The enigma of subjective lymphedema: Why do patients report lymphedema after breast cancer treatment without an objective measurable swelling? The role of sensory processing and subclinical lymphedema – LymphSens Trial

Breast cancer related lymphedema (BCRL) is one of the most disabling complications of breast cancer treatment. Self-reported BCRL is defined as the diagnosis of lymphedema based on a patient-reported difference in size between the upper limbs. Prevalence rates of self-reported BCRL are higher when compared to objectively diagnosed BCRL. Indeed, up to 40% of breast cancer patients do report signs and symptoms of BCRL but do not have objectively detectable swelling (i.e. subjective BCRL). At this moment, it is not clear what the underlying mechanisms may be. We hypothesize that four mechanisms might be associated with the presence and the degree of self-reported BCRL, including sensory processing disturbances (1. nociceptive, 2. neuropathic, and 3. central sensory problems) and the presence of disturbed lymphatic transport without clinical manifestation (4. subclinical BCRL). To understand the contribution of sensory processing, and the presence of disturbances in lymphatic transport (i.e. subclinical BCRL) to self-reported BCRL at different time points after breast cancer surgery, a multi-center longitudinal study will be performed. This will be the first study investigating the underlying mechanisms of self-reported BCRL at different time points (starting pre-surgery up to 6 months postradiotherapy); and comparing possible mechanisms between patients without self-reported BCRL (control group), with objective and with subjective BCRL up to 6 months post-radiotherapy.