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Keywords:

  • breast carcinoma;
  • sentinel lymph node biopsy;
  • neoadjuvant chemotherapy;
  • periareolar injection

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES

BACKGROUND

The feasibility and accuracy of sentinel lymph node (SLN) biopsy after neoadjuvant chemotherapy (NAC) for patients with breast carcinoma have been investigated primarily for the situation in which the radiocolloid imaging agent is injected peritumorally. No such study has involved periareolar injection of radiocolloid, although the usefulness of this injection technique has been demonstrated in patients with early-stage breast carcinoma who have not been treated with NAC. The objective of the current study was to determine the feasibility and accuracy of SLN biopsy using periareolar injection of radiocolloid for patients with breast carcinoma who were treated with NAC.

METHODS

Forty-seven patients with AJCC Stage II or III breast carcinoma who were treated with NAC were enrolled in the study. All patients underwent SLN biopsy, which involved a combination of periareolar injection of radiocolloid (technetium 99m tin colloid) and peritumoral injection of isosulfan blue dye, followed by backup axillary lymph node dissection. SLN metastases were examined by hematoxylin and eosin staining and immunohistochemical analysis using an anticytokeratin antibody.

RESULTS

An SLN was identified successfully in 44 patients (94%). Twenty-nine patients (66%) had positive SLNs. Fifteen patients had negative SLNs, and 4 patients had positive non-SLNs. Thus, the false-negative rate was 12.1% (4 of 33 patients). The false-negative rate tended to be higher, although not statistically significantly so, among patients who had clinically positive axillary lymph nodes before and/or after NAC (15.8%; 3 of 19 patients) compared with patients who had clinically negative axillary lymph nodes both before and after NAC (7.1%; 1 of 14 patients).

CONCLUSIONS

SLN biopsy using periareolar injection of radiocolloid is feasible after NAC. In patients with clinically negative axillary lymph nodes both before and after NAC, SLN biopsy was capable of predicting axillary lymph node status with an accuracy comparable to the accuracy associated with SLN biopsy for patients with early-stage carcinoma who have not been treated with NAC. Cancer 2004. © 2004 American Cancer Society.

It is well established that sentinel lymph node (SLN) biopsy can predict axillary lymph node status with high accuracy in patients with early-stage breast carcinoma.1–3 Recently, an increasing number of patients with breast carcinoma have undergone SLN biopsy, with axillary lymph node dissection (ALND), which is associated with higher morbidity than is SLN biopsy, being spared for most patients for whom SLNs are found to be negative for disease. Another advantage of SLN biopsy is that it allows pathologists to focus on a smaller amount of specimen, resulting in a more precise pathologic evaluation of axillary lymph node status.4, 5

National Surgical Adjuvant Breast and Bowel Project Trial B-18 demonstrated that neoadjuvant chemotherapy (NAC) does not improve disease-free or overall survival in patients with primary breast carcinoma but increases the percentage of patients who undergo breast-conserving surgery.6, 7 In addition, NAC allows in vivo evaluation of tumor sensitivity to particular chemotherapeutic agents, and tumor response (pathologic complete response) serves as a predictor of favorable patient prognosis. Although NAC had been used primarily in patients with locally advanced breast carcinoma to downstage the disease so that it becomes operable, recently, increasing numbers of patients with operable tumors that were judged to be too large for breast-conserving surgery have been treated with NAC to increase the likelihood of breast conservation.8

Recently, several studies have demonstrated the feasibility and accuracy of SLN biopsy using peritumoral injection of radiocolloid for patients with breast carcinoma who were treated with NAC. However, the false-negative rates varied considerably among those studies.9–17 It is possible that tumor response to chemotherapy may alter normal lymphatic drainage and cause false-negative SLN biopsy results. Thus, the usefulness of SLN biopsy using peritumoral injection of radiocolloid in patients with breast carcinoma who are treated with NAC has yet to be established.

Recently, several studies, including one performed by our group, have demonstrated that areolar (i.e., periareolar or subareolar) injection of radiocolloid is superior to peritumoral injection in terms of the success rate of lymphoscintigraphy (LSG) and SLN detection,18–21 probably because the areolar area is rich in lymphatic vessels, facilitating the uptake of radiotracer into the lymphatic lumen. The objective of the current study was to determine the feasibility and accuracy of SLN biopsy using periareolar injection of radiocolloid in patients with breast carcinoma who were treated with NAC.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES

Patients

Forty-seven patients with T2–4N0–2 (Stage II or III) breast carcinoma who had been treated with NAC were enrolled in the current study at the Department of Surgical Oncology, Osaka University Hospital (Osaka, Japan), during the period between December 1997 and October 2002. The study was approved by the Osaka University Institutional Review Board. Of the five patients with T4 tumors, two had small satellite skin nodules, and the remaining three had small edemas of the skin overlying the tumor; none of these patients had inflammatory breast carcinoma, ulceration of the skin, or chest wall invasion. Informed consent was obtained from each patient. Patient characteristics are summarized in Table 1. In all patients, the tumor was diagnosed as invasive ductal carcinoma using core needle or incisional biopsy before chemotherapy. The patients were evaluated with mammography, ultrasonography, and magnetic resonance imaging (MRI) before and after chemotherapy to assess the effects of chemotherapy. Thirty-six patients received 4 cycles of docetaxel (60 mg/m2), 3 patients received 4 cycles of cyclophosphamide (600 mg/m2) plus epirubicin (60 mg/m2) (CE), and 8 patients received 3 cycles of CE followed by 3 cycles of docetaxel. After chemotherapy, all patients underwent SLN biopsy using a combination of blue dye and radiocolloid.

Table 1. Characteristics of Patients who Underwent Lymphoscintigraphy and Sentinel Lymph Node Biopsy
CharacteristicNo. of patients
  1. DCIS: ductal carcinoma in situ.

Age (yrs) 
 Mean51.3
 Range28–65
Menopausal status 
 Premenopausal17
 Postmenopausal30
Tumor classification 
 Before neoadjuvant chemotherapy 
  T00
  T10
  T232
  T310
  T45
 After neoadjuvant chemotherapy 
  T06
  T111
  T224
  T32
  T44
Tumor size in cm (mean ± SD) 
 Before4.5 ± 1.8
 After2.4 ± 1.7
Lymph node status 
 Before neoadjuvant chemotherapy 
  N025
  N118
  N24
 After neoadjuvant chemotherapy 
  N032
  N112
  N23
Tumor location 
 Upper outer quadrant18
 Lower outer quadrant7
 Upper inner quadrant13
 Lower inner quadrant1
 Central8
Method of diagnosis 
 Core biopsy45
 Incisional biopsy2
Tumor type 
 DCIS0
 Invasive ductal40
 Invasive lobular4
 Other3

SLN Biopsy Procedure

On the day before surgery, 30–80 megabecquerels of technetium 99m (99mTc)-tin colloid (Nihon Medi-Physics Co., Hyogo, Japan) in sterile saline (total volume, 2 mL) was injected into 4 periareolar sites (at the 3, 6, 9, and 12 o'clock positions around the areola) after local anesthesia with 1–2 mL lidocaine (1% solution), as is described elsewhere.21 LSG was performed routinely 1–2 hours after injection of the radiotracer. Immediately before surgery (19–29 hours after the injection of radiocolloid), 2 mL isosulfan blue dye (1% Lymphazurin; U.S. Surgical Company, Norwalk, CT) was injected into the parenchyma surrounding the tumor (peritumoral injection), and the injection site was massaged manually for approximately 5 minutes. During surgery, the SLN was localized with a γ-detection collimated probe (Navigator; U.S. Surgical Company). An SLN (hot) was defined as a lymph node with ex vivo radioactivity (counts per second) measuring ≥ 400% of the radioactivity of the axillary background. An SLN (blue) was defined as a lymph node that was stained partially or completely by blue dye or that was connected to a blue-stained afferent lymphatic tract. All patients underwent concurrent complete ALND regardless of axillary lymph node status.

Histologic Examination

SLNs were fixed in 10% buffered formalin, processed overnight, and sectioned serially in slices of approximately 2 mm. All slices were embedded in paraffin and were examined via hematoxylin and eosin (H & E) staining and immunohistochemical analysis (avidin-biotin-peroxidase method) using an anticytokeratin antibody AE1/AE3 (Histofine; Nichirei Company, Tokyo, Japan). Metastases were considered positive when at least one cluster of immunohistochemically positive cells was identified. Lymph nodes with single, scattered positively stained cells were not considered metastatic. The SLN was diagnosed as positive when either the H & E or immunohistochemical staining results were positive. For histologic examination of non-SLNs, one representative paraffin section of each lymph node was examined using H & E staining. If the SLN was negative on the H & E section, and if all other lymph nodes also were negative on that section, then one additional section from each nonsentinel lymph node was subjected to further immunohistochemical analysis.

Statistical Analysis

Differences in categoric variables were analyzed using the chi-square test, and differences in the mean values of continuous variables were analyzed using the Student t test. P values < 0.05 were considered significant.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES

Response to NAC

The rate of clinical response to NAC was 77% (complete responses in 6 patients and partial responses in 30 patients, with no change in 10 patients and disease progression in 1 patient). A pathologic complete response was achieved in five patients. The mean tumor size on clinical examination was reduced from 4.5 cm to 2.4 cm by NAC. Eight patients underwent breast-conserving surgery, and 39 patients underwent mastectomy.

LSG

A focal accumulation of radioactivity (i.e., a hot spot) was visualized successfully by LSG in 41 patients (87%) (Table 2). This frequency was comparable to the frequency observed (90%) among patients who had not been treated with NAC in our previous study.21 Forty patients exhibited hot spots in the ipsilateral axilla. Among these 40 patients, hot spots also were observed in the internal mammary region in 2 patients, in the supraclavicular region in 2 patients, and in the intramammary region in 1 patient. Another patient had a hot spot in the contralateral axilla but not in the ipsilateral axilla (Fig. 1). This patient underwent bilateral ALND. More than 10 lymph nodes with massive metastases that exhibited various degrees of replacement by fibrous tissue, suggesting a response to NAC, were identified in the ipsilateral axilla, and 1 lymph node with metastasis was identified in the contralateral axilla. Thus, overall, six patients had extraaxillary hot spots. The corresponding frequency of extraaxillary hot spots (15%) was higher than the frequency noted among patients who had not been treated with NAC (6%) in our previous study,21 but the difference was not statistically significant.

Table 2. Lymphoscintigraphic Visualization of ‘Hot Spots’ in the Axillary and Extraaxillary Lymph Nodes
 No. of patients (%)
  1. AN: axillary lymph nodes; IMN: internal mammary lymph nodes; SC: supraclavicular lymph nodes; IN: intramammary lymph nodes.

Visualized41 (87)
 AN only35
 AN + IMN2
 AN + SC2
 AN + IN1
 Contralateral AN1
Not visualized 6 (13)
thumbnail image

Figure 1. Lymphoscintigraphy shows a focal accumulation in the contralateral axillary lymph node (arrowhead) but not in the ipsilateral axillary lymph node. IS: injection site.

Download figure to PowerPoint

SLN Detection

An SLN was identified successfully in 44 patients (94%) (Table 3). The identification rate was not affected by patient age, tumor size, clinical lymph node status, or type of malignancy. The mean number of SLNs removed per patient was 2.1 (range, 1–5). The mean ex vivo radioactivity of SLNs was 101 counts per second (range, 5–336 counts per second), which was similar to the SLN radioactivity (117 counts per second; range, 5–900 counts per second) observed in patients who were not treated with NAC, as is described in our previous study.21 An SLN was identified by both radiocolloid and blue dye in 37 patients (84%), by radiocolloid alone in 3 patients (7%), by blue dye alone in 3 patients (7%), and by mismatch (i.e., some SLNs were identified by radiocolloid, whereas others were identified by blue dye, but none were identified by both methods) in 1 patient (2%).

Table 3. Results of Sentinel Lymph Node Biopsy Using Radiocolloid and Blue Dye
 No. of patients (%)
  1. SLN: sentinel lymph node.

Total no. of patients47 (100)
SLN identified44 (94)
SLN positive29 (66)
SLN was only positive lymph node9 (31)
SLN identification method 
 Radiocolloid and blue dye37 (84)
 Radiocolloid only3 (7)
 Blue dye only3 (7)
 Mismatch1 (2)

SLN Metastases

Of the 44 patients in whom an SLN could be identified, 29 (66%) had positive SLNs. For 9 of those 29 patients (31%), the SLN was the only tumor-positive lymph node. One patient had micrometastasis that was detected on immunohistochemical staining but not on H & E staining. Among the 15 patients who had negative SLN results on both H & E and immunohistochemical sections, it was found that 3 patients had positive nonsentinel lymph nodes on routine H & E sections. In the remaining 12 patients, who had SLNs that were negative on both H & E and immunohistochemical sections, 1 additional section was obtained from each of 129 nonsentinel lymph nodes and was subjected to immunohistochemical staining, resulting in the identification of micrometastasis in only 1 nonsentinel lymph node. Thus, 4 patients had confirmed false-negative results, yielding a false-negative rate of 12.1% (Table 4). In the subgroup of patients with clinically negative lymph node status both before and after NAC, the false-negative rate was 7.1% (Table 5), whereas in the subgroup of patients with clinically positive lymph node status before and/or after NAC, the false-negative rate was 15.8% (Table 6). Thus, the false-negative rate tended to be lower in the former subgroup compared with the latter, but the difference was not significant.

Table 4. Comparison of Lymph Node Status of Sentinel Lymph Nodes and Nonsentinel Lymph Nodesa
SLN statusNonsentinel LN status
PositiveNegative
  • LN: lymph node; SLN: sentinel lymph node.

  • a

    False-negative rate, 12.1%.

Positive209
Negative411
Table 5. Comparison of Lymph Node Status of Sentinel Lymph Nodes and Nonsentinel Lymph Nodes in Patients with Clinically Negative Axilla before and after Neoadjuvant Chemotherapya
SLN statusNonsentinel LN status
PositiveNegative
  • LN: lymph node; SLN: sentinel lymph node.

  • a

    False-negative rate, 7.1%.

Positive76
Negative110
Table 6. Comparison of Lymph Node Status of Sentinel Lymph Nodes and Nonsentinel Lymph Nodes in Patients with Clinically Positive Axilla before and/or after Neoadjuvant Chemotherapya
SLN statusNonsentinel LN status
PositiveNegative
  • LN: lymph node; SLN: sentinel lymph node.

  • a

    False-negative rate, 15.8%.

Positive133
Negative31

DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES

Because many studies have proven that SLN biopsy can predict axillary lymph node status with high accuracy in patients with early-stage breast carcinoma,1–3 this technique is now widely used as an alternative to ALND in such patients. However, controversy remains regarding the feasibility and accuracy of SLN biopsy in patients with breast carcinoma who are treated with NAC, because NAC may damage lymphatic drainage from tumors, resulting in a low identification rate of SLN as well as a high false-negative rate. However, the identification rate associated with SLN using the combination of periareolar radiocolloid and peritumoral blue dye in the current study was as high as 94%; this identification rate is similar to the rates reported in studies of SLN biopsy in patients with early-stage breast carcinoma who had not been treated with NAC. The identification rate of SLN by radiocolloid only was 87% in the current study, a rate that is comparable to the rates obtained in studies involving patients who had been treated with NAC (Table 7). These results suggest that periareolar injection is a suitable technique for SLN biopsy in patients who have been treated with NAC. It has been speculated that one advantage of periareolar injection is that the areola is rich in lymphatic vessels, which facilitate the uptake of radiotracer into the lymphatic lumen; another advantage is that the tissue around the areola is unlikely to be affected by NAC (i.e., lymphatic drainage is unlikely to be damaged) unless the areola has tumor involvement. In fact, the ex vivo radioactivity count observed in SLNs (mean, 101 counts per second) in the current study was similar to the count observed in SLNs obtained using periareolar injection from patients with early-stage breast carcinoma who had not been treated with NAC, and the ex vivo count in SLNs that was obtained using periareolar injection was significantly higher compared with the count obtained using peritumoral injection.21

Table 7. Studies of Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy
StudyNo. of patientsStage of diseaseTumor size (cm)Injection siteNo. (%) of successful SLN biopsiesPositive SLNSLN was only positiveFalse negative (%)
Before NACAfter NACRadiocolloidDye
  • LN: lymph node; SLN: sentinel lymph node; NAC: neoadjuvant chemotherapy; PT: peritumoral; NS: not stated; PA: periareolar.

  • a

    Mean Value

  • b Mean value ± SD.

  • c One patient received a subareolar injection of radiocolloid.

Breslin et al., 2000951Stage II or III (T1N1M0 or T2–3N0M0)5.02.0PTPT43 (84.3)22103 (12)
Miller et al., 20021035T1–3N03.51.1PTPT30 (86.0)940 (0)
Stearns et al., 20001134T3–4, any N5.01.8NonePT29 (85.0)1353 (14)
Haid et al., 20011233T1–3, any N3.3 ± 2.02.0 ± 3.0PTPT29 (88.0)18110 (0)
Julian et al., 200113 and 20021431Stage I–IINSNSPTPT29 (93.5)1150 (0)
Tafra et al., 20011529Any T, N01.4 ± 1.3NSPTPT27 (93.0)15NS0 (0)
Brady, 20021614Stage I–IIBNSNSSAaPT13 (93.0)1060 (0)
Nason et al., 20001715T2–4N0NSNSPTPT13 (87.0)603 (33)
Current study47Stage II or III (T2–4N0–2)4.52.4PAPT44 (93.6)2694 (12)

False-negative results are highly problematic in SLN biopsy, because they lead to incorrect lymph node staging, which results in the undertreatment of patients as well as an increase in the incidence of axillary lymph node recurrence. Generally, the acceptable false-negative rate associated with SLN biopsy for patients with early-stage breast carcinoma is approximately 5%.22 Recently, the results of several studies on SLN biopsy for patients with breast carcinoma who had been treated with NAC have been reported (Table 7). The false-negative rates varied widely, ranging from 0% to 33% among the studies. The false-negative rate in the current study was relatively high (12.1%) when all patients were considered (Table 4). However, this rate was low (7.1%) among patients with clinically negative lymph node status both before and after NAC (Table 5). In contrast, the false-negative rate was high (15.8%) among patients with clinically positive lymph node status before and/or after NAC (Table 6). Although there was no statistically significant difference in the false-negative rate between patients with clinically negative lymph node status before and after NAC and patients with clinically positive lymph node status before and/or after NAC, these results nonetheless appear to indicate that the false-negative rate (7.1%) among patients with clinically negative lymph node status both before and after NAC is comparable to the rate reported for patients with early-stage breast carcinoma (approximately 5%). These findings suggest that SLN biopsy following NAC can predict the axillary lymph node status of patients with clinically negative lymph node status both before and after NAC, but not the axillary lymph node status of patients with clinically positive lymph node status before and/or after NAC, with a high degree of accuracy (i.e., comparable to the degree of accuracy associated with SLN biopsy for patients with early-stage breast carcinoma).

Because SLN biopsy typically is not indicated for patients with clinically positive lymph node status, patients with clinically positive lymph node status after NAC are not considered candidates for SLN. Patients who experience a change in axillary lymph node status from positive to negative also are unlikely to be good candidates for SLN biopsy; in the current study, of the 7 patients who had their axillary lymph node status changed from positive to negative by NAC, 2 had false-negative results, and, thus the false-negative rate for those 7 patients was as high as 33.3%;. Kuerer et al. speculated that SLN biopsy was accurate for patients who had their metastatic axillary lymph node status downstaged only if the metastatic deposits in each axillary lymph node responded homogeneously to NAC.23 Thus, if NAC has eradicated metastatic foci in the SLN but not in nonsentinel lymph nodes, then false-negative results will occur. Furthermore, it has been speculated that among patients who have their axillary lymph node status downstaged by NAC, tumors also typically respond to NAC and shrink, so that damage to and alteration of the lymphatic flow from the tumor tissues to the axillary basin are more likely to occur.

Although some studies involving patients with smaller tumors who were treated with NAC have reported no false-negative results, other studies involving patients with larger tumors who were treated with NAC have reported relatively high false-negative rates, ranging from 12% to 33% (Table 7). In the current study, 3 of 4 patients who had false-negative results had tumors that measured > 4 cm before NAC and that still measured > 3.5 cm after NAC. These findings suggest that large tumor size is associated with an increasing false-negative rate. It has been suggested that peritumoral and periareolar injections may be unable to reach all of the lymphatic channels from tumor tissue to the SLN in large tumors. It also has been speculated that the shrinkage of large tumors may lead to a more severe distortion of lymphatic channels.

Although 99mTc-sulfur colloid and 99mTc colloidal albumin typically are used in SLN biopsy, we used 99mTc-tin colloid. The particle size of 99mTc-tin colloid (range, 400–5000 nm) is larger than the particle size of 99mTc-sulfur colloid (range, 50–1000 nm) and much larger than the particle size of 99mTc colloidal albumin. It is difficult for a large-particle colloid to pass into the lymphatic channels; however, the use of such a colloid reduces the risk of labeling a nonsentinel lymph node, and once the colloid is trapped in a lymph node, it is retained for a relatively long time, allowing surgeons to detect the SLN readily using a γ-detection probe, even on the day following injection. We injected radiocolloid on the day before surgery. The advantages of this day-before injection method are that the background counts become very low and that more time is allowed for tracer migration to the SLNs. The high detection rate of SLNs in the current study appears to be attributable in part to the fact that 99mTc-tin colloid was injected on the day before surgery.

LSG is useful in that it can detect the lymphatic flow to extraaxillary lymph nodes, such as internal mammary and supraclavicular lymph nodes.24 In the current study, 15% of patients with successful LSG results had focal accumulations in the extraaxillary region. This frequency of LSG visualization of extraaxillary accumulations is greater, although not statistically significantly so, compared with the frequency observed among patients who were not treated with NAC (6%) in our previous report.21 Although the clinical significance of extraaxillary accumulations of radioactivity remains to be established, biopsy of such extraaxillary lymph nodes may be helpful in staging disease with more accuracy and making decisions regarding adjuvant chemotherapy and postoperative radiotherapy to the internal mammary and supraclavicular regions.

In conclusion, the results of the current study suggest that SLN biopsy after NAC using periareolar injection of radiocolloid is feasible and can predict axillary lymph node status with high accuracy for patients with clinically negative lymph node status both before and after NAC. Patients who have had their axillary lymph node status downstaged from positive to negative and patients with large tumors are not appropriate candidates for SLN biopsy. Further studies involving larger numbers of patients will be required to fully establish the feasibility and accuracy of SLN biopsy for patients with breast carcinoma who have been treated with NAC.

Acknowledgements

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES

The authors thank nuclear medicine technologists Yukio Nakamura and Michihiro Sasagaki for their dedication and expertise in performing lymphoscintigraphy in the current study.

REFERENCES

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. Acknowledgements
  7. REFERENCES