Unlike acute inflammation, such as that caused by a wound or infection, chronic inflammation refers to a state of general low-intensity inflammation that lasts over time. This type of inflammation has been associated with prevalent diseases such as diabetes, cardiovascular disease, kidney dysfunction or cancer, where it can promote tumour progression and metastasis. Although the relationship between these inflammatory processes and breast cancer is not yet entirely clear, we know that inflammation can be promoted by excess weight, while physical activity exerts an anti-inflammatory effect. This state of chronic inflammation has been proposed as a factor that could influence not only the appearance of breast cancer, but also its prognosis once the diagnosis has been established.
Now, a study carried out by IDIBELL and ICO in collaboration with the International Agency for Research on Cancer, IARC, offers new clues about this phenomenon. Published in the British Journal of Cancer, it is a prospective study that analyzed the association between the blood levels of various inflammation markers, measured in more than 1500 women before they were diagnosed with breast cancer, and the long-term survival of the same patients.
The study included more than 1500 women with breast cancer
The analysis included 1,538 women from the EPIC cohort, belonging to eight different European countries, who have suffered from breast cancer throughout the follow-up of the study. On the one hand, blood levels of a series of cytokines, molecules related to inflammation, have been quantified from samples extracted before cancer diagnosis. After an average follow-up of 7 years, the risk of survival and mortality due to breast cancer or other causes has been analyzed according to the blood levels of these molecules.
The results have shown that elevated levels of some cytokines, such as interleukin 6 (IL-6), interleukin 10 (IL-10) and tumor necrosis factor alpha (TNFα), are associated with lower survival, with a greater impact on women who were postmenopausal at the time of diagnosis.
“We detected an association between higher levels of these biomarkers and an increase in overall mortality. Specifically, women with higher levels of IL-6, IL-10 and TNFα have a 20% to 40% increase in the overall mortality risk (from any cause),” says Dr. Carlota Castro, first author of the study and postdoctoral researcher in the IDIBELL and ICO nutrition and cancer group. “In addition, elevated IL-6 levels have also been linked to higher breast cancer-specific mortality,” he adds.
This finding supports the hypothesis that chronic inflammation may play an important role in the progression of breast cancer, although the researchers stress the importance of conducting other studies that collect and analyze blood samples taken at different times before and after cancer diagnosis. In addition, it is essential that these studies include a sufficient representation of all breast cancer subtypes in order to be able to draw more specific conclusions in relation to these biological mechanisms.
The EPIC Cohort
The European Prospective Investigation into Cancer and Nutrition study, EPIC, is a large-scale, long-term collaborative project that investigates the relationships between diet, nutrition, lifestyle, environmental factors, and the incidence of cancer and other chronic diseases in different European countries. Considered one of the largest and most detailed cohort studies in existence, it compiles data on lifestyle, diet, anthropometric measurements and blood samples from 519,978 participants from 10 European countries. The analysis of the EPIC data has led to the publication of more than 3,000 scientific articles, revealing relevant associations between environmental, dietary and lifestyle factors and cancer.
In Spain, the implementation and monitoring of the EPIC cohort is coordinated by the IDIBELL and ICO nutrition and cancer research group.
The Bellvitge Biomedical Research Institute (IDIBELL) is a biomedical research center created in 2004. It is participated by the Bellvitge University Hospital and the Viladecans Hospital of the Catalan Institute of Health, the Catalan Institute of Oncology, the University of Barcelona and the City Council of L’Hospitalet de Llobregat.
IDIBELL is a member of the Campus of International Excellence of the University of Barcelona HUBc and is part of the CERCA institution of the Generalitat de Catalunya. In 2009 it became one of the first five Spanish research centers accredited as a health research institute by the Carlos III Health Institute. In addition, it is part of the “HR Excellence in Research” program of the European Union and is a member of EATRIS and REGIC. Since 2018, IDIBELL has been an Accredited Center of the AECC Scientific Foundation (FCAECC).