Modeling of Lymphedema Distribution and Complex Decongestive Therapy Effectiveness

Background: Lymphedema is a potential chronic degenerative secondary condition of oncologic treatments. Complex decongestive therapy (CDT) is the only treatment. Quantitative dimensional characterization of lymphedema is a topic of great clinical interest that has not been sufficiently analyzed yet. We aimed to develop statistical models that evaluate lymphedema's local spatial distribution and the effectiveness of CDT. Methods and Results: Retrospective observational analysis of 74 individuals (220 medical records) with unilateral upper or lower limb lymphedema who completed at least one cycle of the first phase of CDT. Statistical mixed-effects models were used to quantify the local distribution of lymphedema through the circumference of eight detection points and the efficacy of CDT according to the entity and the etiology of lymphedema. The coefficients of the models considered both fixed (i.e., the effect at the population level) and random (i.e., subject) effects. All points significantly reduced between pre- and posttreatment. Lymph stagnation occurred in the forearm and below the knee. The dimensions and effective treatment were similar between primary and secondary lymphedema and between mild and moderate lymphedema. The median global volume reduction of the upper limb was 55.1%, while it was 55%, 44.8%, and 41.7% in mild, moderate, and severe lymphedema; 50.6% and 49.4% in primary and secondary lymphedema. The median global volume reduction of the lower limb was 49.5%, while it was 64%, 49.4%, and 48.2% in mild, moderate, and severe lymphedema. Conclusion: A modeling of lymphedema distribution was provided, finding a dysmorphic pattern driven by the gravitation effect, with lymphedema accumulating on the lower part of the limbs, which is also the part that mostly responded to CDT. The response to CDT was assessed locally and not in terms of global volume change. A new segmental proportional technique was proposed that allows making comparisons between and within subjects.