Rationale and objectives: Breast cancer is the leading cause of mortality in women worldwide. Lymphatic mapping with sentinel node biopsy has the potential to reduce the morbidity associated with breast cancer staging in women after neoadjuvant therapy.
Materials and methods: A systematic search of world literature between 1996 and 2007 of sentinel node mapping in patients with early-stage breast carcinoma after chemotherapy was undertaken. Potentially eligible studies were identified using database-specific search strategies incorporating appropriate Boolean combinations of the keywords sentinel node biopsy or sentinel node localization or lymphatic mapping; breast cancer or malignancy or neoplasm; and preoperative or neoadjuvant chemotherapy. The electronic searches were augmented with a manual search of reference lists from identified articles. Successful lymph node mapping, defined as successful identification rate (SIR), and false-negative rate (FNR) was summarized using a bivariate random effects mixed model. The extent of heterogeneity was assessed using the inconsistency statistic. The effect of study level covariates, such as use of immunohistochemistry or dual mapping technique, and individual quality criteria, such as study design or multi-institution participation, on SIR and FNR were analyzed using metaregression.
Results: A total of 24 trials of 1799 subjects were reported that met eligibility criteria. All studies identified were published between 2000 and 2007. Lymph node involvement was found in 758 patients (37%) and ranged from 25% to 96% across studies. The proportion of patients who had successful lymph node mapping ranged from 63% to 100%, with 79% of studies reporting a rate of less than 95%. The summary successful identification rate was 0.896 (95% confidence interval [CI] 0.860-0.923) with moderate heterogeneity. The summary FNR was 0.084 (95% CI 0.064-0.109) with no significant heterogeneity. Increasing prevalence of lymph node involvement and same-day mapping and lymph node dissection both significantly reduced the FNR.
Conclusions: The present systematic review demonstrates robust estimates of successful identification rate and false-negative rates of sentinel lymph node mapping and biopsy after neoadjuvant therapy for early-stage breast cancer patients. With a 90% SIR and 8% FNR, this technique is a reliable tool for planning treatment in this population as an alternative to completion axillary lymph node dissection.