Triple-negative breast cancer is:
So the growth of triple-negative disease isn’t driven by the hormones estrogen or progesterone or by the presence of too many HER2 receptors. This means that triple-negative breast cancer doesn’t respond to hormonal therapy (such as tamoxifen or an aromatase inhibitor) or therapies that target HER2 receptors, such as Herceptin (chemical name: trastuzumab), Tykerb (chemical name: lapatinib), Perjeta (chemical name: pertuzumab), or Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine).
About 15% to 20% of breast cancers -- more than one out of every 10 -- are triple-negative. Triple-negative breast cancer tends to be more aggressive than other types of breast cancer.
Triple-negative breast cancer usually is treated with a combination of surgery, radiation therapy, and chemotherapy.
A study has found that women age 70 and older diagnosed with early-stage, triple-negative breast cancer who had radiation after lumpectomy were 6 times more likely to be alive than women who didn’t have radiation after lumpectomy.
This is the first study to look at how much radiation after lumpectomy improved survival in older women diagnosed with triple-negative disease.
Doctors call treatments given after surgery adjuvant treatments.
The research was presented on Sept. 25, 2015 at the American Society of Clinical Oncology Breast Cancer Symposium in San Francisco. Read the abstract of “Outcomes associated with adjuvant radiation after lumpectomy for elderly women with T1-2N0M0 triple-negative breast cancer: SEER analysis.”
To do the study, the researchers downloaded information from the SEER databases. The SEER databases are large registries of cancer cases from sources throughout the United States maintained by the National Institutes of Health.
The researchers looked at the records of 974 women ages 70 and older who were diagnosed with early-stage, triple-negative breast cancer between 2010 and 2011:
- all the women had lumpectomy to remove the cancer
- 662 women (68%) had radiation after lumpectomy
The researchers compared overall survival and disease-specific survival among the two treatment groups, controlling for other factors such as whether the women had chemotherapy or not, the grade of the cancer, the women’s ages, and whether the women had been diagnosed with other types of cancer.
Overall survival is how long the women lived, whether or not the cancer came back (recurred). Disease-specific survival means the researchers looked at how many women didn’t die from breast cancer.
About 2 years after treatment, women who had lumpectomy plus radiation had much better overall survival than women who had only lumpectomy:
- 98.2% of the women who had lumpectomy plus radiation were alive
- 85.6% of the women who had lumpectomy alone were alive
Disease-specific survival also was better for the women who had lumpectomy followed by radiation:
- 99% of the women who had lumpectomy plus radiation were alive
- 94% of the women who had lumpectomy alone were alive
This means that 1% of the women who had lumpectomy plus radiation died of breast cancer and 6% of the women who had lumpectomy alone died of breast cancer.
Both of these survival differences were statistically significant, which means the difference was likely because of the radiation and not just due to chance.
“By quantifying the benefit associated with adjuvant radiation, this provides perspective and enables more statistical objectivity in the process outlined by NCCN [National Comprehensive Cancer Network] to evaluate and manage elderly patients," said Sean Szeja, M.D., of the University of Texas Medical Branch at Galveston, who was one of the study authors. "Prior to this study, there has not been any measurement of the reduction of breast cancer specific mortality from the addition of radiation to lumpectomy in this patient population."
The study did have some weaknesses. Although the researchers were able to control for many important variables, such as age and cancer grade, they couldn’t control for two very important factors:
- whether the women had any other health problems
- the women’s overall health
So it’s likely that more intensive treatment plans, which would include chemotherapy and radiation, were recommended for healthier women. This means that some of the survival benefits of radiation could have happened because overall healthier women were in the treatment group that got radiation while radiation wasn’t recommended for less healthy women.
Still, this study offers encouraging news for older women diagnosed with triple-negative breast cancer.
If you’re 70 or older and have been diagnosed with triple-negative disease and are making treatment decisions, you might want to talk to your doctor about this study. Ask your doctor which treatments are recommended for you and why, as well as about the risks and benefits of each treatment.
Together, you can develop a treatment plan that makes the most sense for your unique situation.
For more information, visit the Breastcancer.org Triple-Negative Breast Cancer pages.