Background: All edemas result from an imbalance between capillary filtration and tissue (lymph) drainage. This basic approach was adopted to investigate mechanisms for chronic arm edema following breast carcinoma treatment.
Methods: A review of causes of lymphedema is presented plus the traditional pathophysiology of breast carcinoma related lymphedema (postmastectomy edema; PME). A summary of recent research that explored capillary filtration as a surrogate for lymph flow in the steady state is presented.
Results: A reduced interstitial protein concentration (relative to plasma) argues against lymphatic obstruction. Evidence exists that total arm blood flow (in some patients) and vascular bed size are increased in PME.
Conclusions: The primary insult to the axillary lymphatic system by surgery and radiotherapy presumably is the root cause of PME; however, there is strong evidence to suggest that hemodynamic factors are contributory to the chronic swelling.