DCIS is mammographically suspected by the presence of micro calcifications subsequently requiring a biopsy to confirm the diagnosis histologically. The incidence of DCIS has increased over the last few years with the advent of powerful and more sophisticated screening mammography for invasive breast cancer. According to the American Cancer Society statistics, DCIS is diagnosed in 1 of every 4 new breast cancer cases in the US posing a significant public health threat.
The current treatment of breast cancer requires a multidisciplinary approach and DCIS is no exception to this approach. The management of DCIS is personalized and depends on multiple factors such as age, co-morbidities, expectations, and prognostic markers. The current prognostic markers used are Estrogen Receptor (ER) positivity or negativity and grade level (low grade: not so aggressive, high grade: aggressive, intermediate grade: moderately aggressive). Women with DCIS will require surgical excision with negative margins (no cancer left behind), possibly radiation therapy, and possibly anti-estrogen therapy.
So where is the controversy?
- What is the significance in the increased incidence of DCIS?
- Are we “over diagnosing” DCIS? and therefore,
- Are we over treating patients with DCIS?
The controversy is of excesses. A recent large observational study article in JAMA Oncology by Narod et al showed an extremely low breast cancer specific mortality of 3.3% from DCIS. The investigators demonstrated that radiation therapy after lumpectomy reduced the risk of ipsilateral (same side as the original cancer side) invasive breast cancer recurrence, but did not have any impact on breast cancer specific survival. Prior to the use of mammographic technology the diagnosis of DCIS was rarely made. Studies suggest that up to 60% of DCIS cases will progress to invasive breast cancer. It should be helpful to stratify DCIS into risk categories. Some patients with DCIS will never have their disease progress (low risk), others will have such an aggressive DCIS that extensive treatment should be recommended (high risk), and still other patients will have disease that progresses slowly over many years (intermediate risk).
So what is an oncologist to recommend and a patient to do?
Although the data presented by Narod and colleagues is based on a large number of patients it is an observational study after all. It is indeed provocative and it should spark future investigations on this somewhat neglected non-invasive breast cancer. Mammographic findings and biopsy results should be interpreted cautiously and in the context of the patient. Treatment should be multidisciplinary in nature, consultation with the medical oncologist and radiation oncologist should be seriously considered prior to performing unnecessary mutilating surgery. Radiation treatment should not be routinely offered to low risk patients and molecular profiling should then be considered for more appropriate guidance regarding this modality of treatment. Hormonal or anti-estrogen therapy should be discussed in those patients with ER+ DCIS only and after careful evaluation of the risks and benefits of this therapy.
The most powerful tool that patients, family and caregivers have is information. Bringing a list of pertinent questions and asking for a multidisciplinary approach prior to initiating surgical treatment may allow the patient to have a better understanding of this misunderstood process as is DCIS. Remember, DCIS should be appropriately managed but is not an emergency as some have tried to portray it. Do not be scared, be knowledgeable.
J. Daniel Cuevas, MD
Director Clinical Research
St Louis Cancer Care LLP
JAMA Oncol. Published online August 20, 2015. doi:10.1001/jamaoncol.2015.2510