Match detection analysis on SentiMag® system and standard technique in SLNB of breast cancer

INTRODUCTION

In breast cancer surgery, there are techniques for sentinel lymph node biopsy (SLNB) that do not require Nuclear Medicine, such SentiMag®, which uses ferromagnetic particles. The main purpose of this analysis is to study the degree of concordance in SLNB between SentiMag® and the standard method (Tc99 radiotracer). The secondary objective is to identify factors that impact in sentinel node detection rate and matching detection rate between both probes.

METHODS

Observational and retrospective study performed from January to December 2021 focused on patients undergoing breast surgery and SLNB who were injected with both tracers, the ferromagnetic SentiMag® and Tc99 radiotracer. Once the diagnostic accuracy tests were performed, a further evaluation of the detection rate for each probe and the concordance between probes were accomplished. After those results, a deeper analysis of differences in detection rates for each probe and concordance between probes were assessed for various factors: neoadjuvant therapy, BMI, mitotic index, and triple-negative immunohistochemical profile.

RESULTS

The clinical study had a sample size of 70 patients. The overall false-negative rate (FNR) was 4.3%. The detection rate was the same for each technique (85.7%). A total of 106 nodes were biopsied, with a concordance rate of 70.75%. Significant differences were found in concordant nodes according to neoadjuvant therapy (p-value 0.012). For the Ki-67 factor (<20 or ≥20), significant differences were found in detected nodes (p-value 0.031 gamma probe; p-value 0.124 SentiMag®).

CONCLUSIONS

The detection rates of SentiMag® and the gamma probe are equivalent. The application of the dual technique minimizes the FNR. A high mitotic index affects the detection rate of the gamma probe, and neoadjuvant therapy negatively impacts the concordance rate.

Metastasis to the thyroid gland from primary breast cancer presenting as diffuse goiter: A case report and review of literature

BACKGROUND

Metastasis to the thyroid gland (TM) from primary breast cancer is uncommon and usually presents as thyroid nodules; however, diffuse goiter without thyroid nodules is the first sign of TM in rare cases. Skip metastases (SMs) to the lymph nodes in breast cancer, defined as discontiguous higher-level metastases in the absence of lower levels of contiguous metastases, have been reported in the contralateral cervical area of the primary tumor site in rare cases.

CASE SUMMARY

A 49-year-old previously healthy Chinese woman was diagnosed with right lateral invasive ductal carcinoma and underwent neoadjuvant chemotherapy treatment and bilateral mastectomy with axillary lymph node dissection. No malignancy of the left breast or axillary or distant metastases were identified preoperatively. However, enlarged left cervical lymph nodes were detected 36 mo after surgery, and rapidly enlarging thyroid glands without nodules were detected 42 mo after surgery. Fine-needle aspiration cytology was performed on the left cervical lymph nodes and left lobe of the thyroid, which were both revealed to contain metastases from the primary breast cancer. Additionally, the immunostaining profiles changed in the process of metastases. The patient was discharged with the NP (vinorelbine and cisplatin) regimen for subsequent treatment, and stable disease was determined when the curative effect was evaluated.

CONCLUSION

Diffuse goiter may be the first sign of TM, and enlarged lymph nodes in the contralateral cervical area may be SMs of primary breast cancer.

Breast Cancer Skip Metastases: Frequency, Associated Tumor Characteristics, and Role of Staging Nodal Ultrasound in Detection

BACKGROUND. Staging nodal ultrasound (US) evaluates locations beyond those assessed during routine surgical dissection and has an increasing role in breast cancer management given the growing use of neoadjuvant systemic therapy before surgical staging. OBJECTIVE. The purpose of this study is to identify the patterns of nodal spread of breast cancer observed at staging nodal US and to determine the frequency of skip metastases and associated tumor characteristics. METHODS. This retrospective study included 1269 consecutive patients (31 with bilateral synchronous cancers) who had 1300 newly diagnosed, untreated, invasive breast cancers and underwent US examination of the ipsilateral regional nodal basins from January 2016 through March 2017. Cases with suspicious nodes on US underwent fine-needle aspiration (FNA) biopsy. Cases with benign results on FNA and no suspicious nodes on US underwent sentinel lymph node biopsy. Results of US with FNA were compared with final surgical pathology. Skip metastases were defined as spread across discontiguous nodal levels or distant metastases in the absence of ipsilateral nodal metastases. The incidence and patterns of spread of skip metastases were summarized; associations with tumor characteristics were tested using the Fisher exact test. RESULTS. A total of 591 metastatic cases (45.5%) were confirmed by needle biopsy or sentinel lymph node biopsy, comprising 463 nodal metastases (N+) confirmed by FNA, 121 nodal metastases (N+) confirmed by sentinel lymph node biopsy, and seven distant organ metastases without nodal metastases (N0M1) confirmed by CT-guided biopsy. US with FNA had sensitivity of 86.0%, specificity of 100.0%, PPV of 100.0%, NPV of 89.5%, and accuracy of 93.6%. There were 34 skip metastases, for an incidence of 2.6% (34/1300) (95% CI, 1.8-3.6%) among all invasive cancers and 7.2% (34/470) (95% CI, 5.1-9.9%) among metastatic cancers detected by US and FNA. Skip metastases occurred to axillary level III (n = 4), the supraclavicular nodal basin (n = 21), the contralateral axilla (n = 2), and distant organs (n = 7). Cancers with skip metastases, compared with those with nonskip metastases, had higher rates (p = .005) of lobular histology (23.5% vs 6.7%) and mixed ductal and lobular histology (11.8% vs 6.7%). Skip metastases were not associated with grade, T category, or molecular subtype (p > .05). CONCLUSION. Skip metastases to locations beyond standard surgical axillary dissection occur in 7.2% of metastatic breast cancers. CLINICAL IMPACT. Staging nodal US identifies skip metastases that otherwise would be undetected, helping to achieve more accurate staging and minimize undertreatment.

Validation of Breast Cancer Models for Predicting the Nonsentinel Lymph Node Metastasis After a Positive Sentinel Lymph Node Biopsy in a Chinese Population

Objectives:

Over the years, completion axillary lymph node dissection is recommended for the patients with breast cancer if sentinel lymph node metastasis is found. However, not all of these patients had nonsentinel lymph node metastasis on final histology. Some predicting models have been developed for calculating the risk of nonsentinel lymph node metastasis. The aim of our study was to validate some of the predicting models in a Chinese population.

Method:

Two hundred thirty-six patients with positive sentinel lymph node and complete axillary lymph node dissection were included. Patients were applied to 6 models for evaluation of the risk of nonsentinel lymph node involvement. The receiver–operating characteristic curves were shown in our study. The calculation of area under the curves and false negative rate was done for each model to assess the discriminative power of the models.

Results:

There are 105 (44.5%) patients who had metastatic nonsentinel lymph node(s) in our population. Primary tumor size, the number of metastatic sentinel lymph node, and the proportion of metastatic sentinel lymph nodes/total sentinel lymph nodes were identified as the independent predictors of nonsentinel lymph node metastasis. The Seoul National University Hospital and Louisville scoring system outperformed the others, with area under the curves of 0.706 and 0.702, respectively. The area under the curve values were 0.677, 0.673, 0.432, and 0.674 for the Memorial Sloan-Kettering Cancer Center, Tenon, Stanford, and Shanghai Cancer Hospital models, respectively. With adjusted cutoff points, the Louisville scoring system outperformed the others by classifying 26.51% of patients with breast cancer to the low-risk group.

Conclusion:

The Louisville and Seoul National University Hospital scoring system were found to be more predictive among the 6 models when applied to the Chinese patients with breast cancer in our database. Models developed at other institutions should be used cautiously for decision-making regarding complete axillary lymph node dissection after a positive biopsy in sentinel lymph node.