Troubleshooting Sentinel Lymph Node Biopsy in Breast Cancer Surgery

BACKGROUND

Performing a sentinel lymph node biopsy (SLNB) is the standard of care for axillary nodal staging in patients with invasive breast cancer and clinically negative nodes. The procedure provides valuable staging information with few complications when performed by experienced surgeons. However, variation in proficiency exists for this procedure, and a great amount of experience is required to master the technique, especially when faced with challenging cases. The purpose of this paper was to provide a troubleshooting guide for commonly encountered technical difficulties in SLNB, and offer potential solutions so that surgeons can improve their own technical performance from the collective knowledge of experienced specialists in the field.

METHODS

Information was obtained from a convenience sample of six experienced breast cancer specialists, each actively involved in training surgeons and residents/fellows in SLNB. Each surgeon responded to a structured interview in order to provide salient points of the SLNB procedure.

RESULTS

Four of the key opinion surgical specialists provided their perspective using technetium-99 m sulfur colloid, and two shared their experience using blue dye only. Distinct categories of commonly encountered problem scenarios were presented and agreed upon by the panel of surgeons. The responses to each of these scenarios were collected and organized into a troubleshooting guide.

DISCUSSION

We present a compilation of 'tips' organized as a troubleshooting guide to be used to guide surgeons of varying levels of experience when encountering technical difficulties with SLNB.

10-yr follow-up results of NSABP B-32, a randomized phase III clinical trial to compare sentinel node resection (SNR) to conventional axillary dissection (AD) in clinically node-negative breast cancer patients

1000

Background: NSABP B-32, the largest surgical prospective randomized phase III trial was designed to compare overall survival (OS), disease-free survival (DFS), and morbidity between SNR alone vs SNR + AD in SN negative (-) pts. We present 10 yr outcome data for primary endpoints as well as updated data on the effect of occult metastases, found later in the SN by central, detailed pathologic analysis. Methods: 5,611 women with operable, clinically N0, invasive breast cancer were randomized to SNR + AD (Group [Grp] 1) or to SNR alone with AD only if SNs were positive (Grp2). 3,989 (71.1%) of 5,611 pts were SN-. 3,986 (99.9%) of these SN- pts had follow-up information: Grp 1: 1,975, Grp 2:2,011. Median time on study was 9.4 yrs. Cox proportional hazard models adjusting for study stratification variables were used to compare OS and DFS between the two groups. Two-sided p values were used. HR values > 1 indicate a more favorable outcome in Grp 1 Results: At 10 yrs, there continues to be no significant difference in OS between the two groups (HR: 1.11, p = 0.27). 10 yr Kaplan-Meier (K-M) estimates for OS are 87.8% for SNR alone and 88.9% for SNR + AD. There continues to be no significant difference in DFS between the two groups (HR: 1.01, p=0.92). 10-yr K-M estimates for DFS were 76.9% for both groups. Occult nodal disease was originally detected in 3,884 pts (15.8%) with SN- on initial H and E analysis. Comparisons between the groups with and without occult disease yielded an adjusted HR for OS: 1.25 (p = 0.08) with an absolute difference at 10 yrs of 2.8% and a HR for DFS: 1.24 (p = 0.018) with an absolute difference of 4.1%. The cumulative incidences of local-regional events were low (10-yr values: SNR 4.0%, SNR+AD, 4.3%) and not significant (HR: 0.95, p = 0.77). Conclusions: At 10 yrs there continues to be no significant differences in OS and DFS between SNR and SNR + AD in pts with negative SN. The relative increase in risk of DFS and OS for pts with occult SN metastases remains stable. Support: PHS grants: NSABP: U10CA-12027, U10CA-37377, U10CA-69651, U10CA-69974; VT Ca Cntr: P30 CA22435; DNK: 5RO1CA074137 NCI Dpt HHS. Clinical trial information: NCT00003830.

Effect of occult metastases on survival in node-negative breast cancer

BACKGROUND

Retrospective and observational analyses suggest that occult lymph-node metastases are an important prognostic factor for disease recurrence or survival among patients with breast cancer. Prospective data on clinical outcomes from randomized trials according to sentinel-node involvement have been lacking.

METHODS

We randomly assigned women with breast cancer to sentinel-lymph-node biopsy plus axillary dissection or sentinel-lymph-node biopsy alone. Paraffin-embedded tissue blocks of sentinel lymph nodes obtained from patients with pathologically negative sentinel lymph nodes were centrally evaluated for occult metastases deeper in the blocks. Both routine staining and immunohistochemical staining for cytokeratin were used at two widely spaced additional tissue levels. Treating physicians were unaware of the findings, which were not used for clinical treatment decisions. The initial evaluation at participating sites was designed to detect all macrometastases larger than 2 mm in the greatest dimension.

RESULTS

Occult metastases were detected in 15.9% (95% confidence interval [CI], 14.7 to 17.1) of 3887 patients. Log-rank tests indicated a significant difference between patients in whom occult metastases were detected and those in whom no occult metastases were detected with respect to overall survival (P=0.03), disease-free survival (P=0.02), and distant-disease-free interval (P=0.04). The corresponding adjusted hazard ratios for death, any outcome event, and distant disease were 1.40 (95% CI, 1.05 to 1.86), 1.31 (95% CI, 1.07 to 1.60), and 1.30 (95% CI, 1.02 to 1.66), respectively. Five-year Kaplan-Meier estimates of overall survival among patients in whom occult metastases were detected and those without detectable metastases were 94.6% and 95.8%, respectively.

CONCLUSIONS

Occult metastases were an independent prognostic variable in patients with sentinel nodes that were negative on initial examination; however, the magnitude of the difference in outcome at 5 years was small (1.2 percentage points). These data do not indicate a clinical benefit of additional evaluation, including immunohistochemical analysis, of initially negative sentinel nodes in patients with breast cancer. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT00003830.).

Sentinel-lymph-node resection compared with conventional axillary-lymph-node dissection in clinically node-negative patients with breast cancer: overall survival findings from the NSABP B-32 randomised phase 3 trial

BACKGROUND

Sentinel-lymph-node (SLN) surgery was designed to minimise the side-effects of lymph-node surgery but still offer outcomes equivalent to axillary-lymph-node dissection (ALND). The aims of National Surgical Adjuvant Breast and Bowel Project (NSABP) trial B-32 were to establish whether SLN resection in patients with breast cancer achieves the same survival and regional control as ALND, but with fewer side-effects.

METHODS

NSABP B-32 was a randomised controlled phase 3 trial done at 80 centres in Canada and the USA between May 1, 1999, and Feb 29, 2004. Women with invasive breast cancer were randomly assigned to either SLN resection plus ALND (group 1) or to SLN resection alone with ALND only if the SLNs were positive (group 2). Random assignment was done at the NSABP Biostatistical Center (Pittsburgh, PA, USA) with a biased coin minimisation approach in an allocation ratio of 1:1. Stratification variables were age at entry (≤ 49 years, ≥ 50 years), clinical tumour size (≤ 2·0 cm, 2·1-4·0 cm, ≥ 4·1 cm), and surgical plan (lumpectomy, mastectomy). SLN resection was done with a blue dye and radioactive tracer. Outcome analyses were done in patients who were assessed as having pathologically negative sentinel nodes and for whom follow-up data were available. The primary endpoint was overall survival. Analyses were done on an intention-to-treat basis. All deaths, irrespective of cause, were included. The mean time on study for the SLN-negative patients with follow-up information was 95·6 months (range 70·1-126·7). This study is registered with ClinicalTrials.gov, number NCT00003830.

FINDINGS

5611 women were randomly assigned to the treatment groups, 3989 had pathologically negative SLN. 309 deaths were reported in the 3986 SLN-negative patients with follow-up information: 140 of 1975 patients in group 1 and 169 of 2011 in group 2. Log-rank comparison of overall survival in groups 1 and 2 yielded an unadjusted hazard ratio (HR) of 1·20 (95% CI 0·96-1·50; p=0·12). 8-year Kaplan-Meier estimates for overall survival were 91·8% (95% CI 90·4-93·3) in group 1 and 90·3% (88·8-91·8) in group 2. Treatment comparisons for disease-free survival yielded an unadjusted HR of 1·05 (95% CI 0·90-1·22; p=0·54). 8-year Kaplan-Meier estimates for disease-free survival were 82·4% (80·5-84·4) in group 1 and 81·5% (79·6-83·4) in group 2. There were eight regional-node recurrences as first events in group 1 and 14 in group 2 (p=0·22). Patients are continuing follow-up for longer-term assessment of survival and regional control. The most common adverse events were allergic reactions, mostly related to the administration of the blue dye.

INTERPRETATION

Overall survival, disease-free survival, and regional control were statistically equivalent between groups. When the SLN is negative, SLN surgery alone with no further ALND is an appropriate, safe, and effective therapy for breast cancer patients with clinically negative lymph nodes.

FUNDING

US Public Health Service, National Cancer Institute, and Department of Health and Human Services.

Morbidity results from the NSABP B-32 trial comparing sentinel lymph node dissection versus axillary dissection

BACKGROUND AND OBJECTIVES

Three year post-surgical morbidity levels were compared between patients with negative sentinel lymph node dissection alone (SLND) and those with negative sentinel node dissection and negative axillary lymph node dissection (ALND) in the NSABP B-32 trial.

METHODS

A total of 1,975 ALND and 2,008 SLND node negative breast cancer patients had shoulder range of motion and arm volumes assessed along with self reports of arm tingling and numbness. Relative shoulder abduction deficits and relative arm volume differences between ipsilateral and contralateral arms were calculated.

RESULTS

Shoulder abduction deficits >or=10% peaked at 1 week for the ALND (75%) and SLND (41%) groups. Arm volume differences >or=10% at 36 months were evident for the ALND (14%) and SLND (8%) groups. Numbness and tingling peaked at 6 months for the ALND (49%, 23%) and SLND (15%, 10%) groups. Logistic regression correlates of residual morbidity included treatment group, age, handedness, tumor size, systemic chemotherapy, and radiation to the axilla.

CONCLUSIONS

Although residual morbidity for both treatment groups was evident, the results of the NSABP B-32 study indicate the superiority of the SLND compared to the ALND treatment approach relative to post-surgical morbidity outcomes over a 3-year follow-up period.

Surgeon training, protocol compliance, and technical outcomes from breast cancer sentinel lymph node randomized trial

BACKGROUND

The National Surgical Adjuvant Breast and Bowel Project B-32 trial was designed to determine whether sentinel lymph node resection can achieve the same therapeutic outcomes as axillary lymph node resection but with fewer side effects and is one of the most carefully controlled and monitored randomized trials in the field of surgical oncology. We evaluated the relationship of surgeon trial preparation, protocol compliance audit, and technical outcomes.

METHODS

Preparation for this trial included a protocol manual, a site visit with key participants, an intraoperative session with the surgeon, and prerandomization documentation of protocol compliance. Training categories included surgeons who submitted material on five prerandomization surgeries and were trained by a core trainer (category 1) or by a site trainer (category 2). An expedited group (category 3) included surgeons with extensive experience who submitted material on one prerandomization surgery. At completion of training, surgeons could accrue patients. Two hundred twenty-four surgeons enrolled 4994 patients with breast cancer and were audited for 94 specific items in the following four categories: procedural, operative note, pathology report, and data entry. The relationship of training method; protocol compliance performance audit; and the technical outcomes of the sentinel lymph node resection rate, false-negative rate, and number of sentinel lymph nodes removed was determined. All statistical tests were two-sided.

RESULTS

The overall sentinel lymph node resection success rate was 96.9% (95% confidence interval [CI] = 96.4% to 97.4%), and the overall false-negative rate was 9.5% (95% CI = 7.4% to 12.0%), with no statistical differences between training methods. Overall audit outcomes were excellent in all four categories. For all three training groups combined, a statistically significant positive association was observed between surgeons' average number of procedural errors and their false-negative rate (rho = +0.188, P = .021).

CONCLUSIONS

All three training methods resulted in uniform and high overall sentinel lymph node resection rates. Subgroup analyses identified some variation in false-negative rates that were related to audited outcome performance measures.

Technical outcomes of sentinel-lymph-node resection and conventional axillary-lymph-node dissection in patients with clinically node-negative breast cancer: results from the NSABP B-32 randomised phase III trial

BACKGROUND

The goals of axillary-lymph-node dissection (ALND) are to maximise survival, provide regional control, and stage the patient. However, this technique has substantial side-effects. The purpose of the B-32 trial is to establish whether sentinel-lymph-node (SLN) resection can achieve the same therapeutic goals as conventional ALND but with decreased side-effects. The aim of this paper is to report the technical success and accuracy of SLN resection plus ALND versus SLN resection alone.

METHODS

5611 women with invasive breast cancer were randomly assigned to receive either SLN resection followed by immediate conventional ALND (n=2807; group 1) or SLN resection without ALND if SLNs were negative on intraoperative cytology and histological examination (n=2804; group 2) in the B-32 trial. Patients in group 2 underwent ALND if no SLNs were identified or if one or more SLNs were positive on intraoperative cytology or subsequent histological examination. Primary endpoints, including survival, regional control, and morbidity, will be reported later. Secondary endpoints are accuracy and technical success and are reported here. This trial is registered with the Clinical Trial registry, number NCT00003830.

FINDINGS

Data for technical success were available for 5536 of 5611 patients; 75 declined protocol treatment, had no SLNs removed, or had no SLN resection done. SLNs were successfully removed in 97.2% of patients (5379 of 5536) in both groups combined. Identification of a preincision hot spot was associated with greater SLN removal (98.9% [5072 of 5128]). Only 1.4% (189 of 13171) of SLN specimens were outside of axillary levels I and II. 65.1% (8571 of 13 171) of SLN specimens were both radioactive and blue; a small percentage was identified by palpation only (3.9% [515 of 13 171]). The overall accuracy of SLN resection in patients in group 1 was 97.1% (2544 of 2619; 95% CI 96.4-97.7), with a false-negative rate of 9.8% (75 of 766; 95% CI 7.8-12.2). Differences in tumour location, type of biopsy, and number of SLNs removed significantly affected the false-negative rate. Allergic reactions related to blue dye occurred in 0.7% (37 of 5588) of patients with data on toxic effects.

INTERPRETATION

The findings reported here indicate excellent balance in clinical patient characteristics between the two randomised groups and that the success of SLN resection was high. These findings are important because the B-32 trial is the only trial of sufficient size to provide definitive information related to the primary outcome measures of survival and regional control. Removal of more than one SLN and avoidance of excisional biopsy are important variables in reducing the false-negative rate.

Detection of occult sentinel lymph node micrometastases by immunohistochemistry in breast cancer

BACKGROUND

Occult metastases, by definition, are not detected on initial examination. They may be present on slides but missed during screening or may be present in paraffin embedded tissue blocks and undetected without additional levels. Anticytokeratin immunohistochemistry (CK IHC) enhances detection of occult metastases, particularly micrometastases (> 0.2 mm but not larger than 2.0 mm) or isolated tumor cell clusters (< or = 0.2 mm). This study defines the rate at which pathologists miss metastases on CK IHC of sentinel lymph nodes (SLN).

METHODS

CK IHC sections 0.5 and 1.0 mm from the original surface of SLN tissue blocks were screened by pathologists using standard bright field light microscopes (LM) and by supervised computer assisted cell detection (CACD). All blocks were from breast cancer patients, initially classified 'node negative' on review of routinely stained sections from the surface of each block. Cases missed by LM screening but detected by CACD defined false negative screens.

RESULTS

Of 236 cases screened, LM detected 34 (14.4%; 95% CI: 9.6-20.2) cases and, in the 202 cases negative by LM, CACD detected an additional 30 (14.9%; 95% CI: 9.6-21.2%) cases with occult metastases. Occult metastases missed by LM screening ranged from 0.01 to 0.1 mm in greatest dimension. The probability of missing an occult metastasis < or = 0.02 mm; < or = 0.05 mm, and < or = 0.10 mm was 75%, 69.2%, and 61.2%, respectively. No occult metastases larger than 0.10 mm were missed by LM screening.

CONCLUSIONS

Pathologists screening the CK IHC stained slides may frequently miss detecting metastases < 0.10 mm.

The detection of isolated tumor cells in bone marrow comparing bright-field immunocytochemistry and multicolor immunofluorescence

BACKGROUND

The detection of isolated tumor cells in bone marrow by immunocytochemistry (ICC) has been reported to predict progression of early-stage breast cancer. The most common staining procedure uses bright-field ICC with cytokeratin (CK) antibodies to label isolated tumor cells. However, this method can result in false-positive staining events. We used multicolor immunofluorescence (IF) to develop a more specific assay for detecting isolated tumor cells in marrow samples from breast cancer patients.

METHODS

We compared ICC and IF side by side for detection of cancer cells and false-positive staining events on bone marrow aspirates from breast cancer patients, bone marrow from healthy donors, and healthy donor blood spiked with cancer cells. The primary target for isolated tumor cell detection was CK for both methods. IF used an additional set of antibodies to label hematopoietic cells (HCs).

RESULTS

The detection rate of CK+ events in breast cancer patient bone marrow aspirates was 18 (58%) of 31 for ICC and 21 (68%) of 31 for IF. However, with IF, 17 of 21 CK+ cases were stained with HC markers and thus were identified as false-positive events. A surprisingly high CK+ event rate was observed in healthy donor blood and marrow. In all healthy donor samples, CK+ events were readily identified as HCs by IF. Detection sensitivity of spiked cancer cells in donor blood was similar for both methods.

CONCLUSIONS

There is a high frequency of CK+ events in blood and marrow, and it is important to note that this is observed both in patients with and those without cancer. IF with multiple HC markers allows straightforward discrimination between CK+ cells of hematopoietic and nonhematopoietic origin.

Sentinel lymph node biopsy in breast cancer

Sentinel lymph node biopsy techniques have evolved in a short period of time to become a highly accurate method for the pathologic staging of clinically node-negative breast cancers. Multiple single and multi-institutional studies have confirmed a high accuracy of pathologic staging (95-100%) with reasonable false-negative rates (0-15%). The use of vital blue dyes, radioactive isotopes, or a combination of the two are the most commonly employed techniques used for this procedure. Currently, two large prospective randomized Phase III clinical trials supported by the National Cancer Institute are underway, which will define the effectiveness of these techniques as compared to standard axillary dissection in regards to regional disease control and patient survival.

Prerandomization Surgical Training for the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-32 trial: a randomized phase III clinical trial to compare sentinel node resection to conventional axillary dissection in clinically node-negative breast cancer

OBJECTIVE

To train surgeons in a standardized technique of sentinel lymph node biopsy and to prepare them for the requirements of a prospective randomized surgical trial.

SUMMARY BACKGROUND DATA

The NSABP B32 trial opened to accrual in May 1999. A significant component of this trial was a prerandomization training phase of surgeons performed by a group of core surgical trainers. The goals of this training phase were to expeditiously instruct surgeons in a standardized technique of sentinel lymph node biopsy and to educate those same surgeons in complete and accurate data collection and source documentation for the trial.

METHODS

This study is a description of the training data collected in a prospective fashion for the training component for surgeon entry into the B32 trial, evaluating the effectiveness of the training program in regards to surgical outcomes and protocol compliance.

RESULTS

Two hundred twenty-six registered surgeons underwent site visit training by a core surgical trainer and 187 completed training and were approved to randomize patients on the trial. The results of 815 training (nontrial) cases demonstrated a technical success rate for identifying sentinel nodes at 96.2% with a false negative rate of 6.7%. A protocol compliance analysis, which included the evaluation of 94 separate fields, showed mean protocol compliance of 98.6% for procedural fields, 95.5% for source documentation fields and 95.0% for data entry fields.

CONCLUSIONS

This training and quality control program has resulted in a large number of surgeons capable of performing sentinel lymph node biopsy in a standardized fashion with a high degree of protocol compliance and pathologic accuracy. This will ensure optimal results for procedures performed on the randomized phase of the trial.

NSABP-32: Phase III, randomized trial comparing axillary resection with sentinal lymph node dissection: a description of the trial

The NSABP-32 trial is a randomized, phase III clinical trial to compare sentinel node (SN) resection to conventional axillary dissection in clinically node-negative breast cancer patients. The primary aims of the trial are to determine if removal of only SNs provides survival and regional control equivalent to those of axillary dissection, while diminishing the magnitude of surgically related side effects. In order to ensure consistency of the outcomes for this trial, a standardized method of SN surgery has been utilized for all cases. A secondary aim of the B32 trial is to evaluate whether patients with "occult" metastases in the SNs have worse survival. Accrual is taking place at 73 institutions in North America, and 217 surgeons are enrolling patients.

Comparison of pathologist-detected and automated computer-assisted image analysis detected sentinel lymph node micrometastases in breast cancer

Sentinel lymph node biopsy has stimulated interest in identification of micrometastatic disease in lymph nodes, but identifying small clusters of tumor cells or single tumor cells in lymph nodes can be tedious and inaccurate. The optimal method of detecting micrometastases in sentinel nodes has not been established. Detection is dependent on node sectioning strategy and the ability to locate and confirm tumor cells on histologic sections. Immunohistochemical techniques have greatly enhanced detection in histologic sections; however, comparison of detection methodology has not been undertaken. Automated computer-assisted detection of candidate tumor cells may have the potential to significantly assist the pathologist. This study compares computer-assisted micrometastasis detection with routine detection by a pathologist. Cytokeratin-stained sentinel lymph node sections from 100 patients at the University of Vermont were evaluated by automated computer-assisted cell detection. Based on original routine light microscopy screening, 20 cases that were positive and 80 cases that were negative for micrometastases were selected. One-level (43 cases) or two-level (54 cases) cytokeratin-stained sections were examined per lymph node block. All 100 patients had previously been classified as node negative by using routine hematoxylin and eosin stained sections. Technical staining problems precluded computer-assisted cell detection scanning in three cases. Computer-assisted cell detection detected 19 of 20 (95.0%; 95% confidence interval, 75-100%) cases positive by routine light microscopy. Micrometastases missed by computer-assisted cell detection were caused by cells outside the instrument's scanning region. Computer-assisted cell detection detected additional micrometastases, undetected by light microscopy, in 8 of 77 (10.4%; 95% confidence interval, 5-20%) cases. The computer-assisted cell detection-positive, light microscopy-missed detection rate was similar for cases with one (3 of 30; 10.0%) or two (5 of 47; 10.6%) cytokeratin sections. Metastases detected by routine light microscopy tended to be larger (0.01-0.50 mm) than did metastases detected only by computer-assisted cell detection (0.01-0.03 mm). In a selected series of patients, automated computer-assisted cell detection identified more micrometastases than were identified by routine light microscopy screening of cytokeratin-stained sections. Computer-assisted detection of events that are limited in number or size may be more reliable than detection by a pathologist using routine light microscopy. Factors such as human fatigue, incomplete section screening, and variable staining contribute to missing metastases by routine light microscopy screening. Metastases identified exclusively by computer-assisted cell detection tend to be extremely small, and the clinical significance of their identification is currently unknown.

Lymphoscintigraphy and sentinel node biopsy accurately stage melanoma in patients presenting after wide local excision

BACKGROUND

Patients have traditionally been considered candidates for sentinel node biopsy (SNBx) only at the time of wide local excision (WLE). We hypothesized that patients with prior WLE may also be staged accurately with SNBx.

METHODS

Seventy-six patients, including 18 patients from the University of Virginia and 58 from a multicenter study of SNBx led by investigators at the University of Vermont, who had previous WLE for clinically localized melanoma underwent lymphoscintigraphy with SNBx. Median follow-up time was 38 months.

RESULTS

Intraoperative identification of at least 1 sentinel node was accomplished in 75 patients (98.6%). The mean number of sentinel nodes removed per patient was 2.0. Eleven patients (15%) had positive sentinel nodes. Among the 64 patients with negative SNBx, 3 (4%) developed nodal recurrences in a sentinel node-negative basin simultaneous with systemic metastasis, and 1 (1%) developed an isolated first recurrence in a lymph node.

CONCLUSIONS

This multicenter study more than doubles the published experience with SNBx after WLE and provides much-needed outcome data on recurrence after SNBx in these patients. These outcomes compare favorably with the reported literature for patients with SNBx at the time of WLE, suggesting that accurate staging of the regional lymph node bed is possible in patients after WLE.

Sentinel lymph node--why study it: implications of the B-32 study

Surgical removal of the regional lymph nodes by a level I and level II axillary dissection remains the standard of care for patients with surgically resectable breast cancer. Axillary dissection provides accurate pathologic staging and excellent regional disease control, and likely provides a small benefit in patient survival. Axillary dissection, however, is associated with significant patient morbidity. Sentinel lymph node (SLN) biopsy procedures have been found to provide very accurate pathologic staging when compared to axillary dissection; however, their effect on regional disease control and patient survival is not yet known. The National Cancer Institute (NCI) has sponsored a Phase III prospective, randomized clinical trial (the B-32 trial) through the National Adjuvant Breast and Bowel Project (NSABP), to compare results of patients treated with SLN biopsy alone vs. SLN biopsy with completion axillary node dissection in patients with clinically node-negative breast cancer. Results of this trial will provide evidence of the safety of SLN biopsy procedures in the management of patients with breast cancer.

Gamma probe guided biopsy of the sentinel node in malignant melanoma: a multicentre study

Sentinel lymph node biopsy was attempted in 336 patients with clinically node-negative cutaneous melanoma. All patients were injected with technetium-99m labelled radiocolloid, with 108 patients simultaneously receiving vital blue dye for sentinel node identification. Sentinel lymph nodes were identified in 329 patients, giving a technical success rate of 97.9%. Metastatic disease was identified in 39 (11.9%) of the patients in whom sentinel nodes were found. Patients with negative sentinel nodes were observed and patients with positive sentinel nodes underwent comprehensive lymph node dissection. The presence of metastatic disease in the sentinel nodes and primary tumour depth by Breslow or Clark levels were joint predictors of survival based on Cox proportional hazards modelling. Disease recurrences occurred in 26 (8.8%) patients with negative sentinel lymph nodes, with isolated regional recurrences as the first site in 10 (3.4%). No patients with Clark level II primary tumours were found to have positive sentinel nodes or disease recurrences. One patient with a thin (<0.75 mm) Clark level III primary had metastatic disease in a sentinel node. Patients with metastases confined to the sentinel nodes had similar survival rates regardless of the number of nodes involved.

Pathologic analysis of sentinel and nonsentinel lymph nodes in breast carcinoma: a multicenter study

BACKGROUND

Axillary lymph node status is a powerful prognostic factor in breast carcinoma; however, complications after axillary lymph node dissection are common. Sentinel lymph node biopsy is an alternative staging procedure. The sentinel lymph node postulate is that tumor cells migrating from the primary tumor colonize one or a few lymph nodes before colonizing subsequent lymph nodes. To validate this hypothesis, the distribution of occult and nonoccult metastases in sentinel and nonsentinel lymph nodes was evaluated.

METHODS

Original pathology material was reviewed from 431 patients enrolled on a multicenter validation study of sentinel lymph node biopsy in breast carcinoma patients. Paraffin embedded tissue blocks of sentinel and nonsentinel lymph nodes were obtained for 214 lymph node negative patients. Additional sections from 100 and 200 microm deeper into the paraffin block were examined for the presence of occult metastatic carcinoma. Both routine and cytokeratin immunohistochemical stains were employed.

RESULTS

Metastases were identified in 15.9% of sentinel lymph nodes and 4.2% of nonsentinel lymph nodes (odds ratio [OR] 4.3[ P < 0.001]; 95% confidence interval [95% CI], 3.5-5.4). Occult metastases were identified in 4. 09% of sentinel lymph nodes and 0.35% of nonsentinel lymph nodes (OR 12.3 [P < 0.001]; 95% CI, 5.6-28.6). The overall case conversion rate was 10.3%. All the occult metastases identified were < or = 1 mm in greatest individual dimension. The likelihood (OR) of metastases in nonsentinel lymph nodes was 13.4 times higher for sentinel lymph node positive than for sentinel lymph node negative patients (P < 0. 001; 95% CI, 6.7-28.1).

CONCLUSIONS

The distribution of occult and nonoccult metastases in axillary lymph nodes validates the sentinel lymph node hypothesis. In addition, pathology review of cases confirmed the authors' previously reported finding that the sentinel lymph nodes are predictive of the final axillary lymph node status. Occult metastatic disease is more likely to be identified in sentinel lymph nodes, allowing future studies to focus attention on one or a few sentinel lymph nodes. However, the relation between occult metastatic disease in sentinel lymph nodes, disease free survival, and overall survival must be evaluated prior to endorsing the intensive analysis of sentinel lymph nodes in routine practice. [See editorial on pages 971-7, this issue.]

Intraoperative ultrasound localization to guide surgical excision of nonpalpable breast carcinoma

BACKGROUND

This report describes a technique of intraoperative tumor localization by ultrasound without the use of a needle or wire to guide the excision of nonpalpable breast cancers. The results of our experience with pathologic margin status are reviewed.

STUDY DESIGN

From 1994 to 1998, 65 breast cancers in 62 patients with biopsy-proved nonpalpable breast cancer were excised using intraoperative ultrasound localization. The pathologic status of the margins from the initial surgical excision specimen and any further excisions, either at the first operation or later procedures, was recorded. The distance from the tumor to the closest margin of excision was also determined.

RESULTS

The overall success in achieving pathologically negative excision margins at first operation was 97% (63 of 65 cancers). Three patients underwent a second operative procedure, two for positive margins and one for a margin less than 1 mm (second operation = 4.8% of patients). After completion of the first operative procedure, the mean distance to the closest margin of excision was 0.8 cm.

CONCLUSIONS

Intraoperative ultrasound localization for excision of nonpalpable breast cancers is feasible and gives results, in terms of pathologic margins, that are comparable with those achieved by standard needle-wire-guided excisions.

Submission of lymph node tissue for ancillary studies decreases the accuracy of conventional breast cancer axillary node staging

Pathologists are under increasing pressure to submit fresh tissue for ancillary studies and research protocols. In several tumor types (breast, lung, melanoma, colorectal, prostate), increased interest in detecting submicroscopic nodal metastases through reverse transcriptase polymerase chain reaction analysis of mRNA from portions of lymph nodes has precluded histologic analysis of the entire node for metastases. A retrospective review was undertaken of 227 breast cancer patients prospectively entered on a research protocol examining the usefulness of sentinel lymph node surgery. All of the patients ultimately underwent complete lymph node dissection. The research protocol required that all nodes greater than 8 mm in size be bisected and submitted separately. Positive lymph nodes were evaluated for unilateral or bilateral involvement in the node sections. Sixty node-positive patients were identified, yielding 230 positive nodes. One hundred seven of these nodes were confirmed to have been bisected. Carcinoma was identified in both lymph node sections in 64 (59.8%) nodes and in only one-half of the bisected lymph node in 43 (40.2%) nodes. Involvement of both sections was more likely when patients had multiple nodes positive. In 12 patients, involvement of one-half of the bisected nodes was the only evidence of metastatic disease (20.0% of node-positive patients). This evidence suggests that submission of less than the complete lymph node for histologic evaluation of metastatic disease decreases the accuracy of lymph node staging. Furthermore, a significant proportion of patients may be erroneously classified as histologically node negative.

Melanoma complicating pregnancy

The incidence of malignant melanoma is rising, and this may be the most frequently encountered malignancy during pregnancy. Because effective treatment of advanced or metastatic disease remains elusive, the key to adequate therapy is surveillance for early disease with prompt diagnostic work-up and treatment. Review of the most prominent reports in the literature fails to yield a consensus on whether pregnancy contributes to a worse prognosis. It seems clear that after controlling for all known prognostic variables, prognosis is unchanged; however, groups of patients diagnosed during pregnancy may have a disproportionately high incidence of high-risk primary lesion sites and increased tumor thickness. Surgical treatment during pregnancy should be prompt, with appropriate avoidance of general anesthesia during the first trimester. There is as yet insufficient evidence to warrant the use of adjuvant chemotherapy or biologic therapy during pregnancy.

Localization of regional lymph nodes in melanomas of the head and neck

OBJECTIVES

To study the efficacy of gamma-probe radiolocalization of the first draining (sentinel) lymph node (SLN) in stage N0 melanoma of the head and neck and to evaluate its potential role in the staging and treatment of this disease.

DESIGN

Gamma-probe radiolocalization, a new alternative to blue-dye lymphatic mapping, uses a scintillation (gamma) probe to identify radiolabeled SLNs. In a consecutive sample clinical trial, gamma-probe radiolocalization of the SLN is compared with lymphoscintigraphy and blue-dye lymphatic mapping. Follow-ups ranged from 1.7 years to 4 years, with a mean follow-up of 2.5 years.

SETTING

Tertiary and private care teaching hospital.

PATIENTS

Between June 1993 and November 1995, 23 patients with stage N0 intermediate-thickness melanoma of the head and neck were enrolled in this volunteer sample.

INTERVENTIONS

Twenty-four hours prior to surgery, a radioactive tracer was intradermally injected around the circumference of a primary melanoma. Twelve patients also had blue dye injected just prior to surgical resection. Using a handheld gamma probe, radiolabeled lymph nodes were identified and selectively removed with minimal dissection. In patients with nodes with histologic evidence of metastases, a regional lymphadenectomy was performed.

MAIN OUTCOME MEASURES

The successful identification of radiolabeled SLNs, the correlation of SLN radiolabeling to lymphoscintigraphy and blue-dye mapping, and the long-term development of regional metastases.

RESULTS

Surgeons successfully resected the radiolabeled SLNs in 22 (96%) of 23 patients. The success rate of blue-dye lymphatic mapping was 8 (75%) of 12 patients and lymphoscintigraphy was 20 (91%) of 22 patients. One hundred percent of blue-stained lymph nodes were radiolabeled. The one patient in whom no SLN could be identified developed regional disease at 17 months.

CONCLUSIONS

Gamma-probe radiolocalization and resection of the radiolabeled SLN is a simple and reliable method of staging regional lymph nodes and determining the need for elective lymphadenectomy.

Minimal-access surgery for staging of malignant melanoma

OBJECTIVE

To develop a simple, minimally invasive technique of determining whether regional node metastasis has occurred in patients with melanoma.

SETTING

Teaching hospital tertiary care and private practice settings.

PATIENTS

Between February 1993 and October 1994, 121 patients with invasive malignant melanoma and clinically negative lymph nodes were enrolled in this clinical trial.

DESIGN

Consecutive sample clinical trial. Within 24 hours prior to lymph node resection, a radioactive tracer was injected into the dermis around the site of the primary melanoma. Forty-four patients also had blue dye injected immediately prior to surgical resection. Measurement of radioactivity in the lymph nodes and surgical localization were made using a handheld gamma detector. Radiolabeled nodes were selectively removed with the least dissection possible. In patients with pathologically positive radiolabeled nodes, regional lymphadenectomy was performed.

OUTCOME MEASURES

Successful identification of radiolabeled sentinel lymph nodes, correlation of radiolabeling with injection of blue dye, and regional node recurrence rate.

RESULTS

Surgeons successfully resected the radiolabeled sentinel lymph nodes in 118 (98%) of 121 patients. One hundred percent of blue-stained lymph nodes were successfully radiolabeled. Fifteen patients had pathologically positive sentinel lymph nodes. In 10 patients, the sentinel node was the only node with metastasis. Two systemic and one regional node recurrences occurred during a mean follow-up of 220 days.

CONCLUSIONS

Selective gamma probe-guided resection of the radiolabeled sentinel lymph node is possible in over 95% of patients with melanoma. This technique offers a simple and reliable method of staging of regional lymph nodes in these patients without performing a regional lymphadenectomy.

Intraoperative photodynamic therapy as an adjunct to surgery for recurrent rectal cancer

BACKGROUND

Locally recurrent rectal cancer is a difficult management problem for the surgical oncologist. Current therapies including radical surgery, radiation and chemotherapy have had little success in producing curative results for these patients. This study incorporated intraoperative photodynamic therapy (PDT) as an adjunct to radical surgery for the treatment of locally recurrent rectal cancer.

METHODS

Twenty-two patients were enrolled in a prospective feasibility study and injected with Photofrin (Quadra Logic Technologies, Vancouver, British Columbia, Canada) before surgery. Eight patients were found to be candidates and received PDT after surgical exploration and resection. Seven patients had rectal adenocarcinoma and one had squamous cell carcinoma of the anal canal.

RESULTS

Based on the indication for PDT, three patient groups were evaluated: group A, resection of all gross disease with negative pathologic margins in four patients; group B, resection of gross disease with positive pathologic margins in two; and group C, residual bulky tumor in two patients. There was one perioperative death (12.5%), not related to PDT, and one major morbidity due to PDT (12.5%). Local recurrence occurred in six patients (two in group A, two in group B, two in group C). Mean overall survival was 15.4 months for group A, 6.5 months for group B, and 24.5 months for group C.

CONCLUSIONS

The results of this study suggest that intraoperative PDT may be administered safely in patients undergoing resection of recurrent rectal cancer. However, its use in the present state of technology appears to be inadequate for control of disease, particularly if bulky tumor or residual microscopic disease is left behind.

Detection of HER-2/neu oncogene amplification in flow cytometry-sorted breast ductal cells by competitive polymerase chain reaction

BACKGROUND

The amplification and/or overexpression of the HER-2/neu oncogene has been proposed as an important prognostic marker in breast cancer. However, contradictory results from various groups regarding whether there is statistical significance in HER-2 amplification or overexpression in predicting overall and disease free survival in node positive versus node negative patients exist in the literature. Current assays on quantifying the HER-2 oncogene rely on DNA extracted from homogenized breast tissue. Not only is a large amount of tissue required, but also, the DNA extract is contaminated with DNA from stromal cells and leukocytes, leading to decreased specificity and sensitivity of the HER-2 assay. Improving the specificity (DNA from breast ductal cells) and the sensitivity (competitive polymerase chain reaction [PCR]) of the HER-2 amplification detection assay will help resolve some of these controversies.

METHODS

Using multiparameter flow cytometry (FCM), ductal cells from breast biopsies and fine needle aspirations (FNAs) are identified and selectively sorted using anti-cytokeratin, anti-HER-2 antibody labeling and DNA staining. HER-2 amplification in these sorted cells is then quantified by competitive DNA PCR using a competitive reference standard mutant template that is susceptible to the restriction enzyme Sma-1.

RESULTS

Applying this strategy, SK-BR-3, an HER-2 amplified breast cancer cell line, was found to have approximately 9x baseline HER-2 oncogene copies. In addition, MCF-7, a known HER-2 nonamplified breast cancer cell line, was found to have baseline HER-2 oncogene copies. In the 10 clinical breast samples tested, 4 of the 10 breast cancers were HER-2 amplified using as few as 1000 cells. The cytokeratin positive cells of these cancers, in contrast to the cytokeratin negative cells, have detectably higher HER-2 amplification (7.2 +/- 2.8x versus 3.2 +/- 1.1x, respectively). Hence, HER-2 gene amplification would have been underestimated if unsorted cells were used because of stromal dilution. In the cytokeratin positive cells that were HER-2 oncogene amplified, corresponding HER-2 oncoprotein overexpression was detected by FCM.

CONCLUSIONS

Using FCM, the ductal cell subpopulation of a breast specimen can be successfully sorted from breast biopsy and FNA specimens. Moreover, by applying the technique of competitive PCR, improved specificity and sensitivity in HER-2 oncogene amplification detection is achieved. The entire procedure can be accomplished in 1 day, allowing for a cost-effective assay and rapid turnaround time.

Quantitation of c-myc gene amplification by a competitive PCR assay system

Gene amplification is a common event in the progression of human cancers. The detection and quantitation of certain amplified oncogenes has been shown to have prognostic importance in certain human malignancies. A method is described that utilizes the principles of competitive PCR for quantitation of the c-myc gene copy number in relation to the copy number of a reference gene (tissue plasminogen activator [t-PA] gene) located on the same chromosome (8) as the c-myc gene. This ratio gives the true level of amplification of the c-myc gene, accounting for variables such as cell number, cell cycle phase, and chromosome 8 ploidy. The determination of gene amplification depends on the precise measurement of the ratio of target and reference genes. An important feature of this assay is that the competitive reference standards used for target gene c-myc and reference gene t-PA have been linked to form a hybrid. This simple modification guarantees that both reference gene and target gene assay tubes get identical amounts of the competitive template for each gene, thereby eliminating a significant source of error. This method has the same desirable attributes of standard PCR in that very small sample sizes are required and that results can easily be obtained in < 24 hr. In addition, this technique does not require the use of radioactivity or expensive DNA detection kits, and thus, may give it wider applicability for the study of human cancers.

Chromosomes 8, 12, and 17 copy number in Astler-Coller stage C colon cancer in relation to proliferative activity and DNA ploidy

Fluorescence in situ hybridization using centromere-specific DNA probes to chromosomes 8, 12, and 17 was applied to 23 archival paraffin-embedded stage C colonic cancer specimens. Chromosome copy number was related to flow cytometric determinations of S-phase fraction and DNA ploidy. Three to eight copies of chromosomes 8, 12, and 17 were observed at mean frequencies of 28.7%, 37.8%, and 20.9%, respectively. The mean frequency of multiple copies of chromosome 12 was significantly greater than that for chromosome 17 (P < 0.0025). The mean frequency of single copies of chromosome 17 was significantly greater than that for chromosomes 8 and 12 (P < 0.0025 and P < 0.0005, respectively). Regarding the fourth quartile of cases, defined on the basis of the frequency of multiple chromosome copies, the proportion demonstrating moderate to high proliferative activity greatly exceeded the proportion displaying low proliferative activity. The same cases (most chromosomally aberrant) also generally demonstrated DNA aneuploidy. The results indicate a substantial degree of karyotypic instability in advanced colon cancer, particularly in cases with high proliferative activity and DNA aneuploidy.

Diagnostic utility of DNA content flow cytometry in follicular neoplasms of the thyroid

Preoperative diagnosis of follicular carcinoma of the thyroid remains a clinical challenge. This study determined the DNA content parameters of ploidy and proliferative activity levels from cells of normal thyroid tissue, follicular adenomas, and follicular carcinomas to evaluate if these parameters could be used as an adjunct to fine needle aspiration in their diagnosis. Statistically significant higher proliferative activity levels were found in the carcinoma groups (mean S-phase fraction [SPF] = 5.0%) compared to 2.9% for follicular adenomas and 1.3% for normal thyroid. DNA aneuploidy was identified in 73% of carcinomas and 36% of adenomas. Because of overlap of SPF values between groups, one could not rule out the presence or absence of malignancy based on DNA content parameters alone. These measurements may, however, be an aid to the decision making in patients who are poor surgical risks.

Prognostic implications of proliferative activity and DNA aneuploidy in Astler-Coller Dukes stage C colonic adenocarcinomas

Paraffin-embedded surgical specimens from 69 patients who underwent resections of otherwise untreated Dukes stage C adenocarcinoma of the colon were examined for proliferative activity, DNA aneuploidy, DNA index, and proportion of aneuploid cells by flow cytometry. Results were correlated to clinical characteristics of the patients and to overall survival times. DNA aneuploid tumors were identified in 60 cases (87%), diploid tumors in 9 cases (13%). The mean S-phase fraction for all cases was 17.6%, with a standard deviation (SD) of 7.8. In univariate statistical analysis, younger patient age, lower tumor proliferative activity, DNA index less than or equal to 1.2, and presence of only 1-4 lymph nodes with tumor involvement were found to be significant predictors of improved patient survival. In multivariate Cox regression analysis, low tumor proliferative activity, younger patient age, and location of the tumor in the right or transverse colon were found to be significant independent predictors of increased patient survival. When tumor proliferative activity was stratified into statistically defined subgroups, patients with tumors of low proliferative activity (S-phase less than mean - 0.5 SD) had significantly longer survival than patients with tumors of moderate proliferative activity (S-phase value greater than mean - 0.5 SD and less than mean +0.5 SD) or high proliferative activity (S-phase greater than mean +0.5 SD). These results suggest that tumor proliferative activity in Dukes C colon carcinoma may be an important biological factor in determining patient prognosis.