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Biomedical subjects

W Lawrence

Publications and source records attributed to W Lawrence.

At least 37 records · Page 2Linked to original sources
PubMed1996

Extremity sarcomas: an analysis of prognostic factors from the Intergroup Rhabdomyosarcoma Study III.

PURPOSE: Prognostic factors for extremity sarcomas have been reported previously, after analysis of Intergroup Rhabdomyosarcomas Studies (IRS) I and II. This report reviews the experience of IRS III (1984-1992), in light of these reported factors, and the pretreatment factors used in the staging system currently being evaluated in IRS IV. The results of treatment of extremity sarcomas in IRS III are reported. METHODS: The charts of all patients entered in IRS III with an extremity-site tumor were reviewed. This group included patients with shoulder girdle and buttock sites. All patients were treated according to IRS III protocols. Survival rates were estimated by the method of Kaplan and Meier, and comparisons among groups of patients were made using a log-rank test. A multivariate analysis was performed to analyze all pretreatment factors that were significant by univariate analysis. RESULTS: Of the 189 patients entered in IRS III with extremity sites, 88 (47%) had the most common alveolar histology. Fifty-nine patients were in group I at the time of presentation (completely resected disease), 48 in group II (microscopic residual disease), 36 in group III (gross residual disease), and 46 in group IV (metastatic disease). By univariate analysis, the significant prognostic factors affecting survival were clinical group, age at time of diagnosis, tumor size, distant metastases, nodal metastases, and local and distant recurrence. By multivariate analysis of pretreatment factors, age at time of diagnosis, nodal metastases, and distant metastases were significant prognostic factors affecting survival; tumor size approached significance. Both the clinical group system and pretreatment staging system (Lawrence/Gehan) predicted significant differences in survival between groups of patients. The lower survival rate among group II and III node-negative patients with a distal tumor (who, with more extensive surgery, could have been in group I) in comparison to group I patients with a distal lesion, approached significance. In patients without distant metastases, survival was significantly different in those patients that had negative nodes from those in whom nodes were not biopsied. CONCLUSION: This review confirms that both clinical grouping and the new pretreatment staging system used in IRS IV can predict the likelihood of survival of children with extremity sarcomas. By multivariate analysis of the elements included in the staging system, nodal metastases, distant metastases, and tumor size were useful in predicting survival. In addition, age was a significant predictor. This study confirms previous suggestions that complete excision with gross and microscopically negative margins is preferable in the treatment of children with extremity rhabdomyosarcomas.

Adolescent↗
PubMed1996

Long-term results of breast conservation therapy for breast cancer.

OBJECTIVE: This study was done to determine the long-term outcome of breast conservation therapy (BCT) for patients with early-stage breast cancer during a period of treatment evolution at a single institution. SUMMARY BACKGROUND DATA: Breast cancer treatment has evolved from extensive surgical extirpation of the breast to treatment options that conserve the breast. Prospective and retrospective studies have confirmed the efficacy of BCT and justify its use for many patients with early breast cancer, but there is no universally accepted consensus as to who benefits from more aggressive application of surgery or radiotherapy in BCT. Prognostic variables for breast cancer and information on factors that contribute to local recurrence help predict BCT results. Continued analysis of BCT still is necessary to improve patient outcome. METHODS: Eighty-five patients treated with BCT (lumpectomy with adjuvant radiation therapy) at the Medical College of Virginia from 1980 to 1990 were identified. Clinicopathologic parameters and treatment details were analyzed for relationship to development of local recurrence, distant metastasis, and survival. Fisher's exact test was used for comparisons. Actuarial survival curves were plotted. The earlier treatment period (1980-1985) was compared with the later treatment period (1985-1990). RESULTS: Median follow-up was 5 years. Actuarial overall survival was 83% at 5 years (69% at 10 years), and 5-year distant metastasis-free survival was 79%. The 5-year actuarial local recurrence rate was 6.6% (crude rate 10.6%, 9/85). Young patients (age < 40 years) were found to be at increased risk for local recurrence (24% < 40 years vs. 6% > or = 40 years, p < 0.05). Tumor margins < or = 3 mm were more frequently found, and lumpectomy site radiation boost was used increasingly from 1986 to 1990. Almost half of all local recurrences occurred after 5 years. CONCLUSIONS: Survival and local recurrence rates were comparable to other series. Young patients were found to be at increased risk for local recurrence. Negative microscopic margins, even when close, can provide low local recurrence rates when adjuvant radiation therapy is administered.

Adult↗
PubMed1995

The National Cancer Data Base report on gastric cancer.

BACKGROUND: Previous Commission on Cancer studies from the National Cancer Data Base (NCDB) have examined time trends in stage of disease, treatment patterns, and survival for selected cancers. The most current (1991) data for gastric cancer are described here. METHODS: Three Calls for Data have yielded a total of 16,992 case reports of gastric cancer for 1985, 1986, and 1991, from hospital cancer registries across the U.S. RESULTS: Gastric cancer was the 15th most frequent cancer reported to the NCDB. The proportion of all reported cancers that were gastric in the two time intervals studied were essentially the same. In 1991, 20.8% of the cases were reported in minorities. Only 46% of gastric cancer cases were staged by the American Joint Committee on Cancer (AJCC) system in 1985 to 86, compared with 77% in 1991. More advanced stages were reported for younger patients, but less advanced stages were noted in the Asian population. Of all patients reported, 41.4% had no reported cancer-directed surgery, 41.1% had partial or hemigastrectomy, and 6.7% had total gastrectomy. More extensive surgery was associated with patients with Stage III disease than with Stages I and II, as might be expected. Survival after treatment remained poor (5-year relative survival; 43% for Stage I, 37% for Stage II, 18% for Stage III, and 20% for Stage IV). CONCLUSION: Improvements in treatment will emerge allowing survival to serve as a better guide for the quality of care in the future. In the interim, the frequency of American Joint Committee on Cancer staging in patient charts and the fraction of patients with Stages I and II as opposed to Stages III and IV disease (as a measure of prompt diagnosis) may serve as measure of how quickly these cancers are being diagnosed.

Adolescent↗
PubMed1995

Conservative management of uterine pediatric rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study III and IV pilot.

Previous studies have suggested that women with uterine rhabdomyosarcomas (RMS) represent a distinct group of patients who present at an older age, are less responsive to treatment, and have a poorer prognosis than patients with vaginal RMS. During the Intergroup Rhabdomyosarcoma Study (IRS) III and the IRS IV pilot study, 14 patients were registered with uterine primary RMS. Three patients presented with cervical tumors that were completely removed (group 1). Eight patients had initial biopsies with gross residual disease (group 3), and 3 had metastatic disease at presentation (group 4). Of the 5 patients treated with primary chemotherapy or chemotherapy and radiation, 2 had delayed hysterectomy and vaginectomy, 1 had no further surgery, and 2 had exploratory laparotomy with no evidence of disease. There were no relapses or deaths in this group. One patient underwent initial resection of a broad ligament mass, experienced an early (3-week) recurrence of the mass while on chemotherapy, and progressed to developing distant metastases and death. Four patients died of chemotherapy toxicity or sepsis, one after achieving a complete response from chemotherapy and hysterectomy. This primary chemotherapy or chemotherapy and radiotherapy regimen resulted in 8 of 9 (89%) patients (not including those who died of chemotoxicity) surviving between 1.5 and 6 years without evidence of disease. Of the surviving patients, 2 had hysterectomy and vaginectomy, but pathological specimens showed only localized microscopic residual tumor. This report suggests that less vigorous operative resection may be possible in combination with primary chemotherapy when treating uterine rhabdomyosarcomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Conservative surgical management of vaginal and vulvar pediatric rhabdomyosarcoma: a report from the Intergroup Rhabdomyosarcoma Study III.

The current management of pediatric vaginal and vulvar rhabdomyosarcoma (RMS) uses cytoreductive chemotherapy before surgical intervention. During the Intergroup Rhabdomyosarcoma Study (IRS)-III (1984 to 1988), 27 evaluable patients were entered on a preoperative chemotherapy protocol. Among 24 patients with vaginal primaries, 20 had an initial biopsy with gross residual (group III), 3 had resection with positive margins (group IIA) and 1 had metastatic disease (group IV). At subsequent surgery, 7 patients underwent partial or complete vaginectomy and 6 of them had no viable tumor identified in the specimen. Only 1 of these 7 patients underwent a cystectomy, whereas 5 underwent hysterectomy. Seventeen patients in this group have no evidence of disease 66 to 108 months after diagnosis; 2 died of chemotoxicity and 1 of unknown causes after achieving a complete response. Ten of these 17 patients were treated with biopsy and chemotherapy only. Four of these 10 had radiotherapy as well. All group IIA patients have no evidence of disease. The 1 group IV patient had rapidly progressive disease with early death. This primary chemotherapy protocol resulted in less need for operative intervention or irradiation compared with previous experience. There was no local recurrence, and 20 of 24 patients remain continuously relapse-free with no evidence of disease. All 3 patients with vulvar primaries were treated by wide local excision and chemotherapy and have no evidence of disease. Conservative surgical intervention for vaginal RMS with primary chemotherapy and adjunctive radiation when necessary appears to result in excellent disease-free survival.

Adolescent↗
PubMed1995

Improved survival with preoperative chemotherapy followed by resection uncompromised by tumor response for advanced squamous cell carcinoma of the head and neck.

BACKGROUND: A total of 93 patients were treated with one of two preoperative chemotherapy regimens over a 15-year period. The study supports the importance of strict adherence to guidelines for ablative surgery. METHODS: A single surgeon performed the surgery and evaluated each patient prior to treatment. The extent of the planned operation was documented. RESULTS: The 5-year absolute survival of 88 patients who completed the protocol was estimated at 55%. The 40 cisplatin/5-fluorouracil-treated patients exhibited a significantly better outcome than the 48 cisplatin/bleomycin-treated patients (76% versus 43%, respectively). Comparison of a subset of 37 patients with a matched group from the standard control arm of the Head and Neck Contracts Program demonstrated a statistically significant improvement in overall survival over standard treatment. CONCLUSIONS: These data suggest that strict adherence to preoperative chemotherapy planning of ablative uncompromised surgery contribute to improved survival. Selective rather than routine postoperative radiotherapy may be advantageous.

Antibiotics, Antineoplastic↗
PubMed1995

A multicenter, randomized, prospective study of endoscopic laser ablation versus transurethral resection of the prostate.

OBJECTIVES: To assess the safety and efficacy of endoscopic laser ablation of the prostate (ELAP), performed with the Urolase fiber and the neodymium:yttrium-aluminum-garnet laser, compared to transurethral resection of the prostate (TURP) in patients with bladder outflow obstruction secondary to benign prostatic hyperplasia (BPH). METHODS: In this multicenter, prospective, randomized study, a total of 151 patients were treated (ELAP, 76; TURP, 75) of whom 137 completed 1 year follow-up (ELAP, 67; TURP, 70). Safety parameters included measurement of preoperative and 24-hour postoperative sodium, hematocrit, and hemoglobin values and careful monitoring of adverse events. Efficacy was assessed with the American Urological Association symptom score (6), urinary flow rates, and residual urinary volume measurements. RESULTS: There was 1 death in each group during the study period unrelated to the treatment procedure. There was a clinically significant improvement in all efficacy parameters in both groups. Between group comparisons favored TURP in maximum flow rate, residual urinary volume, and symptom score. ELAP had a better safety profile than TURP in the defined safety parameters of drop in hemoglobin and hematocrit values. In 16% of patients, a blood transfusion was required after TURP compared with no transfusions in the ELAP group. Urinary tract infections and dysuria were more frequent in the ELAP group. CONCLUSIONS: ELAP performed with the Urolase fiber is a useful alternative therapy to TURP in patients presenting with bladder outflow obstruction secondary to BPH.

Aged↗
PubMed1995

Children with vesical rhabdomyosarcoma (RMS) treated by partial cystectomy with neoadjuvant or adjuvant chemotherapy, with or without radiotherapy. A report from the Intergroup Rhabdomyosarcoma Study (IRS) Committee.

PURPOSE: Children with bladder rhabdomyosarcoma (RMS) are currently treated with primary chemotherapy and usually with local irradiation. More than 30% of this group ultimately require total cystectomy. The purpose of this study was to review the results of the use of partial as opposed to total cystectomy in 40 patients with bladder RMS during Intergroup Rhabdomyosarcoma Study (IRS)-I, -II, and -III (1972-1989). PATIENTS AND METHODS: A total of 171 children with primary RMS of the bladder were enrolled in the IRS during this interval. Partial cystectomy was performed in 40, in 33 before any other therapy and in seven after 10-57 weeks of chemotherapy (primarily vincristine, actinomycin-D, and cyclophosphamide, i.e., VAC) +/- radiotherapy. Surviving patients have been observed for 4-22 years. RESULTS: Thirty-one of 40 patients (78.5%) have been disease free for 2-16 years. Survival among all other IRS cases with bladder RMS during the same interval was 79.5%. Of the 31 surviving patients, one required secondary total cystectomy and two required bladder augmentation procedures for benign bladder contracture. Three quarters of the total group of living patients who have undergone partial cystectomy are without bladder-related symptoms or demonstrable lower urinary tract disease. The remaining patients have a history of functional bladder problems related to contracture or incontinence. CONCLUSIONS: Partial cystectomy is an alternative to total cystectomy for bladder RMS when the tumor site makes it anatomically feasible. In such patients, it should be considered before total cystectomy and in patients with persistent areas of questionable residual tumor after otherwise apparently successful regimens of primary chemotherapy +/- radiotherapy.

Adolescent↗
PubMed1994

Retroperitoneal node biopsy in paratesticular rhabdomyosarcoma.

UNLABELLED: Retroperitoneal lymph node dissection (RPLND) was used in 121 Intergroup Rhabdomyosarcoma Study (IRS) III patients with nonmetastatic paratesticular (PT) rhabdomyosarcoma (RMS) to assess retroperitoneal lymph node (RPLN) involvement so as to determine the need for x-ray therapy (XRT). Clinical node evaluation (CNE) was accomplished by a computed tomography (CT) scan in 105 and a sonogram in six. Pathological node evaluation (PNE) was performed in 113: lymphadenectomy (9 bilateral, 85 unilateral) and biopsy in 19. Vincristine and actinomycin D were used for 1 year postoperatively in 89%; all patients who had positive PNE received RPLN XRT. This study compares CNE with PNE and evaluates predictors of relapse and survival. FINDINGS: There were clinically negative nodes (cN0) in 81% of the 121 patients. Among cN0 patients, 14% had positive nodes (pN1). Of the clinically positive (cN1) patients, 94% had pN1. RPLN relapse occurred in only two of the 121 patients. Initially both had cN0 and one had PNE that was negative. For all 121 patients, the 5-year survival was 91%. For cN0 patients, the 5-year survival was 96% compared with 69% for cN1 patients (P < .001). Among the children in whom treatment failed, nodes were cN1 in 5 of 11 (45%) compared with 15 of 107 (14%) in those whose treatment did not fail (P < .008). CONCLUSIONS: (1) Results of RPLN imaging studies were negative in 81% of patients with PT RMS (specificity 99%, sensitivity 57%). (2) RPLN recurrence is uncommon (even when RPLN are initially involved) if regional XRT and appropriate chemotherapy are used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Patient selection for clinical trials. Risks versus benefits and quality of life issues.

Although some clinician-scientists have expressed reservations regarding utilization of randomized treatment trials, the majority of clinical investigators involved with cancer believe that the well-designed, properly executed clinical trial is the optimal treatment approach if a patient is eligible. To conduct such clinical trials in an ethical fashion, stringent criteria for patient selection are of critical importance both to protect the patient's rights and to assure valid data on outcomes. These selection factors, both ethical and scientific, will be reviewed. Also, the benefits and potential risk factors for participation in the clinical trial that need to be reviewed as part of the informed consent process will be discussed. The cost/benefit ratio should favor participation in the trial, if the trial is properly designed. Quality of life issues, particularly toxicities resulting from one or more treatment alternatives in trial, are an important part of the foregoing analysis. In addition, quality of life endpoints are becoming more important in the planning of clinical treatment trials for cancer, and examples of these will be discussed. In an overall sense, the practical ethics of randomized clinical trials for investigators will be addressed from the standpoint of the impact on potential patient participants.

Clinical Trials as Topic↗
PubMed1993

Diastolic compliance of hypertrophied ventricle is not acutely altered by pharmacologic agents influencing active processes.

OBJECTIVE: To test, by studying the acute effects of drugs that influence active processes, the hypothesis that in humans with marked ventricular hypertrophy, reduced chamber compliance is primarily caused by passive structural changes. DESIGN: An uncontrolled (before-after) study. SETTING: University Medical Center. PATIENTS: Fourteen patients with ventricular hypertrophy (19 +/- 4.5-mm diastolic-wall thickness) and normal resting systolic function were studied while they had invasive cardiac catheterization. INTERVENTION: Intravenous beta-blocker (esmolol) or calcium channel blocker (verapamil) or both. MEASUREMENTS: Left ventricular function was determined by pressure-volume relations. Volume was measured using conductance catheter, providing a continuous voltage signal proportional to chamber volume. Pressure was measured by micromanometer. Cardiac-specific assessment of change in chamber contractility and diastolic compliance due to each drug was determined. RESULTS: Both drugs lowered contractility by approximately 30% (P < 0.01). Esmolol slowed relaxation and reduced early peak filling rate, whereas verapamil delayed the time to peak filling (all P < 0.05). In contrast to the effects of both drugs on active contraction and early diastole, late-diastolic compliance was unaltered, and end-diastolic pressure-volume relations were almost identical. CONCLUSION: Neither beta-receptor nor calcium channel blockade acutely alters left ventricular compliance despite substantial active effects manifest in systole and early diastole. This supports the notion that chamber compliance is principally determined by passive structural elements in the heart rather than by active processes.

Adrenergic beta-Antagonists↗
PubMed1993

Diminished contractile response to increased heart rate in intact human left ventricular hypertrophy. Systolic versus diastolic determinants.

BACKGROUND: Experimental studies indicate that in addition to diastolic dysfunction, hypertrophied myocardium can display depressed contractile responses, particularly at rapid heart rates, compounding reserve limitations. This study tests whether such abnormalities exist in intact human subjects at physiological paced rates and, if so, whether they are linked to simultaneous rate-dependent deterioration in diastolic function. METHODS AND RESULTS: Ten subjects with left ventricular hypertrophy (LVH) and 8 normal control subjects were studied. Most LVH patients presented with dyspnea and/or pulmonary edema and had concentric hypertrophy. Since rapid pacing simultaneously alters cardiac filling volumes and pressures, pressure-volume relation analysis was used to better define changes in contractile response. Patients were instrumented with a conductance catheter and micromanometer for pressure-volume data recording and a balloon occluder at the right atrial-inferior vena caval junction to vary filling and thus generate function relations. Data were obtained at baseline and at three atrial pacing rates (100, 120, 150 min-1). In addition, single-beat force-interval data were used to indirectly examine calcium cycling kinetics. LVH subjects demonstrated baseline diastolic abnormalities, including prolonged relaxation, elevated end-diastolic pressure, and reduced chamber compliance. However, systolic function was similar to that in control subjects. With rapid pacing, normal subjects displayed a positive contractile response, whereas this was markedly diminished in LVH subjects. With abrupt termination of pacing and return to slower sinus rhythm, LVH subjects displayed greater initial potentiation followed by a more rapid decline than control subjects, suggesting abnormalities of calcium handling. Despite contractile abnormalities, diastolic function did not further deteriorate with rapid pacing and thus did not appear to be tightly linked to the systolic changes. CONCLUSIONS: Pacing stress in intact human LVH can result in systolic impairment superimposed on preexisting but not worsened diastolic dysfunction. Abnormal calcium handling probably contributes prominently to this response.

Calcium↗
PubMed1993

Mutagenesis of essential functional residues of rat androgen-binding protein/sex hormone-binding globulin.

Testicular androgen-binding protein (ABP) and liver (plasma) sex hormone-binding globulin (SHBG) are extracellular carrier proteins that bind androgens with high affinity. Both proteins are encoded by the same gene and have the same primary amino acid sequence. Previous affinity labeling experiments to identify the steroid-binding site of ABP/SHBG led to ambiguous results, implicating various residues from 134 to near the C-terminus. To aid in elucidation of the essential functional residues of ABP/SHBG, we created mutant rat proteins by deletion and site-directed mutagenesis. The mutants were expressed in COS 7 green monkey kidney cells and analyzed for immunoreactive cellular and medium ABP and dihydrotestosterone (DHT) binding properties. Analysis of truncated ABP proteins revealed that removal of 26 or more residues from the C-terminus eliminates secretion and DHT-binding activity. Alteration of amino acid residues by site-directed mutagenesis from residue 54 to residue 333 resulted in elimination of DHT binding for 9 of 10 mutants and reduced DHT affinity for one altered protein (ABPGly54-57). Only one of the 10 mutant ABP proteins was secreted by the COS cells. This secreted mutant ABP (ABPArg139) exhibited no detectable DHT-binding activity. Thus, our data demonstrate that modifications of the ABP primary sequence throughout the molecule have a detrimental effect on steroid binding and secretion. These data, taken together with previous affinity labeling experiments, mutagenesis studies, and the conserved residues between rat and human ABP/SHBG, indicate that at least part of active site is located in residues 139-150, but most of the protein is required to maintain the conformation of the active site.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

The effects of group housing on the research use of the laboratory rabbit.

This project evaluated the influence of group housing on common aspects of research use of female laboratory rabbits (Oryctolagus cuniculus). Eight rabbits housed individually in conventional cages were compared to a second group of 8 housed as a social group in a proportionately larger enclosure. The group housing method provided increased opportunities for exercise, social contact, and a more novel environment. As a function of housing style, the 2 experimental groups were compared on humoral and delayed hypersensitivity response, feed intake, growth rate, and selected physiological parameters that are considered to reflect stress in most species. Single and group housed rabbits did not significantly differ in physiological and immunological measurements, indicating that the practical research performance (immune response, stress level, growth rates etc.) of these rabbits was not significantly affected by group housing compared with the more traditional single housing. Analysis of group social behaviour indicated that the rabbits preferred small social groups, had preferences for microenvironments within the enclosure, and exhibited behaviours that are not possible when housed singly. Group housing appeared to be a successful method for enriching the environment of female rabbits and aspects of it should be considered in the approach to housing rabbits used in research.

Animals↗