Study Confirms Radiation Boosts Breast Cancer Survival
Article date: February 13, 2006
Fewer Recurrences, Fewer Deaths When Radiation Part of Treatment
Summary: A new analysis of dozens of breast cancer studies shows that adding radiation to breast cancer treatment doesn't just lower a woman's risk of having a relapse, it also improves survival. The findings were published in The Lancet.
Why it's important: Radiation is standard treatment after breast-conserving surgery (lumpectomy) and is recommended after mastectomy for women with large tumors or whose cancer has spread to many lymph nodes. But many women skip radiation treatment. This study helps explain why they shouldn't.
"These data help strengthen the argument that there is a substantial benefit to radiotherapy [after lumpectomy] and that it should be a rare patient with a very low risk of recurrence or a very short expected life span for whom it should be eliminated," said Christy Russell, MD, chair of the American Cancer Society's Breast Cancer Advisory Group and co-director of the University of Southern California Norris Breast Center. She was not involved in the research.
The study also helps doctors better understand which mastectomy patients could most benefit from radiation, she added.
What's already known: A Canadian study published last year found that radiation after mastectomy could improve survival for women with high-risk breast cancer. But most studies of radiation after any type of breast cancer surgery only showed that the treatment could reduce recurrences -- they didn't show that the treatment helped women live longer. Because this new study includes data from dozens of other studies and thousands of women, it was able to detect a benefit previous research couldn't.
"I believe what this paper does is confirm and add to the data that prevention of a local recurrence can improve your chances of surviving breast cancer," Russell said.
How this study was done: Researchers from the Early Breast Cancer Trialists' Collaborative Group looked at the results of 78 clinical trials involving 42,000 women. The studies had compared different treatment strategies after initial breast cancer surgery: radiation vs. no radiation, more vs. less surgery (with and without radiation), and more surgery vs. radiation. The researchers combined the information from these studies to figure out how much benefit radiation provided in the short-term and the long-term.
What was found: The analysis showed that for every 4 local recurrences prevented by radiation, 1 breast cancer death could be prevented over 15 years.
Among the 7,300 women treated with breast-conserving surgery, radiation reduced the risk of having a relapse in the next 5 years from 26% to just 7%. The risk of dying from breast cancer over the next 15 years dropped from 35.9% to 30.5%.
For the 8,500 women who had a mastectomy, radiotherapy reduced the 5-year risk of local recurrence from 23% to just 6%, and reduced the 15-year risk of death from breast cancer from 60.1% to 54.7%.
The benefits were greatest for women whose cancer had spread to the lymph nodes, and those with larger tumors or higher grade tumors.
The bottom line: Russell said medical oncologists can use the data in this new analysis to help their patients make decisions about whether to seek radiotherapy after breast cancer surgery.
She cautions, though, that the large benefits seen in this analysis may be lower in today's patients.
"Current hormone therapies and chemotherapy regimens are better in reducing local recurrence than those that were used in the clinical trials presented," she explained. "Both those therapies, if used, may make the benefit of radiation therapy less significant with regards to both local recurrence and breast cancer-specific survival."
Citation: "Effects of Radiotherapy and of Differences in the Extent of Surgery for Early Breast Cancer on Local Recurrence and 15-year Survival: An Overview of the Randomised Trials." Published in the Dec. 17, 2005, The Lancet (Vol. 366, No. 9503: 2087-2106). First author: Early Breast Cancer Trialists' Collaborative Group.
Reviewed by: Members of the ACS Medical Content Staff
ACS News Center stories are provided as a source of cancer-related news and are not intended to be used as press releases.
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