NBC special correspondent Tom Brokaw said yesterday that he appears to be beating the cancer he announced publicly in February, reports Newsday contributor Frank Lovece. Filling in for Savannah Guthrie on "Today," Brokaw, 74, said he was "doing fine . . . The myeloma appears to be gone. I've got one more marker to get down . . . and then I'll be all right." He said he hoped to be on a drug-maintenance program within six weeks. "This will not go away, but we can manage it chronically and that's all I can ask."