Research from The Cancer Institute of New Jersey (CINJ) shows that women with triple-negative breast cancer and no more than three positive lymph nodes following a mastectomy have a higher risk of local recurrence than similar women whose disease is not classified as triple-negative. The work will be presented as an abstract during the 54th Annual Scientific Meeting of the American Society for Radiation Oncology (ASTRO) in Boston this week. The Cancer Institute of New Jersey is a Center of Excellence of the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School (RWJMS).
Triple-negative disease occurs in 10 to 25 percent of all breast cancer cases. Some of the most successful breast cancer therapies target certain receptors (estrogen receptors, progesterone receptors or HER2/neu protein) that may cause cancer to spread. These receptors are absent from triple-negative breast cancer cells, thus making the disease resistant to some of these common treatments.
The implications for women with triple-negative breast cancer and just a few positive lymph nodes following mastectomy remain unclear. Most importantly, it is currently unknown which of these women may benefit from post-mastectomy radiation therapy. That is the aspect on which investigators from The Cancer Institute of New Jersey focused their research.
The researchers retrospectively identified 22 women with no more than three positive lymph nodes who suffered a local recurrence following mastectomy whose initial mastectomy tissue was available for study. None of the patients received radiation treatment following their procedure. These patient specimens were compared to those of 28 women with no more than three positive lymph nodes but no evidence of disease at their last follow-up visit. Controls were matched for age (+/- three years) and follow-up duration (less than five years versus more). Tissue specimens were examined for signs of disease.
What investigators found was that women classified as having triple-negative breast cancer were found to be associated with a higher risk of local recurrence. Conversely, being estrogen-receptor positive, progesterone-receptor positive or a combination of both was strongly associated with a lower risk of local recurrence. Use of chemotherapy was also associated with a lower risk.
"By further defining the risk of local recurrence in women with triple negative breast cancer, clinicians can better determine whether radiation treatment should be part of post-mastectomy therapy," noted the lead author of the research, Atif J. Khan, MD, a radiation oncologist at The Cancer Institute of New Jersey and an assistant professor of radiation oncology at RWJMS.
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