Supplementary Material for: Breast cancer related lymphedema: a common challenge among Nigerian breast cancer survivors

Background: Lymphedema is one of the most prevalent, yet under-recognized complication of breast cancer treatment, with its prevalence largely unexplored in Nigeria and across much of sub-Saharan Africa.
Methods: A cross-sectional study was conducted among breast cancer survivors at least 6 months post-mastectomy and axillary lymph node dissection. Lymphedema was diagnosed using multiple methods: patient-reported arm swelling, arm measurements (≥2 cm difference compared to the contralateral arm), a >10% difference in extracellular water (ECW) using bioimpedance analysis, and a lower threshold of 5% to capture subclinical lymphedema. Using patient report as the gold standard, the accuracy of the various diagnostic methods was assessed. The relationship between clinical variables and lymphedema was tested using univariate logistic regression analysis.
Results: Fifty-one patients with a median age of 51years and a median duration of 40 months post-surgery (10-62 months) were evaluated. The prevalence of lymphedema was 39.2% based on symptoms, 33% using arm measurements, 22.2% using bioimpedance analysis at a threshold of >10% difference in ECW and 46.7% at a threshold of 5%. ECW difference of >5% had the highest sensitivity (65%) while ECW difference at 10% threshold had the best specificity (89%). Obesity was the only clinical variable associated with lymphedema in this cohort (p=0.018,).
Conclusion: Breast Cancer Related Lymphedema (BCRL) appears common among Nigerian breast cancer patients. Its occurrence should be pre-empted, particularly in obese patients in whom preventive measures may be instituted. These findings highlight the potential value of incorporating BCRL awareness and management into breast cancer care in Nigeria.