If nothing else, the new guidelines for cancer testing pronounced last week by the American Cancer Society are confusing.

In some cases they are under sharp attack by other members of the medical community who fear the concern they reflect is more for lowering medical costs than for saving life at any cost. In other cases, it is felt that they are based on incomplete or erroneous evidence. Or both.

Some physicians hint broadly that even the timing of the announcement had its mercenary aspects -- coming as it did days before the opening of the society's conference for science writers in Daytona Beach, Fla., and the launching of the society's annual drive for funds.

The society feels misunderstood.Major research organizations -- for example, Johns Hopkins, Sloan-Kettering and Mayo, have indicated they feel, well, had. And the public? At best, we're left with a kind of vague "what's-the-poor-patient-to-do?" feeling, a sense that a lower medical bill might mean a higher risk of an uncaught cancer.

The new guidelines, the first major overhaul in years of the Cancer Society's recommendations, suggest changes -- for the asymptomatic patient at low risk -- in the frequency and types of tests for cancer. These are changes in medical routines with which ACS has been firmly identified, along with its ubiquitous slogan, "Fight cancer with a check -- and a checkup."

The recommendations of this titan of charities have been almost universally accepted in the past as the last word on the war against the Big C. Their current move, however, has provoked the suggestion from at least one major medical figure that they would do better to "stick to public-health education and information and let the doctors practice medicine."

Here is a brief summary of the proposals which apply to men and women at low risk, and who have no cancer symptoms:

A complete cancer checkup and health counseling at age 18; every five years from age 25 to 40; every 2 1/2 years to age 60, and annually thereafter.

Note: This does not apply to a general physical examination. It means that in addition to a routine physical there should be a complete cancer checkup at the stated intervals.

"Health counseling" would mean hearing and heeding, whereever possible, a doctor's advice to avoid cancer risk-taking as in smoking, various environmental factors, methods of contraception, in diet and life style.

Virtual elimination of chest X-rays and sputum cytology tests for detection of early lung cancer, even in smokers.

Limiting use of sigmoidoscopy (or proctoscopy) for rectal examinations to those over 50 (every three years, after two initial negative examinations a year apart, but recommending stool slide tests and manual rectal examinations annually for men and women.

For women:

Lowering the use of the Pap test (for cervical cancer) to once every three years after two successive annual negative tests between the ages of 20 and 65 unless they: Are under 20, but sexually active. Take oral contraceptives. Have an intrauterine device. Are taking estrogens. Have had multiple pregnancies.

Suggesting three years as the interval for pelvic examinations between the ages of 20 and 40 and, subsequently, annually.

Suggesting endometrial tissue samples in most women at menopause.

Continuing the recommendation for breast self-examination monthly, but limiting a physician's breast examinations to once in three years until age 40, and annually thereafter.

Among exceptions here would be women with cystic breast disease and, according to new -- but as yet inconclusive tests -- women who consume coffee or tea or other caffeine-containing products which appear linked to cystic breast problems and possibly breast cancer. In at least one finding, smoking has been implicated as well.

Suggesting a baseline mammogram for women between 35 and 40. Between 40 to 50, as the physician directs. And over 50, every year.

The two most controversial aspects of the guidelines are those dealing with detection of lung cancer and those involving gynecological examinations, principally the use of the Pap test.

The ACS explanation for discarding the chest X-ray, even for heavy smokers over 45, held that although it did pinpoint early malignant lung lesions, there appeared to be no proof that early detection increased chances for survival.

This brought almost instant and furious response from directors of a National Cancer Institute study (of some 30,000 patients at Hopkins, Sloan-Kettering and Mayo) to determine the relationship between early detection and survival.

Said Dr. Robert Fontana of Mayo, "Among our patients who are over 45 and have been heavy smokers, the incidence of lung cancer approaches 1 percent . . . the Cancer Soviety has recommended against the only two tests capable of detecting early lung cancer."

Just as outraged was the response from the American College of Obstetrics and Gynecology, which issued an instant press release to alert its members that it was "seriously concerned about reports rejecting the accepted health-care examination for women."

College president Dr. Martin L. Stone, Stony Brook, L.I., said this week that he had tried to head off the guidelines at least until a forthcoming National Cancer Institute conference could deal with the matter of the Pap test. "My gut reaction (to the data the ACS based its decision upon) is that years of experience by the clinician is better than a computer evaluation of data."

Stone also echoed a popular complaint among physicians over breaking the now fairly well-established routine of yearly examinations: "We know not everyone comes every year . . . what kind of fallout will you have when the time between is stretched?"

He agreed with ACS findings that results of the Pap often vary widely, but also noted, "We're not a cancer society and we feel more than Pap is involved. Other diseases can be detected by yearly examinations and by Pap which, for example, is helpful in finding Herpes, a condition almost epidemic now."

Said Dr. Larry McGowan, director of the George Washington University Medical Center Division of Gynecological Oncology and a Cancer Society panelist: "Pap results depend on so many variables, from the skill of the physician taking the smear, to the quality of the laboratory and the processing and interpretation," that there can be as much as a 25 percent rate of false negatives.

He once more emphasized that fewer examinations were recommended only for the "normal, asymptomatic" woman, who, considering the exceptions, may well be a minority.

Stone and McGowan agreed that quality control of laboratories and technicians was essential. McGowan who was asked by ACS to help explain the guidelines at a Cancer Society press conference last week, said, however, that the Pap test "is not the keystone in the discovery of cervical cancer, but that 80 percent of them can be discovered visually by the examining physician."

"We do recognize," he added, "That cost has to be appreciated and very attempt to reduce total cost has to be carried out."