Breast Cancer Mortality Risk after DCIS Diagnosis

This is disturbing news from a recent Canadian study that was reported in JAMA Network Open. As you know, ductal carcinoma in situ (DCIS) is generally considered to be the best possible breast cancer diagnosis. Don't misunderstand that statement; no one wants to receive any kind of breast cancer diagnosis, but DCIS is not invasive and does not bring the threat of mortality.

This retrospective study found that women with a DCIS diagnosis were more than three times more likely to die of breast cancer than those who had never been diagnosed.

If the area of DCIS is small or contained, most women are successfully treated with a wide excision/lumpectomy and radiation therapy. If the DCIS is widespread throughout the breast, a woman may need a mastectomy. After surgery, women usually consult with an oncologist and may consider taking Tamoxifen for five years as a way to reduce risk of a later breast cancer.

This retrospective study found that women with a DCIS diagnosis were more than three times more likely to die of breast cancer than those who had never been diagnosed. The researchers looked at more than 140,000 women who had been diagnosed with DCIS. In this group, more than 1,540 women eventually died of breast cancer; the expected number among cancer-free women was 458. Women who had received radiation in addition to surgery did better. The rates of cancer death were highest among women who had DCIS before 40 and in African American women. These are shocking numbers. This increased risk persisted for fifteen years after the DCIS diagnosis.

So, what should we make of this? The bottom line seems to be that women who have had DCIS are at higher risk of developing invasive breast cancer in the future. To my non-doctor mind, one obvious conclusion is that all women with DCIS should be encouraged to consult with an oncologist and discuss Tamoxifen as possible risk reduction. It also seems that they should be followed with careful annual screening, possibly both breast MRIs and mammograms, as are other women known to be at high risk.

It is likely that this information will encourage further research. Who are the women who are more likely to later have invasive cancer? Could they be identified at the time of the DCIS diagnosis and, perhaps, treated more aggressively? Should women with this diagnosis be informed about this increased risk and given the chance to consider their treatment options, including surgery, at the start?

I am a fervent believer that knowledge is power, even when the knowledge is distressing. Whenever I speak with women about making tough treatment decisions, I suggest that they consider both what will help them sleep well tonight and sleep well five years in the future.

These decisions matter. We don't ever want to look back and wish we had known something or had a different conversation with our doctors. Most of us choose to hear all the information, even when we don't like it, and are then in the best position to choose wisely.