Show 1228: Why Clinical Trials Matter for COVID-19 and Cancer

Until December of 2019, doctors had no experience with pandemic that has now killed hundreds of thousands of people around the world. As the infection raced from country to country, they tried a lot of different treatments that seemed promising. But in many places, the onslaught of serious cases was so extreme that scientists couldn’t find the time and resources to test those therapies in clinical trials.

Should We Try First or Do Clinical Trials First?

Our guest, Dr. Vinay Prasad, is an expert on medical evidence. He regrets the lost opportunities to learn what really works for COVID-19. Similar waves of enthusiasm are common in his own field of cancer treatment. Sometimes, though, a therapy that seems like a really good idea doesn’t turn out to work as well in practice. Moreover, there’s also the question of side effects. How do we know which approaches will have unacceptable side effects unless we actually do controlled studies?

Overcoming the Confusion of Study Statistics:

It takes practice to be able to read reports on clinical trials and understand exactly what they are saying. Some basic statistics are also useful. Far too often, journalists or even study authors who want to impress their readers present their findings in terms of relative risk instead of absolute risk. What is the difference and why does it matter? How did this distinction trip up FDA Commissioner Stephen Hahn?

TV Drug Ads:

If you’ve ever watched television commercials for cancer drugs, you’ve probably encountered that type of statistical razzle-dazzle. Quite aside from the question of why companies run TV ads for drugs that will benefit very few people, if you are among that select few, you really need to understand the benefit. Also, you’ll want to pay close attention to the list of side effects. Some of them are nearly as serious as the disease the drug is supposed to treat. How can patients who’ve just received a frightening diagnosis, whether cancer or COVID, get reliable information about their condition and its potential treatments?

Screening for Cancer:

For decades, we’ve heard that early detection constitutes our best chance at defeating cancer. As a result, we may be encouraged to participate in screening procedures designed to pick up the first signals of prostate or colon cancer. How good are these tests, and how do we know they are good? Are there any harms that might result from finding a cancer that doesn’t need to be treatment? We’ll consider how to balance significant statistical evidence from clinical trials against unambiguous clinical benefit. Dr. Prasad advocates using real-world data in addition to clinical trials to evaluate the benefits and risks of tests and treatments.

This Week's Guest:

Vinay Prasad, MD, MPH, is a practicing hematologist-oncologist and Associate Professor of Medicine at the University of California San Francisco. He studies cancer drugs, health policy, and clinical trials and better decision making. Dr. Prasad is author of these academic articles, and the books Ending Medical Reversal (2015), and Malignant: How Bad Policy and Bad Evidence Harm People with Cancer (2020). He hosts the oncology podcast Plenary Session, and runs a YouTube Channel VinayPrasadMDMPH. He tweets @VPrasadMDMPH.
Audiobook version of the book Malignant - link to listen with a 30-day free trial of Audible: https://www.audible.com/pd/B08864KFHW/?source_code=AUDFPWS0223189MWT-BK-ACX0-195112&ref=acx_bty_BK_ACX0_195112_rh_us