Coronary artery findings after left-sided compared with right-sided radiation treatment for early-stage breast cancer.
OBJECTIVE
To compare the incidence and distribution of coronary artery disease after left-sided versus right-sided irradiation in patients treated with breast conservation for early-stage breast cancer who subsequently underwent cardiac stress testing and/or catheterization for cardiovascular symptoms.


METHODS
The medical records of 961 stage I-II breast cancer patients treated from 1977 to 1995 at the University of Pennsylvania with conventional tangential beam radiation treatment (RT) were screened for cardiac stress tests and catheterizations performed after RT. The results of these tests were analyzed by laterality of RT and compared with baseline cardiovascular risk.


RESULTS
At diagnosis, patients with left-sided and right-sided breast cancer had the same estimated 10-year risk (both 7%) of developing coronary artery disease. At a median time of 12 years post-RT (range, 2 to 24 years), 46 patients with left-sided and 36 patients with right-sided breast cancer (total, N = 82) had undergone cardiac stress testing. A statistically significant higher prevalence of stress test abnormalities was found among left (27 of 46; 59%) versus right-side irradiated patients (three of 36; 8%; P = .001). Furthermore, 19 of 27 of left-sided abnormalities (70%) were in the left anterior descending artery territory. Thirteen left-side irradiated patients also underwent cardiac catheterization revealing 12 of 13 with coronary stenoses (92%) and eight of 13 with coronary stenoses (62%) solely in the left anterior descending artery.


CONCLUSIONS
Patients treated with left-sided radiation as a component of breast conservation have an increased risk of late, radiation-associated coronary damage. Treatment with modern radiation techniques may reduce the risk of cardiac injury.
Correa
Candace R
CR
Department of Radiation Oncology, Radiology-Cardiovascular Imaging Section, Medicine-Division of Cardiovascular Medicine, and Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USA. ccorrea@mail.med.umich.edu
Litt
Harold I
HI
Hwang
Wei-Ting
WT
Ferrari
Victor A
VA
Solin
Lawrence J
LJ
Harris
Eleanor E
EE
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D006328:Cardiac Catheterization; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality; D003331:Coronary Vessels / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005080:Exercise Test; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008875:Middle Aged; D009367:Neoplasm Staging; D011336:Probability; D011379:Prognosis; D011832:Radiation Injuries / Q000175:diagnosis* / Q000401:mortality; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D011882:Radiotherapy, High-Energy / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis