IT IS SOMETIMES said - but never frequently enough - that the incidence of cancer in American society has reached epidemic proportions. In the past it was also said that this sudden surge in the incidence of cancer reflected nothing more than our medical success, for since we have eliminated most of the infectious scourges that at much younger ages carried off our forefathers - and foremothers for that matter - the naturally occurring cancers of old age finally had a chance to reveal themselves. But this explanation - at best a facile one - is demonstrably false. The appalling fact remains: most of the cancers of Western society, some 75-80 per cent it is estimated, appear to be self-inflicted and the corollary is that we could eliminate them if we chose. There lies the rub.

This is the theme of The Greatest Battle, the fourth book of flow from the fluent pen of Ronald Glasser, a pediatrician from Minnesota. Almost the most forceful sentence in the book is the very first, in the preface, when he reveals that "During the Christmas holidays last year, of the twenty-three children admitted to the largest pediatric ward of the University of Minnesota Hospitals in a single day, eighteen had cancer." It is a shocking statistic; one which, as a society, we are still far too complacent about, and as the author goest on to insist, it is not as if we were ignorant of this situation. We know the facts and we know the remedies, but the mixture of vested interests, fatalism and indifference will no doubt ensure that this situation improves slowly, if at all.

Glasser takes us easily through the basic facts of cancer, in fine detail but with the ease of explanation that we have come to expect of him. So we come quickly to see how and why the chemicals that are poisoning our atmosphere are equally playing havoc with our bodies."In the submicroscopic world of cellular controls, one molecule of the carcinogen, or perhaps two or three at the most, physically couples with the bases or perhaps even the sugars of the nucleoproteins, and like a monkey wrench jamming the control gears running a complicated factory, destroys or interferes with two billion years of finely tuned evolution."

Chapter after chapter the evidence, relentlessly piles up from nicotine, to thalidomide to Red Dye 2. There are plenty of horror stories and sometimes he is kinder than he should be. One chapter tells how in Chicago 70,000 children were affected by twin errors of "medical judgment" and "medical prudence." After World War II, X-rays became a routine treatment and irradiation of infants and children was standard procedure. It was observed that children when young were susceptible to colds and upper respiratory infections but gradually grew out of them - any grandmother could tell you that.But this coincided - it was also observed - with the shrinking of the thymus gland. These two facts are in fact related, for when an infant has its full complement of immune protective bodies the gland shrinks away, its job done. But when it was realized that X-rays could shrink the thymus artificially someone made the erroneous deduction that this would reduce the incidence that this would reduce the incidence of colds and at the touch of a button there was a cure for demanding parents and fussy babies. Without any proof of efficacy whatever, high energy beams were directed into babies' chests, not only onto the thymus but tonsils and adenoids. So these children were deprived of a gland vital for their proper immune function, and so have grown up with a variety of immune deficient diseases. But worse, the X-rays later generated cancer in other places, like the thyroid gland.

Some 15 to 20 years later, as they always to roost. In 1970 a definitive paper appeared which showed that 15 per cent of all adults who had developed thyroid cancers between 1946 and 1968 had been given X-ray treatment to the chest in their earlier years. What was really ominous was the malignant state of these tumors. Glasser calls this story a "medical error," surely an understatment in view of the fact that the damaging effects of radiation had been known for years before!

The publishers claim that this book may well have the stunning impact of Rachel Carson's Silent Spring. I wish this were true but I doubt it. For one thing Rachel Carson had the advantage that she was telling us something not only shocking but new. Glasser is telling us something shocking, but we have known about this for some time. Next, Carson has a wonderfully evocative and forceful way with words, and fluent writer though Glasser may be, he is no match for her as a stylist. Even more important, he evades an issue that Rachel Carson did not evade. To be fair to Glasser it is an issue that almost everyone is evading, so far as environmental cancers are concerned. For it is no longer a medical problem, so much as an ethical and political one, in which personal and governmental ethics are involved.

What is needed is not more exposure but practical action that Rachel Carson initiated and inspired. If Glasser from his popular position could mobilize people and politicians and industry too - or if he could mobilze Ralph Nader - then maybe some impact could be made. Even the forces of the American Cancer Society are not yet really gathered to fight this battle. If one of its vice presidents, Mrs. Marvella (Birch) Bayh, who not only feels wery strongly but is doing something practical about this problem, has her way, public opinion and public action could be mobilized. But one will be meeting commercial interest head on and I know of only one industrial organization that has been willing to sacrifice revenue for the sake of the principle of good health. The Readers Digest - bless its heart - and lungs - has been far ahead of the government in the matter of cigarette smoking, banning advertising of cigarettes for 22 years at a cost of some 105 million dollars in lost revenue. They also published the first disclosures of the lethal effects of the poisonous gas in cigarettes, which the Digest says "kills people." They are right. "The Digest won't help to sell products that are lethal"; they say, and so they turned a medical question into one of principle. Unless others are prepared to follow their example, with other products, we shall no doubt continue to kill ourselves and our children.