[Sentinel node biopsy in breast carcinoma. Interdisciplinary agreement consensus of the German Society for Serology for quality controlled application in routine clinical testing]

Sentinel Lymph Node Biopsy in Patients with Breast Cancer: Comparison of Peritumoral and Periareolar Injection

Introduction: Intradermal periareolar injection technique for sentinel lymph node biopsy (SLNB) may offer an advantage by including multifocal breast cancer as an additional indication. In May 2008 we changed our standard procedure from peritumoral (PT) to periareolar (PA) injection. We compared the results for corresponding periods before and after the change in procedure. Material and Method: A total of 117 patients (pts.) were investigated the year after we changed our technique; a total of 152 pts were investigated in the reference period 2007. We investigated the identification rates for sentinel lymph nodes (SLN) identified scintigraphically and surgically as well as the rates of metastatic involvement (LN). Results: After PT injection, scintigraphic detection of SLN failed in 5/152 pts., and in a further 10 pts. SLN was not found at surgery. In 7 of 15 pts. in whom SLN was not detected, histology demonstrated nodal involvement. Metastases were found in the SLN of 28 of 137 pts. with successful detection of SLN; no other lymph nodes were affected in 21 of these pts. (75.0 % of pts. with positive SLN detection). With PA injection at least one SLN could always be detected using scintigraphy; only 2/117 SLN could not be found intraoperatively. Metastasis was found in SLN in 34/115 pts.; in 19/34 pts., metastatic involvement was limited to the SLN with no other lymph nodes involved (55.9 % of pts. with positive detection of SLN). Discussion: The detection rate for SLN was significantly higher using PA injection (98.3 % vs. 90.1 %). As axillary dissection was not done in SLN-negative patients, rates of false-negative detection cannot be determined. PA injection not only results in better detection rates, it also offers the advantage that the technique can be performed correctly regardless of tumour localisation.

Diagnostic accuracy of dual-time-point 18F-FDG PET/CT for the detection of axillary lymph node metastases in breast cancer patients

BACKGROUND

The diagnostic accuracy of FDG-PET/CT for the detection of axillary lymph node metastases in breast cancer patients acquired 60 min after FDG administration is reported to be only moderate, especially due to low sensitivity.

PURPOSE

To test whether a delayed scan 90 min after FDG administration could enhance the diagnostic accuracy of FDG-PET/CT for the detection of axillary lymph node metastases.

MATERIAL AND METHODS

Thirty-eight women suffering from primary breast cancer (mean age 52 years; range 25-78 years; standard deviation 14 years) underwent a pre-therapeutic dual-time-point FDG-PET/CT scan. The maximum standardized uptake value (SUVmax) of axillary lymph nodes was measured at two different time points (time point T1: 60 min after FDG injection, time point T2: 90 min after FDG injection). SUVmax of axillary lymph nodes at T1 and T2 were assessed for statistical significance using a paired Wilcoxon-Test (P < 0.05). At T1 a qualitative analysis of the FDG-PET/CT scan was performed to define physiologic and metastatic lymph nodes. At T2 an increase of the SUVmax of at least 3.75% over time was rated as indicating malignancy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the accuracy of FDG-PET/CT for the detection of axillary lymph node metastases was calculated at time points T1 and T2. Statistically significant differences were determined using Fisher's exact test (P < 0.05). Histopathology served as the standard of reference. A compartment based analysis was done.

RESULTS

Axillary lymph nodes had a mean SUVmax of 1.6 (range 0.6-10.8; SD 1.9) at T1 and a mean SUVmax of 1.8 (range 0.5-17.9; SD 3.5) at T2. This difference was statistically significant (P = 0.047). The sensitivity, specificity, PPV, NPV, and accuracy of FDG-PET/CT for the detection of axillary lymph node metastases was 81%, 100%, 100%, 88%, and 92% at T1, and 88%, 50%, 56%, 85%, and 66% at T2, respectively. This difference was not statistically significant (P = 0.27).

CONCLUSION

There is a slight increase of the FDG accumulation of axillary lymph nodes between 60 and 90 min after FDG administration. This increase did not translate into a statistical significant enhancement of the diagnostic accuracy of FDG-PET/CT for the detection of axillary lymph nodes. Especially due to false-positive results a delayed FDG-PET/CT scan 90 min after FDG administration is not able to enhance the diagnostic accuracy for the detection of lymph node metastases.

Diagnostic value of full-dose FDG PET/CT for axillary lymph node staging in breast cancer patients

PURPOSE

The aims of this study were (1) to evaluate FDG PET/CT and CT for the detection of axillary lymph node metastases in breast cancer (BC) patients and (2) to evaluate FDG PET/CT as a pre-test for the triage to sentinel lymph node biopsy (SLNB) versus axillary lymph node dissection (ALND).

METHODS

The sensitivity, specificity, positive and negative predictive value (PPV, NPV), and accuracy of FDG PET/CT and CT for axillary lymph node metastases were determined in 61 patients (gold standard: histopathology). According to the equation "NPV = specificity (1-prevalence) / [specificity (1-prevalence) + (1-sensitivity) prevalence]" FDG PET/CT was evaluated as a triage tool for SLNB versus ALND.

RESULTS

The sensitivity, specificity, PPV, NPV and accuracy of FDG PET/CT was 58, 92, 82, 77 and 79% and of CT 46, 89, 72, 71 and 72%, respectively. Patients with an up to approximately 60% risk for axillary lymph node metastases appear to be candidates for SLNB provided that the axilla is unremarkable on FDG PET/CT.

CONCLUSION

FDG PET/CT cannot replace invasive approaches for axillary staging but may extend the indication for SLNB.