Extra radiation lowers risk of breast cancer recurrence
Olga Barrantes, who had a mastectomy to remove breast cancer, receives radiation treatment for skin cancer at a clinic in San Jose, Tuesday, May 26, 2009. (AP / Kent Gilbert)
Published Monday, June 6, 2011 11:51AM EDT
Giving women with early-stage breast cancer an extra dose of radiation to their lymph nodes appears to lower the risk of the cancer recurring or spreading to other parts of the body, according to Canadian research presented at a large cancer conference.
The study from researchers at McMaster University in Hamilton, Ont., presented at the annual meeting of the American Society of Clinical Oncology in Chicago, could change the way that many with breast cancer are treated.
The study involved more than 1,800 women with early stage breast cancer; 85 per cent had one to three lymph nodes test positive for cancer, 10 per cent had high-risk, node-negative breast cancer. Their mean age was 53.
Under current practices, patients whose breast cancer has spread to more than three lymph nodes are generally treated with surgery and chemotherapy followed by radiation to the whole breast and nearby lymph nodes. But women with fewer than three positive nodes generally don't get the added radiation.
Yet there has long been debate about whether this is the best approach.
This study found that offering the radiation to these women did result in benefits.
Among the 1,800 women studied, all had breast-conserving surgery as well as chemotherapy and/or endocrine therapy. Part of the group received either whole breast radiation (WBI), or WBI along with radiation to the surrounding lymph nodes.
Five years later, there were statistically significant benefits for the group receiving the added (lymph node radiation) therapy," the study said.
Women who received radiation treatment to the breast and lymph nodes had a 41 per cent lower rate of recurrences near the tumor site compared to the women who received breast radiation alone.
They also had a 36 per cent lower rate of cancer recurrences in other parts of the body after five years, the study said.
Improvements in overall survival, however, were not statistically significant, said study lead investigator Dr. Timothy J. Whelan, professor of oncology and division head of radiation oncology at McMaster University and the Juravinski Cancer Centre.
There was also an increased risk of lymphedema (excess lymphatic fluid) in the arm on the radiated side, as well as of pneumonitis, a type of lung inflammation.
Still, Whelan called the results "potentially practice-changing."
"They will encourage physicians to offer all women with node-positive disease the option of receiving regional nodal irradiation," he said in a statement.
Dr. Christine Williams, the director of research at the Canadian Cancer Society, which funded the study, says the findings could provide affected women with "an important new treatment option."
"Ultimately, this finding will help more women survive and thrive after treatment," she said in a statement.