A study suggests that women 70 and older diagnosed with stage I, hormone-receptor-positive breast cancer may get little benefit from radiation therapy after lumpectomy if they're also taking tamoxifen, a hormonal therapy medicine, after surgery. These results will be presented at the 2010 American Society of Clinical Oncology annual meeting in June.
Treatments given after surgery are called adjuvant treatments. Adjuvant treatments can include chemotherapy, targeted therapy, radiation therapy, and hormonal therapy given after surgery to lower the risk of the cancer coming back (recurrence).
Women diagnosed with early-stage breast cancer who choose to have lumpectomy instead of mastectomy usually have adjuvant radiation therapy. Much other research has shown that lumpectomy plus radiation therapy is equally effective as mastectomy. Still, doctors wanted to better understand the benefits of radiation therapy after lumpectomy in older women diagnosed with small, low-recurrence risk breast cancers: stage I and hormone-receptor-positive. Stage I, hormone-receptor-positive breast cancers tend to be less aggressive and less likely to come back compared to higher stage or hormone-receptor-negative breast cancers.
The researchers looked at the medical records of 636 women who:
- were 70 or older
- were diagnosed with stage I, hormone-receptor-positive breast cancer
- had lumpectomy instead of mastectomy to remove the cancer
- took tamoxifen after lumpectomy
Some of the women in the study had radiation therapy after lumpectomy. Most of the women were followed for more than 10 years after surgery.
The researchers looked for differences between the group that got radiation therapy and the group that didn't. They found that the outcomes of the women who got radiation therapy were similar to the outcomes of the women who didn't get radiation therapy:
- The likelihood of NOT developing a metastatic recurrence (breast cancer that comes back in place other than the breast area) was the same -- 95% -- whether or not a woman had radiation therapy or not.
Survival was the same between the two groups:
- Overall survival 10 years after diagnosis was 61% for women who didn't get radiation therapy and 63% for women who got radiation therapy; most of the women died from causes OTHER THAN breast cancer.
- The likelihood that breast cancer didn't come back in women surviving for more than 10 years after diagnosis (called 10-year recurrence-free survival) was 96% in women who didn't get radiation therapy and 98% in women who got radiation therapy.
Women who didn't get radiation therapy were more likely to have a recurrence in the breast where the original cancer was removed and that recurrence was likely to happen sooner compared to women who got radiation therapy:
- 9% of women who didn't get radiation therapy had a recurrence in the same area where the original cancer was removed (local recurrence) compared to 2% of women who got radiation therapy
- 8% of women who didn't get radiation therapy had a recurrence in the same breast where the original cancer was removed but away from the area of the original cancer (ipsilateral recurrence) compared to 2% of women who got radiation therapy
What's called an ipsilateral recurrence could be the original breast cancer coming back or could be a new, second breast cancer.
There was a higher rate of recurrence in the women who didn't get radiation therapy. Still, the risk of needing a mastectomy in the 10 years after initial diagnosis was very low (and nearly the same) whether or not a woman got radiation therapy:
- 96% of women who didn't get radiation therapy didn't need a mastectomy in the 10 years after diagnosis compared to 98% of women who got radiation therapy
It's important to remember that this study analyzed the benefits of radiation after lumpectomy in women 70 and older. These results shouldn't be used to make treatment decisions for women younger than 70.
If you're age 70 or older and have been diagnosed with hormone-receptor-positive, stage I breast cancer, your doctor may recommend lumpectomy instead of mastectomy to remove the cancer. Generally, radiation therapy is recommended after lumpectomy. Still, the results of this study suggest that the benefits of radiation therapy are small for women 70 and older. You may want to talk to your doctor about:
- your risk of recurrence based on your specific situation, including your age, the characteristics of the cancer, and how not having radiation therapy might change your recurrence risk
- the benefits, side effects, and risks of radiation therapy
- how other treatments -- hormonal therapy, for example -- can help lower your risk of recurrence
- your treatment preferences
With the right information, you and your doctor can decide on a treatment plan that makes the most sense for YOU.
Visit the Breastcancer.org Radiation Therapy section to learn more about the benefits, side effects and risks of radiation after breast cancer surgery.