When Alex Trebek recently went on national television and described the excruciating belly pain he had experienced due to chemotherapy for Stage 4 pancreatic cancer, it was a moment unlike any other in the history of celebrity illnesses. Trebek rated the pain, which he experienced during the taping of “Jeopardy,” an 11 out of 10 and admitted that upon returning to his dressing room, he “writhed in pain and cried in pain.”

Trebek’s forthrightness highlights how, increasingly over the past 75 years, famous people who become seriously ill have struggled with the issue of disclosure: Should they reveal what is happening or keep it secret? Celebrity illnesses have been important educational moments for both the media and the public, and the growing spotlight of the Internet has accelerated a trend toward more disclosure.

Yet, in their admirable quest to fight diseases in the public eye, these celebrity narratives have also pushed stories that give hope but also misinform. Trebek’s story, which is truly moving and admirable, is notable not only for his disclosure of personal medical details, but also for its honesty about the challenges he is confronting.

For centuries famous people went to great lengths to conceal illness. Disclosure, they believed, would both violate their privacy and make them look vulnerable. Presidents - Grover Cleveland, Woodrow Wilson and John F. Kennedy, to name a few - have long hidden diseases, ranging from cancer to stroke to failure of the adrenal glands, in efforts to maintain an image as healthy and capable leaders.

The rise of celebrity culture in the 1920s brought new people into the media spotlight, and their personal lives became fair game. When actor Rudolf Valentino and illusionist Harry Houdini both unexpectedly died of abdominal infections in 1926, their illnesses were very public events. In the case of Valentino, fans held a vigil outside a New York City hospital until the actor succumbed. Houdini’s obituary in the New York Times dutifully discussed how a ruptured appendix led to streptococcal peritonitis, and speculated whether playful punches that Houdini had received might have contributed to his demise.

Yet, despite this increased attention to personal lives, coverage of illness concealed as much as it revealed. Not only was available information often incomplete, but it also accentuated the positive. After all, didn’t celebrities always receive the best medical care?

This pattern was exemplified by Lou Gehrig, the durable New York Yankees first baseman who was diagnosed with amyotrophic lateral sclerosis, a severe neurological disorder, in 1939. With Gehrig’s permission, the Mayo Clinic announced his ALS in a news release that was covered on the front page of hundreds of newspapers. But these stories notably omitted any discussion of how the disease was universally fatal, avoiding interviews with neurologists who might have been more forthcoming.

Instead, subsequent news reports focused on Gehrig’s participation in a clinical trial of vitamin E to treat ALS, noting his “somewhat improved” status, even though vitamin E was ultimately shown to have no effect on the disease. So, when Gehrig deteriorated in 1940 and passed away the following year, the public was shocked. Medical statistics could easily have predicted his death, but the hope that permeated press coverage notably ignored this reality.

A similar optimism shaped coverage of Margaret Bourke-White, the prolific and pioneering female photojournalist for Life magazine, after she was diagnosed with Parkinson’s disease in 1957. Two years later, a photo essay in Life with the title “The Famous Lady’s Indomitable Fight” featured an experimental brain operation she had undergone to improve her stiffness and hand tremor. Bourke-White called the surgery a “gift.”

The reality was different, however. Whatever positive effects Bourke-White may have experienced diminished over time, and a second operation in 1961 was unsuccessful. The majority of the public would not have known this, even though Bourke-White kept up an admirable and honest correspondence with many fellow Parkinson’s sufferers before dying in 1971. Why? Because when she became increasingly immobilized by the disease, journalists lost interest.

Upbeat narratives were much easier to tell when the outcomes were actually positive. During the 1970s, three famous women - actress and diplomat Shirley Temple Black, then-first lady Betty Ford and philanthropist Happy Rockefeller - all developed breast cancer and went public with their stories. All three gave vivid details of their breast surgery and urged other women to examine their breasts and get annual mammograms. Given how shrouded in secrecy breast cancer still was at the time, these revelations provided an enormous education for American women (and men). Such stories helped to promote Richard Nixon’s “War on Cancer.”

Over time, the reality of serious illness has received greater coverage. In 1994, for example, the family of Jacqueline Kennedy Onassis announced she was declining additional chemotherapy for her non-Hodgkin’s lymphoma and was going home to die. Indeed, by the 1990s, it was becoming difficult for famous people to conceal their illnesses. The growing obsession with celebrity meant it was simply harder to disappear from sight when you were sick - especially with serious diseases.

There were other reasons for this new honesty. Certain celebrities relished the opportunity to educate others even in the face of their impending mortality. Others saw candor as a way to control stories that were certain to generate gossip. For instance, actor Michael J. Fox, who was diagnosed with Parkinson’s disease in 1991 at the very young age of 29, has been quite frank about the deteriorating course of his disease. Fox has made a point of appearing on television while experiencing severe jerking movements that probably made some viewers uncomfortable.

Despite this growing openness among seriously ill celebrities, Trebek’s story is still striking for its immediacy and honesty. On March 6 of this year, he announced he had incurable Stage 4 pancreatic cancer. Not only had Trebek recently learned of the diagnosis, and thus not had much time to process it, but he also released his news online via a video. The same man who amicably read the answers on “Jeopardy” was calmly telling viewers he had a fatal disease. The video was far more dramatic than a news release or even a news conference and was thus a great educational moment. In fact, several of my patients have asked me about pancreatic cancer screening in the wake of Trebek’s news.

Trebek provided even more vivid information on May 12 on CBS’s “Sunday Morning,” when he described the excruciating stomach cramps that he attributes to his chemotherapy. In so doing, Trebek was thoroughly rejecting the old calculus in which ill celebrities concealed information so as not to appear vulnerable.

Yet at the same time, Trebek has continued to overemphasize hope. When initially diagnosed, he said he planned “to beat the low survival rate statistics for this disease.” “Keep the faith,” he added, “and we’ll win,” even jokingly remarking that he needed to survive at least three years to fulfill his “Jeopardy” contract.

Although it may seem odd that celebrity illnesses matter, they do. As one woman with Parkinson’s said of Fox, “I just tried to follow right behind him and step in the footprints.”

But Trebek’s case reminds us of the complicated nature of these narratives. Although they can alert the public to diseases and the latest scientific knowledge, they are ultimately individual stories and depend on who is telling them and what they are willing to say. Just as ordinary people may have difficulty accepting their own mortality, the same is usually true for famous patients. Indeed, as public figures, celebrities may even feel an obligation to be optimistic and inspirational.

So let’s wish Trebek the best and appreciate how he has handled such a major personal challenge with grace, equanimity and even humor. But let’s also recognize the limitations of what we can learn from his story.

Barron H. Lerner, professor of medicine and population health at New York University Langone Health, is the author of “The Good Doctor: A Father, A Son and the Evolution of Medical Ethics.”