Decreased risk of stroke among 10-year survivors of breast cancer.
OBJECTIVE
To assess treatment-specific risk of cerebrovascular events in early breast cancer (BC) patients, accounting for cerebrovascular risk factors.


METHODS
We studied the incidence of cerebrovascular accidents (CVA; stroke and transient ischemic attack [TIA]) in 10-year survivors of early BC (n = 4,414) treated from 1970 to 1986. Follow-up was 96% complete until January 2000. Treatment-specific incidence of CVA was evaluated by standardized incidence ratios (SIRs) based on comparison with general population rates and by Cox proportional hazards regression.


RESULTS
After a median follow-up of 18 years, 164 strokes and 109 TIAs were observed, resulting in decreased SIRs of 0.8 (95% CI, 0.6 to 0.9) for stroke and 0.8 (95% CI, 0.7 to 1.0) for TIA. Significantly increased risk of stroke was found in women who had received hormonal treatment (HT; tamoxifen) and in women who had hypertension or hypercholesterolemia, with hazard ratios (HRs) of 1.9, 2.1, and 1.6, respectively. Patients irradiated on the supraclavicular area and/or internal mammary chain (IMC) did not experience a higher risk of stroke (HR = 1.0; 95% CI, 0.7 to 1.6) or TIA (HR = 1.4; 95% CI, 0.9 to 2.5) compared with patients who did not receive radiotherapy or who were irradiated on fields other than the supraclavicular area or IMC.


CONCLUSIONS
Long-term survivors of BC experience no increased risk of cerebrovascular events compared with the general population. HT is associated with an increased risk of stroke. Radiation fields including the carotid artery do not seem to increase the risk of stroke compared with other fields.
Hooning
Maartje J
MJ
Department of Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Dorresteijn
Lucille D A
LD
Aleman
Berthe M P
BM
Kappelle
Arnoud C
AC
Klijn
Jan G M
JG
Boogerd
Willem
W
van Leeuwen
Flora E
FE
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D018714:Radiotherapy, Adjuvant; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology*; D015996:Survival Rate; D017741:Survivors / Q000145:classification / Q000706:statistics & numerical data