CHICAGO – Breast cancer patients who have a breast-sparing operation but forgo radiation therapy are putting their lives at risk, according to a study released Thursday that could change how medical scientists understand the disease.
More than 200,000 U.S. women are diagnosed with invasive breast cancer every year. Doctors generally recommend post-operative radiation for any woman who has surgery that removes the tumor but leaves most of the breast, often called lumpectomy. They also recommend radiation for many patients who have mastectomy, or removal of the entire breast. But those recommendations are not always followed.
According to the American College of Surgeons National Cancer Data Base, at least 25 percent of lumpectomy patients skip radiation. And the more advanced their disease, the more likely they are to do without.
Some may live far away from a hospital and find a six-week course of radiation too burdensome. Others may be too ill, or may fear the side effects of radiation – which can include cancer and heart disease. But until now, many doctors believed the only thing those women were risking was a local recurrence – a relapse in the same breast, which could be treated by further surgery.
They based that belief on a landmark study, supported by the National Cancer Institute and first reported in 1985, that compared mastectomy, simple lumpectomy and lumpectomy followed by radiation for women with early breast cancer. That study found that the women who got lumpectomy without radiation had a much higher chance of a local recurrence, but they were no more likely to die of their disease.
Thursday’s issue of the prestigious British medical journal The Lancet turns that on its head. An overview of 40,000 breast cancer patients by researchers at Oxford University found that radiotherapy confers a significant long-term survival advantage.
Fifteen years after breast-sparing surgery, 30.5 percent of women who got radiation had died of their disease, compared to 35.9 percent of those who did not – five extra breast cancer deaths for every 100 women.
Radiation offered the same benefit to women who got mastectomies if their cancer had already spread to the lymph nodes under their arms: After 15 years, 54.7 percent of those who had radiotherapy had died of breast cancer, compared to 60.1 percent of those who did not.
There was no advantage for women who had their entire breast removed if the cancer had not spread beyond the breast. The risk of a recurrence for those patients is so low that any benefit of radiation is likely to be outweighed by its side effects.
Cancer experts said this study would have a major impact on breast cancer treatment.
Dr. William Gradishar of Northwestern Memorial Hospital said it’s now very clear that “reducing the risk of local recurrence – whether in the preserved breast or in the chest wall – translates into a significant improvement in overall survival.”