Written by Susan S Johnson, PhD, Biochem. Fish oil supplementation showed 32% reduction in incidence of breast cancer.
Invasive ductal carcinoma (IDC) is the most common form of invasive breast cancer. It accounts for 55% of breast cancer incidence in the US as of 2004 (1). It begins with a proliferation of cells in the milk duct but progresses to invade surrounding tissue. Invasive lobular carcinoma (ILC) accounts for 5-10% of invasive breast cancers. It begins in the termini of a milk duct called a lobe (2).
In this new community survey study, 35,000 US postmenopausal women under age 76 were observed to see if their use of fish oil and other specialty supplements could be correlated with incidences of invasive breast cancer. This population is known as the VITAL cohort (3). Each participant filled out dietary questionnaire at the beginning of the study to determine frequency of dietary supplementation with a variety of specialty supplements. Incidences of invasive breast cancers, ductal and lobal, were recorded from 2000-2007 which was the duration of the study.
Statistical analyses for trends in breast cancer incidence versus the use of individual supplements were performed. In addition, trends for subpopulations with other diseases were assessed.
Overall, only fish oil supplementation being taken at the time the study was initiated showed any statistical correlation in reduced incidence of breast cancer – the hazard risk being 0.68 compared with nonusers or a 32% reduction in risk (p for the trend 0.02)*. When the population was split into localized or spreading ductal and lobal cancer groups, the trend only held for localized ductal carcinomas.
No statistically significant correlations between invasive breast cancer incidents and other anti-inflammatory (e.g. glucosamine, chondroitin, MSM, CoQ10, and fish oil) or women’s health supplements (e.g. black cohosh, St. John’s wort, and dong quai) were observed.
To support the validity of these findings, age at menstruation, hormone therapy, family history of breast cancer, and age at initial childbearing were all significantly correlated with invasive breast cancer incidence (p for these trends <0.01)* as also shown in many studies to date.
Since this study was designed to suggest potential dietary interventions, further study of fish oil supplementation is warranted.
It is estimated that 207,090 US women will be diagnosed with and 39,840 women will die of cancer of the breast in 2010. Based on rates from 2005-2007, 12.15% of women born today will be diagnosed with cancer of the breast at some time during their lifetime. This number can also be expressed as 1 in 8 women will be diagnosed with cancer of the breast during their lifetime. The good news is that the 5 year survival rate for localized breast cancers is 98% (4). US breast cancer care costs were estimated to total $13.8 billion dollars in 2006 which include initial care, continual care and last year of life care (5).
* p <0.05 is considered to be a significant trend
Source: Brasky, Theodore M., et al. “Specialty supplements and breast cancer risk in the VITamins And Lifestyle (VITAL) Cohort.” Cancer Epidemiology and Prevention Biomarkers 19.7 (2010): 1696-1708.
© 2010 American Association for Cancer Research
Posted August 4, 2010.
References:
- See Wikipedia.
- See Wikipedia.
- White E, Patterson RE, Kristal AR, et al. VITamins And Lifestyle cohort study: study design and characteristics of supplement users. Am J Epidemiol 2004;159:83–93.
- See the National Cancer Institute website.
- See the National Cancer Institute website.
