Two very different books on cancer have come out recently, both of which are provocative enough to warrant mention.

One of them, "Choices," by Marion Morra and Eve Potts, has won a rare endosement from the American Cancer Society. The other, "The Cancer Syndrome," by Ralph Moss, is a broadside attack on the cancer establishment which, of course, includes the ACS.

"Choices" (Avon, $8.95) sets out a wealth of information for the cancer patient, or the family, about available treatments, how to go about selecting them, and questions for which a patient should insist upon answers.

"The Cancer Syndrome" (Grove Press, $12.95) takes the tack that in its headlong rush to find an absolute, positive, final, one-and-for-all cure for cancer (and one, says author Moss, which is also profitable), the so-called cancer establishment -- drug companies, the government, charitable foundations and the major cancer centers -- have dismissed some unconventional discoveries and treatments without giving them fair trials.

"Choices": Written by sisters, one of them (Morra) the communications director of the Yale University Medical School's Comprehensive Cancer Center and the other (Potts) a veteran medical writer, the book is intended as "a sort of Dr. Spock" for the cancer patient. As Eve Potts puts it, "something you can go to in the middle of the night and find out why you're feeling this way or that way. . . ."

The women, both of whom live in Connecticut, decided to do the book shortly after Morra took over the communications job at Yale, and Potts found she was her first customer -- on behalf of a friend who had lung cancer.

"One particular thing was happening," Potts recalls. "She was having radiation in the chest area, and one day when I called her she was particularly depressed. She said, 'I've had a sore throat for weeks, and I know the darn thing has spread into my throat.'

"Have you talked to your doctor about it?' I asked.

"'Well no, I'm afraid to ask. . . ."

So Eva Potts called her sister and sure enough, sore throats are a common side-effect of the kind of radiation the friend was having.

"People," says Potts, "with such a serious disease, shouldn't have to be worrying about things like that."

The book is well-researched and extraordinarily up-to-date. (An "Update" appendix includes a description of the use of ice-caps ("chemo-caps") to help prevent hair loss during chemotherapy, discusses the work being done by Dr. John Minton at Ohio State University on the link between coffee, tea, cola drinks and chocolate and cystic breast disease, and touches on holistic approaches and other techniques.

Clear and forthright, it's the kind of book you hope you'll never have to use. But if you should, it is a valuable reference.

"The Cancer Syndrome": -- Ralph W. Moss, a former classics professor at Hunter College, New York City, found that his knowledge of Greek and Latin made him a natural for explaining science to the layman. As such, he served as assistant director of public affairs at Memorial Sloan-Kettering Cancer Center in New York.

Although he was fired by Sloan-Kettering after he publicly attacked the center's handling of their work on laetrile, he cannot be dismissed simply as a malcontent out for vengeance.

His book examines a number of alternative cancer treatments that Moss feels showed promise in ameliorating cancers, but were either unpatentable -- such as interferon -- simply not dramatic enough.

"I know that there's not a conspiracy in terms of a conscious plan to stop a cure for cancer," says Moss. "I don't think there is one [a cure] in the offing, either orthodox or unorthodox. But most of the people involved in the supression of unorthodox methods are consciously aware that they are supressing something of value."

"The Cancer Syndrome" examines the history of unorthodox methods and intimates that some of them, long discarded, should be re-examined. The book also paints a gloomy picture of the way some large companies, whose products may well contribute to carcinogens in the environment, can exert undue influence over cancer research.

Moss concedes a "danger of quackery . . . after all, no one is more desperate than a cancer patient." But he believes it's a crime to let anybody die of cancer without using them to test methods that show promise -- if they want an experimental method.

"I think that qualified doctors should be authorized by the Food and Drug Administration to administer a certain number of these unorthodox treatments under a humanitarian investigation of new methods . . . perhaps license, say, 1,000 doctors to use laetrile under controlled conditions with careful records." (In fact, clinical studies of laetrile, under the sponsorship of the National Cancer Institute, began July 1 at four major cancer research centers: the Mayo Clinic, Rochester, Minn; Sloan-Kettering, New York; the Johnsson Cancer Center at UCLA and the University of Arizona in Tucson.)

Of course, says Moss, "There should not be unlimited freedom for any entrepreneur to enter the market place and hold something out as a cure."