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Biomedical subjects

D H Leung

Publications and source records attributed to D H Leung.

At least 19 recordsLinked to original sources
PubMed2000

Dermatofibrosarcoma protuberans: A clinicopathologic analysis of patients treated and followed at a single institution.

BACKGROUND: Despite optimal surgical therapy for patients with dermatofibrosarcoma protuberans (DFSP), some patients still continue to develop local recurrence. The authors' objective was to identify and analyze clinicopathologic factors for disease free survival in a large group of patients who were followed prospectively at a single institution. METHODS: Prospectively collected data and pathology slides were available for review from 159 patients with primary or recurrent DFSP who underwent treatment between July 1950 and July 1998. The study group was comprised of patients with either the "classic" form of DFSP or the fibrosarcomatous "high grade" variant of DFSP (FS-DFSP). Patient, tumor, pathologic, and treatment factors were analyzed using the log rank test for univariate influence and Cox regression analysis for multivariate influence. Local recurrence free survival was determined by the Kaplan-Meier actuarial method. RESULTS: Of the 159 patients who comprised the current study group, 134 (84%) had the classic form of DFSP. The FS-DFSP variant was found in the remaining 25 patients (16%). The overall 5-year local recurrence free survival rate was 75%, with a median follow-up of 4. 75 years. The 5-year recurrence free survival rate for each group was 81% and 28%, respectively. On univariate analysis, age > 50 years, very close (< 1 mm) to positive microscopic margins, FS-DFSP variant, high mitotic rate, and increased cellularity were unfavorable prognostic factors. Multivariate analysis determined very close (< 1 mm) to positive microscopic margins and FS-DFSP variant to be independent adverse prognostic factors. For the 34 patients who developed a recurrence after surgical resection (21%), the median time to local recurrence was 32 months. Of the patients in this group, two died from metastatic disease. CONCLUSIONS: The prognosis after surgical resection with negative and sometimes positive microscopic margins for patients with DFSP is very good. However, increased age, high mitotic index, and increased cellularity are predictors of poor clinical outcome. The FS-DFSP variant represents a much more aggressive tumor with metastatic potential. Patients who are treated with curative intent for FS-DFSP should undergo aggressive attempts at complete surgical resection. Patients with recurrent classic DFSP without evidence of adverse prognostic features may benefit from conservative management, especially in the setting of potentially unresectable disease.

Adolescent↗
PubMed2000

Alterations of cell cycle regulators in localized synovial sarcoma: A multifactorial study with prognostic implications.

Genetic alterations of cell cycle regulators are thought to represent uncommon and possible secondary events in sarcomas characterized by recurrent chromosomal translocations. The present study investigates this hypothesis on synovial sarcoma (SS), assessing the frequency of expression and possible clinical implications of detecting alterations in critical cell cycle regulatory proteins. A homogeneous cohort of 49 patients with localized SS, restricted to the extremity and with available long-term follow-up information, was selected from our files. We focused our study on molecules involved in the G1 checkpoint and G1-S transition, including cyclins D1 and E, p21(WAF1), p27(Kip1), mdm2, p53, and Ki67. A cutoff point of 10% immunoreactive tumor cell nuclei was selected to define a positive phenotype for any given marker, except for Ki67. High Ki67 proliferative index was considered when >/=20% tumor cells displayed nuclear immunoreactivity. Biphasic SS were analyzed, taking into account separately the expression of these proteins in the spindle and glandular components. Disease specific survival was modeled using the Kaplan-Meier method with log rank test and Cox regression. The cohort of patients analyzed included 23 females and 26 males, and the histological type distribution was 35 monophasic and 14 biphasic SS. The median follow-up for survivors was 53 months, with a 5-year disease-specific survival of 63% and a metastatic disease-free survival of 40%. The positive phenotypes identified for the different markers studied were as follows: cyclin D1, 59%; cyclin E, 29%; p21, 51%; p27, 69%; mdm2, 59%; p53, 16%; and Ki67, 59%. We observed that positive p53, cyclin E, and high Ki67 proliferative index were correlated with survival, but only Ki67 and p53 were independent variables for prognostication. The present study suggests that alterations of cell cycle regulators are more common events in SS than originally thought. p53 overexpression could be of use as a marker together with a high Ki67 proliferative index, in identifying a subset of SS patients with increased risk of tumor relapse.

Adolescent↗
PubMed2000

Perioperative alterations in plasma endothelin-1 and echocardiographic correlates of right heart function.

OBJECTIVE: To determine whether greater changes in plasma endothelin-1 (ET-1) concentrations and right ventricular systolic pressure occur after major thoracic surgery than after major abdominal operations. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Patients undergoing elective thoracotomies (n = 12) or laparotomies (n = 10). INTERVENTIONS: ET-1 was measured from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). Transthoracic echocardiography was performed before surgery and on postoperative day 2 to evaluate right-sided heart function. MEASUREMENTS AND MAIN RESULTS: After abdominal and thoracic surgery, systemic and estimated pulmonary vascular pressures were normal in both groups and unaffected by surgery. Plasma ET-1 concentrations decreased from baseline values during the first postoperative week with no differences between the groups. CONCLUSIONS: In patients without organic heart disease, plasma ET-1 levels do not increase in response to major abdominal or thoracic surgery. Whether or not plasma ET-1 concentrations are elevated in patients developing clinically significant postoperative pulmonary hypertension requires further study.

Aged↗
PubMed2000

Repeat resection of pulmonary metastases in patients with soft-tissue sarcoma.

BACKGROUND: Even after an apparent complete resection of sarcomatous pulmonary metastases, 40% to 80% of patients will re-recur in the lung. The benefit of subsequent re-resection is poorly defined. This study examines patient survival after repeat pulmonary exploration for re-recurrent metastatic sarcoma at a single institution. STUDY DESIGN: Between July 1982 and December 1997, data on 3,149 adult in-patients with soft tissue sarcoma were prospectively gathered. Of these, pulmonary metastases were present or developed in 719 patients and 248 underwent at least one resection. Of the patients relapsing in the lung after an apparently complete resection, 86 underwent reexploration. Disease-specific survival (DSS) after re-resection was the end point of the study. Time to death was modeled using the method of Kaplan and Meier. The association of factors to time-to-event end points was analyzed using the log-rank test for univariate analysis and the Cox proportional hazards model for multivariate analysis. Clinicopathologic factors were analyzed with the Pearson chi-square or Fisher's exact test when appropriate. RESULTS: The median DSS after re-resection for all patients undergoing at least two pulmonary resections was 42.8 months with an estimated 5-year survival of 36%. The median DSS in patients with complete reresection was 51 months (n = 68) compared with 6 months in patients with an incomplete re-resection (n = 16, p<0.0001). Patients with one or two nodules at re-resection (n = 39) had a median DSS of 51 months compared with 20 months in patients with three or more nodules (n = 40, p = 0.003). Patients in whom the largest metastasis re-resected was less than or equal to 2 cm (n = 33) had a median DSS of 44 months compared with 20 months in patients with metastasis greater than 2 cm (n = 43, p = 0.033). Patients with primary tumor high-grade histology (n = 75) had a median DSS of 32 months and patients with low-grade histology (n = 11) had a median DSS that was not reached (p = 0.041). Three independent prognostic factors associated with poor outcomes may be determined preoperatively: > or =3 nodules, largest metastases > 2 cm, and high-grade primary tumor histology. Patients with either zero or one poor prognostic factor had a median DSS > 65 months and patients with three poor prognostic factors had a median DSS of 10 months. CONCLUSIONS: Reexploration for recurrent sarcomatous pulmonary metastases appears beneficial for patients who can be completely re-resected. Outcomes are described by factors that may be determined preoperatively, including metastasis size, metastasis number, and primary tumor histologic grade. Patients who cannot be completely re-resected or those with numerous, large metastasis and high-grade primary tumor pathology have poor outcomes and should be considered for investigational therapy.

Adolescent↗
PubMed2000

Surgical management of intra-abdominal desmoid tumours.

BACKGROUND: Intra-abdominal desmoids are uncommon neoplasms. The aggressive nature of these tumours and the potential for major morbidity secondary to resection can present a difficult surgical dilemma. METHODS: Patients with histologically confirmed intra-abdominal desmoid tumours undergoing laparotomy were identified from a prospective database. Clinical features and outcomes in this group were evaluated. RESULTS: The study group comprised 24 patients. Sixteen patients underwent complete resection of the tumour while eight had biopsy only, with or without intestinal bypass. Small intestinal resection was performed in 12 patients, including three who had a near-total enterectomy. Median follow-up was 62 months, with an actuarial overall survival rate of 73 per cent at 10 years. There was no difference in survival rate between completely resected and unresected patients (P = 0.73). There were seven deaths in the entire group, of which four were in those undergoing complete resection. CONCLUSION: Operation can cure patients with intra-abdominal desmoid tumours, but may result in significant morbidity, especially from loss of small intestine. No other therapy is a predictably good alternative to operation but the natural history of desmoids is often characterized by prolonged periods of stability or even regression. A period of watchful waiting, until significant symptoms develop, may be the most appropriate course in patients who risk mesenteric vascular injury or substantial enterectomy with attempts at resection.

Abdominal Neoplasms↗
PubMed2000

Long-term effects of angiotensin-converting enzyme inhibition and metabolic control in hypertensive type 2 diabetic patients.

UNLABELLED: Long-term effects of angiotensin-converting enzyme inhibition and metabolic control in hypertensive type 2 diabetic patients. BACKGROUND: In hypertensive type 2 diabetic patients, treatment with angiotensin-converting enzyme (ACE) inhibitors is associated with a lower incidence of cardiovascular events than those treated with calcium channel-blocking agents. However, the long-term renal effects of ACE inhibitors in these patients remain inconclusive. In 1989, we commenced a placebo-controlled, double-blind, randomized study to examine the anti-albuminuric effects of enalapril versus nifedipine (slow release) in 102 hypertensive, type 2 diabetic patients. These patients have been followed up for a mean trial duration of 5.5 +/- 2.2 years. We examined the determinants, including the effect of ACE inhibition on clinical outcomes in these patients. METHODS: After a six-week placebo-controlled, run-in period, 52 patients were randomized double-blind to receive nifedipine (slow release) and 50 patients to receive enalapril. After the one-year analysis, which confirmed the superior anti-albuminuric effects of enalapril (-54%) over nifedipine (+11%), all patients were continued on their previously assigned treatment with informed consent. They were subdivided into normoalbuminuric (N = 43), microalbuminuric (N = 34), and macroalbuminuric (N = 25) groups based on two of three 24-hour urinary albumin excretion (UAE) measurements during the run-in period. Renal function was shown by the 24-hour UAE, creatinine clearance (CCr), and the regression coefficient of the yearly plasma creatinine reciprocal (beta-1/Cr). Clinical endpoints were defined as death, cardiovascular events, and/or renal events (need for renal replacement therapy or doubling of baseline plasma creatinine). RESULTS: In the whole group, patients treated with enalapril were more likely to revert to being normoalbuminuric (23.8 vs. 15.4%), and fewer of them developed macroalbuminuria (19.1 vs. 30.8%) compared with the nifedipine-treated patients (P < 0.05). In the microalbuminuric group, treatment with enalapril (N = 21) was associated with a 13.0% (P < 0.01) reduction in 24-hour UAE compared with a 17.3% increase in the nifedipine group (N = 13). In the macroalbuminuric patients, enalapril treatment (N = 11) was associated with stabilization compared with a decline in renal function in the nifedipine group, as shown by the beta-1/Cr (0.65 +/- 4.29 vs. -1.93 +/- 2.35 1/micromol x 10-3, P < 0.05) after adjustment for baseline values. Compared with the normoalbuminuric and microalbuminuric patients, those with macroalbuminuria had the lowest mean CCr (75.5 +/- 24.1 vs. 63.5 +/- 21.3 vs. 41.9 +/- 18.5 mL/min, P < 0.001) and the highest frequency of clinical events (4.7 vs. 5.9 vs. 52%, P < 0. 001). On multivariate analysis, beta-1/Cr (R2 = 0.195, P < 0.001) was independently associated with baseline HbA1c (beta = -0.285, P = 0.004), whereas clinical outcomes (R2 = 0.176, P < 0.001) were independently related to the mean low-density lipoprotein cholesterol (beta = 2.426, P = 0.018), high-density lipoprotein cholesterol (beta = -8.797, P = 0.03), baseline UAE (beta = 0.002, P = 0.04), and mean CCr during treatment (beta = -0.211, P = 0.006). CONCLUSION: In this prospective cohort analysis involving 102 hypertensive, type 2 diabetic patients with varying degrees of albuminuria followed up for a mean duration of five years, we observed the importance of good metabolic and blood pressure control on the progression of albuminuria and renal function. Treatment with enalapril was associated with a greater reduction in albuminuria than with nifedipine in the entire patient group, and especially in those with microalbuminuria. In the macroalbuminuric patients, the rate of deterioration in renal function was also attenuated by treatment with enalapril.

Aged↗
PubMed2000

Strong association of SYT-SSX fusion type and morphologic epithelial differentiation in synovial sarcoma.

Synovial sarcoma is characterized by a specific recurrent translocation t(X; 18), resulting in either the SYT-SSX1 or SYT-SSX2 gene fusion. Because this is the primary genetic alteration in these tumors, we sought to identify the impact of molecular heterogeneity of the t(X;18) on cell proliferation, apoptosis, and epithelial differentiation in synovial sarcoma. Seventy-three patients with synovial sarcoma (18 biphasic, 55 monophasic) were selected on the basis of availability of tumor material for molecular and immunohistochemical analysis. Tumors were classified as biphasic on the basis of morphologic glandular differentiation. SYT-SSX fusion transcripts were examined by reverse transcriptase polymerase chain reaction using tumor RNA extracted from frozen or paraffin-embedded tissue. Cell proliferation was assessed immunohistochemically by the Ki-67 labeling index. Apoptosis was analyzed immunohistochemically with BAX and BCL2 antibodies and by the TUNEL method. Immunohistochemical evidence of epithelial differentiation was assessed using antibodies to cytokeratins and epithelial membrane antigen. Approximately two thirds of the tumors had an SYT-SSX1 and one third had an SYT-SSX2 fusion transcript. There was a strong association between SYT-SSX fusion type and histologic subtype. All biphasic synovial sarcomas had the SYT-SSX1 fusion, whereas all tumors with SYT-SSX2 were of monophasic morphology. There was, however, no association between SYT-SSX fusion type and expression of cytokeratins and epithelial membrane antigen among monophasic tumors. Tumors with SYT-SSX2 had a significantly higher mean and median Ki-67 labeling index than those with SYT-SSX1, but a comparison of Ki-67 according to fusion type, histologic type, and sample source suggested that the main determinants of proliferation rate were the latter two factors. Specifically, monophasic tumors and metastatic tumors showed significantly higher Ki-67 scores. Apoptosis (by TUNEL) was rarely observed, consistent with prominent expression of the anti-apoptotic protein BCL2 in almost all cases. TUNEL, BCL2, and BAX results did not correlate with SYT-SSX fusion type. These data confirm the strong association of SYT-SSX fusion transcript type with morphologic but not immunophenotypic epithelial differentiation in synovial sarcoma.

Apoptosis↗
PubMed2000

Synovial sarcoma: a multivariate analysis of prognostic factors in 112 patients with primary localized tumors of the extremity.

PURPOSE: Synovial sarcoma is a high-grade tumor that is associated with poor prognosis. Previous studies analyzing prognostic factors are limited because of inclusion of heterogeneous cohorts of patients with nonextremity and recurrent tumors. The objective of this study was to determine independent prognostic factors of primary synovial sarcoma localized to the extremity. PATIENTS AND METHODS: Between July 1, 1982, and June 30, 1996, 112 patients underwent surgical resection for cure at our institution and then were followed-up prospectively. Clinical and pathologic factors examined for prognostic value included age, sex, tumor site and location, depth, size, microscopic status of surgical margins, invasion of bone or neurovascular structures, and monophasic or biphasic histology. The end points analyzed were the time to first local recurrence that was not preceded by a distant recurrence, time to any distant recurrence, and time to disease-related mortality. These end points were modeled using the method of Kaplan and Meier and analyzed by the log-rank test and Cox regression. RESULTS: The median duration of follow-up among survivors in this cohort of 112 patients was 72 months. The 5-year local-recurrence, distant-recurrence, and mortality rates were 12%, 39%, and 25%, respectively. Tumor size > or = 5 cm (P =.001; relative risk [RR] = 2. 7; 95% confidence interval [CI], 1.5 to 5.2) and the presence of bone or neurovascular invasion (P =.04; RR = 2.3; 95% CI, 1.0 to 5. 3) were independent adverse predictors of distant recurrence. Tumor size > or= 5 cm (P =.003; RR = 2.3; 95% CI, 1.4 to 6.3) and the presence of bone or neurovascular invasion (P =.03; RR = 2.7; 95% CI, 1.0 to 6.5) were also independent adverse predictors of mortality. CONCLUSION: The natural history of primary synovial sarcoma of the extremity is related to tumor size and invasion of bone and neurovascular structures.

Adolescent↗
PubMed1999

Extremity and trunk desmoid tumors: a multifactorial analysis of outcome.

BACKGROUND: The natural history of desmoid tumors remains an enigma. Previous reports attempting to identify their biology have included recurrent and primary tumors as well as tumors from both intra- and extra-abdominal sites. The purpose of this study was to analyze patients with primary extremity and trunk desmoid tumors treated and followed at a single institution and to determine factors influencing disease free survival. METHODS: Between July 1982 and June 1997, 189 patients with extremity and superficial trunk desmoid tumors were treated and followed prospectively. Of these, 105 presented with primary disease and formed the basis of this study. RESULTS: The median follow-up for the entire group of patients was 49 months; it was 46 months for patients who did not develop a local recurrence. During this time, 24 patients (23%) had a local recurrence. No patients died of disease. The 2-year and 5-year local recurrence free survival rates were 80% and 75%, respectively. None of the prognostic factors analyzed, including age, gender, depth of tumor, size of tumor, or tumor site, were significant for predicting local recurrence. Moreover, positive resection margins were not predictive of recurrence. The selective use of adjuvant radiation therapy did not influence the rate of local recurrence regardless of the margin status. CONCLUSIONS: Attempts to achieve negative resection margins may result in unnecessary morbidity and may not prevent local recurrence. Operations that preserve function and structure should be the primary goal, because the presence of residual disease cannot be clearly shown to impact adversely on 5-year disease free or overall survival.

Adult↗
PubMed1999

Malignant fibrous histiocytoma of the extremity.

BACKGROUND: This study examines prognostic factors and outcomes for a group of patients with malignant fibrous histiocytoma of the extremity treated at a single referral institution. METHODS: A total of 239 patients underwent complete surgical excision between July 1982 and July 1996 and were followed prospectively. RESULTS: The overall 5-year and 10-year disease specific survival rates for this group were 65% and 59%, respectively. Age >50 years, tumor location, and presentation with local recurrence were all associated with increased risk of local recurrence. Tumor size, grade, depth, and presentation with local recurrence were all associated with adverse disease specific and metastasis free survival. Tumor size > or = 10 cm was associated with a particularly unfavorable outcome. CONCLUSIONS: The majority of malignant fibrous histiocytomas of the extremity are associated with a relatively favorable prognosis. Size > or = 5 cm, deep depth, and high grade are all unfavorable factors. Size > or = 10 cm is associated with an even more unfavorable prognosis.

Adolescent↗
PubMed1999

Multifactorial analysis of the survival of patients with distant metastasis arising from primary extremity sarcoma.

BACKGROUND: Despite optimal multimodality limb-sparing therapy for extremity soft tissue sarcoma (STS), a significant number of patients develop distant metastasis. The objective of this study was to analyze patterns of metastatic disease and define prognostic factors for survival in a large group of patients followed prospectively at a single institution. METHODS: Between July 1, 1982, and June 30, 1996, all adult patients admitted to the Memorial Sloan-Kettering Cancer Center with primary extremity sarcoma were treated and prospectively followed. Patients who developed distant metastases constituted the study group. Prognostic factors were analyzed for postmetastasis survival. These included both factors related to the primary tumor and factors related to the pattern of metastasis. Postmetastasis survival was modeled using the Kaplan-Meier method. Statistical significance was evaluated using the log rank test for univariate analysis and the Cox proportional hazards model for multivariate analysis. RESULTS: During the study period, the authors admitted and treated 994 patients with primary extremity STS. The median follow-up was 33 months. Distant metastasis developed in 230 patients (23%). Median survival after distant metastasis was 11.6 months. The lungs were the first metastatic site in 169 patients (73%). Other first sites of metastasis included the skin and soft tissues of the head and neck, trunk, and extremities. There was no statistically significant difference in survival between patients with pulmonary and those with nonpulmonary metastatic disease. In multivariate analysis, resection of metastatic disease, the length of the disease free interval, the presence of a preceding local recurrence, and patient age > 50 years all were significant predictors of postmetastasis survival. Other factors that defined the primary tumor, including histologic grade, depth, and microscopic margins, were not associated with postmetastasis survival. CONCLUSIONS: Despite optimal multimodality therapy, 23% of the patients in this series with primary extremity sarcoma developed distant metastasis. Median survival after metastasis was approximately 1 year. After metastasis, the independent favorable factors that are associated with patient survival include resection of the metastases, a long disease free interval, the absence of preceding local recurrence, and patient age < 50 years. Although a definitive conclusion regarding the benefit of resection can be made only with a randomized clinical trial, these data suggest that resection of metastatic STS may contribute to patient survival, which in some cases may be long term.

Adolescent↗
PubMed1999

Pulmonary metastases from soft tissue sarcoma: analysis of patterns of diseases and postmetastasis survival.

OBJECTIVE: To report the patterns of disease and postmetastasis survival for patients with pulmonary metastases from soft tissue sarcoma in a large group of patients treated at a single institution. Clinical factors that influence postmetastasis survival are analyzed. SUMMARY BACKGROUND DATA: For patients with soft tissue sarcoma, the lungs are the most common site of metastatic disease. Although pulmonary metastases most commonly arise from primary tumors in the extremities, they may arise from almost any primary site or histology. To date, resection of disease has been the only effective therapy for metastatic sarcoma. METHODS: From July 1982 to February 1997, 3149 adult patients with soft tissue sarcoma were admitted and treated at Memorial Sloan-Kettering Cancer Center. During this interval, 719 patients either developed or presented with lung metastases. Patients were treated with resection of metastatic disease whenever possible. Disease-specific survival was the endpoint of the study. Time to death was modeled using the method of Kaplan and Meier. The association of factors to time-to-event endpoints was analyzed using the log-rank test for univariate analysis and the Cox proportional hazards model for multivariate analysis. RESULTS: The overall median survival from diagnosis of pulmonary metastasis for all patients was 15 months. The 3-year actuarial survival rate was 25%. The ability to resect all metastatic disease completely was the most important prognostic factor for survival. Patients treated with complete resection had a median survival of 33 months and a 3-year actuarial survival rate of 46%. For patients treated with nonoperative therapy, the median survival was 11 months. A disease-free interval of more than 12 months before the development of metastases was also a favorable prognostic factor. Unfavorable factors included the histologic variants of liposarcoma and malignant peripheral nerve tumors and patient age older than 50 years at the time of treatment of metastasis. CONCLUSIONS: Resection of metastatic disease is the single most important factor that determines outcome in these patients. Long-term survival is possible in selected patients, particularly when recurrent pulmonary disease is resected. Surgical excision should remain the treatment of choice for metastases of soft tissue sarcoma to the lung.

Adolescent↗
PubMed1999

The enigma of desmoid tumors.

OBJECTIVE: To analyze patients with recurrent extremity desmoids, in whom the surgical therapeutic option was either major amputation or observation. SUMMARY BACKGROUND DATA: The biology and natural history of desmoid tumors are an enigma. These tumors invade surrounding structures and recur locally but do not metastasize. The morbidity of treating these tumors in the context of their relatively benign biology is uncertain. METHODS: Between July 1982 and June 1998, the authors treated and prospectively followed 206 patients with extremity desmoid tumors. All patients underwent standardized surgical resection, the surgical goal always being complete resection with negative margins. When tumors recurred, they were evaluated for reresection. Amputation was considered when resection was not possible because of neurovascular or major bone involvement, or in the presence of a functionless, painful extremity. RESULTS: During this period, 22 patients had disease that was not resectable without amputation. This was out of a total of 115 patients with primary disease and 91 patients with recurrent disease. All recurrences were local; in no patient did metastasis develop. In this group of 22 patients with unresectable disease, 7 underwent amputation and 15 did not. These 15 patients were followed, alive with disease, having no surgical resection. Four patients received systemic treatment with tamoxifen and nonsteroidal antiinflammatories, three received systemic cytotoxic chemotherapy, and two received both tamoxifen and chemotherapy. Six patients received no systemic treatment. The range of follow-up was 25 to 92 months. In all patients, there was no or insignificant tumor progression; in three patients who underwent observation alone, there was some regression of tumor. During follow-up, no patient has required subsequent amputation, and no patient has died from disease. CONCLUSIONS: In desmoid tumors, aggressive attempts at achieving negative resection margins may result in unnecessary morbidity. Function- and structure-preserving procedures should be the primary goal. In select patients, whose only option is amputation, it may be prudent to observe them with their limb and tumor intact.

Adolescent↗
PubMed1998

Subdiaphragmatic and intrathoracic paraspinal malignant peripheral nerve sheath tumors: a clinicopathologic study of 25 patients and 26 tumors.

BACKGROUND: To determine the effects of anatomic site on the presentation and diagnosis of malignant peripheral nerve sheath tumors (MPNSTs) and on the treatment and outcomes of the patients, the authors initiated a study of these tumors at different sites. An earlier report described MPNSTs of the buttock and lower extremity, and the current series analyzes those presenting at intrathoracic (IT) and subdiaphragmatic (SD) paraspinal sites. METHODS: The authors reviewed data on patients with paraspinal MPNSTs who were seen at Memorial Hospital during the period 1960-1995 and for whom histologic slides were available. Various clinicopathologic parameters and their effects on patient outcomes were examined. RESULTS: Twenty-five patients with 26 tumors were evaluated. Seven tumors were IT and 19 were SD; 60% of the patients had neurofibromatosis type 1 (NF1). Most patients presented with pain, and a diagnostic delay (of 3 months to 2 years) was often noted. Mean tumor sizes for SD and IT tumors were 14.3 cm and 6.6 cm, respectively. Most MPNSTs were composed of spindle cells in fascicles. Twenty-seven percent exhibited divergent differentiation. Twenty-four tumors were high grade, and a low grade component was identified in 8 tumors. Surgical resection was attempted for 23 tumors (88%), but complete resection was achieved in only 6 cases (23%). Eighty percent of the patients died of their tumors, 2-year and 5-year survival rates were 35% and 16%, and median survival was 8.5 months. Significant prognostic factors were tumor size <5 cm, the presence of a low grade component, and complete tumor resection. CONCLUSIONS: Paraspinal MPNSTs have more aggressive behavior than peripherally located tumors, mainly because of the difficulty encountered in resecting them completely. Prognoses of patients with MPNST at this site appear to be affected by resection status, tumor size, and tumor grade.

Adolescent↗
PubMed1998

Persistent alterations of the autonomic nervous system after noncardiac surgery.

UNLABELLED: BACKGROUND. Changes in the sympathetic nervous system may be a cause of postoperative cardiovascular complications. The authors hypothesized that changes in both beta-adrenergic receptor (betaAR) function (as assessed in lymphocytes) and in sympathetic activity (assessed by plasma catecholamines and by heart rate variability [HRV] measurements obtained from Holter recordings) occur after operation. METHODS: The HRV parameters were measured in 28 patients having thoracotomy (n = 14) or laparotomy (n = 14) before and for as long as 6 days after operation. Transthoracic echocardiography was performed before and on postoperative day 2. Lymphocytes were also isolated from blood obtained before anesthesia and again on postoperative days 1, 2, 3, and 5 (or 6). They were used to examine betaAR number (Bmax) and cyclic adenosine monophosphate (cAMP) production after stimulation with isoproterenol and prostaglandin E1. In addition, plasma epinephrine, norepinephrine, and cortisol concentrations were determined at similar intervals. RESULTS: After abdominal and thoracic surgery, most time and all frequency indices of HRV decreased significantly, as did Bmax and basal and isoproterenol-stimulated cAMP production. The decrements in HRV correlated with those of Bmax and isoproterenol-stimulated cAMP throughout the first postoperative week and inversely correlated with the increase in heart rate. Plasma catecholamine concentrations did not change significantly from baseline values, but plasma cortisol levels did increase after operation in both groups. Left ventricular ejection fraction was normal in both groups and unaffected by surgery. CONCLUSIONS: Persistent downregulation and desensitization of the lymphocyte betaAR/adenylyl cyclase system correlated with decrements in time and frequency domain indices of HRV throughout the first week after major abdominal or thoracic surgery. These physiologic alterations suggest the continued presence of adaptive autonomic regulatory mechanisms and may explain why the at-risk period after major surgery appears to be about 1 week or more.

Aged↗
PubMed1998

An optimal design for screening trials.

Yao, Begg, and Livingston (1996, Biometrics 52, 992-1001) considered the optimal group size for testing a series of potentially therapeutic agents to identify a promising one as soon as possible for given error rates. The number of patients to be tested with each agent was fixed as the group size. We consider a sequential design that allows early acceptance and rejection, and we provide an optimal strategy to minimize the sample sizes (patients) required using Markov decision processes. The minimization is under the constraints of the two types (false positive and false negative) of error probabilities, with the Lagrangian multipliers corresponding to the cost parameters for the two types of errors. Numerical studies indicate that there can be a substantial reduction in the number of patients required.

Biometry↗
PubMed1997

Soft-tissue sarcoma involving bone or neurovascular structures: MR imaging prognostic factors.

PURPOSE: To determine if magnetic resonance (MR) imaging findings of soft-tissue sarcoma involving bone or neurovascular structures allow prediction of local recurrence, distant metastasis, or disease-specific survival. MATERIALS AND METHODS: Preoperative MR images of 46 patients with soft-tissue sarcoma were reviewed for tumor involving bone or major vessels or nerves. MR imaging findings were correlated with local recurrence, distant metastasis, and disease-specific survival after surgery and chemotherapy and/or radiation therapy. Primary tumors were predominantly in the lower extremity (n = 35 [76%]), deep (n = 44 [96%]), and high-grade (n = 35 [76%]). RESULTS: On MR images, bone invasion occurred in 12 patients (26%), major-vessel encasement in five patients (11%), and major-nerve encasement in seven patients (15%). In patients with (n = 12) and those without (n = 34) bone invasion, frequencies of disease-related death (in nine [75%] and 12 [35%] patients, respectively) were significantly different (P = .02); frequencies of local recurrence or distant metastasis were not significantly different. In patients with and those without major-vessel or major-nerve encasement, there were no significant differences between frequencies of local recurrence, distant metastasis, or disease-specific survival. CONCLUSION: In soft-tissue sarcoma, bone invasion on MR images was predictive of decreased disease-specific survival. MR imaging findings of bone or neurovascular involvement otherwise appear to be more important for tailoring surgery than for predicting local recurrence, distant metastasis, or survival.

Bone Neoplasms↗