The movement to ease the awful pain of some deaths from cancer is showing signs of life. Not inconceivably, the present Congress could make the decisive move: to permit doctors administering to terminally ill patients who have failed to respond to lesser drugs to give injections of heroin.

It has been a very long fight, and Judith Quattlebaum of Washington has led it, unflaggingly. It was more than 10 years ago that she undertook to organize a committee to bring to the attention of Congress, which passes laws regulating the use of drugs, the plight of Americans who suffer great pain of the kind that could be alleviated by such injections of heroin as are routinely administered in Great Britain to those who are certain soon to die.

What Mrs. Q. keeps running into is a) a part of the medical establishment that against all reasonable evidence persists in insisting that a combination of lesser drugs will accomplish the same pain abatement (there are plenty of doctors on the other side, and the British experience is now long, and conclusive); and b) more important, those in Congress who succumb to the argument that to authorize heroin in the hospitals would be to flood the streets with this dangerous drug, augmenting the incidence of drug addiction.

But the data have been carefully accumulated, and the Committee on the Treatment of Intractable Pain has in hand data difficult to contend with. If every milligram of heroin that it is proposed be legally authorized to hospitals tending to cancer patients were stolen from the hospital safes at 2 o'clock in the afternoon and made instantly available to street peddlers of illegal heroin, the result would be to augment the existing supply of illegal drugs by between 2 percent and 4 percent. Since there is little likelihood that 1,000 hospitals would coordinate the circumstances for such an operation, more difficult than the Normandy landing, what we see is a threat of no consequence.

And then the most important figure of all. Since 1980, when the committee came close to winning congressional approval, 8,000 persons per year have died of cancer of that excruciatingly painful variety that might have been sharply mitigated if only Congress had acted.

The good news this season has been the activity of Sen. Daniel Inouye, who is the principal Senate sponsor of the heroin bill. He is joined by a number of senators across the ideological spectrum. Sen. Dennis DeConcini has been very active. Add Sens. John Melcher, Quentin Burdick, Ted Stevens, Thad Cochran, Donald Riegle, Carl Levin, John Warner, Nancy Kassebaum, James McClure, Patrick Leahy -- and, most recently, Robert Dole.

The principal opponent of the measure is Rep. Charles Rangel of Harlem, a man of great charm and persuasion who is, however, a fundamentalist on the drug problem. If heroin is bad, Rangel reasons, then why would Congress authorize its use? Well, Congress authorizes the use of napalm, and every day in every hospital, tools -- and drugs -- are used that, misused, would cause trouble, sometimes death.

But Rangel does not own Congress, and much turns on the position taken, as yet unstated, by the president. And on this particular issue, much turns on the attitude of the first lady, the nation's most adamant and conspicuous opponent of drug abuse. But Mrs. Reagan, daughter of a distinguished doctor, and daughter of an ailing mother, knows the difference between heroin used by a healthy street delinquent and heroin administered by doctors one of whose mandates is to ease pain.

Sen. Edward Kennedy, as chairman of the Committee on Labor and Human Resources, presides over the committee that normally would hear testimony for and against the proposed measure. He has told his colleagues that he is too busy to undertake to examine the proposed bill during this session. But congressional tradition holds that at least one committee of Congress should hear testimony; and back in 1984, the House subcommittee on health and the environment -- which reports to the Committee on Energy and Commerce -- heard such testimony. It would be altogether conventional for the Senate to waive its own hearings, accept those of the other house and move directly to a vote on the floor.

Sen. Kennedy, who often speaks of the unnecessary cruelties of life, ought to react to the principal problem before the house, which is: every day's delay means 25 deaths in unnecessary pain. The whole of Congress should be alerted to this point. It is responsible to pass the bill -- or to vote it down. What is not responsible is simply to dither away another month, year, decade, letting the agony of the hopeless subsidize congressional torpor.