Cancer Cluster Investigation Status Report

Background
  • The Maryland Department of Health and Mental Hygiene in collaboration with the Frederick County Health Department is conducting a preliminary statistical analysis of the cancer case data in the Maryland Cancer Registry.
  • Objective: Determine if the rate of all cancers and/or certain types of cancer is higher than expected and what the likelihood is that an increase in cancer rates could be due to something other than chance alone in what is approximately a 1-mile radius from Ft. Detrick.
  • Graph of the 12-year trend in age-adjusted cancer incidence in Frederick County
Investigative Steps
The following investigative steps are taken by the Maryland Department of Health and Mental Hygiene (DHMH) when conducting a cancer cluster investigation- see Questions and Answers about Cancer Clusters (DHMH) for more details.

Step 1- Initial Information
  • The process established by the Maryland Department of Health and Mental Hygiene to evaluate cancer cluster concerns begins with the local health department evaluating information about each cancer case thought to be part of a cluster.
  • The information needed includes specific information from concerned individuals about the types of cancers, the names and ages of persons diagnosed with those cancers, the dates of diagnosis, and the time period that persons diagnosed with cancer were in the geographic or occupational area of interest.
  • This step was bypassed in the current investigation of concerns raised by residents living near Fort Detrick as there was enough information provided informally to the Frederick County Health Department by residents, and there is the possibility that specific case information collected by an external organization will be provided in the future.
Step 2- Preliminary Investigation
  • This step is currently underway. See details below related to the investigation. Preliminary results were presented in October 2010, January 2011 and March 2011.
  • Preliminary results were presented during the October 4 Community Cancer Concerns meeting. The number of cases of cancer observed in the 3 census tracts examined (for the time period 2000-2007, using the Maryland Cancer Registry source of data, and for the cancers listed below) were not statistically higher than what was expected based on Frederick County rates of cancer, but the number of all cases of cancer observed in the 3 census tracts examined was statistically greater than the number expected based upon the Maryland rate for all cancers in the same time period using the same source of data.
  • Results presented at the January 3, 2011 Community Cancer Concerns meeting included an update on the additional analysis conducted looking at the age of diagnosis of cancers in the 3 census tracts of interest and further analysis is planned.
  • Results presented at the March 14, 2011 Community Cancer Concerns meeting included additional analysis using all complete years in the Maryland Cancer Registry, 1992 to 2008. The analysis was also expanded by space by adding data from additional census tracts encompass a distance of approximately 2-miles from the fence line bordering Fort Detrick Areas A and B.
  • Summary report of the analysis of the Maryland Cancer Registry data for the years 1992-2008 presented at the October 3, 2012 Community Cancer Concerns meeting.
Step 3- Further Investigation
  • This step will be guided by the findings from the Step 2 preliminary investigation.
Sources of Data
  • By law, hospitals, laboratories, cancer treatment centers, and doctors are required to report all new cancer cases diagnosed in Maryland (excluding basal and squamous cell skin cancer) to the Maryland Cancer Registry (MCR) of the Department of Health and Mental Hygiene.
  • The MCR records the home address at the time of diagnosis of cancer. The home address is then associated with a census tract number since the year 2000. Before the year 2000, only zip code level groupings of the data are possible. The zip code areas are much larger than the census tract areas.
  • The initial analysis of data in the MCR will evaluate cancer cases that occurred in the geographic area of analysis based upon census tract level data available for the years 2000-2007. Subsequent analyses will cover the years 1992-1999 and 2008.
Geographic Area of Analysis
  • The initial geographic area defined for the preliminary statistical analysis of cancer rates is roughly a 1 mile radius from Fort Detrick, Area A and Area B.
  • In some cases the initial census tracts examined were more than a mile from the perimeter or fence line of Fort Detrick Area A and B and in some cases little less than a mile.
  • The initial 1 mile area was selected following discussions with cancer data experts and Randy White and his consultants. Based on feedback from the community the geographic are of analysis was expanded by another 7 census tracts extending out approximately 2 miles from the fence line.
  • Analyzing too large of an area may “dilute” findings and too small of an area may not have enough numbers to determine if differences are statistically significant.
Types of Cancer in Analysis
  • The types of cancer to be evaluated are based upon the off-site well contaminants documented.
  • Two chemicals detected on off-site wells, tetrachloroethene (PCE) and trichloroethene (TCE), have been associated with cancer of the brain, leukemia, lymphoma, and kidney cancer.
  • Due to concerns expressed about exposure to dioxin, liver cancer rates will also be evaluated.
  • Additionally, based upon the number of thyroid cases reported at the August 12 Community Meeting, which were more numerous than what might be expected relative to the other cancers reported at the meeting, thyroid cancer was also added to the list of specific cancers being examined.
  • These specific cancers will be evaluated in Step 2 of the investigation.
  • The rates in the smaller geographic area under investigation for the 4 most common cancers (lung, breast, colorectal, and prostate) and the specific cancers of concern listed above will also be compared to Frederick County rates and Maryland rates.
Next Steps
  • The National Academies of Science (NAS) issued a Review of Studies of Possible Toxic Effects from Past Environmental Contamination at Fort Detrick on March 5, 2012. Two of the studies reviewed by the NAS were the interim and summary reports of the Frederick County Cancer Investigation from the Maryland Department of Health and Mental Hygiene.
  • The Maryland Department of Health and Mental Hygiene and the Frederick County Health Department will perform the additional analysis described in the earlier reports presented during meetings with the community and cited in the NAS report.