In 1988, 33.5% of women who were diagnosed with breast cancer in the United States died from the disease.
In 2010, that number dropped to 23.5%, according to research from the National Cancer Institute. This means that 76.5% of diagnosed women survive breast cancer.
The study was published online on July 20, 2015 by the Journal of Clinical Oncology. Read the abstract of “Improvements in US Breast Cancer Survival and Proportion Explained by Tumor Size and Estrogen-Receptor Status.”
The researchers looked at the SEER database to see how many women had been diagnosed and died from breast cancer from 1973 to 2010. SEER databases are large registries of cancer cases from sources throughout the United States maintained by the National Institutes of Health.
The information included 543,171 women diagnosed with a first primary invasive breast cancer.
The improvements in survival didn’t seem to be linked to changes in cancer size or estrogen-receptor status in women younger than 70 years of age, so it’s likely that the better survival is due to better treatments.
"Breast cancer mortality rates following diagnosis have been decreasing over four decades, not only in the first five years after diagnosis but thereafter," said Mitchell Gail, senior investigator in the biostatistics branch of the National Cancer Institute’s Division of Cancer Epidemiology and Genetics and lead author of the study. "Little of the improvement could be explained by changes in tumor size or estrogen-receptor status over time in women under age 70. This suggests a major contribution from treatment for these women."
For women 70 and older, it’s likely that about half of the improvement in survival was linked to changes in tumor size or estrogen-receptor status. This means that in these women, the breast cancers are being found when they’re smaller, which means they’re probably easier to treat. Also, almost all cancers are now tested for hormone-receptor status. If a cancer is hormone-receptor-positive, it can be treated with hormonal therapy.
The researchers also found:
- The number of breast cancer cases went up through the year 2000 and went down slightly after that.
- Rates of estrogen-receptor-positive cancers diagnosed paralleled the overall number of breast cancer cases.
- Rates of estrogen-receptor-negative cancers declined during the years of the study.
- Cancer size declined from 25 mm in the early 1980s to 16 mm in 2009.
- Screening mammography rates increased from 29% in 1987 to about 70% in 2000 and later.
A number of factors likely contributed to the improvement in survival, including:
- better screening, resulting in earlier diagnoses
- better coordination of breast cancer care
- surgery improvements
- new and better chemotherapy medicines
- new medicines that target specific characteristics of the cancer (targeted therapies), including Herceptin (chemical name: trastuzumab), Ibrance (chemical name: palbociclib), Perjeta (chemical name: pertuzumab), and Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine)
- hormonal therapy given after surgery to lower the risk of hormone-receptor-positive cancer coming back (recurrence)
Stay tuned to Breastcancer.org Research News to learn about advances that will lead to better care and even better survival for people diagnosed with breast cancer.