Hormonal regulation of radioiodide uptake activity and Na+/I- symporter expression in mammary glands.

The observation that radioiodide uptake (RAIU) activity, mediated by the Na+/I- symporter (NIS), is significantly increased in lactating breast suggests that RAIU and NIS expression in mammary gland are modulated by hormones involved in active lactation. We showed that both the NIS expression level and RAIU in rat mammary gland are maximal during active lactation compared to those in the mammary glands of virgin and pregnant rats as well as the involuting mammary gland. In the lactating mammary gland, NIS is clustered on the basolateral membrane of alveolar cells as a lesser glycosylated form than NIS in thyroid. The RAIU of lactating mammary gland was partially inhibited by treatment with a selective oxytocin antagonist or bromocriptine, an inhibitor of PRL release. These findings suggest that RAIU and NIS expression in mammary gland are at least in part modulated by oxytocin and PRL. Indeed, we showed that NIS messenger ribonucleic acid level was increased in a dose-dependent manner by oxytocin and PRL in histocultured human breast tumors.

Effects of matrix components on aromatase activity in breast stromal cells in culture.

Local estradiol production within breast tissue is maintained by the aromatase cytochrome P450arom complex, which has been localized primarily to the stromal component of tumors but also has been detected in the breast epithelial cells. Paracrine interactions between stromal and epithelial components of the breast are critical to the sustained growth and progression of breast tumors. Maintenance of the differentiated state, including hormone and growth factor responsiveness, requires extracellular matrix proteins as substrata for cells. This research has focused on developing a cell culture system that more closely mimics in vivo interactions in order to dissect actual paracrine signaling between these two cell types. Human fibroblasts were isolated from breast tissue and were maintained in a cell culture system grown on plastic support or on a collagen I support matrix. The collagen I matrix model supports cell maintenance and subsequent differentiation on collagen rather than maximal proliferation, therefore allowing for a more accurate environment for the study of hormonal control and cellular communication. Initial experiments compared aromatase activity of patient fibroblasts grown on plastic versus collagen I using the tritiated water release method. Constitutive aromatase activity was found to be lower when cells were grown on a collagen gel for 4-7 days (7.7 fold lower) using DMEM/F12 containing 10% dextran coated charcoal stripped serum. However, fibroblasts grown on collagen I appeared to be significantly more responsive to stimulation by 100 nM dexamethasone (plastic: 6.0 fold induction, collagen: 33.2 fold induction) when pretreated for 12 h prior to measurement of aromatase activity. In an effort to examine paracrine interactions between the stromal and epithelial cells in breast tissue, experiments using conditioned media from fibroblast cultures were performed. Testosterone administration to fibroblasts results in the production of estradiol into the media in sufficient concentrations to elicit an increase in pS2 expression when the conditioned media is administered to MCF-7 cells. The addition of a potent aromatase inhibitor resulted in a complete suppression of fibroblast-derived estrogens and showed only a modest increase in pS2 expression. Culturing breast fibroblasts and epithelial cells on extracellular matrix allows for a more meaningful examination of the paracrine interactions between these cell types within the context of an appropriate extracellular environment. This study highlights the need for evaluation of gene expression in cell culture systems that accurately reflect the tissue microenvironment.

2-Methoxymethylestradiol: a new 2-methoxy estrogen analog that exhibits antiproliferative activity and alters tubulin dynamics.

An estradiol metabolite, 2-methoxyestradiol (2-MeOE(2)), has shown antiproliferative effects in both hormone-dependent and hormone-independent breast cancer cells. Previously, a series of 2-hydroxyalkyl estradiol analogs had been synthesized in our laboratories as potential probes for comparison of estrogen receptor (ER)-mediated versus non-ER-mediated effects in breast cancer cells. A methoxy derivative of 2-hydroxymethyl estradiol was prepared for biological evaluation and comparison with 2-MeOE(2). Estrogenic activity of the synthetic analogs was evaluated in two ways, one by examining affinity of the analogs for the estrogen receptor in MCF-7 cells and the other by examining the ability of the analogs to induce estrogen-responsive gene expression. The analog, 2-methoxymethyl estradiol (2-MeOMeE(2)), demonstrated weak affinity for the estrogen receptor (0.9% of estradiol) and weak ability to stimulate estrogen-induced expression of the pS2 gene (0.02% of estradiol). Antitumor activity was evaluated both in vitro and in vivo. The steroidal nucleus seems to be an attractive target for developing novel tubulin polymerization inhibitors. Additionally, such steroidal compounds may have low toxicity compared to the natural products known to interact with tubulin. Interestingly, 2-MeOMeE(2) inhibited tubulin polymerization in vitro at concentrations of 1 and 3 microM and was more effective than 2-MeOE(2). In cells, 2-MeOMeE(2) was effective in suppressing growth and inducing cytotoxicity in MCF-7 and MDA-MB-231 breast cancer cells. The cytotoxic effects of 2-MeOMeE(2) are associated with alterations in tubulin dynamics, with the frequent appearance of misaligned chromosomes, a significant mitotic delay, and the formation of multinucleated cells. In comparison, 2-MeOE(2) was more effective than 2-MeOMeE(2) in producing cytotoxicity and altering tubulin dynamics in intact cells. Assessment of in vivo antitumor activity was performed in athymic mice containing human breast tumor xenografts. Nude mice bearing MDA-MB-435 tumor xenografts were treated i.p. with 50 mg/kg per day of 2-MeOMeE(2) or vehicle control for 45 days. Treatment with 2-MeOMeE(2) resulted in an approximate 50% reduction in mean tumor volume at treatment day 45 when compared to control animals and had no effect on animal weight. Thus, 2-MeOMeE(2) is an estrogen analog with minimal estrogenic properties that demonstrates antiproliferative effects both in vitro and in the human xenograft animal model of human breast cancer.

Fluorodeoxyglucose positron emission tomography as an adjunct to carcinoembryonic antigen in the management of patients with presumed recurrent colorectal cancer and nondiagnostic radiologic workup.

BACKGROUND: The purpose of this study was to determine the role of fluorodeoxyglucose positron emission tomography (PET) in localizing disease in patients with colorectal cancer with radiologically occult symptomatology or increases in carcinoembryonic antigen (CEA) level. METHODS: Two hundred seventy-seven patients with colorectal cancer underwent PET scanning between November 1998 and September 2000 prompted by (1) increasing CEA level and nondiagnostic imaging or (2) symptoms with normal CEA level and nondiagnostic imaging. PET results were correlated with operative findings/histology, clinical follow-up data, and CEA level to determine PET's accuracy in determining the source of symptoms or CEA. RESULTS: Fifteen patients had increasing CEA levels, and 14 had abnormal PET. Two of these 14 were denied exploration because PET suggested widely metastatic disease. Nine patients underwent exploration with curative intent. In 1 patient, recurrence was not pathologically confirmed (false-positive rate, 8%). Two had disease beyond that predicted by PET, and 6 underwent complete resection and normalized their CEA levels. Four symptomatic patients with normal CEA levels and negative x-rays had abnormal PET; at exploration, 3 had no evidence of recurrence. CONCLUSIONS: PET imaging can often accurately localize the source of radiologically occult increases in CEA level and select that subset of patients eligible for therapeutic laparotomy. Symptomatic, PET-positive patients with normal CEA levels frequently undergo nontherapeutic laparotomy, and PET findings should be interpreted with caution in these patients.

Radioimmunoguided Surgery system improves survival for patients with recurrent colorectal cancer.

BACKGROUND: Advanced colorectal cancer is fatal. No systemic therapies have resulted in increased patient survival. METHODS: One hundred thirty-one patients with recurrent colorectal cancer enrolled in two prospective nonrandomized studies using Radioimmunoguided Surgery (RIGS) system from May 1986 to April 1992 have been analyzed. Eighty-six patients were injected with the anti-tumor-associated glycoprotein (TAG) antibody B72.3, and 45 patients were injected with the second-generation anti-TAG monoclonal antibody CC49. Both monoclonal antibodies were radiolabeled with iodine 125. Both traditional and RIGS explorations were used to determine resectability. Follow-up was a minimum of 28 months. RESULTS: Forty-nine (37.4%) of the 131 patients underwent a curative resection. Twenty-seven of the patients (55%) are alive 2 to 8 years after operation. The cancers of the remaining 82 patients were unresectable, and only two patients (2%) are alive. In this unresectable group alternative intraoperative therapeutic methods (intraoperative radiation therapy, intraperitoneal hyperthermic perfusion, hepatic lines, and brachytherapy) were tried in 11 patients with two survivors. There were no survivors in 18 patients whose cancers were found to be traditionally resectable but unresectable with RIGS or in the 53 patients whose cancers were clearly unresectable by traditional exploration. Patients selected for curative resection had significantly increased survival (p < 0.0001). CONCLUSIONS: As an intraoperative tool RIGS significantly improves the selection of patients for curative resection.

Pilot study evaluating the intraoperative localization of radiolabeled monoclonal antibody CC83 in patients with metastatic colorectal carcinoma.

BACKGROUND: CC83, a second-generation monoclonal antibody (MAb) against tumor-associated glycoprotein TAG-72 has been shown to have a higher affinity constant than the anti-TAG MAbs CC49 and B72.3. Clinical studies have shown the effectiveness of both CC49 and B72.3 radiolabeled MAbs in localizing colorectal carcinoma with a hand-held gamma-detecting probe during operation. This current study was designed to assess the safety and tumor-binding ability of radiolabeled CC83 MAb in this setting. METHODS: Seventeen patients with recurrent colorectal cancer underwent intravenous injection with CC83 MAb radiolabeled with iodine 125 (2.0 mCi125I/0.2 mg CC83 MAb). Exploratory laparotomy was carried out 21 to 28 days after injection, consisting of a thorough traditional exploration followed by a survey with a hand-held gamma-detecting probe. All traditionally suspicious and probe-positive tissue was either biopsied or resected and subsequently examined for the presence of carcinoma by using routine histochemical staining techniques. RESULTS: Thirty-two sites were identified as suspicious for cancer by traditional surgical exploration and 39 through intraoperative survey with a hand-held gamma-detecting probe in the seventeen patients completing the study. Biopsy or resection yielded 27 tumor sites when tissue was evaluated by using routine hematoxylin-eosin staining. All 27 tumor sites were localized by the radiolabeled CC83 MAb, whereas 12 additional sites were RIGS positive but hematoxylin-eosin negative, resulting in a sensitivity and positive predictive value of 100% and 69%, respectively. Traditional methods of exploration detected 23 of 27 tumor sites (85% sensitivity), and nine false-positive sites were recorded (72% positive predictive value). Occult tumor was found by using CC83 MAb in four (15%) of 27 sites, altering the surgical plan in three patients. CONCLUSIONS: This initial study indicates that CC83 MAb, when used with RIGS, is safe and sensitive in detecting recurrent intraabdominal colorectal cancer.

Vacuum-assisted stereotactic breast biopsy: histologic underestimation of malignant lesions.

HYPOTHESIS: The histopathologic correlation between stereotactic core needle biopsy and subsequent surgical excision of mammographically detected nonpalpable breast abnormalities is improved with a larger-core (11-gauge) device. DESIGN: Retrospective medical record and histopathologic review. SETTING: University-based academic practice setting. PATIENTS: Two hundred one patients who underwent surgical excision of mammographic abnormalities that had undergone biopsy with an 11-gauge vacuum-assisted stereotactic core biopsy device. MAIN OUTCOME MEASURE: Correlation between stereotactic biopsy histologic results and the histologic results of subsequent surgical specimens. RESULTS: Results of stereotactic biopsy performed on 851 patients revealed atypical hyperplasia in 46 lesions, ductal carcinoma in situ (DCIS) in 89 lesions, and invasive cancer in 73 mammographic abnormalities. Subsequent surgical excision of the 46 atypical lesions revealed 2 cases of DCIS (4.3%) and 4 cases of invasive carcinoma (8.7%). Lesions diagnosed as DCIS on stereotactic biopsy proved to be invasive carcinoma in 10 (11.2%) of 89 patients on subsequent excision. Stereotactic biopsy completely removed 21 (23.6%) of 89 DCIS lesions and 20 (27.4%) of 73 invasive carcinomas. CONCLUSIONS: In summary, 11-gauge vacuum-assisted core breast biopsy accurately predicts the degree of disease in the majority of malignant lesions; however, understaging still occurs in 11% to 13% of lesions showing atypical hyperplasia or DCIS.

Fibrin sealant reduces the duration and amount of fluid drainage after axillary dissection: a randomized prospective clinical trial.

BACKGROUND: Patients who have axillary dissections during lumpectomy or modified radical mastectomy for breast carcinoma accumulate serosanguinous fluid, potentially resulting in a seroma. Currently accepted practice includes insertion of one or more drains for fluid evacuation. This multicenter, randomized, controlled, phase II study was undertaken to evaluate whether a virally inactivated, investigational fibrin sealant is safe and effective when used as a sealing agent to reduce the duration and volume of serosanguinous fluid drainage and to determine the dose response of this effect. STUDY DESIGN: Patients undergoing lumpectomy or modified radical mastectomy were randomized to treatment with 4, 8, or 16 mL of fibrin sealant or control (no agent) at the axillary dissections site. Patients undergoing modified radical mastectomy also received an additional 4 or 8 mL of fibrin sealant at the skin flap site. Efficacy was evaluated by the number of days required for wound drainage and the volume of fluid drainage compared with control. Safety was confirmed by clinical course, the absence of viral seroconversion, and no major complications attributable to the sealant. RESULTS: The 4-mL axillary dissection dose of fibrin sealant significantly reduced the duration and quantity of fluid drainage from the axilla following lumpectomy (p < or = 0.05). In the modified radical mastectomy patients, a 16-mL axillary dissection dose combined with an 8-mL skin flap dose was significantly effective in reducing the number of days to drain removal (p < or = 0.05) and fluid drainage (p < or = 0.01). There were no fibrin sealant patient viral seroconversions and no major complications attributable to the sealant. A number of wound infections were noted, although this may represent a center-specific effect. CONCLUSIONS: Application of fibrin sealant following axillary dissection at the time of lumpectomy or modified radical mastectomy can significantly decrease the duration and quantity of serosanguinous drainage. The viral safety of the product was also supported.

Biodistribution and localization of radiolabeled NR-LU-10 Fab fragment in human breast cancer xenografts.

Radioimmunodetection, which takes advantage of tumor-specific or tumor-associated radio-labeled monoclonal antibodies or other biologic molecules to diagnose the extent of disease in cancer patients, has been of limited use in studies to date in patients with breast cancer. The difficulty is in finding an antibody that is both sensitive and specific enough to localize in breast tumors. This study undertook immunohistochemical and in vivo evaluation of tumor localization and biodistribution of NR-LU-10 Fab (antibody fragment) in breast tumors to determine its ability to bind selectively to malignant tissue. NR-LU-10 Fab recognizes a pancarcinoma glycoprotein antigen found on tumors of epithelial cell origin. NR-LU-10 Fab reacted with 6/6 (100%) breast cancer cell lines and 14/16 (87.5%) breast tumors with varying degrees of immunostaining intensities. Athymic mice bearing ZR-75-1 breast cancer xenografts were injected with 125I-labeled NR-LU-10 Fab (12 microg/5 microCi) and sacrificed at fixed time intervals. These studies demonstrated the highest tumor uptake of labeled Fab at 12 h postinjection (4.58+/-1.59% of injected dose/gram [% ID/g] of tissue); this gradually decreased to 0.13+/-0.05% ID/g of tissue by 72 h postinjection of the radiolabeled Fab. Biolocalization to normal tissues was as predicted for a Fab fragment; i.e., initially high in clearance organs (kidney), followed by rapid clearance over the 72-h test period. NR-LU-10 Fab displays adequate breast tumor localization with minimal biolocalization to normal tissues, thus supporting its potential use in radioimmunoscintigraphy and the RIGS system (radioimmunoguided surgery).

Is carcino-embryonic antigen useful in the follow-up management of patients with colorectal liver metastases?

BACKGROUND: The role of carcino-embryonic antigen (CEA) in monitoring early detection of recurrent or metastatic colorectal cancer, and its impact on resectability rate and patient survival remains controversial. Our objective was to determine any association between the preoperative level of CEA and prognosis, and the resectability and survival by method of diagnosis of colorectal hepatic metastases. METHODS: We analyzed patients who underwent exploration for hepatic resection for metastatic colorectal cancer over a 15-year period. The patient population consisted of those patients who had undergone primary colon or rectal resection and were followed up with serial CEA levels and of patients who were followed up with physical examination, liver function tests (LFTs) or computed tomography (CT) of the abdomen and pelvis that led to the diagnosis of liver metastases. Also included in the study were patients who were diagnosed with liver metastases at the time of the primary colon or rectal resection and underwent planned hepatic resection at a later time. RESULTS: Three hundred and one (301) patients who underwent a total of 345 planned hepatic resections for metastatic colorectal cancer between January 1978 and December 1993 were included in this analysis. The median preoperative CEA level was 24.8 ng/mL in the resected group, 53.0 ng/mL in the incomplete resection group, and 49.1 ng/mL in the nonresected group (P = 0.02). More of the patients who had a preoperative CEA < or =30 ng/mL were in the resected group, while those who had a preoperative CEA >30 ng/mL were likely to be in the nonresected group (P = 0.002). The median survival was 25 months for patients with a preoperative CEA level < or =30 ng/mL and 17 months for patients with a preoperative CEA >30 ng/mL (P = 0.0005). The resectability rate and the survival of patients by method of diagnosing liver metastases-rising CEA versus history and physical, elevated LFTs, CT scan versus diagnosis at the time of primary resection-was not significant (P = 0.06 and P = 0.19, respectively). Given the nonstandardized retrospective nature of the study cohort and relative small groups of patients, the power to detect small differences in survival by method of diagnosis is limited. In the complete resection group of patients with unilobar liver disease (5-year survival of 28.8%) there was no difference in survival between those patients who had normal preoperative CEA and those who had elevated preoperative CEA, and approximately 90% of them had an abnormal preoperative serum CEA level. CONCLUSIONS: CEA is useful in the preoperative evaluation of patients with hepatic colorectal metastases for assessing prognosis and is complimentary to history and physical examination in the diagnosis of liver metastases. Patients with colorectal liver metastases and preoperative CEA < or =30 ng/mL are more likely to be resectable, and they have the longest survival.

Predictors of positive axillary lymph nodes after sentinel lymph node biopsy in breast cancer.

OBJECTIVE: The purpose of this study was to determine the factors that predict the presence of metastasis in nonsentinel lymph nodes (SLN) when the SLN is positive. METHODS: A prospective database was analyzed and included patients who underwent SLN biopsy for invasive breast cancer from July 1997 to August 2000 (n = 442). One hundred (22.6%) patients had one or more positive SLNs, and were analyzed to determine factors that predicted additional positive axillary nodes. RESULTS: Of the 100 patients with a positive SLN, 40 patients (40%) had additional metastasis in non-SLNs. The only significant variables that predicted non-SLN metastasis were tumor lymphovascular invasion (P = 0.004), extranodal extension (P < 0.001), and increasing size of the metastasis within the SLN (P = 0.011). In analyzing just those patients who had lymphovascular invasion, extranodal extension, and a SLN metastasis > 2mm, 92% were found to have additional positive nodes. CONCLUSIONS: In patients with invasive breast cancer and a positive sentinel lymph node, lymphovascular invasion, extranodal extension, and increasing size of the metastasis all significantly increase the frequency of additional positive nodes.

Selective analysis of the sentinel node in breast cancer.

BACKGROUND: This study was designed to determine the minimum number of sentinel nodes necessary to accurately stage patients with breast cancer. METHODS: Between August 1997 and February 2001, 509 consecutive patients were enrolled in a prospective sentinel node database. Nodes were characterized as either blue or hot (>2 times background), or both, and ranked based on the order harvested. Predictive value of the sentinel node based on these characteristics was evaluated to determine the minimum number necessary to stage the basin. RESULTS: In all, 990 sentinel nodes were harvested from 465 basins. Pathologic stage in 126 of 128 positive basins was predicted by the first or second node harvested. The remaining 2 patients were positive by immunohistochemistry only. The hottest node predicted the status in 114 of 128 basins. CONCLUSIONS: Although all nodes should be examined, these data suggest that limiting frozen section analysis to the first two sentinel nodes identified will not compromise the accuracy of staging and may provide a vehicle for resource savings.

Routine preoperative lymphoscintigraphy is not necessary prior to sentinel node biopsy for breast cancer.

BACKGROUND: This prospective study was performed to ascertain the added benefit of lymphoscintigraphy to a standard method of intraoperative lymphatic mapping and sentinel node biopsy for breast cancer. METHODS: Patients with invasive breast cancer were injected with 99mTc sulfur colloid prior to sentinel node biopsy; preoperative lymphoscintigraphy was then performed in half of the patient population. RESULTS: Sentinel node identification was possible in 45 of 50 patients (90%). All 14 patients (31%) with axillary nodal metastases had at least one histologically positive sentinel node (0% false negative rate). Lymphoscintigraphy revealed sentinel nodes in 17 of the 24 patients (70.8%) imaged. All 17 of these patients had one or more axillary sentinel nodes identified using intraoperative lymphatic mapping. In addition, 5 of 7 patients with a negative preoperative lymphoscintogram had an axillary sentinel lymph node(s) identified intraoperatively. None of the tumors showed drainage to the internal mammary lymph node chain by lymphoscintigraphy despite the fact that there were 5 patients with inner quadrant tumors. There was no significant advantage with respect to sentinel lymph node localization (91.7% versus 88.5%, P = not significant) or false negative rate (0%, both groups, P = not significant) in the group undergoing preoperative lymphoscintigraphy when compared with the patients in whom lymphoscintigraphy was not performed. CONCLUSIONS: Preoperative lymphoscintigraphy adds little additional information to intraoperative lymphatic mapping, and its routine use is not justified.

The radioimmunoguided surgery (RIGS) system as a diagnostic tool.

Radioimmunoguided surgery (RIGS) was developed to improve on the intraoperative detection of malignancy. The RIGS system uses a hand-held gamma radiation detection probe to identify radioactive tissues targeted by a preadministered tumor-associated radiolabeled targeting antibody or peptide. Clinical experience with RIGS in colorectal cancer has been favorable; better intraoperative staging has provided the surgeon more information regarding the pattern of disease and individual patients. Pancreatic, breast, ovarian, and prostate cancer have also been studied in clinical trials using RIGS and early results are encouraging. In the future, marked improvements with the RIGS system will be realized with the development of better targeting agents.

Lymphatic mapping for breast cancer: experience at The Ohio State University.

BACKGROUND: Though not yet the standard of care, lymphatic mapping is becoming more widely utilized by surgeons who care for women with breast cancer. The purpose of this study is to report the early experience of lymphatic mapping at a large NCI designated cancer center. METHODS: Beginning in 1997, selected newly diagnosed breast cancer patients at our institution have undergone lymphatic mapping. Blue dye and radiolabelled colloid were used as mapping agents. Patients were entered into a prospective database which recorded demographics, mapping characteristics and pathologic correlation. RESULTS: In total, 352 patients were entered into the study, and 312 (89%) had an identifiable sentinel lymph node at the time of definitive surgery. Eight surgeons contributed to the database, four of whom performed more than 30 lymphatic mapping procedures. 149 patients underwent complete axillary lymphadenectomy either as part of a validation study (68) or because of metastasis disease to the sentinel node (81). The false negative rate was 4%. The surgeon's experience with the procedure was the only independent predictor of the ability to localize a sentinel node. CONCLUSIONS: Sentinel lymphadenectomy at our institution is an accurate means of predicting the status of the draining nodal basin. Experience with the technique correlates with successful localization, but patient selection and an institutional commitment to the procedure are also critical for success.

Radioimmunoguided breast surgery using radiolabeled antibody NR-LU-10 FAB: a pilot study.

AIM AND BACKGROUND: Radioimmunoguided surgery using radiolabeled NR-LU-10 Fab was evaluated as a method of intraoperative breast cancer detection. METHODS: Breast cancer patients were injected intravenously with 125I (74 MBq) labeled NR-LU-10 Fab (5 mg) and then underwent tumor excision 2, 4 or 7 days later, during which time the gamma detector probe was used to evaluate the primary tumor for evidence of radioactive uptake. RESULTS: Intraoperative probing revealed tumor localization in 7 of 10 patients (70%). Gamma probe counts of the excised tumor were elevated in all patients, although high counts in surrounding non-malignant tissue obscured the ability to detect the tumor in vivo in 3 patients. One patient with bilateral breast cancer was found to have a separate focus of occult tumor in each breast using the gamma detector probe. CONCLUSIONS: Radiolabeled NR-LU-10 Fab possesses favorable pharmokinetics and tumor-binding ability as a targeting agent. However, binding to non-malignant tissue limits its role in the intraoperative evaluation of tumor margins in breast cancer patients. Its role in other malignancies should be explored.

Surgical applications of gamma-detecting probes.

The RIGS system is a technology which was developed to provide a more sensitive and accurate method of detecting colorectal cancer during surgery. One of the components of this system is the hand-held, gamma-detecting probe [Neoprobe Model 1000instrument; Neoprobe Corporation, Dublin, Ohio), used by the surgeon to identify preadministered, radiolabeled monoclonal antibody which has localized to dis- eased tissue. RIGSuses sound-directed gamma detection to identify and locate cancer which may not be seen or felt by the surgeon. The success of RIGS has been largely due to the remarkable sensitivity of the gamma- detecting probe in detecting small amounts oflow-energy radioactivity. This attribute has led to the use of the probe for other surgical applications including pre- and intraoperative lymphatic mapping, and parathyroid localization. Surgery for melanoma, breast cancer, parathyroid disease, and colorectal cancer has been af- fected by the increased use of the gamma-detecting probe both in clinical trials and practice. This chapter will review the many applications of this new technology.

Seroma formation following axillary dissection for breast cancer: risk factors and lack of influence of bovine thrombin.

BACKGROUND: Seromas of the axillary space following breast surgery can lead to significant morbidity and delay in the initiation of adjuvant therapy. A prospective, randomized study was undertaken to evaluate the effect of bovine spray thrombin on seroma formation following either modified radical mastectomy (MRM) or lumpectomy with axillary dissection (LAD). In addition, risk factors for seroma formation were analyzed and identified. METHODS: A total of 101 patients were randomized to receive either bovine thrombin (20,000 units) (treatment group) or no thrombin (control group) applied to their axilla following either MRM or LAD. Drains were left in place until the preceding 24-hour drainage was < 40 milliliters. The number of days the drains were in place and wound complications (including seroma formation) were recorded. RESULTS: Forty-nine (n = 49) patients were assigned to the treatment gorup and 52 (n = 52) to the control group. MRM was performed on 60 patients (59%) and LAD oN 41 (41%). Eighteen of the 49 patients (37%) in the thrombin group developed a seroma in comparison to 21 of the 52 control patients (40%) (P = 0.71). Significant risk factors for seroma formation included increased age, patient weight, initial 72-hour wound drainage, and LAD. No statistically significant differences were observed between treatment and control groups with respect to time to drain removal, or the incidence of other wound complications. CONCLUSION: Although thrombin by itself appears to have no effect on subsequent seroma development following axillary dissection, the identification of predictive variables will be helpful in designing future trials aimed at reducing the incidence of this common complication of breast surgery.

Androgens influence estrogen-induced responses in human breast carcinoma cells through cytochrome P450 aromatase.

The aromatase cytochrome P450 complex is responsible for the in vivo conversion of androgens to estrogens. Although breast cancer epithelial cells have been reported to have appreciable aromatase activity, its biologic significance remains uncertain. To address this, the effect of androgens on the expression of the estrogen-regulated gene pS2 in hormone-dependent human breast carcinoma cells in vitro was examined. Steroid-deprived MCF-7 cells were exposed to varying concentrations (1 nM, 10 nM, and 100 nM of androstenedione or testosterone for 2,4, and 6 days. Baseline aromatase activity was 4.9 (+/-3.1) fmol 3H2O/hour/microgram DNA [34.3 (+/-21.3) fmol/hr/10(6) cells] and was not influenced by the androgens. As an indication of estrogen biosynthesis, northern analysis was performed to quantitate pS2 mRNA expression. Although no significant pS2 induction was observed at 2 days, both 4 and 6 day exposure to 100 nM testosterone resulted in a 3-fold increase in pS2 mRNA expression. 5 alpha-dihydrotestosterone (5 alpha-DHT) failed to elicit a similar pS2 response. This testosterone-induced response was inhibited with the aromatase inhibitor 7 alpha (4'-amino) phenylthio-1,4-androstadiene-3,17-dione (7 alpha-APTADD) and with 10 microM tamoxifen. MCF-7 breast cancer cells possess endogenous aromatase activity at high enough levels to convert androgens to estrogens and elicit an estrogen-induced response. The expression of aromatase may offer a potential advantage to hormone-responsive cells, providing an additional autocrine growth pathway which may be exploited.

Variation in axillary node dissection influences the degree of nodal involvement in breast cancer patients.

BACKGROUND AND OBJECTIVES: The number of positive axillary lymph nodes predicts prognosis and is often important in determining adjuvant chemotherapy in breast cancer patients. This study was undertaken to determine if differences in the extent of axillary node dissection would alter the number of reported positive nodes. METHODS: The study population consisted of 302 patients with invasive breast cancer who underwent complete (level I/II/III) axillary lymph node dissection. Assuming that all patients had undergone a level I/II dissection, it was determined how frequently a patient's nodal category (0, 1-3, 4-9, >10 positive nodes) would have been altered if a level I or level I/II/III dissection were performed. RESULTS: Assuming that all 302 patients had undergone a level I/II dissection, performing only level I dissection would have resulted in a change in nodal category in 15.9% of all patients and 36.1% of patients with positive nodes. The corresponding changes for a level I/II/III dissection would have been 4.3% and 9.5%, respectively. CONCLUSIONS: Variations in the level of axillary node dissection for breast cancer can result in significant changes in the number of positive axillary nodes. This can potentially bias adjuvant chemotherapy recommendations if treatment decisions are based on this prognostic factor.