The cancer cluster conundrum

No two words send chills through a community like the term: cancer cluster.

Possible clusters have been discussed on Long Island for decades. Residents have cited toxic plumes, tainted water and contaminated air as causes of cancers in their neighborhoods. Yet as frightening as the term may seem, clusters aren’t easy to prove, even under the broader federal definition that has emerged in recent years.

The Centers for Disease Control and Prevention once defined the term as numerous cases of mostly rare and pediatric malignancies. Now, the agency defines it “as a greater-than-expected number of cancer cases that occur within a group of people in a geographic area over a period of time.”

In 2016, federal lawmakers approved the Frank Lautenberg Chemical Safety for the 21st Century Act, which includes a provision called Trevor’s Law. That measure addresses cancer clusters and childhood exposures.

The CDC has expanded its resources to bolster public understanding of how illnesses can be defined under the cancer-cluster rubric. This year, the agency received a $1 million federal allocation to broaden its cancer-cluster guidelines.

But obstacles persist for individuals attempting to prove their communities are making them sick. Part of that difficulty can be explained by this fact: cancer isn’t a single disease but more than 100.

Multiple influences — age, genetics, smoking, diet, obesity and other variables — all play roles in the transformation of healthy cells into malignant ones. Some cancers take decades to develop, and because people aren’t lifelong residents of a single community, it may be impossible to determine whether a cancer can be attributed to their most recent neighborhood.

For Long Islanders, legitimate concerns have arisen in communities ranging from Bethpage to Elmont to Shirley, among others. Worries have persisted for years.

In the 1990s, experts searched for an environmental source to explain elevated rates of breast cancer on the Island. Local scientists as well as teams of state and federal researchers concluded the cancers were most likely the result of expected causes — genetics, aging and later-in-life childbearing, all of which escalate risks for the disease.

When state health officials raised alarms in 2017 that elevated rates of four cancers had been identified in three communities — Centereach, Farmingville and Selden — fears of a cluster again emerged. After two years of examining why rates of leukemia, lung, bladder and thyroid cancers were unexpectedly high, officials last month attributed the malignancies to smoking, obesity, hazardous workplace exposures, and greater access to health care screenings.

The latter variable as an explanation for elevated cancer rates may seem confusing. But Dr. Shahriyour Andaz, a Long Island cancer surgeon, predicted more than seven years ago that early detection technology would impact cancer statistics in the near future. That future is now.

Andaz, director of thoracic oncology at Mount Sinai South Nassau in Oceanside, led the local arm of a clinical trial in the early 2000s. The study tested a screening method called spiral CT, a low-dose X-ray technique that detects early-stage lung cancers. There was no doubt, Andaz said, that screening would inflate the number of statistically significant lung cancers.

Now widely used, there has been a surge in the number of lung cancers diagnosed earlier. And while it is a good thing to catch cancers sooner, the technology injects another variable into the equation for communities that may, for instance, want to investigate potential airborne toxins, which they think are making residents sick.

In general, proving that local exposures are causes of a community’s cancer burden isn’t impossible to do. But it is becoming increasingly difficult.

Delthia Ricks is a former Newsday health writer.