Choosing the Right Group to Compare: How It Changes Cancer Outlook for WTC Responders

You're trying to figure out if a certain group of people, like those who worked at the World Trade Center (WTC) after the 9/11 attacks, have a higher chance of getting cancer. You'd compare their cancer rates to another group, right? But which group? That's where things get interesting. A study looked at 65, 691 WTC-exposed responders between 2002 and 2015, using data from 13 state cancer registries. They found that the choice of reference group can really change the results. For prostate and thyroid cancer, WTC responders had a higher chance compared to people from New York City (NYC), New York State (NYS), and the US as a whole. But for colon and lung cancer, their chances were lower. The range of these chances varied based on the reference group. Some cancers showed mixed results, depending on who they were compared to. There was a specific change in prostate cancer rates, but only when compared to the whole US population. The main takeaway? Picking the right group to compare can change not just the chance of getting cancer, but also when that chance changes, and how significant it is. It's like looking at a painting from different angles—you see different things each time.