P3-07-45: Role of SPECT-CT in Detecting Sentinel Lymph Nodes in Patients with Ipsilateral Breast Cancer Recurrence and Previous Axillary Lymph Node Dissection.

Abstract

Abstract Background: Use of sentinel lymph node dissection in patients with ipsilateral breast cancer recurrence and a previous axillary lymph node dissection (ALND) is still controversial. Although previous reports have showed extra-axillary drainage in 40–60% of patients, the clinical significance of this drainage is unknown. SPECT-CT may help to localize aberrant sentinel nodes. Material and Methods: Between 2008 and 2011, SLN were performed in 25 patients with ipsilateral breast cancer recurrence and previous ALND. The day before surgery 99Tc nanocolloid was injected retroareolar in the affected breast and injected intratumorally when the recurrence was after a mastectomy. Linfoscintigraphy was obtained in all patients and a SPECT-CT was performed in all cases even when planar images showed no drainage. During surgery, the sentinel node was identified using a gamma probe. During the procedure the surgeon decided to remove the sentinel node if it was considered technically feasible. The project was IRB approved and all patients signed an informed consent. Results: Records from the previous ALND showed 9 patients with positive axillary nodes with a mean of 19 (range 10–35) lymph nodes excised. Twenty four patients had undergone a lumpectomy and 1 patient a mastectomy. After the injection, the SPECT-CT showed at least one hot spot in 20 patients, with a mean of 1.8 hot spots (range 0–5). Hot spots on SPECT-CT were located as follows: in 10 patients axillary, 1 subclavicular, 7 internal mammary, 1 intramammary, 1 mediastinic and 7 patients had a contralateral axillary hot spot. In 4 patients we don't found any hot spot on SPECT-CT. After excising 2 axillary nodes and 1 intrammary node in 3 patients, the pathologist didn't identify any lymph node in the hot spot removed. This are considered as false positives (15%). In 4 patients although hot spots were identified, sentinel node dissection wasn't performed because it was arguable the benefit for the patients taking into account the location and number of hot spots. All this 4 patients are free of disease and any of them have developed recurrences. In 14 (56%) patients all the sentinel nodes were identified and removed. Three (3/14 = 21%) patients had positive sentinel nodes (1 in the ipsilateral axilla, 1 internal mammary and 1 in the contralateral axillary). One patient had 2 positive contralateral axillary sentinel nodes so an ALND was performed with no additional positive nodes. No surgical complications were observed. Conclusions: In patients who had a previous ALND who develop a breast cancer recurrence, the SPTC-CT might show the exact location of aberrant hot spots but, some of the identified as hot spots may not be lymph nodes. We must consider the exact location of the hot spot and the likelihood of false positives to avoid additional morbidity on the procedure. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-45.