Retired Philadelphia Phillies catcher Darren Daulton revealed he was diagnosed with glioblastoma. That makes seven Major League Baseball (MLB) players or managers to succumb to the disease in recent years. Is there a cancer cluster in baseball?
Baseball fans were jolted by the sad news that Daulton, 51, has been diagnosed with the aggressive form of brain cancer, which has a median survival rate of just 15 months and a five-year survival rate of 4%. Some people do defy those odds, and Daulton’s family and his legion of fans are rooting for him to be one of them.
But the news also raised a deeper kind of worry. Glioblastoma is a rare cancer, but it does seem to turn up with disturbing frequency in the MLB. The disease has claimed the lives of a near-All Star roster of names that includes Gary Carter, Dick Howser, Johnny Oates, Ken Brett, Tug McGraw, Johnny Vukovich and more in the past decade or so. This, not surprisingly, has led people to look for a connection between the cancer and the sport. Is there something about baseball—which involves nowhere near the ferocious contact that football does but does have its share of collisions—that is causing the trauma that leads to the disease? Daulton, Oates and Carter all played catcher, which is the most physical of all of the positions in the diamond. Is there something about a particular team or the geographic in which it plays? Brett, Oates, Vukovich and McGraw, like Daulton, spent at least part of their careers in Philadelphia.
Many of these questions were raised in 2011, when Carter’s diagnosis was announced. Doctors understand the human need to look for patterns and causes in the incidence of disease—indeed, that’s what the science of epidemiology is about. But in Daulton’s case, as in Carter’s and all of the others, there’s simply no plausible link. In 2011, Henry Friedman, one of Carter’s doctors and one of the deputy co-directors of Preston Robert Tisch Brain Tumor Center, associated with Duke University addressed the head trauma link first: “There is no data that relates concussions to brain tumors in any way shape or form,” he said bluntly, a conclusion that has continued to hold.
The much greater threat, as the National Football League is painfully learning, is brain damage that can lead to early-onset dementia, sometimes culminating in suicide. Chewing tobacco, which is still commonly used in baseball, is also a potential culprit, but again, there’s little plausible link. “Yes, it leads to cancer of the mouth and jaw,” said Friedman in 2011. “But even with some getting into the stomach and then into the bloodstream, it wouldn’t be in sufficient quantities to affect brain tissue.” Then, there’s the issue of steroids, which have been baseball’s long disgrace and still taint the sport. As I wrote when the Carter story broke:
Steroids…have long been linked with brain cancer in the public mind, at least since the death of NFL defensive lineman Lyle Alzado, who died of the disease in 1992 after a career of anabolic steroid use. He went to his grave blaming his doping for his illness. But while Alzado was a tragic authority on the multiple deadly effects of steroids, he wasn’t a doctor.
“Alzado had a brain lymphoma, he did not have a glioblastoma,” says Dr. Gary Green, medical director of Major League Baseball. What’s more, Carter and the other baseball figures who have contracted the disease played the game in the pre-steroid era, and they all got sick long after they retired from playing. Neurosurgeon Alex Valadka, Major League Baseball’s medical consultant on brain trauma, even points out that in some cases steroids are actually used to treat brain tumors. “When the brain is injured, it swells,” he says, “and steroids help bring that down.”
All of this suggests that Daulton, like Carter, Oates and the others, may simply be a victim of demographics, age and gender and nothing more. Glioblastoma strikes about 18,000 Americans per year, or .00006 of the 300 million U.S. population. About 1,600 men play in the MLB in any one season; over the course of 25 years that adds up only to about 5,200 individuals, since some play for years and years and others play for just a single season or less. Against that, the incidence of glioblastoma within baseball matches up pretty neatly with that in the overall population. And men, as a rule, have a higher incidence of the disease than women.
None of this is comfort for Daulton and his family, who are facing a challenging time. But it’s a reminder that disease clustering is often far more complicated than it looks, and that other players can safely hold Daulton in their prayers without worrying unduly that they’ll be the ones being prayed for next.