Reliable lymphatic drainage to axillary sentinel lymph nodes regardless of tumor location within the breast

Expression of SIRT1 and apoptosis-related proteins is predictive for lymph node metastasis and disease-free survival in luminal A breast cancer

Luminal A breast cancer can present with early, unexpected lymph node metastasis, and sentinel lymph node biopsy has been reported false negative in some cases. We aimed to construct a biomarker-based model that predicts lymph node metastasis in luminal A breast cancer, using expression of silent mating type information regulation 2 homolog 1 (SIRT1) and apoptosis-related factors, which are known to be closely related. We selected tissue samples of 278 cases of luminal A invasive ductal carcinoma, constructed tissue microarrays, and performed immunohistochemical staining for SIRT1 and four apoptosis-related proteins. In constructing the best predictive model for lymph node metastasis, six clinicopathological parameters and five molecular markers were considered. Independent factors predictive of lymph node metastasis were pT stage (OR 1.829, p = 0.027), lymphovascular invasion (OR 4.128, p < 0.001), and decreased expression of caspase-3 (OR 0.535, p = 0.034) and of SIRT1 (OR 0.526, p = 0.053). A combination nuclear grade, lymphovascular invasion, increased B-cell lymphoma 2 (Bcl-2) expression, and reduced expression of caspase-3 and of SIRT1 yielded the strongest predictive performance for lymph node metastasis with an area under the curve (AUC) of 0.696. This combination was also predictive of shortened disease-free survival (73.1 vs. 67.7 months, p = 0.003). Our data support a role of SIRT1 protein as tumor suppressor in luminal A breast cancer, in association with apoptosis-related proteins. Our model based upon a combination of these biomarkers is expected to increase accuracy of prediction of lymph node metastasis in luminal A breast cancer. This might serve as a valuable tool in determining the optimal surgical strategy in breast cancer patients.

A histomorphologic predictive model for axillary lymph node metastasis in preoperative breast cancer core needle biopsy according to intrinsic subtypes

The aim of this study is construction of a pathologic nomogram that can predict axillary lymph node metastasis (LNM) for each intrinsic subtype of breast cancer with regard to histologic characteristics in breast core needle biopsy (CNB) for use in routine practice. A total of 534 CNBs with invasive ductal carcinoma classified into 5 intrinsic subtypes were enrolled. Eighteen clinicopathological characteristics and 8 molecular markers used in CNB were evaluated for construction of the best predictive model of LNM. In addition to conventional parameters including tumor multiplicity (P < .001), tumor size (P < .001), high histologic grade (P = .035), and lymphatic invasion (P = .017), micropapillary structure (P < .001), the presence of small cell-like crush artifact (P = .001), and overexpression of HER2 (P = .090) and p53 (P = .087) were proven to be independent predictive factors for LNM. A combination of 8 statistically independent parameters yielded the strongest predictive performance with an area under the curve of 0.760 for LNM. A combination of 6 independent variables, including tumor number, tumor size, histologic grade, lymphatic invasion, micropapillary structure, and small cell-like crush artifact produced the best predictive performance for LNM in luminal A intrinsic subtype (area under the curve, 0.791). Thus, adding these combinations of clinical and morphologic parameters in preoperative CNB is expected to enhance the accuracy of prediction of LNM in breast cancer, which might serve as another valuable tool in determining optimal surgical strategies for breast cancer patients.

Localization of sentinel lymph node in breast cancer. A prospective study

INTRODUCTION

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for staging axillary lymph nodes in women with breast cancer and clinically negative nodes. It is associated with reduced arm morbidity, moderated or severe lymphoedema, and a better quality of life in comparison with standard axillary treatment. Unfortunately, skip metastases makes all minimally invasive approaches, such as axillary sampling, unreliable. The aim of the present clinical prospective study is to evaluate the position of SLN in an important number of cases and establish the real incidence of skip metastases in clinically node-negative patients.

PATIENTS AND METHODS

A cohort of 898 female patients with breast carcinoma was considered, from 2001 to 2008. Once SLN was localized, by means of radio-colloid or blue dye staining, and isolated, a biopsy was performed. Only those positive for metastases were submitted to axillary dissection.

RESULTS

Only in nine cases a SLN was not isolated. We had 819 cases of first level SLN (group A) and 69 cases of second level SLN (group B). Considering all of 889 cases, SLN was localized in the second level in 69 patients (7.8%); but if we consider metastatic SLN alone (340 cases), it was in the second level in 23 subjects (6.8%). In total, we had a positive second level SLN in 2.3% of cases (23/889).

CONCLUSION

Second level SLN could be considered only an anomalous lymphatic axillary drainage and it does not linked to particular histological variants of the primitive tumour. In our study, skip metastases were recognized in only 2.6% of cases, therefore, whenever a SLN is not isolated for any reason, the first level sampling represent a viable operative choice.

Management of the axilla in women with breast cancer: current clinical practice and a new selective targeted approach

BACKGROUND

Axillary nodal status is the most important prognostic factor for patients with breast cancer. Clinical assessment and imaging modalities are not always reliable. Surgical removal and histopathological examination of axillary lymph nodes remain essential methods of staging the axilla. However, the optimal management of the axilla remains uncertain.

METHODS

We performed Medline searches to identify relevant systematic reviews, meta-analysis, and nonrandomized and randomized controlled trials for the past 5 years (up to December 2007), as well as important historical articles and clinical guidelines relating to management of the axilla in women with breast cancer.

RESULTS

Axillary lymph node dissection (ALND) has been the standard surgical approach for many years. It is, however, associated with marked morbidity; survival benefit remains uncertain. Axillary node sampling, widely practiced in the United Kingdom, is a reliable alternative procedure in staging the axilla, with less morbidity. Sentinel lymph node biopsy (SLNB) has become an accurate method for staging the axilla in women with operable, clinically node-negative breast cancer. SLNB alone appears to be a safe and acceptable procedure for patients with uninvolved SLNs. Completion ALND or axillary radiotherapy remains the standard treatment for patients with tumor-involved SLNs. SLNB is associated with less morbidity than ALND. However, long-term follow-up and therapeutic outcomes are being awaited from randomized controlled trials.

CONCLUSIONS

Several procedures are available for staging and treating the axilla. A tailored surgical approach, with careful assessment of risk-benefit and patient preference, is guiding the evolving modern management of the axilla for women with breast cancer.

Sentinel node biopsy in patients with multiple breast cancer

BACKGROUND

Multicentric or multifocal breast cancer is considered a limitation for sentinel lymph node biopsy (SLNB). Studies showing that all quadrants of the breast drain via common afferent lymphatic channels indicate that multiple tumors do not affect lymphatic drainage. We therefore assessed the accuracy of SLNB in patients with multiple breast tumors.

METHODS

Of the 942 breast cancer patients who underwent SLNB using radioisotope at Asan Medical Center between January 2003 and December 2006, 803 had unifocal and 139 had multiple tumors. Axillary dissection after SLNB was performed on 884 patients, 757 with unifocal and 127 with multiple tumors. All patients underwent lymphatic scintigram for removal of sentinel lymph nodes (SLNs). The clinical characteristics and accuracy of SLNB was compared in patients with unifocal and multiple breast cancer.

RESULTS

In the multiple tumor group, 2.68 +/- 0.84 SLNs were identified in 136 of 139 patients (identification rate, 97.84%); 81.5% of SLNs were identified by scintigram. The incidence of axillary metastases was 29.50% (41/139). SLNB accuracy was 97.63% (124/127), with a false negative (FN) rate of 7.89% (3/38). In the unifocal group, 2.67 +/- 0.96 SLNs were identified in 787 of 803 patients (identification rate, 98.00%); 84.8% of SLNs were identified by scintigram. The incidence of axillary metastasis was 22.04% (177/803). SLNB accuracy was 98.02% (742/757), with a FN rate of 8.62% (15/174). The accuracy and FN rate of SLNB did not differ significantly between unifocal and multiple breast cancer.

CONCLUSION

The accuracy of SLNB in multiple breast cancer is comparable to its accuracy in unifocal cancer. These findings indicate that SLNB can be used an as alternative to complete axillary lymph node dissection in patients with multiple breast tumors.

Sentinel lymph node biopsy in multiple breast cancer using subareolar injection of the tracer

We performed subdermal injection of (99m)Tc-labelled albumin combined with subareolar (SA) injection of blue dye to axillary lymphatic mapping and sentinel lymph node biopsy (SLNB) in patients with multifocal and multicentric breast cancer to evaluate the feasibility and accuracy of this technique. A retrospective analysis of our experience on 235 SLNB showed that 30(12.7%) had multiple cancer (MC) on final pathologic examination and was considered in relation to the aim of the study. Mean age was 57.19 years (range 24-90). Mean number of SLNs identified was 1.93 (range 1-5). Mean number of axillary LNs examined was 18.10 (range 12-27). Overall successful identification was 100% with a false negative (FN) rate of 6.25%. Overall accuracy of lymphatic mapping and sensitivity was 96.6% and 93.7%, respectively. SLNB using the SA injection technique may be an alternative to complete axillary dissection in patients with multiple breast cancers and a clinically negative axilla.

Contraindications of sentinel lymph node biopsy: are there any really?

BACKGROUND

One of the most exciting and talked about new surgical techniques in breast cancer surgery is the sentinel lymph node biopsy. It is an alternative procedure to standard axillary lymph node dissection, which makes possible less invasive surgery and side effects for patients with early breast cancer that wouldn't benefit further from axillary lymph node clearance. Sentinel lymph node biopsy helps to accurately evaluate the status of the axilla and the extent of disease, but also determines appropriate adjuvant treatment and long-term follow-up. However, like all surgical procedures, the sentinel lymph node biopsy is not appropriate for each and every patient.

METHODS

In this article we review the absolute and relative contraindications of the procedure in respect to clinically positive axilla, neoadjuvant therapy, tumor size, multicentric and multifocal disease, in situ carcinoma, pregnancy, age, body-mass index, allergies to dye and/or radio colloid and prior breast and/or axillary surgery.

RESULTS

Certain conditions involving host factors and tumor biologic characteristics may have a negative impact on the success rate and accuracy of the procedure. The overall fraction of patients unsuitable or with multiple risk factors that may compromise the success of the sentinel lymph node biopsy, is very small. Nevertheless, these patients need to be successfully identified, appropriately advised and cautioned, and so do the surgeons that perform the procedure.

CONCLUSION

When performed by an experienced multi-disciplinary team, the SLNB is a highly effective and accurate alternative to standard level I and II axillary clearance in the vast majority of patients with early breast cancer.

Localization of the Sentinel Node of the Upper Outer Breast Quadrant in the Axillary Quadrants

BACKGROUND

Sentinel node (SN) biopsy is associated with much less morbidity than axillary dissection. In patients with early breast cancer, lymphatic mapping and SN biopsy accurately stage the axillary nodes. Both currently available lymphatic mapping agents, radiocolloid and blue dye, have some limitations that may make perioperative or preoperative SN identification difficult. In such cases, exact knowledge of the topography of the axilla and the most probable location of the SN may be crucial.

METHODS

In 12 fresh female cadavers with no history of breast carcinoma, injections of patent blue dye were used to visualize the SNs in the axillary quadrants and their lymphatic collectors from the upper outer quadrant of the breast, which is the most common location of breast cancer. The axilla was divided into quadrants with regard to the intersection of the thoracoepigastric vein and the third intercostobrachial nerve.

RESULTS

All SNs were located within a circle of 2-cm radius of this intersection in the fatty tissue at the clavipectoral fascia. In most cases, the SN was located in the fatty tissue near the clavipectoral fascia in the lower ventral quadrant of the axilla (n = 14, 58%). In seven cases (29%), the SN was located in the upper ventral quadrant, in two cases (8%) in the upper dorsal quadrant, and in one case in the lower dorsal quadrant.

CONCLUSIONS

The results of this anatomical study may facilitate SN biopsy in patients with breast cancer.

Symmetrization reduction mammaplasty combined with sentinel node biopsy in patients operated for contralateral breast cancer

BACKGROUND AND OBJECTIVES

Occult invasive cancer found in reduction mammaplasty specimen in the contralateral breast in breast cancer patients requires axillary lymph node dissection (ALND) to assess the lymph node status. Routine Sentinel node (SN) biopsy in these patients may avoid secondary ALND when an occult cancer is found and the SN is negative in the permanent histological examination.

METHODS

One hundred sixty-nine breast cancer patients underwent contralateral reduction mammaplasty for symmetrization and with SN biopsy of the non-cancer breast. SN mapping was done using a vital blue dye alone (n = 136) or in combination with a radiocolloid (n = 33).

RESULTS

A mean number of 1.4 SNs (range 1-3 SNs) was identified in 158 of 169 patients (identification rate 93.5%). One of 158 patients revealed a positive SN but no tumor was found in the reduction mammaplasty/mastectomy specimen, whereas the SN was negative in 157 patients. Histological examination of the 169 reduction mammaplasty specimen revealed 5 occult invasive cancers and 4 patients with high grade DCIS but due to a negative SN biopsy the patients were spared a secondary ALND.

CONCLUSION

The small number of patients with occult contralateral cancers may not warrant routine SN mapping in patients scheduled for contralateral reduction mammaplasty.

Clinicopathologic factors associated with false-negative sentinel lymph-node biopsy in breast cancer

SUMMARY BACKGROUND DATA

Previous studies have suggested a variety of factors that may affect the false negative (FN) rate for sentinel lymph node (SLN) biopsy in breast cancer. Because FN results are relatively rare, no prior studies have had sufficient sample size to allow detailed statistical analysis of factors predicting FN results.

METHODS

Patients with clinical stage T1-2, N0 invasive breast cancer were enrolled in a prospective, multicenter study. All patients underwent SLN biopsy, followed by planned completion axillary dissection regardless of the SLN results, to assess the FN rate. SLN biopsy was performed using radioactive colloid injection in combination with isosulfan blue dye in 94% of cases. Dermal, subdermal, peritumoral, or subareolar radioactive colloid injection techniques were used at the discretion of each institution. Univariate and multivariate analyses were performed to identify factors associated with a FN result.

RESULTS

SLNs were identified in 3870 of 4117 patients (94%). There were 1243 true positive, 2521 true negative, and 106 FN results. Age, histologic subtype, the number of non-SLN removed, tumor palpability, type of breast biopsy, and SLN injection technique were not significant factors. On multivariate analysis, tumor size <2.5 cm, upper outer quadrant tumor location, removal of only a single SLN, minimal surgeon experience, presence of a single positive axillary LN, and use of immunohistochemistry (IHC) for SLN analysis were independently associated with an increased risk of FN results.

CONCLUSIONS

Surgeon experience, tumor size and location, and the number of SLN removed are preoperative and intraoperative factors that independently predict the risk of a FN result. In contrast to suggestions from other smaller studies, age does not affect the likelihood of a FN result; a lesser, rather than greater, number of positive axillary nodes was associated with an increased likelihood of a FN result; and IHC analysis of the SLN increases, rather than decreases, the risk of FN results.

Incidence of internal mammary node metastases after a sentinel lymph node technique in breast cancer and its implication in the radiotherapy plan

PURPOSE

To analyze the frequency in determining pathologically proven metastatic involvement of internal mammary nodes (IMN) after sentinel lymph node (SLN) technique in breast cancer and to evaluate the implications for radiotherapy (RT) management of patients.

METHODS AND MATERIALS

Two hundred and twenty-five patients who underwent lymphatic mapping for early breast cancer treated with breast-conserving surgery and radiation (80%) or mastectomy (20%) were evaluated. There were two phases in the study: the validation phase (105 patients, 52 T1, 53 T2 < or = 4 cm), and the application phase (120 patients, 70 T1, 50 T2 < or = 2.5 cm). In the validation, if a drainage pathway to the IMN was identified, no biopsy was performed in this phase. In the application, if the study showed metastases in the IMNs, biopsy was performed. When histologically proven IMN metastases were detected, RT was included on the IMN chain planned with a 3D treatment system using conformal techniques. At the beginning of the study the injection site was subdermal and subsequently, the injection site was changed to peritumoral and intratumoral to search for IMN.

RESULTS

In 31 patients of 225 (14%) hot spots were observed in the internal mammary chain (11.5% and 17.2% in the validation and application phases, respectively). In the validation phase, in 11 cases (11.5%) IMN drainage was observed, and in the application phase, in 20 cases (17.2%). Sampling of the internal mammary basin based on lymphoscintigraphy results was successful in 69% of the cases (14 of 20) and revealed metastatic involvement in 14% (2 of 14). This represents incidence of only 1.7% (2 of 116) in early breast cancer patients with SLN study in the application phase. In both cases the axillary SLN was also positive. Both patients with metastatic involvement of the IMN area received RT on the IMN chain next to the remaining breast after conservative surgery.

CONCLUSIONS

We can conclude that 14% of the patients with intraoperative drainage into the IMN surgical examination of the lymph nodes had pathologically positive metastases. The percentage in pathologically proven metastatic involvement of IMN after the SLN technique in early breast cancer is low, but it is not negligible. Moreover, it is expected to increase since the international recommendations have established a 3-cm cutoff for practicing the SLN technique. Although the real value of IMN irradiation in early breast cancer is not known, including this chain in postoperative radiotherapy is not recommended unless pathologically proven IMNs have been produced by the SLN technique. To avoid overdosage or underdosage in the joint between the medial tangential and IMN fields, an individualized 3D dosimetry study is mandatory to enhance dose distribution and reduce the heart volume to lessen side effects.

Lymphatic mapping and sentinel lymphadenectomy for breast cancer

Lymphatic mapping and sentinel lymphadenectomy has become an important tool for axillary lymph node staging in women with early-stage breast cancer. This review examines data regarding the staging accuracy, indications and technical aspects of the procedure, and clinical trials investigating the technique. Multiple studies now confirm that sentinel lymphadenectomy accurately stages the axilla and is associated with less morbidity than axillary dissection. Blue dye, radiocolloid, or both can be used to identify the sentinel node, and several injection techniques may be used successfully. Many patient factors previously thought to affect accuracy of the procedure have now been shown to be of limited significance. The indications for the procedure are expanding, and the histopathologic evaluation of the sentinel node and the role of lymphoscintigraphy have been clarified. Clinical trials are now underway that will determine the prognostic significance of micrometastases and the therapeutic benefit of axillary dissection in women with and without sentinel node metastases. Incorporation of sentinel lymphadenectomy into routine clinical practice will maintain accurate axillary staging with lower morbidity and improved quality of life for women with early-stage breast cancer.

The Optimal Number of Sentinel Lymph Nodes for Focused Pathologic Examination

The sentinel lymph node (SLN) procedure provides an alternative method for assessing the axillary lymph nodes in patients with breast cancer. The SLN is typically subjected to a focused pathologic examination involving the examination of multiple tissue levels and/or keratin immunohistology. The number of SLNs submitted may vary widely, in some cases rivaling that of a complete axillary dissection (CAD). We examined our experience over the last 2 years in order to determine the optimal number of SLNs for focused pathologic evaluation. All SLN cases for the years 2000 and 2001 were retrieved from the files of the Pathology Department at Magee-Womens Hospital and were tabulated to determine the average number of SLNs per case, the number of SLNs submitted, the actual SLN that was positive for each case, the type of metastasis, and the average number of SLNs per case for each surgeon. There were 662 operative cases that yielded 1576 SLN accessions and 1758 total SLNs. The range of SLNs submitted was 1 to 11. Overall there was a mean of 2.4 SLNs accessioned per case and a mean of 2.7 SLNs per case. A study of the statistics of SLNs submitted by seven surgeons yielded two distinct groups, with one group submitting virtually all of the cases where there were consistently more than four SLNs per case. Ninety-seven percent of positive SLNs were discovered in the first three SLNs submitted, regardless of surgeon identity. The SLNs beyond numbers one to three yielded positive results by keratin in only four cases. Focused pathologic examination of SLNs was most effective for the first three SLNs submitted for any given case. The variation in the number of SLNs submitted per case was different based upon the different practice patterns of surgeons. It is suggested that for more than three SLNs submitted, simple routine lymph node examination would be appropriate.

Obesity and lymphatic mapping with sentinel lymph node biopsy in breast cancer

BACKGROUND

With increasing sentinel lymph node experience, patient subsets associated with lower success rates are being identified. Obesity may be one such subset.

METHODS

A retrospective review was conducted of breast cancer patients who underwent sentinel lymph node biopsy from March 1997 to September 2002. Factors examined included demographics, body mass index (BMI), breast size, tumor characteristics, lymphoscintigraphy drainage, and success of mapping. Chi-square and exact P values were used for statistical analysis.

RESULTS

One hundred seventy-four breast cancer patients had sentinel lymph node biopsy. Sixty-seven patients were normal weight (BMI <25.1); 56 patients were overweight (BMI 25.1 to 29.9); and 51 patients were obese (BMI >29.9). Failure to identify a sentinel lymph node and the false negative rate were not statistically different (P = 0.7783 and P = 0.9290, respectively) among the three groups.

CONCLUSIONS

Obesity has no significant effect on sentinel node identification rate or false negative rate.

Validation of axillary sentinel lymph node detection in the staging of early lobular invasive breast carcinoma

BACKGROUND

Previous reports have shown that regional lymph node involvement in patients with early-stage breast carcinoma can be evaluated by resection of axillary sentinel lymph nodes (ASLN). Axillary lymphadenectomy may be unnecessary in the absence of ASLN involvement. In the current study, the authors compared the results of ASLN resection in patients with lobular invasive carcinoma (LIC) with the results from patients with ductal invasive carcinoma (DIC) in terms of detection rates and false-negative rates.

METHODS

For ASLN detection, technetium 99m sulfur-colloid and patent blue were injected around the tumor. Each patient underwent both ASLN resection and complete axillary lymphadenectomy. Detection rates and false-negative rates were evaluated in patients with LIC and in patients with DIC.

RESULTS

Two hundred forty-three patients with invasive, early-stage breast carcinoma were enrolled in the study (208 patients with DIC and 35 patients with LIC). The median patient age, pathologic tumor size, hormone receptor status, and rates of involved lymph nodes were equivalent for both groups. ASLN detection and false-negative rates did not differ for patients with LIC and patients with DIC.

CONCLUSIONS

The ASLN detection rate was not dependent on the pathologic type of invasive carcinoma. Pathologic examination of ASLN in patients with LIC and in patients with DIC predicted axillary lymph node status with the same predictive value in terms of lymph node metastasis. For patients with LIC, ASLN examination overestimated the rate of micrometastasis as diagnosed by immunohistochemical techniques. These results will require confirmation in larger studies.

The accuracy of sentinel lymph node biopsy in multicentric and multifocal invasive breast cancers

BACKGROUND

Sentinel lymph node biopsy (SLNB) has proved to be an accurate alternative to complete axillary lymph node dissection (ALND) in clinically node-negative breast cancer patients. Multicentric (MC) and multifocal (MF) invasive breast cancers are considered to be relative contraindications to SLNB. We examine the accuracy of SLNB in patients with MC and MF invasive breast cancers.

STUDY DESIGN

From September 1996 to August 2001, a total of 3,501 patients with clinically node-negative breast cancer underwent SLNB using both blue dye and radioisotope at our institution. A total of 70 patients had MC or MF invasive breast cancer, a successful SLNB, and mastectomy for local control. All had >/=10 axillary nodes excised (including the SLN) in a planned ALND. Exclusion criteria included MC and MF in situ carcinoma; breast conservation; previous breast irradiation, ALND, or SLNB; recurrent breast cancer; neoadjuvant chemotherapy; or ALND based solely on SLNB pathologic examination. RESULTS; The incidence of axillary metastases was 54% (38 of 70). SLNB accuracy was 96% (67 of 70), sensitivity 92% (35 of 38), and false-negative rate 8% (3 of 38). All patients with an inaccurate SLNB had a dominant invasive tumor >5 cm and one patient had palpable axillary disease intraoperatively. The SLN was the only site of axillary metastasis in 37% (14 of 38). Results were compared with those of published SLNB validation studies, most of which reflect experience with single-site invasive breast cancers. No statistically significant difference was noted for accuracy, sensitivity, or false-negative rate.

CONCLUSIONS

SLNB accuracy in MC and MF disease is comparable with that of published validation studies. MC and MF patients with a dominant T3 tumor (>5 cm) or axillary disease palpable intraoperatively should have a concurrent formal ALND. Our retrospective data suggest SLNB may be used as a reliable alternative to conventional ALND in selected patients with MC or MF disease. Further studies in this patient population are warranted.

Peritumoural versus subareolar administration of technetium-99m nanocolloid for sentinel lymph node detection in breast cancer: preliminary results of a prospective intra-individual comparative study

The scintigraphic detection of sentinel lymph nodes (SNs) in early-stage breast cancer is a widely accepted diagnostic method. However, which radiotracer administration mode should be used is still controversial. This prospective study aimed to intra-individually compare the detection rates obtained after peritumoural versus subareolar injection with regard to SN number and localisation. Fifty-one women (age, 32-76 years) with breast cancer were investigated on two consecutive days. On day 1, 140-400 MBq technetium-99m nanocolloid was injected along the peripheral tumour margins. Static lymphoscintigrams of the axilla, thorax and neck were taken in various views 1 and 19 h p.i. On day 2, 10 MBq (99m)Tc-nanocolloid was injected subareolarly in the clock position of the tumour and dynamic and static scans were performed immediately. Thereafter, 30 MBq (99m)Tc-nanocolloid was administered peri-subareolarly and lymphoscintigrams were acquired in a dynamic and static manner. In 49/51 women, the different injection techniques disclosed the identical number and location of SNs in the axilla. In seven patients, the peritumoural injection detected additional SNs in the parasternal group. Axillary SNs were detected as early as 2-15 min following subareolar injection, both in the clock position and peri-subareolarly, as compared with about 1 h after peritumoural administration. Sixteen patients showed at least one tumour-positive SN, and nine also had tumour-positive non-SNs. One patient with a tumour-negative SN, visualised concordantly by both subareolar and peritumoural administration, demonstrated two metastatic non-SNs, yielding a false-negative rate of 5.9%. In conclusion, a simple subareolar injection in the clock position is sufficient for SN detection in breast cancer, if it is accepted that parasternal lymph node detection has no therapeutic consequences.