Epidemiology of uterine cervical cancer.
Brinton LA; Fraumeni JF
J Chronic Dis 1986;39(12):1051-65
The epidemiology of cervical
cancer presents a number of unique challenges, mainly with respect to
disentangling correlated factors and to elucidating biological mechanisms.
The available evidence suggests a complex multifactorial etiology, although
the relative contributions of risk factors and their interactions remain
obscure. Infectious agents are strongly suspected, but as yet not conclusively
identified. It is also unclear whether there are subgroups of women or
periods of life that are most susceptible to the action of infectious
agents, and the contribution of the "male factor" needs to be
defined. Several epidemiologic leads can be pursued through biochemical
and molecular techniques. Most promising is the recent evidence linking
certain HPV types to cervical abnormalities, including cancer, and newly
developed probes can be incorporated into epidemiologic studies to evaluate
an array of risk factors. Endocrine and metabolic assays may be helpful
in clarifying the role of exogenous and possibly endogenous hormones.
The effects of cigarette smoking may be further evaluated by studying
constituents of tobacco smoke and their metabolites in cervical mucus.
Finally, the relationship of diet to cervical cancer should be assessed
by examining the levels of micronutrients, trace minerals, and other nutritional
indices in body tissues and fluids, as well as through interview data.
An understanding of cervical cancer etiology will require a better identification
of risk factors for precursor lesions as well as factors that enhance
their progression to invasive cancer. Through studies that focus on disease
stage and time-related events, it should be possible to clarify the multi-stage
processes involved in cervical carcinogenesis, and those factors that
may inhibit as well as promote transition rates. The protective effects
of screening programs deserve further attention, and research into dietary
factors may lead in time to nutritional intervention. Investigation by
cell type should also be pursued to define the epidemiology of the rarely
occurring adenocarcinomas and adenosquamous carcinomas of the cervix.
Finally, preventive strategies should be targeted to high-risk populations,
especially those of the lower socioeconomic classes and with limited access
to medical care. The need for a renewed focus on epidemiology and prevention
is emphasized by recent increases in exposure to several postulated risk
factors, including sexual promiscuity, oral contraceptives, and smoking.