For early-stage breast cancer, lumpectomy followed by radiation therapy has been shown to be as effective as mastectomy without radiation for removing the cancer AND minimizing the risk of the cancer coming back (recurrence).
Radiation therapy given after surgery is called adjuvant radiation therapy. Adjuvant radiation therapy can destroy any cancer cells that may have been left behind after surgery, making recurrence in the same breast (also called ipsilateral recurrence) less likely. Depending on the characteristics of the cancer, chemotherapy, hormonal therapy, and targeted therapy medicines also may be given after surgery to reduce the risk of the cancer coming back in the same breast or other places in the body.
But research suggests that not all women need radiation therapy after lumpectomy. Two large studies have shown that some women 70 or older diagnosed with early-stage, estrogen-receptor-positive breast cancer who take tamoxifen or another hormonal therapy medicine for 5 years after lumpectomy can skip radiation therapy after surgery. Because of these results, the National Comprehensive Cancer Network (NCCN) changed its treatment guidelines in 2011 to say that women age 70 or older diagnosed with estrogen-receptor-positive, stage I breast cancer who take hormonal therapy for 5 years or more after lumpectomy can safely skip radiation therapy.
But many older women continue to get radiation therapy after lumpectomy despite the research and the NCCN guidelines. This is probably for many reasons, including research that shows many women stop taking hormonal therapy early. Assuming a woman is likely to not finish a full 5 years of hormonal therapy, doctors also may prescribe radiation therapy for older women to help keep the risk of recurrence as low as possible.
To help doctors better understand exactly which older women can safely skip radiation therapy after lumpectomy, researchers have developed a new predictive tool called a nomogram. The study was published online on June 25, 2012 by the Journal of Clinical Oncology. Read the abstract of “Nomogram to Predict the Benefit of Radiation for Older Patients With Breast Cancer Treated With Conservative Surgery.”
In this study, the researchers looked at the records of 16,092 women age 66 to 79 who were diagnosed with breast cancer and had lumpectomy between 1992 and 2002. They also recorded the characteristics of the cancer, including whether cancer was in the lymph nodes, and looked to see how many women had radiation therapy after lumpectomy as well as how many needed to have mastectomy after lumpectomy because the cancer came back. The information came from a large U.S. National Institutes of Health database call SEER. Half the women were followed for about 7 years and the other half were followed for longer time periods.
The researchers used all this information to create a nomogram, a tool that predicts how many women will need a mastectomy at 5 years and 10 years after lumpectomy because the cancer came back. To use the tool, doctors enter information about an individual woman, such as:
- cancer size
- estrogen receptor status
- lymph node status
- whether or not radiation therapy was given
The tool then predicts how likely the woman is to need a mastectomy at 5 and 10 years after lumpectomy.
While this new tool looks promising, more research needs to be done to make sure its predictions are accurate and consistent.
If you’re 70 or older and have been diagnosed with early-stage, hormone-receptor-positive breast cancer, you and your doctor will consider the characteristics of the cancer, your unique situation, your surgical options, your treatment options after surgery, and your personal preferences when creating your treatment plan. If you’ll be having lumpectomy, talk to your doctor about why radiation therapy is or isn’t recommended for you after surgery and how that decision was made.
Using the most complete and accurate information possible, you and your doctor can develop a treatment plan that makes the most sense for you. You can learn more about radiation after breast cancer surgery in the Breastcancer.org Radiation Therapy section.