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Vulvar and vaginal cancer precursor lesions are predominantly squamous cell neoplasias that contain HPV DNA. Other risk factors that are similar to CIN include current smoking, a history of prior genital warts or anogenital neoplasia, and multiple sexual partners. Unlike cervical cancer, vulvar and vaginal neoplasias are rare, and prevention beyond visual examination is not a part of routine gynecologic care. Women with impaired immunity (e.g., organ transplant recipients, acquired immunodefi- ciency syndrome patients, and patients who are treated with corticosteroids) should be screened periodically. A history of previous HPV-related diseases should be obtained in these women before determining the frequency of cytologic screening.

Most of what has been learned about the autosomal dominant susceptibility genes, BRCA1 and BRCA2, has been derived from studies of high risk families characterized by large numbers of affected women. While ascertainment of such families was necessary for the mapping of BRCA1 and BRCA2, and analysis of high risk families continues to provide critical data about the type and frequency of mutations in rare families with several affected women, these data do not provide information to women drawn from the general population. Many such women who lack a profound family history of breast cancer (BC), both cancer patients and unaffected women, nevertheless they perceive themselves to be at risk of carrying a mutation in one of these genes because of the presence of one or more affected individuals in their family. We have been interested in understanding the role of BRCA1 and BRCA2 outside the selected venue of high risk families. Generating data on the frequency of BRCA1 and BRCA2 mutations in women with BC drawn from the general population, who have minimal or modest family histories, would provide guidance on the overall impact of these genes within this group, and identify any features that relate to an increased likelihood of carrying a mutation.

During the past ten years, advances in science and technology have changed the types of studies epidemiologists are conducting. New directions for epidemiology include genetic studies, studies of tumor markers, and studies of cancer survival. Although the field of epidemiology is rapidly turning toward these new directions, there are still relatively few published reports in some of these areas. Therefore, this overview will by necessity rely heavily on examples from two population-based, case-control studies of women in Seattle who developed breast cancer (BC) under age 45 (i.e., the Seattle BC studies). Examples from the literature or work in progress from other investigators focusing on breast and ovarian cancer will also be included.

Certain events of reproductive life, especially completed pregnancies, have been found to influence a woman’s risk of breast cancer. Prior studies of breast cancer in relation to a history of incomplete pregnancies have not provided consistent results. Female residents of three Western Washington counties diagnosed with breast cancer to age 46 years (n = 845 and 961 control women identified through random-digit dialing) were interviewed in detail with regard to their reproductive histories, including the occurrence of induced and spontaneous abortions. Among women who had been pregnant at least once, the risk of breast cancer was 50% higher in those who had experienced an induced abortion than in those women who did not. While the size of this increased risk did not vary by the number of induced abortions or by a history of a prior completed pregnancy, it did vary according to the age at which the abortion occurred, as well as the duration of that pregnancy. Highest risks were observed when the abortion was done prior to 18 years of age (particularly, if it took place after eight weeks of gestation), or at age 30 and beyond. There was no increased risk of breast cancer associated with a prior miscarriage. The data from this and other (although not all) epidemiologic studies support the hypothesis that an induced abortion can adversely influence a woman’s subsequent risk of breast cancer. This question should be re-examined in future studies, with particular attention to the potential hazards related to abortions early in life.