Factors affecting sentinel lymph node identification rate after neoadjuvant chemotherapy for breast cancer patients enrolled in ACOSOG Z1071 (Alliance).

OBJECTIVE: To evaluate factors affecting sentinel lymph node (SLN) identification after neoadjuvant chemotherapy (NAC) in patients with initial node-positive breast cancer. BACKGROUND: SLN surgery is increasingly used for nodal staging after NAC and optimal technique for SLN identification is important. METHODS: The American College of Surgeons Oncology Group Z1071 prospective trial enrolled clinical T0-4, N1-2, M0 breast cancer patients. After NAC, SLN surgery and axillary lymph node dissection (ALND) were planned. Multivariate logistic regression modeling assessing factors influencing SLN identification was performed. RESULTS: Of 756 patients enrolled, 34 women withdrew, 21 were ineligible, 12 underwent ALND only, and 689 had SLN surgery attempted. At least 1 SLN was identified in 639 patients (92.7%: 95% CI: 90.5%-94.6%). Among factors evaluated, mapping technique was the only factor found to impact SLN identification; with use of blue dye alone increasing the likelihood of failure to identify the SLN relative to using radiolabeled colloid +/- blue dye (P = 0.006; OR = 3.82; 95% CI: 1.47-9.92). The SLN identification rate was 78.6% with blue dye alone; 91.4% with radiolabeled colloid and 93.8% with dual mapping agents. Patient factors (age, body mass index), tumor factors (clinical T or N stage), pathologic nodal response to chemotherapy, site of tracer injection, and length of chemotherapy treatment did not significantly affect the SLN identification rate. CONCLUSIONS: The SLN identification rate after NAC was higher when mapping was performed using radiolabeled colloid alone or with blue dye compared with blue dye alone. Optimal tracer use is important to ensure successful identification of SLN(s) after NAC.

Sentinel lymph node surgery after neoadjuvant chemotherapy in patients with node-positive breast cancer: the ACOSOG Z1071 (Alliance) clinical trial.

IMPORTANCE: Sentinel lymph node (SLN) surgery provides reliable nodal staging information with less morbidity than axillary lymph node dissection (ALND) for patients with clinically node-negative (cN0) breast cancer. The application of SLN surgery for staging the axilla following chemotherapy for women who initially had node-positive cN1 breast cancer is unclear because of high false-negative results reported in previous studies. OBJECTIVE: To determine the false-negative rate (FNR) for SLN surgery following chemotherapy in women initially presenting with biopsy-proven cN1 breast cancer. DESIGN, SETTING, AND PATIENTS: The American College of Surgeons Oncology Group (ACOSOG) Z1071 trial enrolled women from 136 institutions from July 2009 to June 2011 who had clinical T0 through T4, N1 through N2, M0 breast cancer and received neoadjuvant chemotherapy. Following chemotherapy, patients underwent both SLN surgery and ALND. Sentinel lymph node surgery using both blue dye (isosulfan blue or methylene blue) and a radiolabeled colloid mapping agent was encouraged. MAIN OUTCOMES AND MEASURES: The primary end point was the FNR of SLN surgery after chemotherapy in women who presented with cN1 disease. We evaluated the likelihood that the FNR in patients with 2 or more SLNs examined was greater than 10%, the rate expected for women undergoing SLN surgery who present with cN0 disease. RESULTS: Seven hundred fifty-six women were enrolled in the study. Of 663 evaluable patients with cN1 disease, 649 underwent chemotherapy followed by both SLN surgery and ALND. An SLN could not be identified in 46 patients (7.1%). Only 1 SLN was excised in 78 patients (12.0%). Of the remaining 525 patients with 2 or more SLNs removed, no cancer was identified in the axillary lymph nodes of 215 patients, yielding a pathological complete nodal response of 41.0% (95% CI, 36.7%-45.3%). In 39 patients, cancer was not identified in the SLNs but was found in lymph nodes obtained with ALND, resulting in an FNR of 12.6% (90% Bayesian credible interval, 9.85%-16.05%). CONCLUSIONS AND RELEVANCE: Among women with cN1 breast cancer receiving neoadjuvant chemotherapy who had 2 or more SLNs examined, the FNR was not found to be 10% or less. Given this FNR threshold, changes in approach and patient selection that result in greater sensitivity would be necessary to support the use of SLN surgery as an alternative to ALND. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00881361.

Sentinel lymph node biopsy after neo-adjuvant chemotherapy in breast cancer.

The timing of sentinel node biopsy in the setting of neo-adjuvant chemotherapy for breast cancer is controversial. Sentinel node biopsy performed after neo-adjuvant chemotherapy may save patients with a nodal response the morbidity of an axillary lymph node dissection. A retrospective review of prospectively collected data compared sentinel node biopsies performed after patients had received neo-adjuvant chemotherapy with patients who had not received neo-adjuvant chemotherapy. Demographic factors, tumor characteristics, and the results of the sentinel node biopsies and completion lymph node dissections (when applicable) were compared. A total of 231 axillary procedures (224 patients) were evaluated. The patients who received neo-adjuvant chemotherapy (NEO; N=52) were younger, had higher grade tumors, were more likely to have a mastectomy, and were more likely to have ER-negative and HER-2/neu positive tumors than the patients who did not receive neo-adjuvant chemotherapy (NON; N=179). The mean clinical tumor size in the neo-adjuvant group was 4.5cm (±1.8) prior to chemotherapy; the post-chemotherapy pathologic size was 1.4cm (±1.3). A sentinel node was identified in all cases. There were no significant differences between the groups in the mean number of sentinel nodes removed (NEO=3.3; NON=3.1; p=0.545), the percentage of positive axillae (NEO=24%; NON=21%; p=0.776) or the mean number of positive sentinel nodes (NEO=1.3; NON=1.5; p=0.627). There was no difference in the percentage of completion lymph node dissections with additional positive nodes (NEO=20%; NON=35%; p=0.462); there was a difference in the number of nodes removed in the completion lymph node dissections (mean NEO=12.0; NON=16.4; p=0.047). Sentinel node biopsy performed after neo-adjuvant chemotherapy appears to be an oncologically sound procedure and may save some patients the morbidity of a complete lymph node dissection.

Effect of intraoperative radiocolloid injection on sentinel lymph node biopsy in patients with breast cancer.

BACKGROUND: Preoperative injection of radiocolloid before a sentinel lymph node (SLN) biopsy is painful for patients with breast cancer. Injection after anesthesia eliminates this discomfort but allows less time for radiocolloid migration. Our goal was to validate the efficacy of intraoperative injection. METHODS: In this retrospective study of prospectively collected data, patients underwent periareolar dermal injection of technetium sulfur colloid. Patients in the preoperative injection (PO) group were injected by radiologists in the breast imaging center. Patients in the intraoperative injection (IO) group were injected by surgeons after induction of anesthesia. Consecutive cases were evaluated for radioactive "hotspots," time elapsed before incision, number of SLNs removed, number of positive SLNs, and percentage of positive biopsies. RESULTS: Two hundred fourteen breasts were evaluated (PO = 102; IO = 112). The mean time from injection to incision was significantly shorter by 107 minutes for the IO group. There were no differences in the percentage of positive biopsies (PO: 20.6%; IO: 19.6%; P = 0.863), the number of SLNs removed (PO: 3.3; IO: 3.0; P = 0.091), or the number of positive SLNs (PO: 1.4; IO: 1.4; P = 0.657). CONCLUSIONS: There are no significant differences in the principal results of SLN biopsy between PO and IO injection methods. Dermal radiocolloid injection after induction of anesthesia seems to be an oncologically sound procedure and may be a preferable technique.