Background. The incidence rate of breast cancer is rising rapidly in Hong Kong. Lymphedema is a serious long-term complication of breast cancer surgery and radiation therapy. Objective: The objectives of this study were to evaluate risk factors associated with the development of lymphedema for patients with breast cancer who have had an axillary lymph node dissection and to explore potential factors associated with moderate to severe lymphedema. Methods: This was a matched case-control study of 202 women undergoing a unilateral axillary dissection for breast cancer, consisting of 101 cases with lymphedema and 101 controls who matched cases in terms of surgery date, axillary radiotherapy, and cancer stage. Arm circumferences were measured to determine presence and severity of lymphedema. Potential risk factors were collected by using clinical data and a questionnaire. A multiple logistic regression was used to obtain the adjusted odds ratios for potential risk factors for developing lymphedema. Exploratory analysis was also performed to identify factors associated with the development of moderate to severe lymphedema. Results: Adjusted odds ratios for the development of lymphedema were 3.80 (95% confidence interval [CI] 1.84-7.87) for previous inflammation-infection and 1.06 (95% CI = 1.02-1.10) for an increase of 1 year of age at axillary dissection. On exploratory analysis, adjusted odds ratios for moderate to severe degree of lymphedema were 4.53 (95% CI = 2.16-9.52) for previous inflammation-infection, 2.94 (95% CI = 1.44-6.03) for operation on dominant arm, 1.11 (95% CI 1.01-1.22) for an increase of I kg/m(2) in body mass index (BMI) at recruitment, and 1.05 (95% CI = 1.01-1.10) for an increase of 1 year of age at recruitment time. Discussion: Previous inflammation-infection and advanced age at axillary dissection are risk factors associated with the initiation of lymphedema. Previous inflammation-infection, operation on the side of the dominant hand, obesity, and aging are potential risk factors associated with the aggravation of lymphedema. Greater BMI is still a risk factor for lymphedema progression even in a lower BMI population.
