If Fred Thompson moves forward with a run for the Republican nomination, the former Tennessee senator will not be the first serious candidate to run for president after having undergone treatment for non-Hodgkins lymphoma. That form of cancer was what drove Paul Tsongas of Massachusetts out of the Senate in 1983 — enabling an ambitious Vietnam veteran, John Kerry, to run for his seat.

Tsongas was a quixotic presidential candidate who used his proximity to New Hampshire, the large cities of the state’s southern tier near his Lowell home, and his Yankee-like fiscal sobriety. His campaign’s trademark was its distribution of a booklet, “A Call to Economic Arms,” at all stops. His defining issue was fiscal conservatism, and his seriousness appealed to those Democrats put off by the flurry of personal allegations surrounding the campaign of then-Governor Clinton. Tsongas’s financially strapped campaign met with success in the Northeast. He appeared poised for a strong showing in New York when he abruptly dropped out of the race on March 19, 1992.

The image that reverberates through the years from the Tsongas candidacy is the one of the lanky Greek-American wearing only a Speedo swimsuit, swim goggles, and a bathing cap. Tsongas, a habitual swimmer, made public his athletic regimen to offset concerns about his health. The campaign even aired a television ad of the candidate swimming laps in an Olympic-size pool.

Tsongas nonetheless faced questioning about his health throughout his presidential quest. The campaign’s chief inquisitor of health-related issues was a medical doctor who often wrote on the health of public figures for the New York Times, Lawrence Altman. The Tsongas campaign put forward one of his doctors, Tak Takvorian, to discuss the candidate’s health after the his primary victory in New Hampshire. “There was no hint of a problem,” Dr. Takvorian said of tests Tsongas had undergone. “At the moment, it would appear to be clear sailing.”

Less than a year later, Tsongas received some bracing news. His cancer had returned. As part of his announcement, Tsongas also acknowledged that he had had a recurrence of cancer in 1987; the lack of clarity around this episode was something for which he said he had “paid a price.”

Speaking to Dr. Altman, he called for a national commission to help manage the amount of medical disclosure candidates had to engage in. In the month that would have marked the start of his second term of office, if elected and re-elected, he died.

At this point, it is much too early to equate Tsongas with Mr. Thompson. No two patients’ medical conditions are exactly alike. Under federal law, only the patient or his or her medical caregiver can share details of the patient’s health condition and treatment.

But it is incontrovertible that in today’s press and political environments, candidates have far less of a zone of privacy than they had in Tsongas’s day. One reason John Edwards had to be so public about the return of the cancer of his wife, Elizabeth — something that would have appeared unseemly a generation or two ago — is the demand of the presidential press corps. Given the 24-hour news cycle, Internet news sources, and bloggers, candidates for the nation’s highest office have to deal with these issues whether they want to or not.

Think, for instance, of how few photographs exist of Franklin D. Roosevelt wearing his braces for polio or sitting in his wheelchair, or how little the public knew about the poor health of John F. Kennedy. Today’s candidates don’t have those options. If they run, they have to talk about things they would ordinarily seek to keep private. Perhaps it is a product of our Oprahfied world, but once candidates make a disclosure like Mr. Thompson’s, there’s no downside to making the most of it — both for the candidate and the country.

During his campaign, Tsongas became a symbol of fighting cancer. At one campaign appearance at the University of Maryland, a young man struck up a conversation with Tsongas, who stopped to talk with him. The story was that some months earlier the young man had been diagnosed with a particularly virulent type of cancer and wrote to Tsongas for support.

Tsongas telephoned the young man and urged him to take heart, even when the doctors’ forecast looked grim. “Don’t quit. Fight it,” he told the patient. “They don’t know everything. You can beat this.” After the man heard from Tsongas, his condition began to improve, prompting him to find seek the candidate out at the University of Maryland.

It’s likely that Tsongas believed that what he said applied not only to that young man, but also to himself. Belief like that is what would inspire a candidate with an unlikely cause — deficit reduction — and a hard-to-pronounce last name to seek the presidency in the first place. Given the way Mr. Clinton appropriated much of Tsongas’s fiscal mantra when he took the White House, Tsongas, although he would not have survived his second term had he been in office, certainly touched the political scene in a way he never would have had he not run for president.