An association between oral contraceptives and an easily detectable and curable pre-cancerous genital condition was reported yesterday by a scientist who stressed a need for more studies to try to find out if a cause-effect relationship exists.
The condition, called cancer in situ, occurs in the cervix, the neck of the uterus. With the aid of a simple test called the Pap smear, cervical cancer can be readily detected and cured. Left untreated it can become invasive.
In at least two dozen studies over the years, researcher have neither proved nor disproved a link between the pill and cervical cancer, and sometimes have reached opposite conclusions.
A major reason for their difficulty is that sexual behaviour and the type of contraception affect the incidence of the disease. For example, a woman with multiple sex partners increases the risk of getting cervical cancer: a woman using a diaphragm, or whose partner uses a condom, decreases the risk.
Yesterday, Dr. Savitri Ramcharan reported that in one of the largest and most comprehensive studies ever made of Pill side effect, cervical cancer in women who had used the sexhormone drugs for at least four years was about three to five times as common as in women who never used them.
The study indicated that the risk of cervical cancer increased with the duration of use, with 17 of the 35 cases occuring in women who had taken the Pill for four or more years. The rates per 100,000 person-years of use were: up to one year, 63; one to four years, 97; and four years or longer, 173. The rate for non-users was 32.
Ramcharam emphasized, however, that sexual behavior - particularly a woman's age at first intercourse and the number of sexual partners - "could be responsible for the difference in the incidence of cervical cancer which we found."
"Consequently," she continued, "we initiated in the same population of women a case comparison study to clarify this issue. Preliminary results . . . suggest that sexual behaviour may account for some but not all of the difference."
Should her study cause users to worry about cervical cancer? reporters asked her.
"Definitely not," she replied. Rather. she said, "I think all women on the Pill shold have Pap smears."
The scientist was interviewed after delivering her report at a meeting on the Pill sponsored at the International Inn by the Health Research Group, an arm or Ralph Nader's Public Citizen, Inc. An estimated 50 million women, including as many as 8 million in the United States, use the Pill.
Started in December 1968 uner a contract with the National Institute of Child Health and Human Development, the study finally enrolled and followed up 15,243 women for a total of nearly 117,000 women-years.
All of the women lived in the San Francisco Bay area and were members of the Kaiser Foundation Health Plan. They were Predominantlu white, middle-class and married. Although they ranged in age from 15 to 57, the majority were in the child-bearing age span of 15 to 45.
The study allowed for the effect of eight factors other than the Pill that could affect the results: age, education, marital status, number of Pap smears, religion, number of pregnancies, smoking, and a history of genital infections.
Ramcharan said that she and her colleagues at the Kaiser-Permanente Medical Center in Walnut Creek, Calif., also have turned up an association betwen a rare skin cancer called malignant melanoma and the Pill, particularly in Long-term users. But until additional studies are done, she said, "we cannot rule out the possibility that this was a chance finding."
She and the four other panelists adopted a resolution calling upon Pill manufacturers to share in the costs of further research.