AACR 2019: Does Primary Tumor Surgery Increase Survival in Patients With Advanced HER2-Positive Breast Cancer?
Surgery was associated with higher survival rates for patients with HER2-positive stage IV breast cancer compared with those who did not undergo surgery, according to results presented by Mudgway et al at the American Association for Cancer Research (AACR) Annual Meeting (Abstract 4873).
Between 20% and 30% of all newly diagnosed stage IV breast cancer cases are HER2-positive, explained the study’s lead author, Ross Mudgway, a medical student at the University of California, Riverside School of Medicine. This form of breast cancer once had poor outcomes, but in recent years, advances in targeted therapy such as trastuzumab have led to improved survival. In recent years, most patients with HER2-positive breast cancer have been treated with systemic therapy, which could include chemotherapy, targeted therapy, or hormonal therapy, Mudgway said. Surgery is sometimes offered to these patients, but previous research on whether surgery improves survival has yielded mixed results, he said.
Mudgway and senior author Sharon Lum, MD, Professor in the Department of Surgery-Division of Surgical Oncology and Medical Director of the Breast Health Center, Loma Linda University Health, noted that HER2 status has been reported in large registry data sets since the early 2000s, but the impact of surgery on this type of breast cancer has not been well documented across hospital systems.
Methods
To assess the impact of primary tumor resection on survival in patients with HER2-positive stage IV breast cancer, they conducted a retrospective cohort study of 3,231 women with the disease, using records from the National Cancer Database from 2010 to 2012.
Of these women, 89.4% had received chemotherapy or targeted therapies, 37.7% had received endocrine therapy, and 31.8% had received radiation. Overall, 1,130 women (35%) received surgery.
Findings
The researchers found that surgery was associated with a 44% increased chance of survival, assuming the majority of patients also had systemic treatment.
“This suggests that, in addition to standard HER2 targeted medications and other adjuvant therapy, if a woman has stage IV HER2-positive breast cancer, surgery to remove the primary breast tumor should be considered,” said Dr. Lum.
The study also examined factors associated with receipt of surgery, and found that women with Medicare or private insurance were more likely to have surgery and less likely to die of their disease than those with Medicaid or no insurance. White women were also more likely than non-Hispanic black women to have surgery, and less likely to die of their cancer.
“These results suggest disparities in health care due to race and socioeconomic factors, and these must be addressed,” Mudgway said.
Mudgway and Dr. Lum said numerous factors may contribute to a physician’s decision on whether to recommend surgery, including comorbidities, response to other forms of treatment, and overall life expectancy. They said these findings should be considered in the context of all other factors.
“For patients, the decision to undergo breast surgery, especially a mastectomy, can often be life-changing, as it affects both physical and emotional health,” Mudgway said. “The patient’s own feelings about whether or not she wishes to have surgery should be considered.”
Dr. Lum noted that this is a retrospective study and may not be fully representative of women facing the decision of whether to have surgery. For example, she noted, doctors may be most willing to operate on women who are healthier overall and are, therefore, more likely to experience a positive outcome. Further research would be needed to confirm the survival benefit suggested by this study.
Disclosure: This study was self-funded by the Department of Surgery at Loma Linda University. The study authors’ full disclosures can be found at abstractsonline.com.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
