Women with breast cancer may benefit from surgery to remove their primary tumor even if they are diagnosed at the most advanced stage of disease, according to research presented at the American Association for Cancer Research (AACR) annual meeting this month in Atlanta.

Women with HER2-positive metastatic breast cancer who underwent surgery had a higher overall survival rate compared with those who were not offered or opted out of surgery, reported Ross Mudgway, a medical student at the University of California Riverside School of Medicine.

Stage IV breast cancer that has spread to other parts of the body is considered incurable. Current practice is to treat such patients with systemic therapies, which may include chemotherapy, hormone therapy to suppress hormones that promote cancer growth or targeted therapies that work against cancer with specific characteristics. HER2-positive tumors express human epidermal growth factor receptor 2, which makes them susceptible to HER2-blocking drugs such as Herceptin (trastuzumab) and pertuzumab (Perjeta).

Unlike people with early cancer confined to the breast and nearby lymph nodes, those diagnosed with metastatic breast cancer traditionally have not undergone surgery to remove the original tumor in the breast (although surgery may be done as palliative care to reduce symptoms). Prior research on whether surgery improves survival for women with advanced cancer has yielded mixed results. But surgery may be warranted for those who respond well to HER2-targeted therapies, Mudgway noted as background.

Mudgway and colleagues conducted a retrospective analysis using records from the American College of Surgeons’ National Cancer Database from 2010 (when mandatory reporting of HER2 status began) through 2012. They identified 3,231 women diagnosed with HER2-positive Stage IV breast cancer. Just over 70 percent were white, 18 percent were Black and 6 percent were Latina. Nearly half (46 percent) had private insurance, 32 percent had Medicare and 23 percent had Medicaid or were uninsured. A third were treated at academic or research centers, the rest at community medical centers.

About a third of the women (35 percent) had undergone surgery, 32 percent had received radiation therapy, 38 percent had received hormone therapy and 89 percent had received chemotherapy or targeted therapies; many patients received more than one type of treatment. Women who received surgery were a bit younger, on average, than those who did not (56 years versus 59 years).

After nearly two years of follow-up, the median overall survival for women who underwent surgery was 25 months compared with 18 months for those who did not. That is, receiving surgery was associated with a 44 percent reduction in the risk of death, assuming most patients also used systemic therapies, Mudgway reported.

“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,” senior author Sharon Lum, MD, medical director of the Breast Health Center at Loma Linda University Health, said in an AACR press release.

The researchers also looked at factors associated with receiving surgery. Black women were less likely to undergo surgery than white women (28 percent versus 37 percent) and were more likely to die of cancer, Mudgway reported. Younger women (ages 20 to 39) were more likely to have surgery than those ages 40 to 59 or over 60 (45 percent, 37 percent and 31 percent, respectively).

Women covered by Medicaid or without health insurance (27 percent) were less likely to receive surgery than those with private insurance (42 percent) or Medicare (31 percent). Those treated at academic or research centers were also less likely to receive surgery than those at community centers (29 percent versus 37 percent)—perhaps because they are more likely to enroll in clinical trials of experimental therapies.

Numerous factors can come into play when deciding on surgery, including coexisting health conditions, how well patients respond to other treatment and overall life expectancy, according to Mudgway and Lum. The impact of surgery on quality of life is also an important factor.

“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.”

A potential confounding factor in this retrospective analysis, which looked at past outcomes reported in medical records, is that women who underwent surgery may have been healthier and had a better prognosis than those who did not. Prospective clinical trials of surgery versus no surgery in women receiving modern systemic therapies are currently underway.

Click here to read the study abstract.