Researchers have found that the prevalence of first-degree breast cancer family history of inflammatory breast cancer patients was higher than that of unaffected individuals, and that incidences may be associated with oral contraceptive use and regular alcohol intake.
The argument of nature versus nurture has been long-debated; whether hereditary or the environment affects the etiology of certain diseases is a complex problem that researchers strive to unravel. Oftentimes, both genetics and environmental factors play crucial roles. In the case of inflammatory breast cancer, previous studies have suggested that incidences are associated with early maternal age at first birth, high body mass index, trauma, and longer duration of breastfeeding. Others report that the risk may be subjected to seasonal variation and influenced by socioeconomic status or residence. In contrast, some researchers suggest that genetics can predispose individuals to the disease.
Inflammatory breast cancer (IBC) is a relatively rare form of breast cancer. It is characterized by an early age of diagnosis (52 years old, compared to 57 for non-inflammatory breast cancer) and the appearance of red, inflamed breasts,often accompanied with edema. As reported in the journal BMC Cancer, researchers compared IBC patients with select comparison groups to assess the etiologic components of IBC. Comparison groups included both population-based and hospital-based non-inflammatory breast cancer and ovarian cancer cases, as well as healthy individuals as controls. Ovarian cancer cases were used for comparison because it is known that first-degree family history of breast cancer is a risk factor for ovarian cancer. First-degree breast cancer family history was interpreted as the occurrence of at least one case of breast cancer affecting the mother or sister(s). In addition, they appear to share similar environmental risk factors and susceptibility genes that can predispose them to the disease.
All subjects involved in the case-control studies were of Caucasian background with either IBC, non-inflammatory breast cancer, ovarian cancer, or were unaffected as controls. Questionnaires were given to collect information with regards to family history as well as previous reproductive and medical conditions. Pedigrees were used to validate responses, for which 100% agreement was found. Data for comparisons were gathered from case-control studies from Cancer Genetic Markers of Susceptibility, the Women’s Health Initiative, and the University of Toronto. Subsequently, statistical analysis was used to examine cases based on a wide range of environmental variables.
Comparisons have revealed that IBC cases had a lower or similar prevalence of first-degree breast cancer family history compared to breast cancer and ovarian cancer patients. On the other hand, a higher prevalence was found when compared to unaffected controls. This implies that the importance of hereditary to IBC risk cannot be overlooked. As a secondary objective, researchers had also determined whether there are any environmental or lifestyle factors that may be associated with an increased risk of IBC. It was demonstrated that a higher prevalence of nulliparity (condition of having borne no offspring), use of oral contraceptives, and regular alcohol consumption (more than one drink daily) may be associated with IBC. While this is notable, further investigations are necessary to confirm these findings.
Ultimately, results from the case-comparison study emphasized the significance of collecting information on medical conditions of family members. By doing so, researchers are better equipped to recognize any possible genetic links to diseases.
Written By: Michelle Tu, BSc