A case control study on risk factors of lymphedema after axillary lymph node dissection for breast cancer in Hong Kong

9048 Background: Lymphedema is a relatively common occurrence after treatment for breast cancer. Some of the causes are well known such as axillary surgery and axillary radiation therapy. However, many of the potential modifiable factors such as weight-bearing exercises and airline travel have been inadequately studied. Methods: A matched case-control study was designed to evaluate potential factors associated with lymphedema for breast cancer patients. Subjects were 202 women undergoing a unilateral axillary dissection for breast cancer, consisting of 101 cases with lymphedema and 101 controls without lymphedema who were matched cases in terms of surgery date, having received axillary radiotherapy or not and stage of cancer. Potential risk factors were collected by using clinical data and questionnaire. Two-arm circumferences were measured to determine presence and severity of lymphedema. A multiple logistic regression was used to obtain the adjust odds ratios for potential risk factors. Results: Adjusted odds ratio (OR) for lymphedema were separately 3.80 (95% CI 1.84- 7.87) for previous inflammation-infection, and 1.06 (95% CI 1.02–1.10) for an increase in one year of age at axillary dissection. Adjusted ORs for moderate to severe degree of lymphedema were separately 4.49 (95% CI 2.16–9.30) for previous inflammation-infection, 2.97 (95% CI 1.46- 6.03) for operation on dominant arm, 1.11 (95% CI 1.01–1.21) for an increase in 1kg/m2 body mass index at recruitment, and 1.05 (95% CI 1.01–1.10) for an increase in one year of age at recruitment time. Leisure activities requiring walking once a week to twice a week was a protective factor with adjusted ORs of 0.23 (95% CI 0.08–0.66) for developing lymphedema and 0.19 (95% CI 0.05–0.69) for developing moderate to severe lymphedema. Hypertension and tumor location at upper-outer or outer quadrant in breast were not important factors. Conclusions: Previous inflammation-infection and older age at axillary dissection are risk factors for initiating lymphedema. Previous inflammation-infection, operation on the side of dominant hand, obesity and aging are risk factors for aggravating lymphedema. No significant financial relationships to disclose.