By Megan Brooks
NEW YORK (Reuters Health) - 5/4/2019
Surgery is associated with higher survival rates in women with HER2-positive stage-4 breast cancer treated with systemic therapy, a retrospective study shows.
"This suggests that, in addition to standard HER2 targeted medications and other adjuvant therapy, if a woman has stage 4 HER2+ breast cancer, surgery to remove the primary breast tumor should be considered," senior author Dr. Sharon Lum, medical director of the Breast Health Center, Loma Linda University Health in California, said in a statement.
Her colleague, Ross Mudgway, a medical student at the University of California, Riverside School of Medicine, presented the study at a press briefing April 2 during the American Association for Cancer Research (AACR) annual meeting in Atlanta.
Most women with HER2+ breast cancer are now treated with chemotherapy, targeted therapy, or hormonal therapy. Surgery may be offered, but previous studies demonstrated "mixed results" about the survival benefit of excision of the primary tumor, Mudgway explained.
To assess the impact of primary tumor resection on survival in HER2+ stage IV breast cancer patients, the researchers took a look back at 3,231 women with the disease, using records from the National Cancer Database from 2010 to 2012.
Of the total cohort, 89.4% had received chemotherapy or targeted therapies, 37.7% had received endocrine therapy and 31.8% had received radiation; 1,130 women (35%) had surgery.
Median follow-up was 21 months (range 0 to 52 months). Median survival was 25 months with surgery and 18 months without surgery. After controlling for confounding factors, surgery was associated with significantly better odds of survival (hazard ratio, 0.56; P=0.0004), Mudgway reported.
"Surgery should be discussed with patients as an option alongside targeted therapy and other standards of care," he told the briefing.
Dr. Lisa Newman, chief of the section of breast surgery at NewYork-Presbyterian/Weill Cornell Medical Center, in New York City, told Reuters Health by email that the study is "noteworthy because it provides additional data regarding the possible role of breast surgery in women diagnosed with metastatic breast cancer. Improvements in systemic and targeted therapy for breast cancer have resulted in prolonged survival among women with Stage IV disease, and resulted in a resurgence of interest regarding the role of surgery in women found to have metastatic disease when newly diagnosed."
Dr. Newman, who was not involved in the work, said it "confirms the improved outcomes that we can achieve in HER2-overexpressing cancer through targeted anti-HER2 therapy, even in the setting of metastatic disease. Surgery to the breast may possibly contribute to this improved outcome, but each case should be evaluated individually to assess for evidence of response to initial/primary systemic therapy and overall fitness for surgery. Most importantly, each patient should be fully informed that surgery is optional, and definitive evidence of any survival benefit is lacking at this point in time."
"Since this was a retrospective study, it is subject to selection bias, which means that surgery was more likely to have been offered to patients that appeared to have the better-prognosis disease," she cautioned.
AACR 2019 Annual Meeting