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What is the COMET Study?

COMET stands for Comparison of Operative to Monitoring and Endocrine Therapy for low-risk ductal carcinoma in situ (DCIS). This study will look at different management strategies for DCIS. It is the first national study in the United States (US) to do so. A randomized clinical trial will enroll 1200 women with low-risk DCIS. Enrollment will take place at about 100 cancer centers throughout the US. The study is funded by the Patient-Centered Outcomes Research Institute (PCORI).

Why is the COMET Study needed?

Currently, many types of DCIS are treated the same as invasive breast cancer. Surgery and radiation are considered standard care in the US. Endocrine therapy is also often recommended. This is usually a pill taken once a day for five years. Yet these treatments may cause physical, emotional or psychological burden. Many women experience short and long-term side effects. These may include pain, infection, scarring, loss of feeling, and other breast changes.

Studies have shown 70-80% of DCIS may never become invasive breast cancer. This is the case even when DCIS is left untreated. Many breast cancer experts believe that low-risk DCIS is being overtreated. They also suggest that women may do just as well if monitored more frequently. This is called active surveillance. Instead of having immediate surgery, a woman is watched over time. This is done by follow-up exams and tests such as mammograms. A woman will only have surgery if tests show her condition has changed in a way that requires it.

The COMET Study will provide information to better understand low-risk DCIS. In particular, it will provide information on the trade-offs between immediate treatment and monitoring. This will help determine if more patients are able to avoid standard treatment. It will also help to personalize treatment choices. These treatment choices may better reflect individual values and preferences. Currently, all women diagnosed with DCIS are treated as if they have invasive breast cancer. We hope that the COMET study will show that active surveillance is a safe and effective alternative to surgery and radiation for women with low-risk DCIS.

What can I expect if I participate in the COMET Study?

The COMET study will look at two different interventions for DCIS:

  1. Standard care. This may include surgery (lumpectomy or mastectomy). It may also include radiation therapy.
  2. Active surveillance. This includes mammograms and physical exams every six months. Surgery is only recommended if needed.

In either group, you and your doctor will decide whether endocrine therapy is a good option.

Once you join the trial, you will be randomized to one of these two groups. This will be done by chance, using a computer. You will not get to choose which group you are assigned to. This is done to achieve the best study results. It ensures that both groups are similar and avoids any bias. It is also done because we don’t know if one intervention is better than the other.

Throughout the study, you will be asked to complete surveys. These surveys will ask about your quality of life and treatment or surveillance experience. The surveys are very important. They will help to compare risks and benefits between standard care and active surveillance. They will also enable a better understanding of the DCIS experience.

The study will last a minimum of five years. However, you may be asked to remain in the study for up to seven years. The study team may also ask to follow your progress for up to ten years.

How will I be monitored in the COMET Study?

Throughout the study, you will be regularly monitored by your surgeon and possibly a medical/radiation oncologist. In addition, you will have a clinical trial support team. This will include a clinical trials coordinator. Over the course of the five-year study, you will receive periodic screening and access to specialist advice. Regular follow-up examinations will include mammograms, ultrasounds or MRIs. If you are assigned to the active surveillance group, you will have a mammogram every six months (as opposed to every 12 months).

If changes in the breast are found on a mammogram, a biopsy (tissue sample taken from the breast) may be recommended. If the biopsy shows invasive cancer you may be safely treated with standard care (breast surgery and sometimes radiation therapy). Endocrine therapy may also be recommended.

What happens if I want to leave the COMET Study?

You are free to leave the COMET Study at any time. For example, if you are assigned to a group that you do not wish to join you can leave, although we will request that you continue to complete the surveys. There will be no penalty or loss of benefits to you, and you will not lose medical care or any legal rights. During the course of this study, the clinical trial staff and your physician will help guide you through these decisions.


Some members of the COMET Study Patient Leadership Team

Some members of the COMET Study Patient Leadership Team

Dr. Shelley Hwang, Principal Investigator of the COMET Study

Dr. Shelley Hwang, Principal Investigator of the COMET Study

Some members of the COMET Study Team

Some members of the COMET Study Team

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