Almost all women get radiation therapy after lumpectomy to reduce the risk of the cancer coming back (recurrence).
Lumpectomy plus radiation has been shown to be as effective as mastectomy without radiation for most women diagnosed with early-stage breast cancer.
Early-stage breast cancer is stage 0, I, and II.
Radiation isn’t given routinely after mastectomy, but some women benefit from it. Research has shown that women diagnosed with breast cancers that:
- are larger than 5 cm (about 2 inches)
- have spread to four or more lymph nodes (called positive nodes)
- have positive margins (cancer is found in the rim of tissue around the cancer that is also removed)
- have spread to the skin
benefit from radiation after mastectomy.
But it hasn’t been clear if radiation after mastectomy to remove breast cancer with just one to three positive lymph nodes offers benefits. Some studies found that radiation improved survival. Other studies showed no benefits.
Now, a new analysis shows that women diagnosed with early-stage breast cancer with only one to three positive lymph nodes under the arm are less likely to have a recurrence and more likely to survive breast cancer if they have radiation after mastectomy.
The research was presented on March 19, 2014 at the European Breast Cancer Conference in Glasgow and published online the same day by the Lancet. Read “Effect of radiotherapy after mastectomy and axillary surgery on 10-year recurrence and 20-year breast cancer mortality: meta-analysis of individual patient data for 8,135 women in 22 randomised trials.”
This study was a meta-analysis -- a study that combines and analyzes the results of many earlier studies. In this case, the results of 3,786 women in 14 studies that started between 1964 and 1982 were analyzed. All the women had mastectomy to remove early-stage breast cancer and then were randomly assigned to get radiation therapy or not after surgery.
The women were put into three categories:
- no cancer in the lymph nodes (700 women)
- breast cancer in one, two, or three lymph nodes (1,314 women)
- breast cancer in four or more lymph nodes (1,772 women)
The women were followed for about 11 years. The researchers had information on the number of recurrences and deaths from breast cancer up to 2009.
These 3,786 women were part of a larger group of 8,135 women in 22 studies on radiation therapy after mastectomy.
The researchers wanted to know if getting radiation after mastectomy reduced the risk of recurrence and improved survival.
In the 700 women with no cancer in the lymph nodes, radiation after mastectomy didn’t reduce the risk of recurrence and didn’t improve survival rates.
In the 1,314 women with breast cancer in one to three nodes, radiation after mastectomy:
- reduced the risk of recurrence by 32%
- improved survival rates by 20%
compared to not getting radiation after mastectomy.
Looking at the results in a different way, radiation therapy after mastectomy in women with early-stage breast cancer in one to three lymph nodes led to almost 12 fewer breast cancer recurrences per 100 women after 10 years and eight fewer deaths per 100 women after 20 years.
These benefits were the same for women who had breast cancer in one lymph node and women who had breast cancer in two or three lymph nodes.
It also didn’t matter if the women were in studies that prescribed chemotherapy or hormonal therapy after surgery:
- 65% of the women with breast cancer in one to three lymph nodes got chemotherapy
- 21% of these women got hormonal therapy
In the 1,772 women with breast cancer in four or more lymph nodes, radiation after mastectomy:
- reduced the risk of recurrence by 21%
- improved survival rates by 13%
compared to not getting radiation therapy.
In other words, radiation therapy after mastectomy in women with early-stage breast cancer in four or more lymph nodes led to nine fewer breast cancer recurrences per 100 women after 10 years and nine fewer deaths per 100 women after 20 years.
The researchers pointed out that the standard of care is for women with early-stage breast cancer in four or more lymph nodes to get radiation after mastectomy -- the results of this study confirm that.
What hasn’t been clear is whether women with early-stage breast with one to three positive lymph nodes would benefit from radiation after mastectomy. The results of this study strongly suggest that radiation therapy after mastectomy makes sense for women diagnosed with early-stage breast cancer that has spread to one, two, or three lymph nodes.
If you’ve been diagnosed with early-stage breast cancer, you and your doctor will consider the specifics of the cancer, your unique situation, and your treatment options after surgery when creating your treatment plan. If you’ve had or will be having mastectomy and your pathology report says one or more lymph nodes are involved, you might want to talk to your doctor about this study and whether you could benefit from radiation after mastectomy. It’s also a good idea to ask your doctor about the possible side effects of radiation.
Using the most complete and accurate information, 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.