Last night on the NBC News (and also on the same station the night before) I heard a report on a new cancer drug touted as being almost miraculous. The drug was called daraxonrasib, was described as working by blocking a mutated promoter of tumor growth in people with metastatic pancreatic cancer—a notoriously fatal disease (the median survival period after diagnosis of this stage is about 3-6 months, and the five-year survival rate is 3.2%). But the news confused survival time with survival rate, saying something like “the drug doubles the survival rate. . . .from 6 months to 13.2 months”. (I may have gotten the figures wrong as I’m working from memory.) I knew that something was wrong, as metastatic pancreatic cancer is almost always fatal, so the survival rate, which the percentage of people still alive after a specified period of time (often five years), cannot be expressed in months.
Sure enough, this mistake, expressing the effects as a doubling of survival rate, was not only misleading, but widespread. It’s easy to find similar errors in the press; just google the drug name and “survival rate”:
From CBS News (click all screenshots to read):
An excerpt (all excerpts are indented). I’ve put the confusing bits in bold:
A new, experimental medication nearly doubled overall survival rates for patients with advanced pancreatic cancer, according to the results of a study published Sunday.
Researchers say the findings are a significant marker of progress toward treating a notoriously deadly type of cancer, for which there have historically been limited effective options for therapies.
The drug is called daraxonrasib and it blocks a mutated protein that fuels tumor growth in more than 90% of pancreatic cancer cases — a target that had eluded treatment for decades.
“While not curing the cancer, it is a very large step forward,” said Dr. Zev Wainberg, of the University of California, Los Angeles, who helped lead the study.
The research team found that taking the medication, as a daily pill, reduced the risk of death by 60% for patients with metastatic, or spreading, pancreatic cancer who had previously received treatment. That was compared with survival rates of patients receiving standard chemotherapy, according to UCLA Health.
It randomly assigned the experimental drug or more chemotherapy to 500 patients whose metastatic cancer had quit responding to prior treatment. The findings were published in the New England Journal of Medicine and presented Sunday at the American Society for Clinical Oncology meeting in Chicago.
Those taking daraxonrasib lived for a median of 13.2 months compared with 6.7 months for chemotherapy recipients. While that may seem like a small improvement, Wainberg said it marked the first drug to show a substantial advantage over chemotherapy.
Note that while CBS says that it reduces the risk of death by 60%, there are NO DATA showing that. The risk of death is again nearly 100%, though survival time increases by a bit more than two. Also, “survival rates” have not been doubled. There are no data on that, at least not in the article.
From USA Today:
Excerpt:
An experimental drug nearly doubled the overall survival rates of pancreatic cancer patients, according to the results of its latest clinical trial.
The drug, daraxonrasib, targets the gene mutation behind most pancreatic cancer diagnoses.
In the phase 3, randomized trial, published in the New England Journal of Medicine on May 31, researchers found patients who received the drug lived a median of 13.2 months compared with 6.7 months for those who received chemotherapy.
They use “rate” but give “times.”
It’s easy to find similar conflations. This one, less excusable because of the venue, is from The Clinical Trial Vanguard:
They give the results correctly but characterize them as showing “death risk”:
A 60% reduction in the risk of death—HR 0.40—in previously treated metastatic pancreatic cancer is not a number the oncology community has seen before, in any phase 3 trial, in any line of therapy. That is the threshold RASolute 302 crossed. Revolution Medicines enrolled 500 patients, randomized them between once-daily oral daraxonrasib and investigator’s choice of standard cytotoxic chemotherapy, and watched median overall survival reach 13.2 months on the experimental arm versus 6.6 months on chemotherapy in the RAS G12 mutant population. Doubling median OS in second-line pancreatic ductal adenocarcinoma, a disease where incremental gains have defined ambition for decades, reframes what the endpoint space for this indication even looks like.
Nope; the chance of dying within a year or two remains about the same, I’d guess.
. . . and a post from someone on Facebook (I won’t give a name), touting a “60% reduction in the risk of death”. That’s wrong: the risk of death is probably still about 100%
The BBC gets it right, however:
This is correct:
A pill has been found to almost double the survival time for advanced pancreatic cancer patients, with experts describing the trial as a game changer.
The drug, called daraxonrasib, appears to be a breakthrough in managing a disease that has the highest mortality rate of all major cancers.
It helps prevent the spread of cancer by locking onto and shutting off the mutated KRAS gene, which is in more than 90% of pancreatic tumours and spurs cancer growth.
The trial, which included 500 patients in North America, Europe, and Asia, found the average survival time for patients on chemotherapy was 6.6 months, compared with 13.2 months for patients on daraxonrasib. It also caused fewer side-effects.
One other point: if “death risk” is meant to say “death risk over the course of the study,” then that might be accurate. But then the journalists must clarify it.
There are two points to be made, and they’re obvious. First, more than a few science/medicine journalists, including some writing on medical websites, don’t understand statistics, mistaking “rate” for “time”. I asked a science-friendly doctor if this mistake is common, and he replied, “All the time. Sometimes, I’m not sure it’s an unintentional mistake.”
Which leads us to the second point: this kind of conflation could provide false hope for cancer patients and their families. Knowing that you will live, on average, 6½ months longer if you take the new drug is a very different thing from knowing that you will still die with near certainty. It’s easy for one to think—and this is what I thought when I heard the teaser on television—that the drug will reduce the chance of dying by half. Seriously, journalists, please brush up on your statistics, for this one is not rocket science!
Good post on the use of survival rate vs survival time terms
The BBC got part of it right, but not this part: “locking onto and shutting off the mutated KRAS gene”. It does not “shut off a gene”. It (daraxonrasib) interferes with the activated RAS protein in a novel way. It does not affect gene expression, but it does affect protein function in cell signaling.
Pancreatic cancer is so difficult to treat that a significant increase in survival time is good news for some patients. It’s certainly too early to learn if appropriate treatment with this drug will lead to extended remission. A lot of us have personal experience involving friends or relatives who have succumbed to or are afflicted with pancreatic tumors.
Pancreatic cancer is a horrible disease, my wife was diagnosed in October of 2022 and lost her battle at the end of November 2022. Often by the time you have symptoms it is already stage 4. Even with these misleading statistics, I wish I had the chance to spend an extra 6 months with her.
I see this kind of thing all the time, journalists saying stuff that doesn’t even make sense when you read it carefully. I often wonder if they even know what they are saying. What I do hope is that the researchers and the people charged with drug approvals know how to interpret data.
We had a dear friend suffer from the disease for three years, before finally dying peacefully. My condolences go out to Lee Beringsmith (above), who had to endure tragedy at the hands of pancreatic cancer. The reporters may have made a mess of things, but if medical researchers are applauding the research, maybe there’s hope.