a. Increases with increasing age (Harris, pp 159–167.)
Breast cancer is rarely seen before the age of 20, but thereafter its incidence increases inexorably. While the prevalence of breast cancer (the raw number of patients alive with disease) is greatest among perimenopausal women, the incidence of breast cancer (the number of new cases per 100,000 population) rises so sharply that it is twice as common among women between 80 and 85 years of age as among those 60 to 65. In addition, the age-adjusted incidence has increased steadily since the mid-1940s. No data is presently available consistently linking the incidence of breast cancer to dietary factors. A possible linkage between breast cancer and alcohol consumption at an early age is being studied.