Surgery may improve survival in advanced breast cancer
Surgical resection of the primary tumour improves overall survival (OS) in patients with advanced breast cancer, a new retrospective analysis shows.
“After adjusting for the clinical factors, it has been demonstrated that surgery was … independently associated with improved survival rates,” the researchers wrote.
Over a median follow-up of 24 (1 to 178) months, the median OS of 223 stage IV breast cancer patients was 39 months. Median survival was significantly longer in patients who underwent surgery (n=177;) than in those who did not (n=46; 45.6 vs 21.3 months; p<0.001). [Medicine 2017;96:e7048]
Moreover, patients in the surgery group had significantly better complete or partial responses to neoadjuvant systemic therapy prior compared with first chemotherapy in the nonsurgery group (p=0.003). Despite this, 35 percent (n=62) of patients in the surgery group opted for direct surgery.
“Patients with surgery had dramatically longer OS than those without surgery. No differences were found in the patient characteristics between surgery and nonsurgery groups,” the investigators said.
In the surgery group, 115 of 117 patients underwent modified radical mastectomy while the remaining 55 had radical mastectomy. There was no significant difference in survival rate between the two surgery type groups (p=0.939).
“[W]e found that modified radical mastectomy or radical mastectomy could not affect the OS, which suggested that modified radical mastectomy instead of radical operation may act as the primary surgical selection for stage IV breast cancer,” the researchers explained.
Aside from a smaller tumour size (hazard ratio [HR], 2.831; 95 percent CI, 1.150 to 6.969; p=0.024), no lymphatic invasion (HR, 1.818; 0.893 to 3.701; p=0.047) and a positive hormone receptor (HR) status (HR, 0.532; 0.361 to 0.785; p=0.001), surgery was also associated with OS (HR, 0.332; 0.216 to 0.509; p<0.001) in univariate Cox analysis.
The association between surgery and OS in stage IV breast cancer remained significant (HR, 0.569; 0.329 to 0.984; p=0.044) despite adjusting for potential confounders.
Further stratification of patients showed that surgery significantly increased median OS in pre- and postmenopausal women (p<0.001 and p=0.001, respectively), those with HR-positive and negative disease (p<0.001 and p=0.018, respectively), and nontriple negative breast cancer patients (p<0.001).
The current literature about the impact of surgical resection on OS in stage IV breast cancer patients is conflicting. In a 2014 paper cited by Dr Mona Tan, principal surgeon at the MammoCare clinic in Singapore, Dr Seema Khan of the Feinberg School of Medicine in Northwestern University in US argued that surgery in stage IV breast cancer confers no significant benefit. [J Surg Oncol 2014;110:51-57]
“Review of the retrospective data suggests that there may be a survival advantage to locoregional therapy in women with metastatic breast cancer, which is not conﬁrmed by two unpublished randomized trials,” Khan wrote.
“Given the present limitations of the data, and the fact that surgery and radiation carry some risk, locoregional therapy for the primary tumour should be offered to patients only with full disclosure of the lack of evidence of a survival beneﬁt,” she added.
Electronic records of stage IV primary invasive breast cancer patients included in the present study were retrieved from the West China Hospital, Sichuan University in Southwest China. Mastectomy, radical mastectomy, modified radical mastectomy, palliative surgery and breast-conserving therapy were all considered as surgeries.