Left-Sided Breast Cancer Radiation Boosts Coronary Risk

By David Douglas

NEW YORK AUG 09, 2007 (Reuters Health) - Early-stage breast cancer patients treated with left-sided radiation as a component of breast conservation have an increased risk of late, radiation-associated coronary damage, according to researchers.

Nevertheless, "the benefits of radiation therapy for breast cancer still clearly outweigh the risks," lead investigator Dr. Candace R. Correa told Reuters Health. "However," she added, "there may still be room for improvement in radiation techniques, which can potentially spare late-onset radiation-associated sequelae, such as coronary artery disease among left-side irradiated patients."

In a study published in the July 20th issue of the Journal of Clinical Oncology, Dr. Correa of the University of Michigan, Ann Arbor, and colleagues examined the medical records of 961 stage I-II breast cancer patients.

At diagnosis, patients with left-sided and those with right-sided breast cancers both had a 7% estimated 10-year risk of developing coronary artery disease.

At a median of 12 years after radiotherapy, 46 of the left-sided group and 36 of the right-sided group had undergone cardiac stress testing.

The results showed that 59% of those in the left-sided group had abnormalities, significantly more than the 8% proportion in the right-sided group (p = 0.001). Moreover, 70% of the abnormalities in the left-sided group were in the left anterior descending artery territory.

Thirteen women in the left-sided group also underwent cardiac catheterization, which revealed coronary stenoses in 92%, of which 62% were solely in the left anterior descending artery.

"Careful monitoring and long-term follow-up to assess these risks by treating physicians is important," Dr. Correa continued.

For patients, she added, "it is most prudent to optimize their cardiovascular health by living a healthy lifestyle and speaking with their doctors about risk reduction tools and interventions that may be appropriate for their situation."

SOURCE:

• J Clin Oncol 2007;25:3031-3037.