E31: Oncologic safety of immediate lymphatic reconstruction in breast cancer patients who require axillary lymph node dissection: no increase in distant recurrence

After axillary lymph node dissection (ALND) and radiation for breast cancer, up to 30-50% of patients develop upper extremity lymphedema, which is associated with significant morbidity. Some retrospective studies have shown that immediate lymphatic reconstruction (ILR) may decrease the risk of lymphedema. However, there is a theoretical concern that anastomosis of lymphatics to the venous system could increase distant recurrence; there are currently no studies assessing recurrence patterns in these patients. The objective of this study was to compare rates of lymphedema and distant recurrence between patients who had ALND with and without immediate lymphatic reconstruction.

Methods:

Patients with clinical stage II-III breast cancer (at least cN1) who had ALND from 4/2019 to 10/2021 at a single institution were retrospectively reviewed. Patients who did and did not have ILR were compared using t-test for continuous variables and Fisher’s exact or Chi-square for categorical variables. Multivariable logistic regression was performed to assess factors associated with lymphedema.

Results:

Of 186 patients who had ALND, 44 patients (24%) had ILR and 142 patients (76%) did not. In the ILR group, mean age was younger (48 vs 55 years, p=0.001) and there was a higher proportion of pre-menopausal patients (66% vs 37%, p=0.001), but cohorts were similar in pathologic features and receipt of adjuvant treatments. At median follow-up of 3.2 years, patients who did and did not have ILR did not differ significantly in rates of lymphedema (36% vs 31%, p=0.580) or distant recurrence (7% vs 11%, p=0.571). In multivariable analysis, number of positive lymph nodes (OR=1.22 [1.09-1.36], p< 0.001) and upfront ALND rather than targeted axillary dissection followed by completion ALND (OR=4.03 [1.65-9.84], p=0.002) were associated with higher rates of lymphedema while extranodal extension (OR=0.34 [0.13-0.85], p=0.021) was associated with a lower rate of lymphedema.

Conclusions: In this study, increased risk of lymphedema was associated with higher pathologic nodal stage and upfront ALND but not age, clinical nodal stage, mastectomy, or number of lymph nodes removed. In this cohort, ILR was not protective against development of lymphedema. However, at median follow-up of 3.2 years, there was no increase in distant recurrence among patients who had ILR, making it an oncologically feasible option for select patients.