Prognostic and Therapeutic Impact of Sentinel Node Micrometastasis in Patients with Invasive Breast Cancer

Expression of human mammaglobin as a marker of bone marrow micrometastasis in breast cancer

The aim of the present study was to detect the expression of human mammaglobin (hMAM) mRNA in the bone marrow (BM) of patients with breast cancer and determine the relationship between micrometastasis and clinicopathological parameters as well as selected molecular markers and breast cancer prognosis. The expression of hMAM mRNA in the BM of patients with breast cancer was determined by RT-PCR. The expression of ER, PR and Cath-D in cancer tissues was detected by immunohistochemistry. A positive expression rate for hMAM of 38.2% in 102 patients with stage I-III breast cancer was found. The expression of hMAM was higher in patients with T(2-3) (>2 cm) tumors than in those with T(1) tumors (≤2 cm) (χ(2)=19.20, P=0.001) and in patients with stage II or III tumors than in patients with stage I tumors (χ(2)=15.101, P=0.001). The expression of hMAM in the BM of breast cancer patients categorized as grade 1 was lower than that in those of grade 2 or 3 (χ(2)=8.522, P=0.014), and hMAM expression was related to the pathological type of tumor (χ(2)=6.892, P=0.032) and the degree of axillary lymph node metastasis (χ(2)=14.050, P=0.001). The expression of hMAM in BM was much higher in patients with ER(-) or ER(+) tumors than in those with ER(++ or +++) (χ(2)=11.800, P=0.003), and those with PR (χ(2)=8.759, P=0.013). hMAM expression in BM was also significantly positively correlated with Cath-D expression (χ(2)=6.623, P=0.036). However, no correlation was found between hMAM expression and patient age (χ(2)=1.056, P=0.304). There was a strong correlation between patients with positive expression of hMAM in the BM and the presence of distant metastases (P=0.009). In conclusion, micrometastasis in the BM correlates with certain clinical pathological parameters and several tumor markers. Patients with positive expression of hMAM in the BM have a greater chance of distant metastasis and poor prognosis. The detection of micrometastasis may be one of the most advantageous markers for predicting the prognosis of breast cancer.

Current status of sentinel lymph-node biopsy in patients with breast cancer

Axillary node status is the most important prognostic indicator for patients with invasive breast cancer. Sentinel lymph-node biopsy (SLNB) is widely accepted and the preferred procedure for identifying lymph-node metastasis. SLNB allows focused excision and pathological examination of the most likely axillary lymph nodes to receive tumor metastases while avoiding morbidities associated with complete axillary nodal dissection. Since its introduction in the early 1990s, the process of SLNB has undergone continual modification and refinement; however, the procedure varies between institutions and controversies remain. In this review, we examine the technical issues that influence the success of lymph node mapping, discuss the controversies, and summarize the indications and contraindications for axillary node mapping and biopsy in clinical practice.

Value of frozen section and primary tumor factors in determining sentinel lymph node spread in early breast carcinoma

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is the standard of care to assess the metastasis in breast carcinoma. Accuracy of intraoperative frozen section examination to evaluate SLN in detecting metastasis is important as it determines the further management of axilla. Primary tumor characteristics determining the metastasis to the lymph node will help in predicting the probability of spread and to determine the nature of disease. It also helps in refining selection of patients for SLNB. We evaluated all these criteria on Indian patients for the better management.

MATERIALS AND METHODS

Between January 2005 and April 2009, 114 consecutive patients of all age group of both sex, with cytology or biopsy proven carcinoma breast, clinical stage T1/T2 N0 M0 at Manipal Comprehensive Cancer Center, Manipal Hospital, Bangalore were subjected to SLNB and introperative frozen examination. First 75 cases had complete axillary clearance irrespective of SLNB result and subsequently, positive cases underwent axillary lymph node dissection (ALND). Age of the patient and primary tumor characteristics like size, grade, lymphovascular invasion (LVI), perineural invasion, ER/PR status, Her2-neu status and histological sub-types were evaluated for predicting the SLN metastasis. Feasibility of SLNB in previously treated patient is also evaluated.

RESULTS

The age of the patient ranged from 23 to 87 years and its association with SLN spread is not significant. Frozen section examination had accuracy of 97.37% in determining metastatic sentinel node with sensitivity of 96.15% and specificity of 100% with value P < 0.001. SLN remained significant indicator of the status of rest of axilla with value P < 0.001. Primary tumor characteristics like histological subtypes, grade (P = 0.353), ER/PR status (P = 0.839), Her2-neu status (P =0.296) were not significantly associated with SLN metastasis. Size of the primary tumor (P = 0.002), LVI (P < 0.001), perineural invasion (P = 0.084+) were significant factors determining the SLN metastasis. SLNB evaluation had no false negative values in previously treated breast.

CONCLUSION

SLNB is a valuable method of determining the axillary nodal metastasis. Intraoperative frozen section examination is highly ac-curate in detecting nodal metastasis. Primary tumor characteristics like size, LVI and perineural invasion are significant in predicting SLN metastasis. SLNB remains an important method of predicting axillary metastasis even in previously treated breast carcinomas.

A model for predicting non-sentinel lymph node metastatic disease when the sentinel lymph node is positive

BACKGROUND

Women with axillary sentinel lymph node (SLN)-positive breast cancer usually undergo completion axillary lymph node dissection (ALND). However, not all patients with positive SLNs have further axillary nodal disease. Therefore, in the patients with low risk of further disease, completion ALND could be avoided. The Memorial Sloan-Kettering Cancer Center (MSKCC) developed a nomogram to estimate the risk of non-SLN disease. This study critically appraised the nomogram and refined the model to improve predictive accuracy.

METHODS

The MSKCC nomogram was applied to 118 patients with a positive axillary SLN biopsy who subsequently had completion ALND. Predictive accuracy was assessed by calculating the area under the receiver-operator characteristic (ROC) curve. A further predictive model was developed using more detailed pathological information. Backward stepwise multiple logistic regression was used to develop the predictive model for further axillary lymph node disease. This was then converted to a probability score. After k-fold cross-validation within the data, an inverse variance weighted mean ROC curve and area below the ROC curve was calculated.

RESULTS

The MSKCC nomogram had an area under the ROC curve of 68 per cent. The revised predictive model showed the weighted mean area under the ROC curve to be 84 per cent.

CONCLUSION

The modified predictive model, which incorporated size of SLN metastasis, improved predictive accuracy, although further testing on an independent data set is desirable.

Can axillary dissection be avoided in patients with sentinel lymph node metastasis?

BACKGROUND

Who should undergo a completion dissection following identification of a +sentinel lymph node (SLN) is controversial.

METHODS

The records of 1,133 patients who underwent SLN mapping were reviewed. The association between patient, tumor, and treatment characteristics and the presence of +SLNs and +nonSLNs was analyzed using two-way tables of frequency counts and Pearson chi2 test. Possible predictors of +SLNs and +nonSLNs were analyzed using simple and multiple logistic regression.

RESULTS

One thousand one hundred forty-eight SLN procedures were performed. 367 procedures (32%) yielded +SLNs. For patients with a +SLN, on multiple logistic regression analysis LVSI, increasing numbers of +SLNs, decreasing numbers of negative SLNs, and increasing size of the largest SLN metastasis were statistically significantly associated with increased likelihood of nonSLN involvement. No subgroup was identified that did not have a significant rate of nonSLN involvement on completion axillary dissection, except those who had a large number of negative SLNs (> or =3) and small size of the largest SLN metastasis (<10 mm).

CONCLUSIONS

A definitive answer to the question of who needs a completion axillary dissection awaits the results of ongoing trials. In the interim, our data does not support eliminating dissection for any subgroup of patients with +SLNs.

The role of axillary lymph node dissection in breast cancer patients with sentinel lymph node micrometastases

AIM

To identify by means of clinical and histopathological features a subset of breast cancer patients with sentinel lymph-node (sN) micrometastases and metastatic disease confined only to the sN in order to spare them an unnecessary axillary lymph node dissection (ALND).

MATERIALS AND METHODS

From January 1998 to December 2004, 116 patients with sN micrometastases underwent standard ALND for early-stage (T1-2 N0 M0) invasive breast cancer; clinical and histopathologic parameters were prospectively collected and evaluated by means of univariate and logistic regression analysis in order to identify which patients with sN micrometastases were free of metastasis in axillary non-sN.

RESULTS

Sixteen of 116 patients with sN micrometastases had tumour involvement of non-sN, with six and 10 patients having non-sN micrometastases and macrometastases, respectively. None of 19 patients with primary tumour measuring </= 10 mm had tumour-positive non-sN; moreover, none of 15 patients with G1 tumours had non-sN metastases. The mean tumour size in patients with non-sN involvement was 21.3 mm (range, 12-40 mm). Univariate test of association between clinical and histopathologic features and non-sN status showed that the primary tumour size (P=0.005) and the presence of lymphovascular invasion (P=0.000) were the only significant predictors of non-sN involvement. By logistic regression, primary tumour size (P=0.011), lymphovascular invasion (P=0.001), and size of sN micrometastases were the only variables remaining into the model, although the latter parameter was not statistically significant.

CONCLUSIONS

In patients with sN micrometastases, primary tumour size and lymphovascular invasion significantly predict non-sN status; notably, no patient with T1a-T1b and/or G1 tumours had non-sN metastases so that they could be spared an unnecessary ALND.

Primary tumor characteristics predict sentinel lymph node macrometastasis in breast cancer

Selective sentinel lymphadenectomy (SSL) is rapidly becoming the standard of care in the surgical management of patients with early breast cancer. Sentinel lymph node macrometastasis has been well documented in the literature to have a higher risk of nonsentinel node tumor involvement when compared to micrometastasis. The aim of our study was to determine the primary tumor characteristics associated with sentinel node macrometastasis that will allow us to preoperatively determine this subgroup of patients at risk. This study was a retrospective review of 644 patients who underwent successful SSL as part of their surgical treatment of breast cancer at the University of California San Francisco Carol Franc Buck Breast Care Center from November 1997 to August 2003. All patients underwent preoperative lymphoscintigraphy followed by wide excision or mastectomy and sentinel lymphadenectomy with or without axillary lymph node dissection. One hundred twenty-two patients had positive sentinel nodes on histology. Micrometastasis was present in 43 of these patients and macrometastasis in the remaining 79. Statistical analysis showed that a tumor size greater than 15 mm, poor tubule formation by the tumor cells, and lymphovascular invasion were significantly associated with sentinel node macrometastasis. A high mitotic count showed a trend but was not significant in our study. Patients with a tumor size greater than 15 mm, poor tubule formation, and lymphovascular invasion are at risk of having sentinel node macrometastasis. These patients can be identified preoperatively based on imaging and biopsy criteria, allowing the option of selective intraoperative pathologic evaluation of the sentinel node and immediate completion axillary dissection as necessary.

Ratio of Positive to Total Number of Sentinel Nodes Predicts Nonsentinel Node Status in Breast Cancer Patients

Selective sentinel lymphadenectomy (SSL) has replaced axillary lymph node dissection (ALND) for many patients with early breast cancer and negative sentinel lymph nodes (SLNs). Yet many patients with a positive SLN are undergoing unnecessary ALND, as no further disease is found in the axilla. The aim of our study was to determine factors associated with additional positive lymph nodes in the axilla in patients who have a positive SLN. This was a retrospective study of patients undergoing SSL with ALND as part of their treatment for breast cancer at a single institution from November 1997 to August 2003. Only patients with one or more positive SLNs were selected for this study. There were 86 patients who fit our study criteria. Of these, 38% had further positive lymph nodes upon ALND. More than one positive SLN and a ratio of positive SLNs to total SLNs of greater than 0.5 were found to be predictors for additional axillary nodal involvement in both univariate and multivariate analyses. The number of positive SLNs and the ratio of positive SLNs to total SLNs is an indication of total tumor burden in the sentinel nodes and may be a reflection of the propensity of the tumor for further lymphatic invasion in the axillary basin.

Sentinel node micrometastasis in breast carcinoma may not be an indication for complete axillary dissection

The decision whether to proceed with complete axillary node dissection based on sentinel node status is clear for patients with negative or macrometastatic disease. However, the course of action based on sentinel node micrometastasis remains controversial. We reviewed 358 cases from 6/1999 to 7/2003. All sentinel nodes were evaluated at three levels by frozen section, touch preparation, and scrape preparation. Micrometastasis was defined as tumor deposits between 0.2 and 2 mm. Size, grade, and lymphvascular invasion of the primary tumor, as well as number, status, size of metastatic disease, and presence of extranodal capsular extension of sentinel and nonsentinel nodes were recorded. Of the 358 cases, 89 had positive sentinel nodes, 29 of which represented micrometastases. Only one (3%) of the 29 cases contained a nonsentinel node with macrometastasis. In 60 of the 89 cases sentinel nodes contained macrometastases. Of these, 38 cases (63%) had metastatic tumor in nonsentinel nodes. Intraoperative consult was performed in 53 of the 89 cases with positive sentinel nodes. Only 1 of the 19 (5%) intraoperative consult cases with micrometastatic sentinel nodes had positive nonsentinel nodes, while 21 of 34 (62%) of macrometastatic sentinel nodes at intraoperative consult had tumor in nonsentinel nodes. No single variable studied discriminated between micro- vs macrometastatic disease. At intraoperative consult, macrometastatic disease was present in all three diagnostic preparations, while diagnostic material in micrometastatic sentinel nodes was usually present in only one modality. This analysis suggests that the risk of finding tumor in nonsentinel nodes differs significantly between cases with micro (3%)- vs macro (63%)-metastatic disease in sentinel nodes. This holds true for cases assessed by intraoperative consult. Considering the known morbidity of complete axillary dissection, assessments of risk vs benefit of undertaking this procedure should be performed on a case-by-case basis in patients with sentinel node micrometastases.

Surgical implications of sentinel node with micrometastatic disease in invasive breast cancer

AIM

To assess the rate of positive axillary clearance (AC) when the sentinel node biopsy (SNB) contains micrometastatic disease in invasive breast cancer and to evaluate the factors that could predict positivity.

PATIENTS AND METHODS

This is a prospective study carried out on 542 successive women undergoing SNB for unifocal T0-T1 N0 invasive breast cancer without previous treatment.

RESULTS

Five hundred and twenty-five sentinel nodes (SN) were found, 142 contained metastases. Fifty-five of the positive SN contained micrometastatic disease only. Of them, 40 patients underwent completion of AC. Six out of 40 patients who had micrometastatic SN had a positive AC, five for micrometastasis between 0.2 and 2 mm (5/34), one for isolated cells in the SN (1/6). None of the studied factors (age, histological tumour size, histological grade, estradiol receptor (ER), histological tumour type, size and method of micrometastasis detection) could significantly predict the status of the AC.

CONCLUSION

As long as the results of ongoing prospective randomised studies are unknown, it remains necessary to perform AC when the SNB contains micrometastatic disease, whatever the size or the detection mode of the metastasis.

Meta-analysis of non-sentinel node metastases associated with micrometastatic sentinel nodes in breast cancer

BACKGROUND

The need for further axillary treatment in patients with breast cancer with low-volume sentinel node (SN) involvement (micrometastases or smaller) is controversial.

METHODS

Twenty-five studies reporting on non-SN involvement associated with low-volume SN involvement were identified using Medline and a meta-analysis was performed.

RESULTS

The weighted mean estimate for the incidence of non-SN metastases after low-volume SN involvement is around 20 per cent, whereas this incidence is around 9 per cent if the SN involvement is detected by immunohistochemistry (IHC) alone. Subset analyses suggest that studies with axillary dissection after any type of SN involvement result in somewhat higher estimates than studies allowing omission of axillary clearance, as do studies with more detailed histological evaluation of the SN compared with those with a less intensive histological protocol. Higher-quality papers yield lower pooled estimates than lower-quality papers.

CONCLUSION

The risk of non-SN metastasis with a low-volume metastasis in the SN is around 10-15 per cent, depending on the method of detection of SN involvement. This should be taken into account when assessing the risk of omission of axillary dissection after a positive SN biopsy yielding micrometastatic or immunohistochemically positive SNs.

Sentinel Lymph Node Micrometastasis as a Predictor of Axillary Tumor Burden

The sentinel lymph node biopsy (SLNB) procedure is an alternative method for assessing the axillary lymph node (ALN) status in patients with breast cancer. The SLNB carries the risk of a false-negative result, with patients harboring positive ALNs in the face of a negative SLNB examination. In addition, the significance of a SLNB with cells identified only with keratin or with deposits less than 0.2 mm remains unresolved. We analyzed our SLNB data over the past 5 years in order to determine the relationship between SLN tumor burden and ALN tumor burden. Pathology files for the past 5 years at Magee-Womens Hospital were searched for all SLNB cases that had an axillary lymph node dissection (ALND). Each SLNB case was reviewed and tabulated for breast tumor size, SLN tumor size, and largest tumor size in the ALND. Correlation and frequency distribution were performed for the status of all SLNs and ALNDs. Patterns of lymph node metastasis were recorded and the sizes of the SLN metastases were reported according to the recent Philadelphia Consensus Conference on Sentinel Lymph Nodes and the revised American Joint Committee on Cancer (AJCC) staging. SLN metastases were classified as immunohistochemistry (IHC) positive if only single keratin-positive cells or clusters were present and were not observed with standard tissue stains, as submicrometastatic (SMM) if tumors were less than 0.2 mm (excluding IHC positive), as micrometastatic if tumors were larger than 0.2 mm but </=2 mm, or as macrometastatic if tumors were larger than 2 mm. A total of 445 patients had both SLNB and ALND. Fifty percent (224/445) of cases were SLN positive, including 58 SLN positive/ALN positive cases and 166 SLN positive/ALN negative cases. Of the 221 patients in the SLN-negative group, 4 were ALN positive (false-negative SLN). The incidence of SLN metastases increased with tumor stage, with the percentage of SLN positives as follows: T1a, 2.1%; T1b, 10.9%; T1c, 51.7%; and T2, 35.3%. There were 4 of 41 patients (10%) with SLNs that were IHC positive that had macrometastases in a solitary ALN. Three of 22 patients (13.6%) that were SMM positive had ALN macrometastasis in a solitary ALN. Four of 49 patients (8.1%) with micrometastatic SLNs had a solitary positive ALN, 3 of which were macrometastases (6.1%). Overall a total of 10 of 112 patients (9.0%) with traditionally defined SLN micrometastases of 2.0 mm or less had a solitary ALN macrometastasis. The vast majority (90%) of these macrometastases were found with T1c and T2 breast tumors. There was a significant difference in the means of SLN tumor sizes for the SLN-positive/ALND-negative (4.5 mm) versus SLN-positive/ALND-positive (10.1 mm) patients, although the range of SLN tumor sizes within each group were similar. There is an increasing incidence of SLN-positive and ALN-positive cases with increasing T stage. Overall in this series, 9% of patients with SLN metastases </=2 mm had a solitary axillary macrometastasis. Ninety percent of these metastases occurred with T1c/T2 breast tumors, indicating the important codependence of T stage. Overall there is a subset of patients who are IHC positive, SMM positive, or micrometastatic positive with ALNs that are macrometastatic who are at risk of harboring axillary macrometastases. Keratin IHC of breast SLNs is useful for defining these subsets.

[Study of the sentinel node in breast cancer using lymphoscintigraphy and a fast method for cytokeratin]

INTRODUCTION

Histopathological examination of the axillary sentinel node (SN) is becoming a routine procedure in the surgical phase of infiltrating ductal carcinoma of the breast (IDC). The SN exam may yield false negative cases mainly due to identification failure of the SN but some of the false negative cases may be the result of the pathological examination procedure applied.

MATERIAL AND METHODS

Sixty two (62) cases of clinically staged N0 IDC of the breast by TNM nomenclature were assigned to breast surgery along with conventional axillary node dissection. The identification technique included lymphoscintigraphy and intraoperative gamma-detecting probe after peritumoral injection of 99mTc-labeled colloids.The histological study of SN was performed with paired 4 microm slices and staining with hematoxylin-eosin and with a fast method of cytokeratins for freezing.

RESULTS

In only two of the 62 patients, it was not possible to identify the SN. Eighteen of the remaining 60 had SN involvement by metastasis, having no metastases in the other nodes of the axillary dissection in 6 of them. Ten of those were micrometastasis (size of metastasis= or <0.2 cm). In two out of these last 10 cases, diagnosis of the micrometastasis was only possible using slices stained with CK. There were no false negative results.

CONCLUSIONS

The lymphoscintigraphy, after peritumoral injection of small volumes and low dose of the tracer, makes it possible to obtain excellent results in the intraoperative detection of the SN in breast cancer. The study of this SN with a fast method for CK decreases the number of false negative results of the technique.