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Surgery for Metastatic Breast Cancer Associated With High Complication Rate

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Key Points

  • Breast cancer patients who present with metastatic disease may have more complications from surgery than patients operated on for earlier-stage disease.
  • In the adjusted analysis, morbidity rates were 1.6 times higher for metastatic patients vs early-stage patients undergoing resection as primary treatment of breast cancer.

Surgery for metastatic breast cancer conveys a significantly increased risk for morbidity and mortality at 30 days vs surgery for earlier-stage disease, according to researchers from the University of Toronto who presented their findings at the American Society of Breast Surgeons Annual Meeting in Las Vegas.

“Three to five percent of breast cancer patients present with stage IV disease at diagnosis, and we have been unsure of the role of primary breast surgery for these patients. One question that has not been answered is whether postoperative complications are increased in patients undergoing primary surgery for metastatic breast cancer,” lead researcher Erin Cordeiro, MD, said at a press briefing in advance of the meeting. “Clinicians often don’t know what to do, outside of selected patients.”

“We demonstrated that breast surgery in the setting of metastatic disease has approximately a 1.5-times increased odds of postoperative complications, and 30-day all-cause mortality was significantly higher in the metastatic group compared to the nonmetastatic group (stage I–III disease),” she reported.

Analysis of 68,000 Patients

This is the first study to document the morbidity and mortality associated with breast surgery in the setting of metastatic breast cancer, according to the investigators. They compared these outcomes with those from patients with early-stage breast cancer in the National Surgical Quality Improvement Program (NSQIP) database, a prospectively collected registry of 30-day inpatient and outpatient morbidity and mortality.

All patients had undergone a unilateral primary breast surgical procedure. Patients were excluded if they had high-risk comorbidities, underwent bilateral surgery, had surgery elsewhere (ie, liver resection) that was considered primary, or had synchronous high-risk surgery (ie, oophorectomy in conjunction with breast resection). Patients with nonmetastatic breast cancer who also had primary surgery served as matched controls.

Searching records from 2005 to 2012, Dr. Cordeiro and her team identified 1,031 patients (1.5% of the population) with primary metastatic disease and 67,285 with nonmetastatic disease.

“We found patients with metastatic disease vs early-stage disease had many differences at baseline, but the important one was that they were more likely to have received chemotherapy and radiation therapy before their operation,” she noted.

Higher Rate of Morbidity, Mortality

At the 30-day time point, in the unadjusted analysis, the metastatic disease patients had a higher rate of complications, including infection; respiratory issues; thromboembolic, cardiac, and bleeding problems; and unplanned readmissions. Wound infections and renal complications were not significantly higher. The overall morbidity rate was 7.5% for this group vs 3.7% for nonmetastatic patients (odds ratio [OR] = 2.1).

Strikingly, the mortality rate was significantly higher: 1.8% vs 0.1% (OR = 30.8), respectively. Dr. Cordeiro believes this is due to a systemic process associated with metastatic disease.

In the multivariable logistic regression analysis, having metastatic cancer carried an adjusted odds ratio of 1.6 for morbidity. A number of other factors were also independently associated with morbidity as well, though preoperative chemotherapy and radiotherapy were not, she said.

However, Dr. Cordeiro cautioned that in spite of these numbers, “generally, [surgery for metastatic breast cancer] is a safe procedure.”

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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