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Featured researches published by Keoni Nguyen.


Annals of Surgical Oncology | 2001

Randomized Prospective Evaluation of a Novel Technique for Biopsy or Lumpectomy of Nonpalpable Breast Lesions: Radioactive Seed Versus Wire Localization

Richard J. Gray; Christopher Salud; Keoni Nguyen; Emilia L. Dauway; Jay L. Friedland; Claudia Berman; Eric S. Peltz; George F. Whitehead; Charles E. Cox

AbstractBackground: Standard wire localization (WL) and excision of nonpalpable breast lesions has several shortcomings. Methods: Ninety-seven women with nonpalpable breast lesions were prospectively randomized to radioactive seed localization (RSL) or WL. For RSL, a titanium seed containing 125I was placed at the site of the lesion by using radiographical guidance. The surgeon used a handheld gamma detector to locate and excise the seed and lesion. Results: Both techniques resulted in 100% retrieval of the lesions. Fewer RSL patients required resection of additional margins than WL patients (26% vs. 57%, respectively; P = .02). There were no significant differences in mean times for operative excision (5.4 vs. 6.1 minutes) or radiographical localization (13.9 vs. 13.2 minutes). There were also no significant differences in the subjective ease of the procedures as rated by surgeons, radiologists, and patients. All WLs were carried out on the same day as the excision, whereas RSL was performed up to 5 days before the operative procedure. Conclusions: RSL is as effective as WL for the excision of nonpalpable breast lesions and reduces the incidence of pathologically involved margins of excision. RSL also reduces scheduling conflicts and may allow elimination of intraoperative specimen mammography. RSL is an attractive alternative to WL.


Journal of The American College of Surgeons | 2001

Learning curves for breast cancer sentinel lymph node mapping based on surgical volume analysis

Charles E. Cox; Christopher Salud; Alan Cantor; Siddarth S. Bass; Eric S. Peltz; Mark D. Ebert; Keoni Nguyen; Douglas S. Reintgen

BACKGROUND Implementation of new procedures, including lymphatic mapping for breast cancer, must be done and overseen by the medical community in a responsible way to ensure that the procedures are performed correctly. This study addresses the issues of adequacy of training and certification of surgeons performing lymphatic mapping. Ensuring quality in surgical care requires outcomes measures that are described in this study. STUDY DESIGN Sixteen surgeons performed lymphatic mapping in 2,255 patients with breast cancer using a combination blue dye and Tc99m-labeled sulfur colloid to identify the sentinel lymph nodes (SLNs). All participants were trained in a 2-day CME-accredited course. The Cox learning curve model (total number of mapping failures/total number of mapping cases) for a consecutive series of lymphatic mapping cases is described. The relationship of the Surgical Volume Index, the cases performed in a 30-day period, to the failure rate for each surgeon was modeled as a logistic regression curve (y = e(a+bx)/[1 + e(a+bx)]). RESULTS Surgeons performing less than three SLN biopsies per month had an average success rate of 86.23% +/- 8.30%. Surgeons performing three to six SLN biopsies per month had a success rate of 88.73% +/- 6.36%. Surgeons performing more than six SLN biopsies per month had a success rate of 97.81% +/- 0.44%. CONCLUSIONS This experience defines a learning curve for lymphatic mapping in breast cancer patients. Data suggest that increased volumes lead to decreased failure rates. These data provide surgeons performing SLN biopsy with a new paradigm for assessing their skill and adequacy of training and describes the relationship between volume of cases performed and success rate of SLN detection.


Breast Journal | 2002

Age and Body Mass Index May Increase the Chance of Failure in Sentinel Lymph Node Biopsy for Women with Breast Cancer

Charles E. Cox; Elisabeth L. Dupont; George F. Whitehead; Mark D. Ebert; Keoni Nguyen; Eric S. Peltz; Darian Peckham; Alan Cantor; Douglas S. Reintgen

Age and body mass index (BMI) have been shown to correlate with an increased incidence of failure in identifying a sentinel lymph node (SLN). Mapping senior, overweight adults is common; therefore, the relationship of patient age and BMI on SLN biopsy success is essential. This study examines the mapping failures as they relate to age and BMI. From April 1994 to May 1999, patients underwent an injection of radiocolloid (450 mci) and blue dye (5 cc) prior to SLN biopsy. SLN biopsy failure was defined as lymph nodes being unidentifiable by blue dye or having an in vivo node radiocolloid count of less than 3:1 over background count. BMI was measured as (weight in pounds)(703)/(height in inches) 2; 1,356 patients were attempted for SLN mapping, and 54 failed (3.98%). The radioactive node count was inversely proportional to age ( p < 0.0001). The radioactive node count decreased by a mean of 34 counts per node with each additional year ( p < 0.001). The estimated odds ratios for success were 0.945 for age and 0.946 for BMI. Therefore, every increase of 1 year of age or one unit of BMI decreased the odds of success by approximately 5%. The mean BMI was 29.54 in failed patients and was 26.42 in successful mapping patients ( p = 0.042). Surgeons should be aware that node counts will decrease with increasing age and that increased age and BMI are potential risk factors for SLN mapping failure. However, increased age and/or BMI alone do not appear to be contraindications for SLN biopsy in older or overweight patients.


American Journal of Surgery | 2001

Clinical relevance of internal mammary node mapping as a guide to radiation therapy

Elisabeth L. Dupont; Chris Salud; Eric S. Peltz; Keoni Nguyen; George F. Whitehead; Ni Ni Ku; Douglas S. Reintgen; Charles E. Cox

BACKGROUND The surgical management of breast cancer has changed markedly with the development of lymphatic mapping and sentinel lymph node (SLN) biopsy. Lymphatic mapping technique varies with respect to injection method, mapping agent, and surgical technique. The decision to pursue the internal mammary nodes (IMN) is another source of controversy. METHODS From April 1998 to November 2000, 1,470 patients underwent lymphatic mapping for breast cancer and were prospectively entered into the breast database. The combined technique method was used, consisting of both isosulfan blue dye and technetium-99 labeled sulfur colloid. Patients with inner quadrant lesions and suspicion for internal mammary metastasis had preoperative lymphoscintigraphy. Those with internal mammary radioactivity noted by either lymphoscintigraphy or gamma probe underwent removal of the internal mammary sentinel nodes. RESULTS Thirty-six of the 1,470 (2.4%) patients mapped had at least 1 internal mammary lymph node removed. Inner quadrant lesions were present in 24 of the 36 (67%) IMN mapped patients. Of the 36 patients mapping to the IM area, 5 (14%) had at least 1 IM node positive. Two of the 5 (40%) had only IM metastasis, with 1 of these patients having 5 of 5 IMN positive and no disease detected in her axilla. A total of 2 of the 5 (40%) IM positive patients had more than 1 IMN positive. Twenty-eight of the 36 (78%) IM node harvested patients had preoperative lymphoscintigraphy, with 18 (64%) IMN appearing on imaging. Complications occurred in 3 of the 36 (8%) IMN mapped patients, without clinical significance. CONCLUSIONS Mapping to the IMN basin with the finding of metastasis results in N3 disease by the current staging system. The consequence for these patients is radiation therapy to the IMN basin. It is significant to note that 14% (5 of 36) were upstaged as result of IMN detection and 40% (2 of 5) had multiple positive IMNs. Substantial disease was detected in these 5 patients necessitating additional radiation therapy while avoiding IM radiation and its attendant complications in 86% of patients mapping to the IM basin.


Annals of Surgical Oncology | 2001

Utility of Internal Mammary Lymph Node Removal When Noted by Intraoperative Gamma Probe Detection

Elisabeth L. Dupont; Charles E. Cox; Keoni Nguyen; Christopher Salud; Eric S. Peltz; George F. Whitehead; Mark D. Ebert; Ni Ni Ku; Douglas S. Reintgen

Background: Lymphatic mapping LM for breast cancer has made internal mammary node IMN detection practical and dependable. This study demonstrates the necessity of IMN removal when suggested by intraoperative radioguided surgery detection.Methods: From April 1998 to July 2000, 1273 patients underwent LM for breast cancer. LM was performed using the combined dye and radiocolloid technique. Patients were scanned operatively with a gamma probe over the IMN area, and most underwent preoperative lymphoscintigraphy. Nodes were removed from patients in whom radioactivity was detected in the internal mammary area.Results: Thirty of the 1273 2.4% patients mapped had at least one IMN removed. Twenty-two of 30 73.3% had inner quadrant lesions. Five of 30 16.7% patients had IMNs that were positive for metastatic disease. Three of these five had no metastatic spread to the axillary sentinel lymph node SLN. One of thirty 3.3% patients with IMN localization had neither hot nor blue nodes detected in an SLN procedure.Conclusions: Radioguided SLN detection should be attempted in the IMN basin with all tumors. If an IMN is identified, it should be removed. IMN biopsy is a feasible, low-risk procedure when directed by radioguided LM and provides a guide for radiotherapy for patients with positive IMNs.


Cancer Control | 2001

The effect of sentinel node selective axillary lymphadenectomy on the incidence of postmastectomy pain syndrome.

Rafael Miguel; Ann M. Kuhn; Alan R. Shons; Patricia Dyches; Mark D. Ebert; Eric S. Peltz; Keoni Nguyen; Charles E. Cox

BACKGROUND Postmastectomy pain syndrome (PMPS) has been reported following procedures involving complete lymph node dissection (CLND). Since the triggering event is probably related to nerve injury, sentinel lymph node dissection (SLND) should decrease the incidence of PMPS. The purpose of this report is to determine the impact of SLND on the number of patients referred to the pain clinic for PMPS treatment. METHODS The records of all breast surgical patients with a diagnosis of PMPS referred to the Moffitt Cancer Center pain clinic were reviewed. The criterion for diagnosis of PMPS was a history of postoperative pain in the upper anterior chest wall, upper extremity, axilla, and/or shoulder in the absence of recurrent disease. RESULTS A total of 55 patients with a diagnosis of PMPS were seen in the pain clinic since 1991. Treatments included local anesthetics/corticosteroid injection, stellate ganglion block, and tricyclic antidepressants. A decrease from 15 patients in 1991 to 3 in 1998 was observed. All but one of the 55 patients with PMPS had CLND, and none referred to the pain clinic had undergone SLND. CONCLUSIONS PMPS is a complication of CLND. The increased use of SLND in our center has reduced the number of referrals to the pain clinic for treatment of PMPS. This benefit of SLND reduces suffering in the postoperative breast patient.


Journal of The American College of Surgeons | 2000

A biological approach to prevention and treatment of incisional hernias

Michael G. Franz; M.A Kuhn; Keoni Nguyen; X Wang; F Ko; T.E Wright; M.O Robson

Introduction: Despite improvement in abdominal wall closure, 200,000 incisional hernia repairs are performed in the U.S. each year. In fact, the greatest risk factor for incisional hernia formation is a previous incisional hernia. A biological intervention at the host:wound level designed to optimize fascial healing may prevent and/or treat incisional hernias. To date, systematic studies have been difficult due to lack of a reproducible animal model.


American Surgeon | 2001

Importance of lymphatic mapping in ductal carcinoma in situ (DCIS): why map DCIS?

Charles E. Cox; Keoni Nguyen; Richard J. Gray; Christopher Salud; Ni Ni Ku; Elisabeth L. Dupont; Lorraine Hutson; Eric S. Peltz; George F. Whitehead; Douglas S. Reintgen; Alan Cantor


Journal of Surgical Research | 2001

Transforming Growth Factor β2 Lowers the Incidence of Incisional Hernias

Michael G. Franz; M.Ann Kuhn; Keoni Nguyen; Xiaoning Wang; Francis Ko; Terry E. Wright; Martin C. Robson


Journal of Surgical Research | 2001

Learning curves and breast cancer lymphatic mapping : Institutional volume index

Elisabeth L. Dupont; Charles E. Cox; Steve Shivers; Chris Salud; Keoni Nguyen; Alan Cantor; Doug Reintgen

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Charles E. Cox

University of South Florida

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Eric S. Peltz

University of South Florida

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Christopher Salud

University of South Florida

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Mark D. Ebert

University of South Florida

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Ni Ni Ku

University of South Florida

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