Can we agree to stop calling it the cancer moonshot?

That’s how President Obama referred to a renewed effort to cure cancer in his State of the Union address last month, which Vice President Joe Biden would lead.

“I’m putting Joe in charge of Mission Control,” Mr. Obama said in the speech. “For the loved ones we’ve all lost, for the families that we can still save, let’s make America the country that cures cancer once and for all.”

When the White House later released the details of that “National Cancer Moonshot,” the budget was close to $1 billion. One billion dollars.

You can see why the news media has latched on to the phrase. “Moonshot” has echoes of President’s John F. Kennedy’s stirring 1961 speech in which he called for a space program that could send a man to the moon and return him safely — a goal that was achieved only eight years later.

It’s become a popular metaphor for national cancer cures. In 1971, President Richard Nixon announced his so-called War on Cancer in his own State of the Union speech. Here’s what he said: “The time has come in America when the same kind of concentrated effort that split the atom and took man to the moon should be turned toward conquering this dread disease.” When George W. Bush was running for president in 2000, he, too, called for a “medical moonshot” to cure cancer.

Even fictional presidents have made the moon landing comparison. In an episode of the “The West Wing,” staff members were drafting language for a State of the Union address that cited the moon landing as evidence that a cancer cure could be achieved within 10 years. In the show, the proposal was cut from the speech.

The moonshot metaphor is appealing because it describes a seemingly impossible task that was nevertheless achieved through good old American know-how and lots of federal spending. Decades of research have suggested, however, that the NASA space program is not a good comparison.

That has become increasingly clear since Nixon began the National Cancer Institute with $100 million. At that time, many scientists thought cancer was a single disease that might be cured using a single strategy. There was little government research into cancer and little focus on it. At that time, the space comparison made sense.

Mr. Biden’s priorities emphasize just how much that thinking has changed. We now know that cancer is not one disease, but many, with complex causes and triggers, and that there will be no single cure for all of them. Just look at the array of initiatives included under the moonshot banner: vaccines for some cancers, combination drug therapies for others, immunotherapy treatments for still other types.

Cancer treatment has, of course, improved significantly since the 1970s, and there are many opportunities for improvement. But the fight against cancer has increasingly become more fragmented and subtle, with some of the most promising new treatments being used on only the narrowest slices of patients.

The name suggests a broad, revolutionary new set of initiatives, but the Biden program’s funding represents a tiny fraction of the current national spending on cancer research. The total — nearly a billion dollars — sounds like a lot when compared to the recent Powerball jackpot — or even Nixon’s initial investment of $600 million in inflation-adjusted dollars — but it really isn’t much money, as even Dr. Evil eventually comes to realize.

It’s a small component of the nearly $4 trillion federal budget. As health reporters at Bloomberg and pointed out recently, the original moonshot cost $160 billion in today’s dollars; the annual budget for the National Cancer Institute is $5.2 billion; and the Tufts Center for the Study of Drug Development estimates that bringing a single new drug to market costs about $1.4 billion (though my colleague Aaron Carroll has argued that number is inflated).

The prospect of additional cancer funding has been welcomed by researchers, who have not enjoyed the usual funding increases in recent years as the budget has gotten tighter. But that does not mean $1 billion will transform their work.

The White House can call it a National Cancer Moonshot. But the rest of us don’t have to.