When Obesity Meets Lymphedema: Interaction Effects on Lymphatic Pain Among Chinese Breast Cancer Survivors.

[BACKGROUND] Lymphatic pain is an underrecognized symptom among breast cancer survivors and may indicate early lymphatic dysfunction. This study examined the prevalence of lymphatic pain and its associated factors, with a particular focus on the interaction between obesity and breast cancer-related lymphedema (BCRL).

[METHODS] A secondary analysis was conducted using datasets from 2 previously completed studies. 894 participants who completed arm circumference measurements and symptom assessments were included. Independent t-tests, chi-square tests, Fisher's exact tests, and binary logistic regression analyses were performed to explore group differences and potential predictors of lymphatic pain. An interaction term between obesity and BCRL was incorporated to evaluate effect modification.

[RESULTS] The prevalence of lymphatic pain was 18.12% (n = 162, 95% CI, 15.8%-20.8%). Participants with lymphatic pain reported a greater number, higher severity, and higher frequency of all symptoms compared to those without lymphatic pain (all P < .001). BCRL was the strongest independent predictor of lymphatic pain (OR = 2.955, 95% CI, 1.957-4.460). Although the main effect of obesity was not statistically significant, a significant obesity × BCRL interaction was identified (P = .032). Predicted probabilities indicated that obesity had minimal effect among participants without BCRL, but increased lymphatic pain risk among those with BCRL.

[CONCLUSION] Obesity and BCRL are key factors associated with lymphatic pain, and obesity markedly amplifies pain risk in the presence of BCRL. These findings highlight the need for early lymphatic assessment and weight-management-informed survivorship care. Ongoing research is needed to clarify mechanisms and to evaluate targeted interventions.