A veteran medical writer once said there are only two types of cancer developments to report to the public -- "no hope" stories and "new hope" stories. On Wednesday, national attention focused on a "new hope," and the result for thousands of cancer sufferers was yet another emotional cresting of expectations.

Though the news was couched in caution, network television reports that the National Cancer Institute had been experimenting with a promising new cancer treatment prompted a flood of calls to the institute from desperate callers wanting to take part in the tests -- only to be told that NCI, with its limited facilities, was not accepting any new patients.

When newspapers headlined the story the next morning, the number of calls multiplied into the thousands.

While the news media generally reported that the treatment was experimental, had potentially dangerous side effects and was extremely expensive, those caveats went selectively unheard by thousands of cancer patients and their family members who grope every day for any sign that the elusive "cancer breakthrough" may be near.

"In many cases, these were people who had no other hope," said Judy Stein, project director of NCI's Cancer Information Service, which received an estimated 1,000 calls yesterday. "Their hopes were raised, and we kind of let them down," Stein said. "People grab onto things when they're desperate."

The latest news was the early success on fewer than a dozen patients of a novel technique that turns the body's own white blood cells into cancer-killers to attack tumors. This development in cancer treatment -- and the way the news was presented to the public -- illustrates the extreme sensitivity involved in reporting any news about battlefield victories in the seemingly intractable war on cancer.

The publicizing of this treatment also demonstrates the pitfalls of publicizing any news of medical advances, and the difference between what scientists and laymen might consider a breakthrough. Hopes were raised for a cancer breakthrough many times in the past, when thymidine was introduced in 1978, when laetrile was set for trial, and when interferon held out promise five years ago.

"For people who are not suffering from the disease, the tendency is to say any news is terrific," said Lois Callahan, public relations director of the American Cancer Society here. "But for anybody who's suffering from the disease, it's always frustrating to know there may be something on the horizon that may not benefit them."

The excitement over the new treatment, a form of immunotherapy, was pegged to the publication Thursday of an article in the respected New England Journal of Medicine. But the treatment, and its success in a small number of advanced-cancer patients, was already well-known in cancer research circles and was the subject of a cover story in the Nov. 25 Fortune magazine under the dramatic headline "CANCER BREAKTHROUGH."

The NCI was so cautious about its own testing that it unveiled the news not in a news conference, but in a routine "Update" bulletin mailed to reporters on Friday. Paul Van Nevel, NCI's director of communications, said the institute was torn between the excitement over what was viewed as a genuine advance, and the fear of needlessly raising expectations.

"We expected it was going to raise a lot of attention based on what was written in the scientific journals," Van Nevel said. "But instead it was just like an explosion."

NBC News sent its anchor, Tom Brokaw, to NCI to interview the head of the research team, Dr. Steven A. Rosenberg. ABC News anchor Peter Jennings interviewed Rosenberg through an electronic hookup. Both networks led their evening news shows with the announcement of the treatment and its success.

The CBS "Evening News" aired the report after an item about the resignation of White House national security adviser Robert C. McFarlane and the leave of absence of indicted NASA Administrator James M. Beggs.

Anchor Dan Rather began the report by saying he didn't lead the broadcast with the cancer story "because, frankly, we feel pretty strongly about not raising any false expectations."

The Washington Post ran the story on its front page in all editions. The New York Times ran an Associated Press report on page 19 of its final editions.

People in the cancer research community yesterday said they were satisfied that all the news media treated the story cautiously -- free of hyperbole and exaggeration. The resulting flood of telephone calls, they said, came because when any news about cancer is aired on television, patients tend to hear only what they want to hear.

"Even with all the caveats, people still want to hear that there's a breakthrough," Van Nevel said.

The treatment is scheduled for pilot projects at medical centers around the country. The only one yesterday to announce that it will begin experimenting with the treatment was the University of Wisconsin Cancer Center in Madison, which will accept 18 patients.