Incidence of second primary breast cancer among women with a first primaryin Manitoba, Canada

Citation
Y. Chen et al., Incidence of second primary breast cancer among women with a first primaryin Manitoba, Canada, BREAST CANC, 67(1), 2001, pp. 35-40
Citations number
36
Categorie Soggetti
Oncology,"Onconogenesis & Cancer Research
Journal title
BREAST CANCER RESEARCH AND TREATMENT
ISSN journal
01676806 → ACNP
Volume
67
Issue
1
Year of publication
2001
Pages
35 - 40
Database
ISI
SICI code
0167-6806(200105)67:1<35:IOSPBC>2.0.ZU;2-Q
Abstract
Second primary breast cancer is of importance because of the increasing inc idence of first primary breast cancer and improved survival. There is lack of information on the disease in Canada. We studied 14,220 women with a fir st primary breast cancer (invasive only) diagnosed during the period from 1 970 to 1997, in Manitoba, Canada. A breast cancer was considered to be a se cond primary if it was an invasive lesion diagnosed at least six months aft er the diagnosis of an initial primary breast cancer. The incidence rate of second primary breast cancer was approximately six per 1,000 person-years, and the cumulative incidence during the 28-year study period was 14.3%. Av erage age at diagnosis of first primary breast cancer had increased signifi cantly since 1970. The incidence was higher in 1975-1979, and there was no significant difference among other study periods after adjustment for the a ge at diagnosis of first primary breast cancer. Standardized incidence rati os showed no significant difference among six age groups after adjusting fo r calendar year. However, women with a first primary breast cancer had an i ncreased risk of developing a second primary breast cancer compared with th e risk of developing a first primary breast cancer among the general female population. The SIR was markedly greater among women who had a first prima ry breast cancer before the age of 40 years, and decreased significantly wi th increasing age at diagnosis of first primary breast cancer. The data pro vide epidemiological information on second primary breast cancer risk for t he general female population in Manitoba, Canada.