(RxWiki News) Breast cancer patients with triple negative tumors may be harder to treat, but that doesn’t necessarily mean that radical surgery is needed.
Researchers recently set out to see whether breast conserving surgery for triple negative breast cancers changed the risk of local recurrence of cancer. Local recurrence means a new tumor develops near the same place the first tumor was found.
These researchers found that breast conserving surgery for patients with triple negative breast cancer tumors did not have a higher risk of local recurrence. Tumor size was the only factor that predicted local recurrence.
"Ask your oncologist about therapy options for your tumor type."
This research team led by Alexandra Gangi, MD, from the Department of Surgery at Cedars-Sinai Medical Center in Los Angeles, California, compared the results of breast-conserving therapy for triple negative breast cancer patients to the outcomes of patients who had other types of breast cancer.
Breast cancer tumors can be characterized by the proteins and other markers, called receptors, on their surface. Anti-cancer medications have been developed to target these proteins and markers.
Tumors that lack estrogen receptors (ERs), progesterone receptors (PRs) and v-erb-b2 avian erythroblastic leukemia viral oncogene homolog2 (ERBB2) are called triple negative breast cancers (TNBC). These triple negative tumors are harder to treat, are more aggressive and are associated with a worse overall survival.
Since approximately 10 to 20 percent of all newly-diagnosed breast cancers are TNBC, it is important to look at these distinct tumor types when evaluating therapies for TNBC patients.
Previous clinical trials showed that overall survival was similar for patients who had mastectomies, in which the entire breast was removed, and those who had breast conserving surgery, in which only the tumor and a small amount of breast tissue was removed. Those studies, however, did not look at whether the breast cancers were triple negative.
For their research, Dr. Gangi’s team reviewed data on patients who were evaluated and treated for breast cancer from the beginning of January 2000 through the end of May 2012. Women with stage I through III breast cancer, ages 18 through 85, were included in the study. The researchers included data from women whose ER, PR and ERBB2 receptor status was known. A total of 1,851 patients were included in this research.
Breast cancer tumors were characterized by size, cell type, grade, stage and whether lymph nodes near the tumors had cancer cells in them. Cancer grade refers to how cells look under a microscope and is used to estimate how fast tumors might grow. Cancer stage describes the size of the tumor and how far it has spread from where it started.
Data was collected on where the breast cancer was detected again. A local recurrence was a tumor that showed up in the same or near the same place as the previous tumor. A regional recurrence was a tumor that showed up in lymph nodes and tissue in the general vicinity of the original tumor, and a distant recurrence was a tumor that was found far from the original tumor.
The amount of time the patients lived was measured as overall survival time.
Treatment given to the patients was also noted. These women received radiation therapy for their cancer as standard practice.
The researchers found that 12.6 percent of the tumors were TNBC. Other subtypes of tumors were identified. Luminal A subtype made up 72.4 percent of the tumors, luminal subtype B made up 11.5 percent and ERBB2-enriched subtype was found in 3.5 percent.
Independent of whether a tumor was TNBC or not, tumors greater than 5 cm in size were linked to a 4.7-fold higher risk of local recurrence in five years than tumors 2 cm or less.
Any stage II tumors were associated with a 5.2-fold higher risk of regional recurrence in five years compared to stage I, and any stage III tumors carried an 8.3-fold higher risk of regional recurrence compared to stage I.
TNBC tumors were linked to a five times smaller risk of regional recurrence in five years compared to tumor subtype ERBB2-enriched.
Any tumor size greater than 2 cm was linked to a 3.5-fold higher risk of distant recurrence in five years, and any tumor over 5 cm was associated with a 5.5-fold higher risk of distant recurrence in five years. Compared to tumors of the luminal A type, TNBC tumors were linked to a 2.5-fold higher chance of distant recurrence in five years.
Women age 50 and older had 2.2-fold worse overall survival odds.
Stage III cancer was linked to 2.8-fold worse overall survival odds than stage I, and tumors 5 cm and larger were linked to 4.2-fold worse overall survival odds. TNBC patients had 3.5-fold worse survival odds compared to patients with luminal A type and 3.7-fold worse survival odds compared to patients with luminal B tumors.
Overall, the researchers showed that when five-year outcomes were compared in patients who had breast conserving surgery, only tumor size was associated with local recurrence. Tumor stage was associated with regional recurrence and both tumor stage and size were associated with distant recurrence in five years.
Age, tumor stage and tumor size, as well as triple negative breast cancer, was associated with decreased overall survival.
In patients who received breast conserving surgery, triple negative breast cancer was not a predictor of cancer recurrence in five years.
“Breast-conserving therapy is appropriate for TNBC patients and should be routinely offered,” Dr. Gangi and team concluded.
“Triple negative breast cancer is an aggressive disease, more so than the majority of breast cancer, however, this does not necessarily mean the disease will return in the breast," said Dr. Subhakar "Sub" Mutyala, Associate Director of the Baylor Scott & White Cancer Institute and Associate Professor at Texas A&M College of Medicine in Temple, Texas.
"This study shows that patients with triple negative breast cancer can be treated with breast conserving therapy and not require a mastectomy,” said Dr. Mutyala, who was not involved in this study.
This research was published in the January issue of JAMA Surgery.
The authors of this study did not disclose any conflicts of interest.
Support for this research was provided by the Fashion Footwear Charitable Foundation of New York, Inc, Associates for Breast and Prostate Cancer Studies, the Avon Foundation, the Margie and Robert E. Petersen Foundation, and Linda and Jim Lippman.