written by Dick Clapp, DSc MPH
CHE Partner and member of the ATSDR Camp Lejeune Community Assistance Panel
A recent scientific report has shed some light on chemical exposures and breast cancer, this time on male breast cancer in Marines who had spent time at Camp Lejeune, North Carolina. Last month, the online journal Environmental Health published a study titled “Evaluation of contaminated drinking water and male breast cancer at Marine Corps Base Camp Lejeune, North Carolina: a case-control study,” by Perri Ruckart, Frank Bove and co-authors at the Agency for Toxic Substances and Disease Registry. The study was based on information about 71 male breast cancer cases in Marines and 373 controls that were in the Department of Veterans Affairs (VA) cancer registry and diagnosed between 1995 and May of 2013. For those subjects who were at Camp Lejeune, it was possible to assign exposure levels to various drinking water contaminants based on previous models developed for mortality studies published earlier.
The results of this recent male breast cancer study indicated increased risk with exposure to tetrachloroethylene (PCE), dichloroethylene (DCE) and vinyl chloride in drinking water. The excess risks were modest, with odds ratios ranging from 1.19 to 1.50, and the confidence intervals were wide and included 1.0. This means that the results were not formally statistically significant, although the estimate of the effect of exposure was toward increased risk. Similarly, there was a modest increased risk of earlier diagnosis of breast cancer in Marines who served at Camp Lejeune and were exposed to chemically contaminated drinking water. The major limitation of the analyses in this publication is the small numbers of male breast cancer cases who were exposed at Camp Lejeune. This is primarily due to the reliance on the VA cancer registry, which only collects data on about a quarter of the US veteran population.
While this latest publication is a preliminary indication of increased risk of male breast cancer from exposure to chlorinated chemicals in drinking water, and it supports the contention by former Marines and family members that there were excess cases, it is not the final word on this issue. Previous studies of PCE in drinking water and female breast cancer in Cape Cod, Massachusetts, women have suggested an increased risk from this exposure. Occupational studies of women exposed to chlorinated solvents at work and breast cancer risk are inconsistent and limited in statistical power. As Dr. Patrick Breysse, director of the CDC National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry, said in a recent interview, it will be examined in more detail in a larger Camp Lejeune cancer incidence study currently in the planning stage.
October is Breast Cancer Awareness Month.