Increasing incidence of and declining mortality from breast carcinoma. Trends in Malmö, Sweden, 1961-1992.
BACKGROUND
The incidence of breast carcinoma is increasing in most populations, whereas mortality caused by this disease is fairly constant. The authors analyzed the incidence of and mortality from invasive breast carcinoma in a population with access to good medical care, into which mammographic screening was introduced in 1976 and adjuvant therapy in 1978.


METHODS
In a consecutive series of patients with invasive breast carcinoma from Malmö, 1961-1991, changes in age-adjusted incidence were analyzed and compared with incidence of the disease in the rest of Sweden. Age-adjusted breast carcinoma mortality was studied for the period 1964-1992.


RESULTS
The introduction of mammographic screening was associated with an increase in breast carcinoma incidence. This was restricted to the age group that was eligible for screening (age 45-69 years) and to Stage I disease. Between 1977 and 1992, age-adjusted breast carcinoma mortality decreased in Malmö by 43% (95% CI, 26-56%) as compared with 12% (95% CI, 8-16%) in the rest of Sweden. The decrease was statistically significant in both populations and significantly greater in Malmö than in the rest of Sweden (P < 0.001). In Malmö the decrease was seen in two age groups, age 45-69 years and age 70 years and older. In the rest of Sweden the decrease was seen only among women age 70 years and older. In the rest of Sweden the decrease was seen only among women age 70 years and older. There were no changes in incidence or mortality among women younger than 45 years in either population.


CONCLUSIONS
Breast carcinoma incidence was strongly related to diagnostic activity, especially mammographic screening. The decrease in mortality occurred in temporal relation to the introduction of screening and adjuvant therapy, making a causal relation likely. The difference in results between Malmö and the rest of Sweden indicates an important role for screening in mortality reduction.
Garne
J P
JP
Department of Surgery, Malmö University Hospital, Sweden.
Aspegren
K
K
Balldin
G
G
Ranstam
J
J
D000328:Adult; D017677:Age Distribution; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D006801:Humans; D015994:Incidence; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D013548:Sweden / Q000453:epidemiology