A study has found that women diagnosed with DCIS (ductal carcinoma in situ) who were treated with radiation therapy after lumpectomy to remove the DCIS were less likely to have cancer come back (recur) in the same breast compared to women who didn't have radiation therapy after surgery.
The results were presented at the 2011 annual meeting of the American Society of Breast Surgeons (ASBS).
DCIS is the most common form of non-invasive breast cancer. DCIS usually is treated by surgically removing the cancer -- lumpectomy in most cases. After surgery, many women get radiation therapy. Radiation therapy after surgery for DCIS was common in the past, but newer guidelines for treating DCIS say that radiation therapy after surgery doesn't have to be given routinely to all women. If the DCIS is hormone-receptor-positive (most are), hormonal therapy medicine also may be recommended.
In this study, researchers looked at the medical histories of 1,014 women who had lumpectomy to remove DCIS:
- 651 women had only surgery (the "excision-alone" group); the average follow-up period for this group was 6 years
- 353 women had surgery plus radiation therapy (the "excision plus radiation therapy" group); the average follow-up period for this group was 9 years
The researchers identified women who had breast cancer recur in the same breast where DCIS was first diagnosed and looked at the types and locations of the recurrent breast cancer. They also figured out the risk of breast cancer recurrence over 10 years for each group.
They calculated that 30% of the women diagnosed with DCIS who were treated only with surgery would have a recurrence in the 10 years after surgery and 18% of the women treated with surgery and radiation therapy would have a recurrence.
When breast cancer recurs after DCIS treatment, it can be non-invasive DCIS again or it can be invasive breast cancer. Recurrence risk was much lower in women treated with radiation therapy after surgery. Still, if cancer did recur in women who got radiation, there was a more than 50% risk that the cancer would be invasive compared to a 38% risk in women who didn't get radiation therapy after surgery.
Most of the recurrences in both groups happened in the same area (quadrant) of the breast where the DCIS was first diagnosed. Still, recurrence in a different area of the breast occurred in some women from both groups. In these cases the location of the cancer suggests that the cancer was a second, new cancer, rather than a return of the original cancer. This was more likely in women who were treated with radiation therapy after surgery, compared to those who were not.
Of the women who had a recurrence, 28% of women who had surgery and radiation therapy had the recurrence in a different place in the breast than the original DCIS compared to 10% of women who had only surgery.
Late recurrence (cancer coming back more than 10 years after the original DCIS diagnosis) also was more likely in women treated with radiation therapy after surgery. About 33% of women who got radiation after surgery for DCIS who had a recurrence had a late recurrence compared to 9% of women who got only surgery.
If you've been diagnosed with DCIS, your doctor will recommend a treatment plan after surgery tailored to your specific recurrence risk for DCIS or invasive breast cancer. Your treatment plan may include radiation therapy, hormonal therapy, both, or neither. If you're deciding on treatments after DCIS surgery, you might want to talk to your doctor about the role of radiation therapy in your care and the results of this study. Together, you can decide on a treatment plan that makes the most sense for you and your unique situation.
The Breastcancer.org DCIS pages contain more information on DCIS symptoms, diagnosis, and treatment.