Jan. 9 (UPI) -- Breast cancer deaths have dramatically declined as a result of new drugs and better screenings since 2000, six independent groups of researchers have concluded.
Researchers from universities and hospitals wanted to know if the recent advances in drugs -- including chemotherapies and targeted compounds -- and digitizing mammogram technology have made a difference in how many women die of breast cancer.
The researchers' Cancer Intervention and Surveillance Network models showed that screening and treatment reduced breast cancer mortality by 49 percent in 2012, compared with 37 percent in 2000, according to a new study published in the Journal of the American Medical Association.
"These numbers represent very positive news for breast cancer patients," Dr. Sylvia Plevritis, a professor of radiology and biomedical data science at the Stanford University School of Medicine and lead author of the paper, said in a press release. "Advances in screening and treatment are saving patients' lives, and this paper quantifies just how much of a difference these advances are making."
Researchers also were from the Dana-Farber Cancer Institute based in Boston, Erasmus Medical Center in the Netherlands, Georgetown University Medical Center, Albert Einstein College of Medicine in New York, the University of Wisconsin, Harvard Medical School and MD Anderson Comprehensive Cancer Center in Houston.
Breastcancer.org estimates that about 40,610 women in the United States died from breast cancer in 2017. While the mortality rate has declined since 1989, significantly for those under 50, breast cancer death rates are higher than those for any other cancer, aside from lung cancer.
In 2005, Plevritis and her colleagues used data from 1975 through 2000 to reveal how screening and treatment reduced breast cancer mortality rates. They developed models representing how many women would die of the cancer with no screening and no treatments, then simulated the effect of screening and treatment on those mortality numbers.
At the time, the decrease in mortality was split evenly between screening and treatments among women aged 30 to 79 years.
"Now, over 10 years later, a lot has happened in the field," said Plevritis, who heads the Stanford Center for Cancer Systems Biology. "We've moved from film-based mammography to digital; there are new molecularly targeted treatments and new types of chemotherapy regimens. We wondered whether these advances had changed the relative contributions of treatment and screening on breast cancer mortality."
Researchers in independent teams updated their models.
"This time around, it was important to look at molecular subtypes because more women are being treated based on the molecular subtype of their tumor," Plevritis said.
In 2012, researchers found breast cancer mortality was reduced nearly one half. Broken down, 37 percent was due to screening and 63 percent from treatment.
"Newer drugs, particularly ones that are molecularly targeted, are associated with a greater reduction in breast cancer mortality than screening," said Dr. Jeanne Mandelblatt, a professor of oncology and medicine at Georgetown University. "However, screening is still having a significant effect in reducing breast cancer deaths."
The researchers found out the numbers in screening and treatments varied for subtypes of cancer, noting that screening can lead to cancer detected at earlier stages and therefore less intense treatments.
"There have been many investments in screening and treatment; we want to know what impact those investments have had in reducing mortality," Plevritis said. "It also helps us think about the future and how to make sure technologies and drugs that are making the biggest difference are disseminated most widely."