|Data on cancer cases are compiled into state-level registries reported to a national system overseen by the Centers for Disease Control. Above, a student fellow at the National Cancer Institute, another key partner in the national registry system. Photo: National Institutes of Health/David Sone, Flickr Creative Commons. Click to enlarge.|
Reporter’s Toolbox: When Reporting on Toxic Hotspots, Go Deeper With Cancer Registries
By Joseph A. Davis
Few environmental journalists spend much time exploring cancer registries — a key source of data that can deepen investigations of toxic pollution. There are reasons for this neglect, but it’s an unfortunate oversight given the growing attention to cancer-causing pollution.
Most actual U.S. cases of cancer are scrupulously recorded. Data are collected by hospitals and doctors, compiled by individual states into “registries” and ultimately reported to a national system overseen by the Centers for Disease Control. If you want to study the connections between pollution and cancer, this is a good place to start.
The obstacles, however, are daunting. The need for patient confidentiality means data are anonymized and available only at an aggregate level. The spatial resolution of data readily available to the public (and therefore journalists) is rarely finer than the county level. Even when you have the data, the challenges of connecting cancer data causally to pollution data remain huge.
Environmental journalists may be inspired by ProPublica’s recent masterful data project exploring the connections between toxic air pollution and cancer risk (Toolbox wrote about it in a recent column). If you are following up locally and using ProPublica’s incredible map tool, you may want to dig further into relevant cancer registries.
Refineries and chemical plants emit huge
quantities of pollution to air, water and land,
and the exposed front-line neighbors often suffer
from diseases ranging from asthma to cancer.
The main outlines of the larger story have never been a mystery. Refineries and chemical plants emit huge quantities of pollution to air, water and land. That pollution is poorly regulated by state agencies and the U.S. Environmental Protection Agency.
The result is toxic exposure to the people living nearest to the plant — too often poor people of color who lack political power. As a result, the exposed front-line neighbors often suffer from diseases ranging from asthma to cancer.
Journalism can help. As good as it was, the ProPublica project looked mostly at reported pollution and resulting cancer risk based on modelled exposure. Cancer registries can sometimes translate that into actual disease and even deaths.
The data landscape
Most states have cancer registries. The CDC helps fund them in 46 states, the District of Columbia, Puerto Rico, the Pacific island jurisdictions and the U.S. Virgin Islands. Some are listed here, but you might as well Google “cancer registry” and the name of your state. Each works a little differently, and most are prescribed by state and federal law.
The data have everything to do with the origins of the cancer: age, gender, ethnicity, site of cancer, place of residence, treatment, outcome, survival and more. Toxic exposure, while important, is not the only way cancer can get started. Genetics and poverty, for example, matter too.
The hierarchy of data sources is also key. A hospital may have its own registry, as may a pathology lab. Information also comes from radiation centers, diagnostic centers, surgical centers, etc. There are special purpose registries for other uses. For instance, some may be just for Native tribes. Eventually all of it gets gathered at the state and federal levels.
The National Program of Cancer Registries, part of the CDC, collects it all at the national level and sets standardized data formats. It also produces reports summarizing and interpreting the data, for example, via U.S. Cancer Statistics, which is not merely a book, but an array of visualization tools and specialized reports.
Another key partner in the national enterprise is the National Cancer Institute, which is engaged in treatment and research and is a component of the National Institutes of Health.
Using the data smartly
There are lots of places in the huge corridor loaded with chemical plants between Baton Rouge and New Orleans where people who are often poor and often Black say pollution is causing cancer. They have named it Cancer Alley. It has been news for decades.
There are lots of other such problem spots. It’s easy to get excited about possible “cancer clusters,” the occurrence (real or suspected) of a greater-than-expected number of cancers within a certain population. It may be a neighborhood or it may be something else, like a factory.
It takes more than anecdotes
to verify a causal connection
between pollution and cancer.
Clusters are often quite hard to authenticate (although that’s certainly no reason not to investigate). Such stories often start out with anecdotal information (“It seems like everybody on my block has some cancer in the family.”). Yet it takes more than anecdotes to verify a causal connection between pollution and cancer in these cases.
The CDC offers some basic guidelines. But to assess one, you have to know what the expected incidence of cancer is in that population. This is a matter for statistics in the mathematical sense (see U.S. Cancer Statistics, above).
Causality is easier to see when most everybody in the population of concern has the same kind of cancer. And even easier when you can identify a common exposure to a specific cancer-causing class of chemicals associated with that type of cancer. Talk to cancer experts about these connections, some of which are known.
Talking to the experts
Unfortunately, things are rarely that simple. For example, look at the Love Canal incident in 1970s Upstate New York. It took years to sort out, involving at least 82 toxic compounds, 11 of them suspected carcinogens. Ultimately, it led to the Superfund hazardous waste cleanup program.
Resolving such horrors has over the years become a major mission of EPA and other agencies (some at the state level, including health departments).
Talk to these experts — but talk to others as well, such as those at universities and research institutions, or at the National Institute of Environmental Health Sciences.
A key agency to consult may be the Agency for Toxic Substances and Disease Registry, created by Congress for the express purpose of helping communities deal with toxic incidents and concerns. It has intervened in hundreds of toxic incidents. Historically, though, it has not always sided with communities.
Certainly talk to the folks behind the cancer registry in your state — get all the data and perspective you can from them. Finding a researcher or science program to partner with on your story may be wise for many reasons. The most important is that they may have better access to the data than you do as a journalist.
Joseph A. Davis is a freelance writer/editor in Washington, D.C. who has been writing about the environment since 1976. He writes SEJournal Online's TipSheet, Reporter's Toolbox and Issue Backgrounder, and curates SEJ's weekday news headlines service EJToday and @EJTodayNews. Davis also directs SEJ's Freedom of Information Project and writes the WatchDog opinion column.
* From the weekly news magazine SEJournal Online, Vol. 6, No. 44. Content from each new issue of SEJournal Online is available to the public via the SEJournal Online main page. Subscribe to the e-newsletter here. And see past issues of the SEJournal archived here.