It has been said that with knowledge comes understanding.
A research paper and editorial published in this week’s issue of JAMA Oncology may have brought knowledge, but if you read various media reports I am not so certain it has clarified understanding. And the distinction is important, because when a woman is confronted with the diagnosis of a “Stage O” breast cancer (aka ductal carcinoma in situ or DCIS), the decisions she makes about treatment can have far-reaching and long lasting impact for her and those who care about her. [more]
First, some brief background: DCIS was rarely diagnosed before the advent of mammographic screening for breast cancer. Perhaps it was found incidentally when a breast biopsy was done for another reason, or perhaps a woman or her physician felt a mass that turned out to be DCIS. Once mammography became more widespread in the 1970’s, we began to see a marked increase in the number of women diagnosed with DCIS. Today, the American Cancer Society estimates that in 2015 slightly more than 60,000 women in the United States will be diagnosed with this lesion (compared to 234,190 women who will have a more typical invasive breast cancer).
The situation is more complicated because DCIS is non-invasive. That means it does not invade the milk ducts from which it originates, thus decreasing the possibility of spread. Some experts have even advocated that we should not call it a cancer at all, since it has been thought that the chances of spread from this cancer are quite small (putting aside the fact that if such lesions are carefully examined under the microscope there is a small possibility that an area of invasion might indeed be found).
The complexity grows further since the treatment of DCIS has been undergoing a subtle but definite change over the past several years: more women are opting for mastectomy or double mastectomies when told they have DCIS. The reasons are not clear why this is happening, but there is concern that women believe that the surgery will remove all concerns that they could ever have another problem with DCIS or invasive breast cancer at any time in the future, thus reducing their anxiety about recurrence and possibly death from this disease.
Enter the current study, which is the most extensive information we have about DCIS to date.
In this research, the investigators examined records in a well-established database called Surveillance, Epidemiology, and End Results (SEER) which is widely regarded as the most effective collection about cancer patients, their diagnoses and outcomes in the United States. They reviewed the records of about 108,000 women who had been diagnosed with DCIS from 1988 to 2011 to determine what happened to them, including information available about their treatment for their DCIS. It is important to remember that the diagnosis and treatment of DCIS may have changed over that period of time, but the information is still relevant to our understanding of what happens to women after they are diagnosed and treated.
So what did they find?
After being followed for 20 years, one out of 33 women (3.3%) died from breast cancer-which is almost twice as much (1.8 times) as women in the general population. In addition, women diagnosed before the age of 35 had about a 2 ½ times greater chance of dying from breast cancer after a DCIS diagnosis compared to older women. Black women had an almost 3 times greater chance of dying from breast cancer after a DCIS diagnosis than white women. Even more important, a woman who eventually developed another primary invasive breast cancer in the same breast had an 18 times greater chance of death from breast cancer.
What was stunning to me in this report was that there were 517 women-which represented slightly over half the women who died from breast cancer in this study– (out of the 108,000 women studied) did not have any recurrence of cancer or a new cancer in the breast. That includes women who had mastectomies. That leads us to believe that in these women-although a small number compared to all women who were diagnosed with DCIS- there was something about their non-invasive DCIS tumor that was very, very aggressive resulting in distant spread and death.
But then there is the very important question that we need to understand when it comes to the issue of what treatment is best for DCIS. Standard treatment for most women consists of lumpectomy, radiation and possibly longer term hormonal therapy. Some women opt for mastectomy or even having both breasts removed, as previously mentioned.
It turns out from this study that women who had radiation to the entire breast after the DCIS tumor was removed reduced their risk of having a local recurrence with an invasive breast cancer (remember, DCIS is not invasive) 10 years after their lumpectomy from about 5% (1 in 20) to 2.5% (1 in 40). However, there was no difference in the chance of death from breast cancer at the same 10 year time frame. In other words, radiation decreased the risk of the breast cancer returning and becoming invasive, but it didn’t make any difference in the ultimate outcome for the women in this study. When examined at 20 years, the risk of invasive cancer for women who had radiation following lumpectomy was 4.5%, and for women who had lumpectomy without radiation the risk of recurrence was double at 9.5%.
Aside from age and race, there were other factors that the researchers found which increased the risk of a woman dying from breast cancer after a diagnosis of DCIS. These included the size of the cancer, whether or not it was hormone sensitive, and whether there was evidence of necrosis (areas of dead tissue) within the tumor.
Finally, the risk of death from breast cancer in women who had lumpectomy and radiation was 0.4% during follow-up for women who had lumpectomy without radiation, 0.5% died from breast cancer, and for women who had either a single or double mastectomy the rate of death was 0.6%. Not much of a difference, and certainly mastectomies didn’t reduce the risk of death.
So where does that leave us? And more important, what does it mean for a woman who is diagnosed with DCIS?
Unfortunately, the answers are in fact not very clear. The research helps give us a better picture of what happens to women after a diagnosis of DCIS. What becomes clear is that for most women, DCIS is reasonably straightforward: it is a non-invasive lesion that will not impact her life. Radical treatments in most circumstances, such as a double mastectomy, do not improve outcomes. But for some women-in particular African Americans, women under the age of 35, and those who have specific features in their DCIS as noted previously-there may be a need for even more intensive treatment following the diagnosis.
Left uncertain is the question of whether we are treating too many women with this diagnosis.
In an accompanying editorial, Dr. Laura Esserman-who has always challenged the status quo on how we approach DCIS-argues that we need to rethink our standard treatment for DCIS. We need to determine which women really benefit from more aggressive treatment-and be more conservative in the large majority of women who will not benefit from such an approach. Perhaps in an effort to reduce risk we need to observe women and offer preventive strategies such as diet, exercise, moderate alcohol intake, and avoid progesterone in post-menopausal women. Another option would be to use tools such as Oncotype DX to determine whether or not a particular DCIS is more biologically aggressive. And, according to Dr. Esserman, we should consider drugs shown to reduce the risk of breast cancer for those at high risk, when appropriate.
So what we know at this point is that DCIS is not quite the disease we thought it was. We need to rethink our strategy, and consider clinical trials which help us determine what is the best treatment for women diagnosed with DCIS. We may be overtreating some women, and undertreating others. We need to rethink our thoughts that bilateral mastectomies are the answer to reducing the risk of death from breast cancer. We need to understand the role of radiation therapy in the treatment of DCIS.
Dr. Esserman offers some sage advice in her commentary, something that it would be wise for all of us-doctors, other health professionals, and the women we care for-to follow when DCIS is diagnosed:
“Given the low breast cancer mortality risk, we should stop telling women that DCIS is an emergency and that they should schedule definitive surgery within 2 weeks of diagnosis.
“Questions remain-but there is room to innovate. If we want the future to be better for women with DCIS, we have to be committed to testing new approaches to care.”
Maybe it is now time to move on. Fear should not be the driving force when it comes to DCIS. We need to look more carefully at the science, and let the evidence be our guide.