the United States. This makes for a research climate in which an objective scientific study of abortion and breast cancer risk can be done free of political pressure and threat of violence. Second, the data were taken from very reliable sources: the Swedish Medical Birth Register, the Swedish Cancer Register, and prenatal medical records. Third, because this was a prospective study, it avoided the possible bias sometimes attributed to studies that have depended on women to report whether they had an abortion. It has been suggested that women with breast cancer might be more likely than their counterparts without the disease to report accurately previous induced abortions. If that were the case, the study results would indicate a false association between abortion and risk of breast cancer.
This study should put to rest the contention that abortion increases breast cancer risk. Indeed, the results of this study show exactly the opposite. Neither spontaneous nor induced abortions were found to increase risk of breast cancer. The researchers found a reduced risk of breast cancer among women who had had at least one abortion compared to no abortions. These data indicate that pregnancy has a protective effect against breast cancer regardless of the outcome. [excerpt]
There can be bias to prove there is no connection, too.
This study should put to rest the contention that abortion increases breast cancer risk.
We shall see.
After all,Swedish women are not representative of all women of the world. The researchers might have been a little too ethnocentric (Swedo-centric?)
Comparison of women with breast cancer in Singapore and Sweden, Karolinska Institutit
Project leader: Per Hall
Background: Singapore and Sweden are highly industrialized countries with similar health care systems. Despite similar quality of cancer registration, postmenopausal breast cancer incidence rates are two to three times higher in Sweden than in Singapore.
Life style factors such as age at first full time birth, number of children, the use of hormone replacement, oral contraceptives, and breast-feeding could explain the differences.
The Swedish Cancer and the Stockholm Breast Cancer Registry will be used to evaluate age at diagnosis and calendar period effects.
It could be argued that postmenopausal breast cancer in Singapore and Sweden differs not only in numbers but also in origin and tumor characteristics. The Swedish breast cancers could be more influenced by female sex hormones and thus have a different gene expression pattern. Our aim is to compare 50 Swedish and 50 Singaporean breast tumors on a gene expression level.
Ongoing tasks: We will compare the breast cancer incidence and mortality rates of Singapore and Sweden taking stage of the disease into consideration. We will also compare the gene expression pattern in 50+50 postmenopausal breast cancer patients from Singapore and Sweden.