TMIST investigators respond
A pair of TMIST investigators commented about the NCI’s planned reevaluation – and what it means.
Etta D. Pisano, MD, the study’s principal investigator, accented the positive: “We have heard nothing of suspending TMIST and are ready to work with NCI to reach TMIST endpoints more efficiently,” she said in an interview.
She also offered a positive spin on TMIST enrollment and trial site enlistment. “Enrollment quadrupled and trial sites doubled in the 14 months prior to the COVID-19 pandemic. An unheard of 19% of the 30,000 women enrolled at 99 sites are African American.”
The trial has “momentum,” said Dr. Pisano, who is also chief research officer at the American College of Radiology.
Dr. Castle, however, noted that enrollment is far behind schedule; the 30,000 women who have been enrolled so far represent less than a quarter of the planned enrollment of 165,000 women, due by the end of 2020.
TMIST is designed to learn whether 3-D mammography is better at finding – and reducing the rate of – potentially lethal cancers than older 2-D technology.
Most 3-D systems are used in conjunction with 2-D. First, two static images of the breast are taken (2-D), and then the unit moves in an arc, taking multiple images of the breast (3-D). This allows radiologists to flip through the images like pages in a book and is considered to offer a superior read of the breast.
TMIST uses “advanced” breast cancers as a novel surrogate outcome. The trial period is 4.5 years, during which women are screened annually to determine which imaging technology results in fewer advanced cancers. These include larger HER2-positive and triple-negative malignancies; those associated with positive nodes; and metastatic disease.
These malignancies correlate with breast cancer mortality, Dr. Pisano said.
“We need this trial to help us learn how to improve the process for identifying high-risk patients and how to utilize both of these technologies better,” said Mitchell Schnall, MD, PhD, from the University of Pennsylvania. He is cochair of the ECOG-ACRIN trial group, which is corunning TMIST.
“Look, we all know that 3-D sees more lesions, but consequently, more women are having additional procedures, including biopsies and excisions. The question that TMIST asks is whether that huge expenditure of time, money, and psychological stress is worth it in terms of better outcomes for each person who has the experience,” Dr. Schnall said in an interview.
“One size should not fit all in breast cancer screening, and the TMIST trial can show the way to a precision approach to screening,” he said.
But, earlier this year, Daniel Kopans, MD, professor of radiology, Harvard Medical School, Boston, said in an interview that TMIST is a “huge waste of money.”
He believes that “radiologists who are experienced in using [3-D] for screening will not go back.
“It would be malpractice since they know there are cancers that they will miss on [2-D] that they can find on tomosynthesis,” said Dr. Kopans. He was involved in the development of the first 3-D unit but no longer profits from its sales because his group’s patent has expired.
TMIST was conceived before 3-D mammogram took off clinically, which may explain the trial’s enrollment and site participation woes. In the lag time between the initial trial design (2012) and study start date (2017), clinical practice in the United States and Canada shifted quickly to embrace the newer technology.
This article first appeared on Medscape.com.