Locoregional therapy recommended for node positive occult breast cancer
MedWire News: Definitive locoregional treatment with mastectomy or breast-conserving therapy (BCT) improves the outcome of patients with axillary lymph node metastasis from an occult primary breast cancer (T0N+), compared with more conservative treatments, US researchers report.
"Single-institution data suggest that treatment with radiation and axillary lymph node dissection (ALND) may be an appropriate alternative to mastectomy for T0N+ breast cancer," say Thomas Buchholz and colleagues from the University of Texas MD Anderson Cancer Center in Houston.
To investigate, Buchholz and team analyzed the cause-specific survival (CSS) and overall survival (OS) of 750 women with T0N+M0 ductal, lobular, or mixed breast cancer registered in the Surveillance, Epidemiology, and End Results database from 1983 to 2006.
Patients were categorized as those who had no ALND, mastectomy, or radiotherapy (observation group), those who had ALND only, those who had mastectomy plus ALND with or without postmastectomy radiation, and those who had BCT with ALND and radiation.
Buchholz and team report that 201 patients (27%) died from all causes, and 128 patients (17%) died of breast cancer during a median follow-up of 4 years.
Patients who underwent mastectomy or BCT (n=470) had a significantly higher 10-year OS rate, at 64.9%, compared with 58.5% for patients who underwent ALND only (n=126), and 47.5% for patients who underwent observation only (n=94).
The 10-year CSS did not differ significantly between the groups, at 75.7%, 73.9%, 71.2%, and 71.9% for the BCT, mastectomy, ALND only, and observation groups, respectively.
In multivariate analyses, patients who underwent mastectomy or BCT had poorer CSS if they had estrogen receptor negative disease (hazard ratio [HR]=2.08), 10 or more positive lymph nodes (HR=5.7), and less than 10 resected lymph nodes (HR=2.9).
"The data from this study further support the National Comprehensive Cancer Network treatment guideline recommendations for locoregional treatment," write Buchholz and co-authors in the journal Cancer.
"Specifically, these data indicate that definitive locoregional treatment with either mastectomy or radiotherapy improves OS in patients with occult breast cancer and axillary metastasis who undergo ALND," they conclude.
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By Laura Dean