The enigma of subjective lymphedema: Why do patients report lymphedema after breast cancer treatment without an objective measurable swelling?

Breast cancer related lymphedema or BCRL is due to its chronicity an extremely dreaded complication after breast cancer treatment. The incidence rate of objective BCRL is declining due to the major shift into the treatment approach of breast cancer. However, prevalence rate of subjective BCRL is much higher than that of objective BCRL. Subjective BCRL is defined as the diagnosis of BCRL based on the patient’s sensation of a difference in size at the upper extremity and/or trunk without any objectively measurable swelling. At this moment, it is not clear how many breast cancer patients experience subjective BCRL and what the underlying mechanisms may be. We hypothesize that four mechanisms might be associated with the presence and the severity of subjective BCRL, including sensory processing problems (1. nociceptive and/or 2. neuropathic and/or 3. central) and the presence of disturbed lymphatic transport without clinical manifestation (4. subclinical BCRL). To understand who and why patients after breast cancer treatment report subjective BCRL, a multi-center longitudinal study will be performed. This will be the first study investigating the prevalence and underlying mechanisms of subjective BCRL at different time points (starting pre-surgery up to 6 months post-radiotherapy), using state-of-the art and innovative assessment methods for both different types of BCRL and their underlying mechanisms.