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Dive into the research topics where Alonzo P. Walker is active.

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Featured researches published by Alonzo P. Walker.


Journal of Clinical Oncology | 2005

Sentinel Node Biopsy After Neoadjuvant Chemotherapy in Breast Cancer: Results From National Surgical Adjuvant Breast and Bowel Project Protocol B-27

Eleftherios P. Mamounas; Ann Brown; Stewart A. Anderson; Roy E. Smith; Thomas B. Julian; Barbara J. Miller; Harry D. Bear; Christopher B. Caldwell; Alonzo P. Walker; Wendy M. Mikkelson; Jay S. Stauffer; André Robidoux; Heather Theoret; Atilla Sovan; Bernard Fisher; D. Lawrence Wickerham; Norman Wolmark

PURPOSE Experience with sentinel node biopsy (SNB) after neoadjuvant chemotherapy is limited. We examined the feasibility and accuracy of this procedure within a randomized trial in patients treated with neoadjuvant chemotherapy. PATIENTS AND METHODS During the conduct of National Surgical Adjuvant Breast and Bowel Project trial B-27, several participating surgeons attempted SNB before the required axillary dissection in 428 patients. All underwent lymphatic mapping and an attempt to identify and remove a sentinel node. Lymphatic mapping was performed with radioactive colloid (14.7%), with lymphazurin blue dye alone (29.9%), or with both (54.7%). RESULTS Success rate for the identification and removal of a sentinel node was 84.8%. Success rate increased significantly with the use of radioisotope (87.6% to 88.9%) versus with the use of lymphazurin alone (78.1%, P = .03). There were no significant differences in success rate according to clinical tumor size, clinical nodal status, age, or calendar year of random assignment. Of 343 patients who had SNB and axillary dissection, the sentinel nodes were positive in 125 patients and were the only positive nodes in 70 patients (56.0%). Of the 218 patients with negative sentinel nodes, nonsentinel nodes were positive in 15 (false-negative rate, 10.7%; 15 of 140 patients). There were no significant differences in false-negative rate according to clinical patient and tumor characteristics, method of lymphatic mapping, or breast tumor response to chemotherapy. CONCLUSION These results are comparable to those obtained from multicenter studies evaluating SNB before systemic therapy and suggest that the sentinel node concept is applicable following neoadjuvant chemotherapy.


Medical Care | 1996

Minimal increase in use of breast-conserving surgery from 1986 to 1990.

Ann B. Nattinger; Mark Gottlieb; Raymond G. Hoffman; Alonzo P. Walker; James S. Goodwin

Substantial geographic and hospital-based variations have been documented in the use of breast-conserving surgery (BCS) in 1986. The authors studied the patterns of adoption of this procedure from 1986 to 1990. National Medicare inpatient claims were used to study women aged 65 to 79 who underwent an operation for local or regional breast cancer in 1986 (38,679 patients) or 1990 (43,083 patients). Breast-conserving surgery was used for 5,509 (14.1%) of the Medicare patients in 1986 and 6,476 (15.0%) in 1990. The only region with an increase in BCS use from 1986 to 1990 was New England. Many hospitals had low volumes of operations, with a median of six to seven patients annually. Ten percent of the hospitals performed 55% of the conservative operations. Large hospitals, urban hospitals, and those with higher patient volumes or a cancer center were somewhat more likely to have increased use of BCS by 1990. Despite the substantial evidence supporting BCS as an alternative to mastectomy, the overall use of BCS in Medicare inpatients increased minimally from 1986 to 1990. Many patients are treated in hospitals with little experience with BCS. Hospitals using more BCS in 1986 were somewhat more likely to increase the use of BCS by 1990.


Annals of Surgery | 1993

Efficacy of a β-lactamase Inhibitor Combination for Serious Intra-abdominal Infections

Alonzo P. Walker; Ronald Lee Nichols; Robert F. Wilson; Brack A. Bivens; Donald D. Trunkey; Charles E. Edmiston; Jeffrey W. Smith; Robert E. Condon

A double-blind trial was conducted in 385 patients with suspected bacterial intra-abdominal infections to compare the efficacy and safety of ampicillin-sulbactam with cefoxitin. Patients were randomized to receive either 3 g ampicillin-sulbactam (2 g ampicillin-1 g sulbactam), or 2 g cefoxitin, every 6 hours. To be evaluable, patients had to demonstrate positive culture evidence of peritoneal infection at the time of operation. A total of 197 patients were evaluable for clinical efficacy. The two treatment groups were comparable in demographic features and in the presence of risk factors for infection. Clinical success (absence of infection and of adverse drug reaction) was observed in 86% of patients in the ampicillin-sulbactam group and 78% in the cefoxitin group. Eradication of infection occurred in 88% of the ampicillin-sulbactam group and 79% of the cefoxitin group. There were no differences in the nature or frequency of side effects observed in the two groups. Ampicillin-sulbactam demonstrated no difference in safety or efficacy when compared with cefoxitin in the treatment of serious intra-abdominal infections of bacterial origin.


Journal of Trauma-injury Infection and Critical Care | 1992

Acute ethanol intoxication increases the risk of infection following penetrating abdominal trauma

Larry M. Gentilello; Roy Cobean; Alonzo P. Walker; Ernest E. Moore; Margaret J. Wertz; E. P. Dellinger

Acute alcohol (ETOH) intoxication as a risk factor for infection in trauma victims to our knowledge has not been previously reported. To determine if ETOH intoxication increases infection risk we examined data from 365 patients with penetrating abdominal trauma who were enrolled in a multi-center antibiotic study. Ninety-four patients sustained an injury to a hollow viscus. To separate acute from chronic ETOH effects, infections were divided into two categories: (1) trauma related; infections caused by bacterial contamination at the time of injury, while blood alcohol level (BAL) was elevated. (2) nosocomial; infections caused by bacteria acquired during hospital stay, after BAL had normalized. A BAL > or = 200 mg/dL was associated with a 2.6-fold increase in trauma-related infections. There was no association between BAL and subsequent nosocomial infection. Since infection rates for intoxicated patients were not higher after BAL had normalized, acute rather than chronic effects of ETOH appear to be responsible.


Journal of The American College of Surgeons | 2002

Does breast tumor location influence success of sentinel lymph node biopsy

Gretchen M. Ahrendt; Prakash Laud; Judy A. Tjoe; Daniel Eastwood; Alonzo P. Walker; Mary F. Otterson; Philip N. Redlich

BACKGROUND Controversy exists regarding the influence of sentinel lymph node (SLN) mapping technique or patient variables on the success rate of SLN mapping. We undertook a prospective study in a single institution series to evaluate multiple variables that could adversely affect SLN identification rates. STUDY DESIGN Data were collected on 174 patients who underwent 177 SLN mapping procedures followed by axillary dissection from October 1996 through January 2000. Patient demographics, body mass index (BMI), biopsy method, tumor size, palpability, and location were recorded. SLNs were identified by blue dye only (n = 31), Tc-99m sulfur colloid only (n = 34), or combined techniques (n = 112). Data were analyzed by logistic regression analysis and expressed as the probability of failure to map the SLN. RESULTS SLNs were identified successfully in 150 of 177 procedures (85%) with a false negative rate of 3.7%. Mapping success reached 93% using combination blue dye and isotope. Variables found to adversely affect SLN mapping success and the odds ratio of failure (OR) included lower inner quadrant (LIQ) location (OR 35.6), blue dye only (OR 42.4), BMI >30 and upper outer quadrant (UOQ) location (OR 14.6), and nonpalpable UIQ location (OR 25). LIQ location adversely affects mapping success independent of technique, tumor size, or obesity. Obesity and nonpalpability were adverse factors when tumors were located in the UOQ and UIQ, respectively. Age, biopsy technique, and tumor diameter did not affect SLN mapping success. CONCLUSIONS SLN mapping success is influenced by technique and tumor location, with best results achieved using combined techniques and for lesions located in quadrants other than the LIQ. Obesity and tumor palpability influence success in the context of tumor location.


International Journal of Radiation Oncology Biology Physics | 2012

Prone Whole-Breast Irradiation Using Three-Dimensional Conformal Radiotherapy in Women Undergoing Breast Conservation for Early Disease Yields High Rates of Excellent to Good Cosmetic Outcomes in Patients With Large and/or Pendulous Breasts

Carmen Bergom; Tracy Kelly; Natalya Morrow; J. Frank Wilson; Alonzo P. Walker; Qun Xiang; Kwang Woo Ahn

PURPOSE To report our institutions experience using prone positioning for three-dimensional conformal radiotherapy (3D-CRT) to deliver post-lumpectomy whole breast irradiation (WBI) in a cohort of women with large and/or pendulous breasts, to determine the rate of acute and late toxicities and, more specifically, cosmetic outcomes. We hypothesized that using 3D-CRT for WBI in the prone position would reduce or eliminate patient and breast size as negative prognostic indicators for toxicities associated with WBI. METHODS AND MATERIALS From 1998 to 2006, 110 cases were treated with prone WBI using 3D-CRT. The lumpectomy, breast target volumes, heart, and lung were contoured on all computed tomography scans. A dose of 45-50 Gy was prescribed to the breast volume using standard fractionation schemes. The planning goals were ≥95% of prescription to 95% of the breast volume, and 100% of boost dose to 95% of lumpectomy planning target volume. Toxicities and cosmesis were prospectively scored using the Common Terminology Criteria for Adverse Effects Version 3.0 and the Harvard Scale. The median follow-up was 40 months. RESULTS The median body mass index (BMI) was 33.6 kg/m(2), and median breast volume was 1396 cm(3). The worst toxicity encountered during radiation was Grade 3 dermatitis in 5% of our patient population. Moist desquamation occurred in 16% of patients, with only 2% of patients with moist desquamation outside the inframammary/axillary folds. Eleven percent of patients had Grade ≥2 late toxicities, including Grade 3 induration/fibrosis in 2%. Excellent to good cosmesis was achieved in 89%. Higher BMI was associated with moist desquamation and breast pain, but BMI and breast volume did not impact fibrosis or excellent to good cosmesis. CONCLUSION In patients with higher BMI and/or large-pendulous breasts, delivering prone WBI using 3D-CRT results in favorable toxicity profiles and high excellent to good cosmesis rates. Higher BMI was associated with moist desquamation, but prone positioning removed BMI and breast size as factors for poorer cosmetic outcomes. This series adds to the growing literature demonstrating that prone WBI may be advantageous in select patients.


Pharmacotherapy | 1998

Pharmacoeconomic Analysis of Ampicillin-Sulbactam versus Cefoxitin in the Treatment of Intraabdominal Infections

Chad R. Messick; Muhammad Mamdani; Ian R. McNicholl; Larry H. Danziger; Keith A. Rodvold; Robert E. Condon; Alonzo P. Walker; Charles E. Edmiston

We conducted a retrospective pharmacoeconomic analysis of a prospective, multicenter, double‐blind, randomized, controlled trial comparing the β‐lactamase inhibitor combination ampicillin‐sulbactam (96 patients) and the cephalosporin cefoxitin (101) in the treatment of intraabdominal infections. An institutional perspective was adopted for the analysis. The primary outcomes of interest were cure and failure rates, development of new infection, and antibiotic‐related adverse events. Epidemiologic data pertaining to outcomes was retrieved primarily from the trial, although results of other published studies were taken into consideration through extensive sensitivity analyses. Data pertaining to potential resource use and economic impact were retrieved mainly from the University Health Consortium and hospital‐specific sources. When considering only costs associated with drug acquisition through cost‐minimization analysis, a potential savings of


Radiotherapy and Oncology | 2013

A phase I/II study piloting accelerated partial breast irradiation using CT-guided intensity modulated radiation therapy in the prone position.

Carmen Bergom; Phillip Prior; Natalya Morrow; E Ahunbay; Alonzo P. Walker; X. Allen Li

37.24/patient may be realized with ampicillin‐sulbactam relative to cefoxitin based on an average 7‐day regimen. Outcome data collected for the entire hospitalization during the trial revealed an approximately 9% greater frequency of failure with cefoxitin relative to ampicillin‐sulbactam. When considering all outcomes of interest in the initial base‐case analysis, a potential cost savings of approximately


Clinical Nuclear Medicine | 1992

Imaging of regional spread of breast cancer by internal mammary lymphoscintigraphy, CT, and MRI.

Turoglu Ht; Nora A. Janjan; Thorsen Mk; Shaffer Ka; Paul S. Ritch; Richard M. Hansen; Alonzo P. Walker; Gai M; Collier Bd

890/patient may be realized with ampicillin‐sulbactam relative to cefoxitin. In assessing the impact of the significant variability in probability and cost estimates, Monte Carlo analysis revealed a savings of


Cancer | 1992

Prognosis for breast cancer surgery and radiation therapy compared with mastectomy alone. A retrospective analysis of 759 patients with stage I/II breast cancer

Nora A. Janjan; Kevin Murray; Patrick D. Conway; Alonzo P. Walker; J. Frank Wilson

425/patient for ampicillin‐sulbactam over cefoxitin (95% CI

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Charles E. Edmiston

Medical College of Wisconsin

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Robert E. Condon

Medical College of Wisconsin

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Candace J. Krepel

Medical College of Wisconsin

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Carmen Bergom

Medical College of Wisconsin

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Claudia M. Gohr

Medical College of Wisconsin

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Phillip Prior

Medical College of Wisconsin

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Andre J. Jackson

Food and Drug Administration

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I. Sparks

Medical College of Wisconsin

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J.F. Wilson

Medical College of Wisconsin

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