Initial Email from Dr. Tillman

When the story initially broke, one of the television stations had an interview with Dr. Ulder Tillman from the Montgomery County Department of Health and Human Services. A day or two later, I contacted Dr. Tillman directly, asking for information on "how your agency is planning to study the potential cancer cluster in Poolesville; the steps to be taken, the timeline and when you expect to publish results. Also, are there any recommended steps which we residents can take while we await results?"

The email below is what I received from her on January 12, 2009

Thank you for your voice message and email. Most of the following is excerpted from material compiled by Maryland Department of Health and Mental Hygiene (DHMH).
Montgomery County Dept. of Health and Human Services (MCDHHS) is first trying to ascertain if a cancer cluster may exist. "A cancer cluster is a greater than expected number of cases of similar cancers occurring in a short period of time among people who live or work near each other."

* We review and share general cancer facts: Cancer is more common than most people realize (It's the second leading cause of death in the U.S. and in Maryland.); the risk of cancer increases with age; cancer is not just one disease but refers to a group of over one hundred diseases that start because abnormal cells grow out of control. Most cancers are related to lifestyle factors (smoking or other tobacco use, diet, obesity and lack of exercise may well account for about 65% of all cancer deaths in the US based on Maryland Cancer Registry, DHMH, 2001) and reseachers believe that environmental exposures, other than tobacco smoke, probably account for less than 10% of all cancers. Cancers diagnosed today usually are related to events that happened many years ago (Ten or more years often pass between mutations or exposure and detectable cancer.) This long period makes it difficult to pinpoint the specific causes of many cancers. Finally, cancer clusters can occur by chance: for some cancer types and some geographic areas, a small number of cases may be enough to change an area's cancer rate from below average to above average and the additional cases may simply be the result of variations that occur randomly or by chance and not be due to a single cause.

* How cancer clusters are investigated in Maryland: We take suspected cancer clusters seriously and work with DHMH to evaluate them. Several state abd local agencies may be involved in the process, as is the case with the Poolesville concern. By law, the Maryland Cancer Registry of DHMH collects cancer information each year from hospitals, laboratories, cancer treatment centers, and doctors on all new cancer cases diagnosed in Maryland (excluding some skin cancers).

* Step one: Gather and evaluate initial information about each cancer case thought to be part of a cluster: age, sex, type of cancer, year of diagnosis, and the geographic area of residence or work at the time cancer was diagnosed or at the time of potential exposure. This information is used to determine if the cases fit the profile of a true cancer cluster. One must verify to the extent possible that the reported "cancer" cases are truly cancer as some diseases may be mistaken for cancer yet be reported as part of a "cancer cluster." Investigators next ask about the primary location in the body of each reported cancer. Cancers that begin in different body locations generally have different causes and characteristics. Also, the initial location of the cancer may be different from the final location due to a process called "metastasis," where cancer cells move about the body, settle, and grow in other tissues. Cancer cells found in the brain, liver, or bone may actually come from a cancer that started elsewhere in the body (such as breast, prostate or colon). With respect to geographic place of residence at the time of diagnosis or exposure, if a cancer diagnosis was made when the person lived or worked in another location, then the person with cancer cannot be considered part of a suspected cluster in the current area or workplace. As more calls come in to our Department with concerns that a particular case may be related to a cancer cluster, we try to gather information about each one that may fit the profile to increase our available information. This timeframe will vary by the number of inquiries received.

* Step two: If the possibility of a cancer cluster cannot be ruled out after studying the initial information, we move on to conducting a preliminary statistical analysis. Montgomery County DHHS and DHMH have begun this preliminary statistical review but this may be altered by the additional information coming in. However, it is important to restate that we are trying to focus on similar types of cancers and not all cancers in Poolesville for the reasons stated in the general cancer facts above. We rely on statistical information from the Maryland Cancer Registry to evaluate whether or not the reported increase in cancer cases could have occurred by chance. The Registry data are available only to certain health officials in Maryland and the data are confidential and protected by law. The data ready for analysis lag behind by several years because cancers reported in the past several years may not be complete and verified and ready for use. The goal at this stage is to make a rough comparison between the actual or "observed" cancer cases, and the number of cancer cases to be expected based on known information about the cancer rate in the town, the county, or in Maryland as a whole. If the comparisons indicate that the observed number of cancer cases is less than the number of cases that would be expected to occur, then the suspected cluster is not "statistically significant" and either the investigation may be ended or a decision to monitor the situation into the future may be made. However, if the observed number of cases exceeds the expected number, then the possibility of a cluster cannot be ruled out and a more detailed investigation may be necessary. Because of the small population in Poolesville (less than 6000), it has been particularly difficult to make a determination of whether there is any pattern of increase or decrease. We must look at possible patterns based on various age groups and gender and other factors and then compare similar breakdowns to see what has been happening in the county and in the state; the small town numbers cause a lot of variation in the pattern when looked at by these categories or groups. If numbers are too few in a certain category, we just can comment on the statistics for that group. We are hoping to review these prelimainary results in the next several weeks, assuming there are no public health emergencies that will force a neceassary delay.

* It is important to note that the above analyses may not be conclusive and if the cancer rate for Poolesville exceeds what we expect for these similar cases, the analyses will not tell us why this is so.

* Step three: Further Investigation may be needed if the cancer data from the Maryland Cancer Registry show that the number of reported cases in the area is statistically significantly increased. In this situation, additional data would be collected with a goal to see what factors the cases may have in common. However, the determination of why the cancer risk is elevated would take a bigger investigation that may last months or years. In cases where a specific risk factor can be identified, measures for protecting the public and actions to remove the hazards would be implemented if exposure is ongoing.

* What interim recommendations?: To date, information of water testing results by your local jurisdiction with review by Montgomery County Department of Environmental Protection (DEP), repeat testing and sending the split samples to two different certified labs by Maryland Department of Environment (MDE) and U.S. Environmental Protection Agency (EPA) review do not suggest a problem with the drinking water in Poolesville over the time period of review. It is not my area of expertise to comment further on the subject of water quality and levels of contaminants in the water so you would need to direct your question to those agencies. Hence, pending results of our preliminary investigation, I can give no interim recommendations at this time other than some information on past investigations in other states and the U.S.

* The combined experience of many states and Federal agencies involved with cancer cluster investigations suggest that statistically significant cancer clusters are extremely rare. Only about 2 of every 1,000 reports of suspected cancer clusters reach the step where further investigation is required to identify common risk factors.

However, since we cannot predict the outcome of each preliminary investigation, every suspected cancer cluster report is treated seriously following the above steps until it is determined whether the reported cluster of cases was not greater than expected, whether the situation needs ongoing monitoring, or whether a true cancer cluster may have occurred and investigation or intervention is needed.

I hope this lengthy explanation addresses your immediate concerns. If you have other questions or wish to share a case of concern that you think may be related, pelase contact Colleen Ryan-Smith at the above email address and she will contact you.

Town Meeting, January 26

Tonight's (2009-01-26) town council meeting included a presentation by Dr. Ulder Tillman from the Montgomery County Department of Health and Human Services and Dr. Cliff Mitchell from the Maryland Department of Health and Mental Hygiene about the work done, and to come, evaluating the potential cancer cluster in Poolesville.

Below are my notes from the meeting. If I've missed something, please let me know by leaving a comment.

Notes
Drs. Tillman and Mitchell report that evaluation work has been going on for 6 weeks, spurred by a number of reports of calls MCDHHS received from the community. An initial evaluation of information from the Maryland Cancer Registry showed no evidence of an atypical pattern in the area, however, according to Dr. Tillman, "further evaluation is warranted."

The Maryland Cancer Registry receives reports of cancer diagnoses from Maryland area doctors, hospitals, and clinics. Complete data is currently available for 1994-2003 and data from the 2004 through 2006 period is expected shortly. Partial data is available from 1992, the inception of the registry, through 1994.

MCDHHS and MDHMH are in communication with the Centers for Disease Control and a formal request for the CDC's participation will be made. This request is expected to be accepted.

The initial phase will be to gather evidence and determine whether or not a non-standard prevalence pattern exists. Dr. Tillman says she expects to "return to you" in six months with information from this phase of the study. The report from that phase will examine overall prevalence as well as age, gender, length of residence, and cancer type trends. Dr. Tillman said that, given their relatively high rates in the general population, lung, breast, prostate, and colorectal cancers are not expected to be a main focus of the study. The geographic area which will be included in the study has not yet been determined.

Resident's with cancer diagnoses prior to 2006 who want to verify their diagnosis is included in the study can contact the Maryland Cancer Registry. Those with diagnoses since 2006 can be included by contacting the MCDHHS.

Contact Information
Montgomery County HHS Information Line: 240.777.1245
Montgomery County Department of Environmental Protection: 240.777.7700

Dr. Ulder Tillman, Mont. Cnty. Dept of Health and Human Services
Ulder.Tillman@montgomerycountymd.gov
Telephone: 240-777-1603
Fax: 301-279-1692

Dr. Cliff Mitchell, MD Dept of Health and Mental Hygiene
cmitchell@dhmh.state.md.us
Department of Environmental Coordination PR office: 410.767.6490
General Information: 410.767.6500 or 1.877.463.3464