Diagnostic and management challenges for MDM2-, CDK4-negative fatty tumors of the retroperitoneum.

BACKGROUND: Neoplasms of the retroperitoneum that contain a major fat component may represent either benign entities, such as lipomas or angiomyolipomas, or malignancy such as liposarcoma. Distinguishing these diagnoses has important implications for management. While liposarcomas often stain positively for MDM2 and CDK4 proteins, absence of these markers can lead to diagnostic and management challenges. METHODS: We examined three cases in our institution of fat-containing masses of the retroperitoneum that lacked MDM2 and CDK4 markers to highlight the challenges in diagnosing and managing these cases. A thorough review of the literature examining radiologic and histologic features that can be used to determine that diagnosis was conducted and summarized. RESULTS: The three cases we present represent the three main diagnostic entities that can be found in among fatty tumors of the retroperitoneum: lipoma, angiomyolipoma, and liposarcoma. While radiologic features and analysis of histology helped to inform management, these cases in conjunction with the literature also illustrate the limitations of the diagnostic work up and importance also factoring the biologic behavior of the tumor in its management. CONCLUSION: Fat-containing tumors of the retroperitoneum that do not stain for MDM2 or CDK4 can pose a diagnostic challenge. Assessing radiologic and pathologic features in conjunction with the biologic behavior of these tumors should inform their management.

Multidisciplinary Tumor Boards in Dermatologic Surgery.

BACKGROUND: Recent advances in diagnostic and therapeutic modalities have made oncologic care ever more challenging, and multidisciplinary tumor boards (MTBs) are increasingly being used as a forum to discuss and coordinate care for complex oncology patients. Literature on the use of MTBs specific to cutaneous oncology and dermatologic surgery remains limited. OBJECTIVE: To share our experiences with cutaneous oncology MTBs at the University of Vermont Medical Center (UVMMC). METHODS: We describe the formation, timing, participation, clinical discussion, case follow-up, and coordination of care of our MTBs. RESULTS: A log of all cases discussed at cutaneous oncology MTBs from August 2018 to August 2019 is presented as an example. Five specific cases are described in further detail to demonstrate critical components of multidisciplinary care. CONCLUSION: The MTBs at UVMMC has created a collaborative environment for providers in multiple specialties to jointly formulate and coordinate optimal treatment plans for difficult cases, particularly when treatment guidelines do not exist or are insufficient. Furthermore, MTBs can serve as an educational forum for all participants.

Identification of tumor-reactive B cells and systemic IgG in breast cancer based on clonal frequency in the sentinel lymph node.

A better understanding of antitumor immune responses is the key to advancing the field of cancer immunotherapy. Endogenous immunity in cancer patients, such as circulating anticancer antibodies or tumor-reactive B cells, has been historically yet incompletely described. Here, we demonstrate that tumor-draining (sentinel) lymph node (SN) is a rich source for tumor-reactive B cells that give rise to systemic IgG anticancer antibodies circulating in the bloodstream of breast cancer patients. Using a synergistic combination of high-throughput B-cell sequencing and quantitative immunoproteomics, we describe the prospective identification of tumor-reactive SN B cells (based on clonal frequency) and also demonstrate an unequivocal link between affinity-matured expanded B-cell clones in the SN and antitumor IgG in the blood. This technology could facilitate the discovery of antitumor antibody therapeutics and conceivably identify novel tumor antigens. Lastly, these findings highlight the unique and specialized niche the SN can fill in the advancement of cancer immunotherapy.

Characterization of sentinel node-derived antibodies from breast cancer patients.

Autoantibodies to breast and other cancers are commonly present in cancer patients. A method to rapidly produce these anti-cancer autoantibodies in the lab would be valuable for understanding immune events and to generate candidate reagents for therapy and diagnostics. The purpose of this report is to evaluate sentinel nodes (SNs) of breast cancer patients as a source of anti-cancer antibodies. Radiotracer lymphatic mapping in 29 patients with breast cancer confirmed the identity of the SNs which provided source cells for this study. Flow cytometry demonstrated ~28% of the MNCs were B cells and ~44% of the B cells were class switched memory B cells. EBV-induced proliferation of B cells yielded tumor binding antibodies from 3 wells per 1000 but cultures were too unstable for detailed evaluations. Hybridomas generated by electrofusion produced IgG (48%), IgM (34%) and IgA (18%) antibody isotypes which were screened for binding to a panel of breast cancer cells of the major molecular subtypes. Tumor lysate binding was observed in 28% of the hybridoma clones and 10% of these bound whole tumor cells with unique binding patterns. More detailed evaluation of selected clones showed binding to the patient's own tumor. SNs are removed from more than 100,000 breast cancer patients in the US per year. Samples from these lymph nodes represent a substantial opportunity to generate anticancer antibodies.

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.

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.

Metastasis detection in sentinel lymph nodes: comparison of a limited widely spaced (NSABP protocol B-32) and a comprehensive narrowly spaced paraffin block sectioning strategy.

The National Surgical Adjuvant Breast and Bowel Project B-32 trial is examining whether patients with initially negative sentinel lymph nodes (SLNs) who have occult metastases detected on deeper levels and cytokeratin immunohistochemistry stains are at risk for regional or distant metastases. The experimental B-32 protocol was designed to detect metastases larger than 1.0 mm by examining sections approximately 0.5 and 1.0 mm deeper into the paraffin blocks (2 levels; wide spacing). This pilot quality assurance study compares detection rates to a comprehensive protocol designed to detect metastases larger than 0.2 mm (multilevel; narrow spacing). All SLNs were sectioned grossly at close to 2.0 mm and all sections embedded in paraffin blocks. For clinical treatment, a single hematoxylin and eosin section was examined from each block. For 54 cases with 1 to 5 SLNs and all SLNs negative, additional cytokeratin immunohistochemistry sections were evaluated every 0.18 mm through the block until no tissue remained. Twenty of 176 (11.4%) blocks harbored occult metastases; the B-32 protocol detected metastases in 11 blocks (6.3%) and 9 additional blocks (5.1%) with metastases were detected on sections that would not have been evaluated (P=0.002; correlated proportions). Median number of levels examined per block on the comprehensive protocol was 11 (range: 3 to 26); the B-32 protocol was fixed at 2 levels (median 2; range: 1 to 2). Median thickness of node sections in the block was 2.1 mm (range: 0.7 to 4.8 mm) and the modal thickness was 2.3 mm. Although more comprehensive sectioning of SLNs detects additional micrometastases, the data suggest diminishing returns and reduced cost effectiveness for the comprehensive strategy.

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.

Quality assessment of neoadjuvant therapy use in breast conservation: barriers to implementation.

Neoadjuvant systemic therapy (NST) for operable breast cancer can increase the options for conservative surgery in patients with breast cancer. We performed an analysis of a breast cancer outcomes database as a quality assessment of neoadjuvant therapy use in relation to breast conservative rate (BCR). Data were reviewed from a breast cancer database established to monitor outcomes of breast cancer surgery at a tertiary care breast cancer clinic. The frequency of NST-use was correlated to tumor size and BCR. Cause-specific factors for omitting NST in patients undergoing mastectomy for tumors 3 cm or greater were determined. NST was employed in 29 of 241 (12%) cases of invasive breast carcinoma treated surgically from 2003 to 2005. Although a significant decrease in BCR occurred in tumors >3 cm, NST was not frequently employed until tumors reached >5 cm. Defined contraindications to breast conservation (65%) and patient choice for mastectomy (30%) were the two most common reasons for omitting NST in tumors > or = 3 cm. Despite the initial appearance of NST under-utilization in tumors measuring between 3-5 cm, appropriate exclusion of patients not suitable for breast conservation and patient choice for mastectomy both emerged as leading factors for the omission of NST in this group. Use of NST is an important quality metric in optimizing breast conservation. Patient education and greater understanding of patient-related barriers to NST may help improve BCR.

Cytokeratin-positive cells in the bone marrow of breast cancer patients and noncancer donors.

Detection of disseminated tumor cells in the bone marrow may provide important prognostic information in breast cancer patients. With few exceptions the number of stained cells scored as cancer is very low; there may be only 1 cell per slide. This makes definitive interpretation of cancer in marrow challenging. False-positive staining of marrow cells with cytokeratin (CK) antibody is relatively common and makes interpretation more difficult. In this report we focus on false-positive staining of marrow specimens from breast cancer patients and noncancer controls and demonstrate that the frequency of false-positive events is common. Bone marrow was collected from 23 cancer-free donors and 60 breast cancer patients. Samples were processed by Ficoll density gradient centrifugation and slides were prepared for immunocytochemical staining with CK and irrelevant (IR) antibody. Slides were evaluated manually and positive cells were categorized as tumor cells, hematopoetic cells, or questionable cells. False-positive staining events were commonly observed in noncancer cases stained with CK or IR antibodies and in breast cancer cases stained with IR antibody. There was little difference in the number of breast cancer marrow specimens scored as tumor cells regardless of whether the antibody used was CK or IR. It is important to devise improved criteria and methods for accurate detection and interpretation of disseminated tumor cells in the marrow of breast cancer patients.

Quality measures for breast cancer surgery: initial validation of feasibility and assessment of variation among surgeons.

OBJECTIVES: To identify and quantify surgical outcomes as possible quality measures of initial breast cancer surgery and to assess variation among surgeons. DESIGN: Descriptive analysis of concurrently collected outcome measures. SETTING: University hospital with a designated breast cancer center. PATIENTS: Patients with a preoperative diagnosis of invasive breast cancer or ductal carcinoma in situ undergoing their initial cancer surgery from April 1, 2003, to March 30, 2008. MAIN OUTCOME MEASURES: Eight measures were identified: (1) total mastectomy rate; (2) close (<1 mm) and positive margin rate following initial partial mastectomy; (3) number of operations required in breast conservation; (4) number of nodes obtained from sentinel lymph node biopsy; (5) number of nodes from axillary dissection; (6) proportion of patients with positive sentinel lymph node biopsy undergoing axillary dissection; (7) use of intraoperative lymph node assessment; and (8) time from diagnosis to surgery. RESULTS: Nine hundred ten operations (218 for ductal carcinoma in situ, 692 for invasive breast cancer) were performed by 6 surgeons. Variation existed among surgeons in the combined close and positive margin rate, number of nodes obtained from sentinel lymph node biopsy, and use of intraoperative lymph node assessment. No significant variation was seen for the overall mastectomy rate, mean number of operations, positive margin rate alone, and number of lymph nodes from axillary dissection. CONCLUSIONS: Quality indicators for breast cancer surgery can be identified and readily monitored. Outcome variation exists at a high-volume breast center. Further study into the causes and effects of this variation on short- and long-term patient outcomes as well as health care costs is needed.

Molecular signatures suggest a major role for stromal cells in development of invasive breast cancer.

BACKGROUND: Breast cancer invasion and metastasis involves both epithelial and stromal changes. Our objective was to delineate the pivotal role stroma plays in invasion by comparing transcriptomes among stromal and epithelial cells in normal tissue and invasive breast cancer. METHODS: Total RNA was isolated from epithelial and stromal cells that were laser captured from normal breast tissue (n = 5) and invasive breast cancer (n = 28). Gene expression was measured using Affymetrix U133A 2.0 GeneChips. Differential gene expression was evaluated and compared within a model that accounted for cell type (epithelial [E] versus stromal [S]), diagnosis (cancer [C] versus normal [N]) as well as cell type-diagnosis interactions. RESULTS: Compared to NE, the CE transcriptome was highly enriched with genes in proliferative, motility and ECM ontologies. Differences in CS and NS transcriptomes suggested that the ECM was being remodeled in invasive breast cancer, as genes were over-represented in ECM and proteolytic ontologies. Genes more highly expressed in CS compared to CE were primarily ECM components or were involved in the remodeling of ECM, suggesting that ECM biosynthesis and remodeling were initiated in the tumor stroma. CONCLUSION: Based on identified molecular cross-talk between the two contiguous cell populations, a mechanistic model that spurs invasion is proposed, that shows breast cancer invasion proceeds through the acquisition of a motile phenotype in tumor epithelial cells and a reactive phenotype in cancer associated fibroblasts.

Cancer associated fibroblasts stimulated by transforming growth factor beta1 (TGF-beta 1) increase invasion rate of tumor cells: a population study.

Cancer associated fibroblasts (CAFs) are believed to promote tumor growth and progression. Our objective was to measure the effect of TGF-beta1 on fibroblasts isolated from invasive breast cancer patients. Fibroblasts were isolated from tissue obtained at surgery from patients with invasive breast cancer (CAF; n = 28) or normal reduction mammoplasty patients (normal; n = 10). Myofibroblast activation was measured by counting cells immunostained for smooth muscle alpha actin (ACTA2) in cultures +/- TGF-beta 1. Conditioned media (CM) was collected for invasion assays and RNA was isolated from cultures incubated in media +/- TGF-beta1 for 24 h. Q-PCR was used to measure expression of cyclin D1, fibronectin, laminin, collagen I, urokinase, stromelysin-1, and ACTA2 genes. Invasion rate was measured in chambers plated with MDA-MB-231 cells and exposed to CM in the bottom chamber; the number of cells that invaded into the bottom chamber was counted. Wilcox Rank Sum tests were used to evaluate differences in CAFs and normal fibroblasts and the effect of TGF-beta 1. There was no difference in percent myofibroblasts or invasion rate between normal and CAF cultures. However, TGF-beta1 significantly increased the percent of myofibroblasts (P < 0.01) and invasion rate (P = 0.02) in CAF cultures. Stromelysin-1 expression was significantly higher in normal versus CAF cultures (P < 0.01). TGF-beta 1 significantly increased ACTA2 expression in both normal and CAF cultures (P < 0.01). Expression of fibronectin and laminin was significantly increased by TGF-beta in CAF cultures (P < 0.01). CAFs were measurably different from normal fibroblasts in response to TGF-beta 1, suggesting that TGF-beta stimulates changes in CAFs that foster tumor invasion.

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. An NSABP protocol B-32 quality assurance study.

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.