The is a ph.d. dissertation about primary prevention of the current breast cancer epidemic. A case-control study has been conducted in order to test the hypo-thesis that a reduced exposure to human seminal factors in the early reproductive lives of women is a risk factor in the development of breast cancer. Many reproductive, biological,
and socioeconomic factors have been suggested as risk factors in breast cancer. Also, hormonal factors have been widely accepted as risk factors in the development of this malignant disease. The research hypothesis in this study involves a third group of factors, related to reduced fertility and some fertility-control methods as causal factors in the development of breast cancer in women.

The hypothesis states that married women who use barrier contraceptive methods (as technically induced male sterility) and women who have infertility characteristics due to male
infertility, are at a higher risk of developing breast cancer than other women in the population. Female exposure to seminal factors is reduced or eliminated by using barrier contraceptive techniques (condom and withdrawal), by eliminating the risk of pregnancy (celibacy, long-term abstinence), and by male infertility (sterility and
subfertility). Included in the non-barrier methods are the diaphragm, pill, intra-uterine devices (IUD), rhythm, foam, jelly, and female sterilization (tubal ligation). The hypothesis is based on the evidence of presence of biologically
active factors, such as prostaglandins, in human seminal plasma. To test this hypothesis, a study was conducted at the Hospital of the University of Pennsylvania in Philadelphia during 1975-1977. The population under study consists of 153
consecutive mastectomy patients who are married or ever-married white women of premenopausal and early post-menopausal age, 35-60 years, at the time of diagnosis. The control group consists of 168 patients with the same characteristics, frequency matched by age and social status (educational level), seeking treatment in the
out-patient clinics of the same institution. Those women with neoplasia or history of neoplasia of breast,
uterus, and ovaries as well as those with hysterectomy and premenopausal hormonal treatment were excluded from the controls. Information was obtained by interviewing the women with a questionnaire covering the reproductive history and contraceptive practices in the childbearing period. The results showed that the exposure to the hypothetical semen-factor deficiency is 4.6 times greater in the breast cancer group than in the controls. In the group of women who use contraceptives the relative risk of exposure to barrier contraceptive methods increased to 5.2, with
95% confidence limits between 3.1 and 8.7. The results were statistically significant, x2 = 40.8, P<.0005. The study did not provide a definite answer to the question of male infertility as a possible risk factor in breast cancer in
women. The observed higher proportion of women with infertility in the breast cancer group (18.3% versus 11.9% in the controls) and the risk ratio of 1.54 was not statistically significant. The risk of developing breast cancer differed in the groups within the population according to the contraceptive practice. Based on this retrospective study it was estimated that 17.4% of women using barrier contraception and 3.9% of women using non-barrier contraceptive techniques will develop breast cancer; this represents a risk ratio of 4.5. It is estimated that the harmful effect is operative when condom and withdrawal are used at a frequency of about 50 percent or more in a 5-year period during the reproductive age of 15-40 years. The results also suggested that a number of reproductive and biological variables, including age at first birth, parity, age at menarche, age at marriage, lactation, and family history of breast cancer are surrogate measures of exposure to seminal factors. Miscarriages were associated with the exposure to infertility. Women of older age
had a higher exposure to barrier practice than the younger women. Also, the results showed that the lower the level of education of women the higher the duration of barrier exposure.

The potential implication of the association between barrier contraceptive practice and breast cancer is the possibility of prevention of the disease. An estimate of the potential impact of primary prevention shows that by eliminating barrier
contraceptive methods the reduction of breast cancer would be approximately 50 percent of the incidence of this malignant disease in the population of married women. For certain ethnic groups, this preventive effect is estimated to be 60-70 percent of the observed incidence. The other potential implications are related to further research in human reproduction, degenerative and neoplastic diseases of reproductive organs in women, and population policy. The possibility of preventive measures within an accepted and adequate family planning program is emphasized.