"The Cancer Confrontation" is an hour of human bravery that takes some measure of courage just to watch. The program, an attempt to replace myths and fears about cancer with solid facts and information, airs as an exemplary public service at 8 tonight on Channel 5.

In conjunction with this broadcast, the Howard University Cancer Center here will open its telephone lines to the public, for questions about cancer and its treatment, during and after the program, until 10 p.m. The center's information service phone number is (202) 636-5700.

Daniel J. Travanti, of "Hill Street Blues," narrates the one-hour film, which opens with Travanti saying, "This is cancer," over microscopic photographs of cancer cells. A number of cancer patients are seen dealing with the disease, and the lessons to be learned from them are spelled out clearly: One should never assume that cancer is always fatal, a second opinion should always be sought when a doctor declares a patient terminal and, to put it simply, there is hope.

Late in the program, alternate and controversial cancer treatments such as the drug Laetrile, and a Mexican clinic where patients are flooded with fruit juices, are looked at; the voice of the late Steve McQueen is heard again thanking Mexican doctors for their unorthodox treatment of the lung cancer that killed him; and there is a brief discussion of the fracas surrounding the antismoking commercials made by Brooke Shields and underwritten, but then disowned by, the federal government.

But by far the most moving and instructive parts of the program come earlier, in segments dealing with people who have survived not only cancer but also, in some cases, painful and debilitating chemotherapy. The most impressive of these cancer victims is 13-year-old Dnart Dennis of Oakland whose leukemia responded to chemotherapy, who was able subsequently to stay off chemotherapy for a full year and who then suffered a relapse.

Nevertheless, the young man remains a model of inspiring, ebullient resiliency. "There is sicker than what I am," he says philosophically, after matter-of-factly noting that "in six, four months, I might be dead." This amazing child was seen in a previous report on cancer, an all but miraculous hour of television called "Can't It Be Anyone Else?" produced by Korty Films and broadcast in July 1980 as an ABC News "Close-Up."

A woman whose husband was cured of testicular cancer speaks of the months of burdensome treatments, and of the traumatic psychological effect the father's illness had on one of the children in the house. "You just do it," she says of the ordeal. "Somehow, you do it." But another man who underwent an experimental new treatment for testicular cancer, and who says on camera that "I have to make the most of what time I have left," died, Travanti says, in July of this year. The program is dedicated to him.

Millions of dollars have not been able to buy a cure for cancer, and the wealthy are hardly immune. Richard Bloch, identified as "the 'R' of H&R Block," recalls the shock of learning he had "incurable" lung cancer--which later was cured. The treatment was arduous, emotionally and physically, but Bloch says, "Just to watch the sun come up one morning, just to put my grandchild on my knee one time, is worth everything I went through. There is no question that I'd do it again."

The last cancer patient seen on the program is Shelley Bruce, one of Broadway's "Annies," and now in "total remission" from leukemia. In a brilliantly effective conclusion to the program, she gives an unprecedented new poignance to "Annie's" hit song, "Tomorrow."

Linda Otto, the executive producer, and Carol L. Fleisher, the producer, wrote the script for "The Cancer Confrontation," an Alan Landsburg production. It is hard to imagine anyone who sees this program not wanting to thank them personally for what they did.