Tears came to Leverne McLean's eyes Monday when he spotted the nasogastric tube in President Reagan's nose in a newspaper photo. He remembered how a similar tube had felt when he awoke after having the same operation in November 1982.

"I know what he's going through," he said.

McLean, a 43-year-old food clerk at a Northwest Washington Safeway, was one of several people interviewed who have undergone the operation -- a right colectomy -- for cancer or for precancerous growths. All have been following the news of Reagan's hospitalization eagerly, comparing reports of his progress with their own.

Besides wishing him well, several wanted to offer advice.

"I'd tell him to walk," said Agnes Hutchison, 65, a retired medical-records specialist from Chevy Chase who had surgery in September 1984. "Every pain I had, everybody told me, 'Walk,' so I just about wore out the halls of Sibley Hospital . That's what did the trick. That's what brings the system back to normal."

Several former patients said they doubted that Reagan will feel like riding a horse by mid-August, during his scheduled vacation at his California ranch.

"I don't think I would suggest that," said James J. Seaberry, 67, a Chicago lawyer whose operation in May 1982 differed slightly in that it was done to remove a growth on the left side. "There's a certain vibration and jarring when you ride a horse, and that's not good for the incision," Seaberry said. "It does irritate the insides."

Most of those who had undergone right colectomies said their energy level returned to normal one to two months after the operation.

Based on their own experiences, they found the public statements by Reagan's doctors about his recovery realistic.

"He has a lot of stamina," said McLean, who went back to work lifting cartons of produce about two months after his operation. "He'll bounce back. I was able to. I do a lot of physical work. His work is more or less mental."

But Dr. Jesse Edwards, 74, a professor of pathology at the University of Minnesota Medical School who had a right colectomy in May 1983, said he thought that Reagan's physicians and aides were overestimating the capacities of someone who had just been through a serious operation.

"During the whole hospitalization you're not feeling well," he said. "You're getting no solid food. Your belly is still sore. You're washed out."

Edwards said he thought that having staff members come into the president's hospital room to confer and ask questions "would be a tremendous drain . . . . I can't envision, during the entire period he's in the hospital, that he's going to be up to doing very much listening and thinking and considering . . . . "

Edwards and the others interviewed said pain was not a major problem after the operation. None experienced severe abdominal pain, although all had some soreness at the site of the incision, especially when they tried to get in and out of bed.

They recalled being eager for the bowels to resume functioning, so that the nasogastric tube -- used to keep the stomach empty of gas and fluid after surgery -- could be removed and they could begin to eat.

Edwards said that, much to his surprise, when he was allowed to eat "food didn't taste very good at first, although I was hungry and anxious for it." The next morning, however, "they gave me an ordinary breakfast and I wished I could have some more."

Like Reagan, several of those interviewed had to come to terms with the news of cancer soon after their surgery. "When they told me . . . I don't like that word, 'cancer,' " said Agnes Foster, 73, a Riverton, N.J., housewife who had a right colectomy last December at Georgetown University Hospital. "But when they told me everything was all right, I felt more at ease."

"I never was terribly upset with the word given to me that I had cancer," Edwards recalled. "For one reason, somehow the word 'small' kept slipping in . . . . I got a certain amount of solace from that, though, as a pathologist, I had seen cancers smaller than your little finger that spread all over the body like crazy."

McLean said that until his operation, his doctors thought he had a different disorder, Crohn's disease. After his surgery, his physician, Dr. LaSalle D. Leffall of Howard University Hospital, told McLean's wife that he had had cancer.

"She knew. I didn't," he said. "My recovery probably went better because I didn't know until I went back for my checkup."

All of those interviewed predicted, based on their own experiences, that Reagan would tire easily for several weeks. They offered opinions about how stress might affect his recovery.

"Nobody knows how hard it is to be president," said Dr. Saul L. Fox, a semiretired physician in Los Angeles who had a right colectomy. Fox, who declined to give his age but said he was "younger than the president," said stress would be a more important factor for a heart-attack victim than for a patient recovering from intestinal surgery. "You can get a heart attack from stress, but you can't get cancer from stress," he said.

Hutchison expressed confidence that Reagan would be able to pace himself. "From what I read, there are a lot of pressures on him, but I think he's a man who seems able to deal with it," she said. "I have a feeling he'll do just fine, the way he did after the assassination attempt."

Reagan underwent surgery in 1981 to remove a bullet from his chest.

Edwards said he doubted the president would have energy for public appearances soon, although White House spokesman Larry Speakes said Reagan plans to greet President Li Xiannian of China next Tuesday. "If a man had a choice for an occupation following a cancer operation," Edwards said, "I would not pick president of the United States."