Women diagnosed with breast cancer that is already at Stage IV, meaning metastatic cancer that has spread to other parts of the body, do not experience a benefit in overall survival from surgery to remove the original tumor, MedPage Today reports.

That’s according to a new randomized trial known as ECOG-ACRIN E2018, the results of which were presented as part of the virtual scientific program of the 2020 American Society of Clinical Oncology (ASCO) Annual Meeting.

Previous retrospective analyses of data on women first diagnosed with breast cancer at Stage IV—known as de novo metastatic breast cancer—suggested that there was a survival benefit from surgery to remove the primary tumor, meaning the root of the cancer. Some 6% of people with breast cancer already have Stage IV disease at diagnosis.

Seema Ahsan Khan, MD, of Northwestern University Feinberg School of Medicine in Chicago, and her colleaguesenrolled 256 women with de novo breast cancer who had received optimized systemic therapy for their metastatic cancer. Enrollment ran from 2011 to 2015.

The study randomized those whose disease did not progress after four to eight months of such treatment to continue receiving the systemic treatment or to receive surgery to remove their primary tumor, with or without radiation therapy. Within this subgroup, a majority had hormone receptor–positive/HER2-negative breast cancer, a third had HER2-positive cancer and the remainder had triple-negative breast cancer, which is harder to treat with systemic medications.

Of the 125 people randomized to the surgery group, 109 actually underwent surgery, and 74 received radiation; 25 of the 131 people randomized to stay on systemic therapy ultimately also received surgery.

Following a median of 53 months of follow-up, there was no difference in the overall survival rate between the women who did and did not receive surgery—it was 54 months in both cases. Nor was there any difference in the two cohorts’ progression-free survival rate, with 89 people in each group dying or experiencing progression of their cancer.

Those who did not receive surgery, however, had a higher rate of progression of their cancer within the breast, chest wall or nearby lymph nodes, as opposed to elsewhere in the body.

The study authors did not rule out that surgery to the primary tumor might help selected people with de novo Stage IV breast cancer.

“Based on the available data, locoregional therapy for the primary tumor should not be offered to women with Stage IV breast cancer with the expectation of a survival benefit,” Khan said. “When systemic disease is well controlled with systemic therapy but the primary site is progressing, locoregional therapy may be considered.”

To read the MedPage Today article, click here.

To read the conference abstract, click here.