In a prospective lymphedema screening trial reported in the Journal of Clinical Oncology, Naoum et al found that although regional lymph node radiation increased the incidence of breast cancer–related lymphedema, the primary driver of risk was the type of axillary surgery used.
Study Details
The study involved 1,815 patients with invasive breast cancer enrolled in an institutional lymphedema screening trial between 2005 and 2018. Patients were categorized into four groups according to axillary surgery approach:
- Sentinel lymph node biopsy alone
- Sentinel lymph node biopsy plus regional lymph node radiation
- Axillary lymph node dissection alone
- Axillary lymph node dissection plus regional lymph node radiation.
Limb volume was assessed by perometer. Lymphedema was defined as a ≥ 10% increase in arm volume occurring > 3 months after surgery. The primary endpoint was the breast cancer–related lymphedema rate across groups. Secondary endpoints included 5-year locoregional control.
Key Findings
The cohort included 1,340 patients who had undergone sentinel lymph node biopsy alone; 121, sentinel lymph node biopsy plus regional lymph node radiation; 91, axillary lymph node dissection alone; and 263, axillary lymph node dissection plus regional lymph node radiation. Median follow-up after diagnosis was 52.7 months.
The 5-year cumulative incidence of breast cancer–related lymphedema was 30.1% in the axillary lymph node dissection plus regional lymph node radiation group, 24.9% in the axillary lymph node dissection–alone group, 10.7% in the sentinel lymph node biopsy plus regional lymph node radiation group, and 8.0% in the sentinel lymph node biopsy–alone group.
On multivariate analysis controlling for age, body mass index, and type of surgery, no significant differences in risk for breast cancer–related lymphedema were observed between the sentinel lymph node biopsy plus regional lymph node radiation vs sentinel lymph node biopsy–alone group (hazard ratio [HR] = 1.33, P = .4) or between the axillary lymph node dissection plus regional lymph node radiation vs axillary lymph node dissection–alone group (HR = 1.20, P = .5). A significantly higher risk was observed for the axillary lymph node dissection–alone group vs the sentinel lymph node biopsy plus regional lymph node radiation group (HR = 2.66, P = .02).
The 5-year cumulative locoregional failure rates were 2.8% with axillary lymph node dissection plus regional lymph node radiation, 3.8% with axillary lymph node dissection alone, 0% with sentinel lymph node biopsy plus regional lymph node radiation, and 2.3% with sentinel lymph node biopsy alone.
The 5-year cumulative distant metastasis rate was highest in the axillary lymph node dissection plus regional lymph node radiation group, at 11%; as noted by the investigators, this finding reflected the more aggressive tumor pathology in this group. Rates were 6% in the axillary lymph node dissection–alone group, 1.7% in the sentinel lymph node biopsy–alone group, and 0% in the sentinel lymph node biopsy plus regional lymph node radiation group.
The investigators concluded, “Although regional lymph node radiation adds to the risk of lymphedema, the main risk factor is the type of axillary surgery used.”
Alphonse G. Taghian, MD, PhD, of the Department of Radiation Oncology, Massachusetts General Hospital, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute, Adele McKinnon Research Fund for Breast Cancer-Related Lymphedema, Olayan-Xefos Family Fund for Breast Cancer Research, and Heinz Family Foundation. For full disclosures of the study authors, visit ascopubs.org.
