By Lydian Kennin
On Jan. 28, the Southern NH Division of Public Health Services (DPHS) Department of Health and Human Services (DHHS) conducted a public information meeting to address concerns about Polyfluoroalkyl substances (PFAS) and their cancer risks in the local area.
In 2016, PFAS were found in drinking water in the Merrimack Valley District (MVD) Water System. In January 2018, the DHHS published the Merrimack Cancer Report, which found that “No cancers associated with PFOA were found to be higher than would be expected.” In 2021, the DPHS reinvestigated this concern and discovered new data on higher-than-usual kidney cancer rates that led the group to conduct a new study.
The DHHS analyzed data for 27 different cancer types in Merrimack and found that the results were consistent with the initial report from 2018, but there was “some evidence” of an association between PFAS and the following types of cancer: Kidney, Testicular and Pancreatic.
The DHHS has looked at cancer data for Merrimack, Litchfield, Bedford and Londonderry. Other towns will be included in the DHHS’s “case definition” because it will provide a larger sample for cases and controls and there is a concern about PFAS exposure and related health impacts in additional areas.
Population Health Bureau Chief Sai Cherala, MD MPH, introduced the discussion by acknowledging the public’s concern for safety.
Cancer Program Administrator Whitney Hammond, MSW MPH, led the meeting by addressing the protocol and steps the DHHS has and will be taking henceforth.
In the 2021 study, the DHHS found a higher number of people with kidney and renal cancers in Merrimack. 66 cases were observed compared with an expected 47 cases between 2009-2018. The group found this to be “statistically significant.”
“Does this mean that there is something in Merrimack that is causing Kidney and Renal cancers? We don’t know,” Hammond said. She emphasized the limitations of the data and reiterated that the DHHS is doing everything in its power to find answers as quickly as possible.
In response to public safety concerns such as this, the DHHS convenes the “Cancer Concerns Review Team” or CCRT to include a full range of expertise in the following: cancer epidemiology, environmental epidemiology, risk communication, cancer prevention, guidelines on cancer cluster investigations, and familiarity with the geographic area and environmental concerns of the community.
As a part of the investigation process, the DHHS utilizes the Standardized Incidence Ratio (SIR).
“The Standardized Incidence Ratio is what is recommended by the CDC as the way we look at cancer in a community,” Hammond said. “We calculate it to give us an estimate of the likelihood that there’s an excess of cases in a certain population of concern.”
Since cancer rates vary by age, the SIR calculates “age-specific” rates, which takes into account the actual age distribution of a population. The SIR is the recommended measure for comparison of cancer in small areas with small numbers of cases rather than comparison of age-adjusted rates. It provides a “signal or indicator” that can lead to further investigation.
Hammond compared the urgency of the SIR to that of a check engine light versus other more serious indicators that can light up on a car’s dashboard. “The SIR is not like that. It’s more like your check engine light. It’s a signal that something could be going on, but it doesn’t tell you what’s wrong.”
The DHHS has operated its response to their findings in three phases.
In Phase One, the DHHS opens to questions and concerns from the public and typically responds to calls and emails within two business days. The DHHS shares a “conclusion summary” with inquiries and logs the concerns on its public website.
In Phase Two, the DHHS conducts a review of NH State Cancer Registry (NHSCR) data and then convenes the Cancer Concern Review Team (CCRT) for input to decide whether or not further investigation should occur. All conclusions and next steps are shared publicly.
In Phase Three, the DHHS convenes CCRT and experts to determine whether or not a new study is feasible. The DHHS then convenes a Community Advisory Group (CAG) to inform the investigation.
“The government isn’t known for moving quickly. It will take time,” Hammond said. “We will do our best to cast a wide net.”
For any public health related questions or concerns, the DHHS accepts inquiries by phone (603) 271-4959, (603) 271-9389 and by email DHHSCCRT@dhhs.nh.gov.