Methodological questions in sentinel lymph node analysis in breast cancer patients

Systematic versus sentinel-lymph-node-driven axillary-lymph-node dissection in clinically node-negative patients with operable breast cancer. Results of the GF-GS01 randomized trial

Purpose

Sentinel-lymph-node (SLN) resection seems to minimize systematic axillary-lymph-node dissection (sALND) side effects in operated breast cancer patients. We explored whether SLN resection achieves similar therapeutic outcomes as sALND but with fewer side effects.

Methods

A randomized, controlled, open-label trial with parallel-group design compared sALND restricted to cases with positive SLN biopsy (test arm, n = 774) versus SLN biopsy followed by sALND (control arm, n = 770).

Results

The five-year overall survivals in control and test arms were 96.42 and 95.64% (P = 0.2925). The estimated difference was nearly zero (precisely, − 0.79%, one-tailed 95% confidence interval (CI) limit − 2.44%). In a multivariate Cox model, the adjusted hazard ratio in the test arm was HR 0.81 (upper 95% CI limit 1.17). Advanced age (HR 1.05 per additional year, CI [1.03–1.08]), negative progesterone receptor (HR 2.17 [1.35–3.45]), SLN metastasis (HR 1.69 [1.03–2.79]), and only one SLN identification technique (HR 4.14 [1.21–14.18]) were associated with lower survival. Patients with ≥ 1 severe side effect at 1 month in control and test arms were 173/703 = 24.6% [21.5–28.0%] and 91/693 = 13.1% [10.7–15.9%] (P < 0.001). The estimated sensitivity of SLN biopsy (control arm) was 145/178 = 81.5% [74.8–86.7%].

Conclusions

Restricting ALND to cases with positive SLN biopsy does not affect the overall survival but reduces by 11.5% [7.5–15.6%] (P < 0.001) the risk of severe short-time side effects of sALND.

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.

Sentinel lymph node biopsy in breast cancer

The concept of sentinel lymph node (SLN) biopsy in breast cancer patients is simple, attractive and rapidly emerging as a new standard of care. Several aspects of the technique of lymphatic mapping, case selection, pathologic analysis and the finding of micrometastases, and the accuracy of the technique are important subjects of study and debate in the literature and will be discussed in this review. High identification rates can be attained by the use of both radioguided and blue dye lymphatic mapping. Intradermal injection of tracers has reported to be successful, suggesting that dermal and parenchymal lymphatics drain to the same SLN. Extra axillary drainage is only seen after peri- or intratumoural injection. SLN biopsy is most widely used for both palpable and non-palpable T1 and T2 tumours, and limited experience exists for other indications. Accuracy is high only in experienced hands. The impact of failure of the procedure on regional disease control and survival will be assessed in a trial of the NSABP (National Adjuvant Breast and Bowel Project). The influence of a positive SLN biopsy with and without axillary dissection on survival and local control will be studied in trials of the BASO (British Association of Surgical Oncology), ACOSOG (American College of Surgeons Oncology Group) and EORTC (European Organisation for Research and Treatment of Cancer). These phase III trials and related studies on the importance of micrometastases in the SLN will give new insights in the safety of the SLN procedure and in the importance of treatment of regional lymph nodes in relation to local disease control and survival.