TMIST trial enrollment: 2-D vs 3-D mammography

By Liz Meszaros, MDLinx
Published October 13, 2017

Key Takeaways

In the upcoming Tomosynthesis Mammographic Imaging Screening Trial (TMIST), researchers will attempt to determine the optimal methods of finding breast cancer in asymptomatic women. The study will be a comparison of two types of digital mammography: standard digital mammography (2-D) and a newer technology known as tomosynthesis mammography (3-D).

Unlike 2-D mammography, which obtains pictures from two sides of the breast to create a flat image, 3-D mammography takes pictures from different angles around the breast, and then builds these images into a 3-D–like image.

In addition, TMIST researchers will also be building a tissue bank for future research. All subjects in the study will be asked to submit tissue samples, such as blood samples and mouth swabs. Researchers hope to obtain information from these samples that will help determine the best ways to screen for breast cancer in the future, with genetics and other personal risk factors taken into account.

Study goals

TMIST’s primary goal is to measure and compare rates of newly diagnosed breast cancer that meet the following criteria:

  • Tumors 20 mm or larger
  • HER2-positive tumors larger than 10 mm
  • Triple-negative tumors larger than 10 mm
  • Cancer that has spread from the breast to at least one nearby lymph node
  • Cancer that has spread from the breast to distant organs in the body

Researchers will also seek answers to the following questions:

  1. In women undergoing 3-D mammography, will harder-to-treat cancers be less frequent in groups such as women with dense breasts, African Americans, premenopausal women, and women on hormone replacement therapy?
  2. Will fewer false-positive tests be found in the whole study group, or among certain subgroups?
  3. Is there a link between certain mammogram findings and the most aggressive breast cancers?

Enrollment for TMIST

TMIST will include mammography clinics throughout the United States and include a few sites in Canada. Researchers plan to include about 100 clinics in the trial with a target enrollment of approximately 165,000 women over the next 2.5 years. Women attending one of the participating clinics may be asked to take part in TMIST, with those aged 45 to 74 planning to have a routine screening mammogram considered eligible.

To enroll, patients and clinicians can contact one of the participating sites, which are listed in the “Locations & Contacts” section of the trial record.

Study design

Women will be randomized to receive either 3-D or 2-D screening mammograms for 5 years. The frequency of their mammograms will be based upon the following characteristics:

  • Age
  • Breast density
  • Family history of breast cancer
  • Presence of genetic changes known to cause breast cancer
  • Use of hormone replacement therapy
  • Menopausal status

For those aged 45 to 69 years with any of the following characteristics, only one mammogram per year will be required, for a total of five mammograms over 5 years:

  • Have regular periods, had most recent period within the past 12 months, or are younger than 52, and have had a hysterectomy but retained their ovaries;
  • Have dense breasts;
  • Take hormone replacement therapy prescribed by a doctor; or
  • Have a family history of breast cancer or genetic changes known to cause breast cancer

Women aged 45 to 69 years who have none of these characteristics will have a mammogram every 2 years, for a total of three mammograms over 5 years.

In women aged 70 to 74 years with dense breasts or who take hormone replacement therapy prescribed by a doctor, one mammogram per year will be required, for a total of five mammograms over 5 years.  Those who have neither will require a mammogram every 2 years, for a total of three mammograms over 5 years.

In women who experience risk changes—including new genetic testing findings, changes in family history, or changes in hormone replacement therapy use—the frequency and number of mammograms may change. Women diagnosed with breast cancer during the study will undergo treatment just as they would if they were not in the study.

Upon completion of the study, women will be followed for 3 years, during which they will decide, in conjunction with their primary care doctor, which type of mammogram they will receive.

TMIST is supported by NCI and coordinated by the ECOG-ACRIN Cancer Research GroupExit Disclaimer.

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