Radiation Benefit for Breast Cancer Shown

The radiation treatments that millions of patients with early-stage breast cancer receive significantly reduce their chances of dying from the disease, according to a large international study that for the first time documents that the therapy saves lives.

The analysis of data collected from more than 42,000 women with early breast cancer worldwide found that those who underwent radiation after having a lumpectomy and mastectomy were about 5 percent less likely to die from the disease over the next 15 years.

Although previous studies have found that radiation reduces the risk of a recurrence, some women still do not have the treatment because of possible side effects and lingering doubt about whether that relapse reduction translates into a reduced risk of dying from the disease. The new findings -- from the largest and most authoritative examination of that question -- should dispel any remaining uncertainty, the researchers said.

"There's been a lot of questions about this. We've, for the first time, shown very clearly that there is a benefit," said Sarah Darby of Oxford University in England, who led the analysis being published in tomorrow's issue of the journal the Lancet. "The message for women is that if their doctors are offering them radiotherapy, they should consider it very seriously. It does save lives."

The findings should also reassure those who have had the treatment that the risks were worthwhile, the researchers said, and women who recently opted against the treatment may want to have it now.

"It might be worth considering . . . for some women who, within just the last year or two, have had lumpectomy for breast cancer or who have had mastectomy for cancer that had spread to the armpit and who didn't get radiotherapy after their surgery because of the side effects," Darby said.

Breast cancer is diagnosed in more than 211,000 U.S. women each year, killing more than 40,000. It is the most common cancer among women and the second-leading cancer killer, after lung cancer.

Doctors recommend that women whose tumors are detected early and are removed through a lumpectomy have the affected breast radiated to kill any remaining cancer cells. In addition, many women who have had a breast removed and whose cancer has spread to their lymph nodes are offered radiation.

But some patients do not have the follow-up treatment, often because of fears of side effects, including swollen arms and increased risk of heart attack and other cancers later.

The new study was conducted by the Early Breast Cancer Trialists' Collaborative Group, based at Oxford, which has been assessing the effectiveness of treatments. In May, the group reported the first data demonstrating that chemotherapy and hormone treatment had dramatically reduced the death rate from early breast cancer.

In the new analysis, the group analyzed data from all 78 studies involving radiation treatment for early breast cancer conducted worldwide through 1995, which included data from 42,080 women.

"This is reassuring," said Susan Love, a breast cancer expert at UCLA. "This confirms the benefits of radiation."

In addition to a reduced risk of recurrence in the first five years after treatment, the study found the risk of dying from breast cancer was 30.9 percent among those who received radiation, compared with 35.9 percent among those who did not -- the first demonstration that the treatment lowers the mortality risk.

Women who received radiation were also less likely to die for any reason, showing that any increased risk was outweighed by the reduced risk of dying from breast cancer, Darby said.

For women who underwent a mastectomy but whose cancer had spread to the lymph nodes under their arms, the 15-year breast cancer mortality risk was 54.7 percent with radiation vs. 60.1 percent without -- a reduction of 5.4 percentage points, the researchers found. There was a similar reduction in overall death risk. Radiation was previously shown to reduce the breast cancer mortality rate, but the new study is the first to show a decrease in overall mortality, Darby said.