President Reagan will have a skin cancer surgically removed from the tip of his nose today at Bethesda Naval Medical Center, the White House announced yesterday, the third such growth to be removed during his presidency.

The operation was scheduled after tests on a small piece of skin from the area revealed a basal cell carcinoma, the same type as two skin cancers taken from the president's nose in 1985.

"Oh, my nose gets laughs all the time," Reagan told reporters at the White House who asked him yesterday if the problem was serious. He added, "I went out into the sun too much and they have to do a little peeling here on the end of my nose."

The operation will be performed late this afternoon under local anesthesia, and the Reagans have canceled plans to spend the weekend at Camp David, White House press spokesman Marlin Fitzwater said. Fitzwater said doctors would decide after the surgery whether Reagan would stay overnight in the hospital.

Performing the procedure will be Capt. Theodore Parlette, chief of dermatology at Bethesda naval hospital, Army Col. John Hutton Jr., the White House physician, and Rear Adm. William M. Narva, the physician to Congress, who is also a dermatologist, Fitzwater said.

Skin-cancer specialists said yesterday that the discovery of a third cancer on the president's nose was not surprising because such growths are extremely common on the faces of fair-skinned, older adults who have spent a lot of time outdoors. Reagan, 76, has long enjoyed horseback riding and other outdoor recreation.

The risks of the type of surgery Reagan will undergo "are close to zero," said Dr. Philip G. Prioleau, director of dermatologic surgery at New York Hospital-Cornell University Medical Center.

Prioleau said basal cell skin cancers "are not really true malignancies," because they cause only local damage and do not spread to other regions of the body. But he added that growths on the tip of the nose are often technically more difficult to remove than those in other areas, sometimes requiring a skin graft to replace the missing patch.

"The tip is the worst area from a reconstructive standpoint," especially in older men, he said. "It's very thick, heavy skin. You try to do as little as possible to get the best cosmetic result."

Fitzwater said the skin sample taken from the growth Wednesday for testing was "two to three millimeters in size," and test results showed that "further excision of tissue" was necessary.

Prioleau said the president's doctors would probably use a procedure called Mohs' technique; The visible growth is first removed with a scalpel, then the surgeon takes a thin, saucer-shaped sample of skin from the base and margins of the wound and sends it to be frozen, cut into thin sections and microscopically examined by pathologists to see if any cancer cells were left behind.

Prioleau said the advantage of the technique is that the surgeon learns within about half an hour whether the skin cancer has been completely removed or whether more tissue should be taken.

Alternatively, he said, surgeons might simply remove the portion of skin containing the growth and send it to pathologists to be chemically treated and examined, a process that takes a day or two.

Prioleau said more than 500,000 skin cancers occur annually in the United States and that "the vast majority" are basal cell carcinomas. He said more than 80 percent of basal cell carcinomas are found on the face, head and neck, and that almost all such cancers are caused by damage to the skin from decades of exposure to sunlight.

Prioleau said that someone who has had one basal cell carcinoma has a 36 percent chance of developing another within five years.

Reagan had a basal cell skin cancer removed from his nose on July 30, 1985, about two weeks after surgery for colon cancer. That episode set off a battle with reporters because the White House did not report the operation until two days later, and did not at first say that it involved skin cancer. A second basal cell skin cancer was removed from Reagan's nose on October 10, 1985.

Fitzwater said yesterday that Reagan's doctors have made "continuous" observations since 1985 to check for further skin cancers. He said no additional medical tests or procedures were planned for today.