Surgery to remove tumors was associated with a 44% increase in chance of survival within a median follow-up period of 21 months, according to the summary, to be presented at the annual meeting of the American Association for Cancer Research in Atlanta this week .
"If breast surgery is considered by patients and providers in deciding the treatment strategy, it will be imperative to address significant disparities between patients receiving surgical treatment," the researchers wrote.
The data showed that the majority of the women, 89.4%, were treated with chemotherapy or immunotherapy; 37.7% underwent endocrine therapy; and 31.8% were submitted to radiation. Overall, 35%, or 1,130 women, underwent surgery; the rest is not.
"Surgery was less likely to be performed in older patients compared to younger, non-Hispanic black patients compared to whites, those treated in an academic or research institution compared to community programs, and those with larger size of the tumor, "she said.
The study also looked at where the surgery fits with other treatment options available to patients, such as targeted medications, said Ross Mudgway, a University of California medical student at Riverside School of Medicine who was the first author of the study.
The findings suggest that surgery to remove a breast tumor should still be considered, in addition to standard targeted medications and other therapies, if a woman presents stage 4 HER2 positive breast cancer.
"We hope our findings encourage doctors to consider surgical treatment for metastatic disease while assessing the potential risks and benefits in this specific subset of patients who have new, effective targeted therapeutic options," Mudgway said.
The study had some limitations, including that there was only one association between surgery and survival, and the data did not include specific information about which other targeted therapies were used among patients.
In addition, "we still do not have results from randomized clinical trials that address the impact of surgical removal of breast tumor in patients with HER2-positive metastatic breast cancer," Lum said.
"Therefore, the use of observational data from the large NCDB dataset can help address the questions about the surgical treatment that providers and patients are doing today," she said.
Traditionally, surgery has been a standard part of the treatment of breast cancer along with drugs and radiation.
"The patients who underwent surgery were the ones who had the best responses to chemotherapy, probably had less metastatic disease and were probably healthier," she said. "So maybe they've lived longer because of the surgery, or maybe they've lived any longer anyway, and the study shows that doctors know how to identify patients who do well."
In other words, more research is needed to determine whether these factors are influencing the findings of the new study, since databases – as used in the new study – may sometimes suffer from selection bias.
"The question of a benefit for surgery can only be answered by a prospective randomized study," said Morrow.
"We look forward to the results," Morrow said.
For example, patients with a good response to first-line or initial therapy would have been selected for subsequent surgery, "while those whose disease was refractory to first-line therapy would not have undergone surgery." Therefore, piling the letters in favor of surgery". the surgery group, "King said.
"The risks and benefits of local therapy – plus radiation surgery – for breast cancer are favorable when surgery is being performed for curative purposes," she said.