Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. Ductal means that the cancer (carcinoma) starts inside the milk ducts. In situ, which means "in its original place," means the non-invasive cancer hasn't spread beyond the milk duct. DCIS isn't life-threatening, but people diagnosed with DCIS are at risk of the DCIS coming back and are at higher-than-average risk of developing invasive breast cancer later on.
Lumpectomy (rather than mastectomy) followed by radiation therapy is the recommended treatment for most DCIS.
A study found that younger women (under 45) who have lumpectomy and radiation therapy to treat DCIS were more likely to have the breast cancer come back (recurrence) compared to older women who had the same treatment. The results were presented at the 2009 ASCO Breast Cancer Symposium.
The researchers looked the medical records of 624 women diagnosed with DCIS and treated with lumpectomy and radiation therapy. After about 8 years of follow-up, the researchers found the following recurrence (either DCIS or invasive breast cancer) rates:
- 12% of women aged 45 to 50 at diagnosis had a recurrence
- 19% of women aged 40 to 44 at diagnosis had a recurrence
- 20% of women younger than 40 at diagnosis had a recurrence
When the researchers accounted for differences in individual treatments (radiation dose, for example), they found:
- women younger than 40 at diagnosis were 83% more likely to have a recurrence
- women between 40 to 44 were 64% more likely to have a recurrence
compared to women older than 45. Despite the differences in recurrence risk, survival rates were similar for all three age groups. This means all the women had the same chance of being alive 5 years after diagnosis.
The researchers aren't sure why the younger women diagnosed with DCIS were more likely to have a recurrence after lumpectomy and radiation therapy. Research has shown that invasive breast cancer in younger women tends to be more aggressive than invasive breast cancer diagnosed in older women, which may be contributing to the results seen here. It's also possible that surgeons may be removing less tissue during lumpectomy in younger women to improve cosmetic results after surgery. This carries the risk that some cancer cells may be left behind unknowingly, which increases the risk of recurrence.
These results DON'T mean that younger women diagnosed with DCIS should choose mastectomy instead of lumpectomy and radiation therapy. Lumpectomy followed by radiation therapy is a good choice for these women. These findings do suggest:
- All women, but especially younger women, diagnosed with DCIS should work with their doctor to create and stick to an aggressive follow-up and screening plan to detect a recurrence or new breast cancer as soon as possible.
- Skipping radiation therapy after lumpectomy is a bad idea for most younger women diagnosed with DCIS. Other research has shown that lumpectomy followed by radiation therapy reduces the risk of recurrence better than lumpectomy without radiation therapy.
Regardless of your age, if you've been diagnosed with DCIS, you and your doctor will work together to develop a treatment and follow-up plan that makes the most sense for your unique situation. If you're younger than 45, you might want to ask your doctor about this study.
You can find more information about DCIS in the Breastcancer.org Ductal Carcinoma in Situ pages.