Biomedical subjects

Luis Burgos

Publications and source records attributed to Luis Burgos.

11 recordsLinked to original sources

PubMed2006

[Methodological quality of an article on the treatment of gastric cancer adopted as protocol by some Chilean hospitals].

BACKGROUND: Surgery is a curative treatment for gastric cancer (GC). As relapse is frequent, adjuvant therapies such as postoperative chemo radiotherapy have been tried. In Chile, some hospitals adopted Macdonald's study as a protocol for the treatment of GC. AIM: To determine methodological quality and internal and external validity of the Macdonald study. MATERIAL AND METHOD: Three instruments were applied that assess methodological quality. A critical appraisal was done and the internal and external validity of the methodological quality was analyzed with two scales: MINCIR (Methodology and Research in Surgery), valid for therapy studies and CONSORT (Consolidated Standards of Reporting Trials), valid for randomized controlled trials (RCT). Guides and scales were applied by 5 researchers with training in clinical epidemiology. RESULTS: The reader's guide verified that the Macdonald study was not directed to answer a clearly defined question. There was random assignment, but the method used is not described and the patients were not considered until the end of the study (36% of the group with surgery plus chemo radiotherapy did not complete treatment). MINCIR scale confirmed a multicentric RCT, not blinded, with an unclear randomized sequence, erroneous sample size estimation, vague objectives and no exclusion criteria. CONSORT system proved the lack of working hypothesis and specific objectives as well as an absence of exclusion criteria and identification of the primary variable, an imprecise estimation of sample size, ambiguities in the randomization process, no blinding, an absence of statistical adjustment and the omission of a subgroup analysis. CONCLUSION: The instruments applied demonstrated methodological shortcomings that compromise the internal and external validity of the.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2006

Gallbladder cancer: an analysis of a series of 139 patients with invasion restricted to the subserosal layer.

The goal was to study our experience in the management of a series of patients with a potentially curative subserosal gallbladder cancer who were prospectively treated by the authors. Between April 1988 and July 2004, 139 patients were enrolled in our prospective database. Of the above, 120 were operated on with an open procedure and the rest with laparoscopic surgery. In only eight patients was the diagnosis suspected before the cholecystectomy. The majority of tumors were adenocarcinoma. Six patients had an epidermoid tumor, and one had a carcinosarcoma. Of the patients, 74 underwent reoperation, while in 55 (70.2%) it was possible to perform an extended cholecystectomy with a curative aim. Operative mortality was 0%, and operative morbidity was 16%. Lymph node metastases were found in 10 (18.8%), while in 7 (13.2%) the liver was involved. The overall survival rate was 67.7%, while in those who underwent resection, the survival rate was 77%. Through the use of a multivariate analysis, the presence of lymph node metastasis was found to be an independent factor with respect to prognosis. The feasibility of performing an extended cholecystectomy in patients with gallbladder cancer and invasion of the subserosal layer allows for a good survival rate. The presence of lymph node metastases represents the main poor prognosis factor, and some type of adjuvant therapy should be studied in this particular group.

Adenocarcinoma↗

PubMed2004

Rapamycin-eluting stents for the treatment of unprotected left main coronary disease.

BACKGROUND: Conventional bare stents have been used to treat unprotected left main (LM) coronary artery stenosis. However, restenosis remains the main limitation. Since rapamycin-eluting stents (RES) appear to inhibit neointimal proliferation, their application to this specific site seems promising. METHODS: Since May 2002, we have studied a series of 52 patients with LM lesions treated with RES. Forty-seven patients presented with de novo stenoses, and 5 had in-stent restenosis; 19 patients required combined stent treatment for other remote lesions in the coronary tree, 6 of them at the level of proximal right coronary artery. The RES was implanted directly at the LM in 39 patients; 13 others needed predilation. Once deployed, the RES was overexpanded with short balloons adjusted to the LM length in 44 patients. Quantitative coronary angiograms were analyzed in the same view before and immediately after treatment and at follow-up. Patients were followed-up closely and new cardiac catheterization was scheduled at 6-month evaluation or earlier in the presence of symptoms. At follow-up study, quantitative coronary angiography and motorized intravascular ultrasound analyses were performed in 35 (67%) patients. RESULTS: Primary success was obtained in 50 patients (96%). Two patients (4%) developed a non-Q-wave myocardial infarction. All patients were symptom-free at discharge. After a mean follow-up of 12 +/- 4 months, 50 patients (96%) remain asymptomatic. No late death or acute thrombosis have been recorded. Two patients became symptomatic 2 and 4 months after treatment, respectively. One had restenosis at a remote site, while the other had in-segment restenosis. None of the remaining 33 angiographically evaluated patients developed restenosis at any site. Target lesion revascularization was 1/52 (2%). CONCLUSIONS: Although longer-term follow-up studies are needed, the tailored treatment of coronary lesions located at the LM by overexpanded RES is feasible and safe. Midterm results seem promising, which might help to shift the orientation of patient management from surgical to percutaneous revascularization.

Angioplasty, Balloon, Coronary↗

PubMed2004

Rapamycin-eluting stents for the treatment of bifurcated coronary lesions: a randomized comparison of a simple versus complex strategy.

BACKGROUND: Rapamycin-eluting stents (RES) have been shown to reduce restenosis in many types of lesions. However, the ideal strategy for the treatment of coronary bifurcated lesions has not been established to date. This randomized study compares 2 strategies for the RES treatment of bifurcation lesions: a simple approach (stenting the main vessel and balloon dilatation for the side branch [SB]) versus a complex approach (stents for both vessels). METHODS: To compare both strategies, a randomized study was conducted in 91 patients with true coronary bifurcation lesions. All patients received an RES at the main vessel, covering the SB. Patients from group A (n = 47) were assigned to balloon dilation of the involved SB (simple strategy); patients in group B (n = 44) were randomized to receive a second stent at the SB origin (complex strategy). There were no differences between groups regarding baseline clinical and angiographic data. RESULTS: Major adverse cardiac events occurred in 3 patients from group A (2 non-Q-wave myocardial infarctions and 1 target lesion revascularization). Six-month angiographic reevaluation was obtained in 80 patients (88%). Restenosis of the main vessel was observed in 1 (2%) patient from group A and in 4 (10%) from group B. Restenosis of the SB appeared in 2 (5%) patients from group A and in 6 (15%) from group B. CONCLUSIONS: Both strategies are effective in reducing the restenosis rate, with no differences in terms of clinical outcome. Elective SB stenting seems to provide no advantages over the simpler stent jail followed by SB balloon dilation.

Angioplasty, Balloon, Coronary↗

PubMed2004

[Neoadjuvant chemoradiotherapy in gallbladder cancer].

BACKGROUND: Gallbladder cancer is generally associated with a poor prognosis, being local recurrence the main pattern of failure. AIM: To evaluate neoadjuvant chemoradiation as a means to improve the prognosis in gallbladder cancer. PATIENTS AND METHODS: Twenty three gallbladder cancer patients were prospectively treated between June 1993 and September 1999 in the Temuco Regional Hospital. Eighteen (82%) patients had subserosal infiltration, while three (13%) had serosal and two (9%) adipose tissue infiltration. Chemotherapy was done with 5-fluorouracil in continuous infusion during 5 days at day 1 and 28 of treatment. Radiotherapy consisted in a total dose of 4500 cGy, divided in 25 sessions. Patients' survival was compared with a series of 19 patients not subjected to chemoradiation, formerly treated at the institution. RESULTS: Twenty patients had hematological problems secondary to the therapy. Leucopenia and thrombocytopenia were the most common toxic effects and eight had leucopenia under 2.0 x 10(3) during the treatment course. Chemoradiation delayed surgical treatment in eight patients. After the chemoradiation protocol, seven patients were excluded from surgical treatment and 14 patients underwent resection. Three of the latter (11%) had liver involvement and four (14%) had lymph node involvement. Among the patients who underwent resection, five are still alive with a follow up of 43.8 months. Treated patients had a worst actuarial survival than subjects not treated with chemoradiation. CONCLUSIONS: In this series of patients chemoradiation had no positive effect and a potentially detrimental effect in patients with gallbladder cancer.

Adult↗

PubMed2004

[Management of gallbladder cancer with invasion of the muscular layer].

BACKGROUND: Gallbladder cancer is the leading cause of death of cancer among women in Chile. Detection of early forms of the disease during the pathological study of the cholecystectomy specimen is common. The management of these cases, specially those with invasion of the muscular layer is under discussion. AIM: To analyze the clinical features of patients with gallbladder cancer and muscular layer invasion and their prognosis after a simple cholecystectomy. PATIENTS AND METHODS: We studied a series of 46 patients with gallbladder cancer and invasion of the muscular layer. In the majority of cases diagnosis was performed at the moment of specimen study. Eleven patients underwent reoperation. Of these, ten underwent lymphadenectomy and liver resection while one patient underwent resection of the cystic duct stump. RESULTS: During follow up, five patients died as a consequence of gallbladder cancer. Overall survival was 78%, with no differences between patients subjected or not a new operation. CONCLUSIONS: Gallbladder cancer with muscular infiltration has a good prognosis, independent of the type of therapy.

Adult↗

PubMed2004

[Pancreatic neuroendocrine tumors].

All pancreatic neuroendocrine tumors derive from Langerhans islet cells and have a low incidence. Half of them are functioning tumors that produce diverse hormones and occasionally cause serious clinical endocrine syndromes. They may be malignant, but they have a better survival, if compared to pancreatic ductal adenocarcinoma. Insulinoma, gastrinoma, glucagonoma, VIPoma (VIP=vasoactive intestinal peptide), somatostatinoma and ACTHoma are functioning tumors and they may also be part of Multiple Endocrine Neoplasia type I (MEN 1) syndrome and of von Hippel-Lindau disease. Diagnosis of non-functioning tumors is usually late, when they reach a big size and have even developed nodal and hepatic metastases. Nowadays, there are effective medical treatments for the medical problems secondary to excessive hormone production. For example, the hypergastrinemia typical of the Zollinger-Ellison syndrome in gastrinoma, can be adequately managed. Surgical resection is the most advisable therapy for pancreatic endocrine tumors, especially when they are small, when long time survival is better. Pre and intra operative imagenology is a great aid to locate these tumors. There are several surgical alternatives, according to the tumor size and location within the pancreas. Furthermore, palliative therapy can be used in disseminated disease. Treatment success is the result of a multidisciplinary medical team work of endocrinologists, surgeons, gastroenterologists, pathologists and geneticists.

Gastrinoma↗

PubMed2003

[Frequency of abdominal aortic aneurysms in adult population with known risk factors].

BACKGROUND: The incidence of abdominal aortic aneurysms has increased. Its predisposing factors are smoking, high blood pressure and dislipidemia. Progressive aneurysmal enlargement may lead to its rupture, which is associated to a mortality rate above 80%. AIM: To assess the prevalence of abdominal aortic aneurysms in Chilean subjects with cardiovascular risk factors. SUBJECTS AND METHODS: Through announcements in open media we invited individuals aged over 60 years, who smoked, had hypertension and/or had occlusive arterial disease, to participate in a study that included medical history and physical examination. An aortic ultrasound was performed in all subjects in whom the aorta was not palpable or there was a suspicion of dilatation. Aortic diameter over 3 cm was considered aneurysmal. RESULTS: Three hundred fifty six subjects aged 67.1 +/- 6.7 years, (73.9% males), were evaluated. The study group included 62% hypertensives, 39% with abnormal lipids and 46% smokers. Known coronary heart disease or peripheral arterial diseases were present in 14% and 10%, respectively. Ultrasound was required in 159 subjects. Aneurysms were detected in 21 persons (5.9%), 7.6% in males and 1.1% in females. The mean transverse diameter of the aneurysm was 4.1 cm (3-7.5). Aneurysm was found in 2.3% of subjects younger than 65 years and 8.3% of subjects aged over 65 years. CONCLUSIONS: In this sample the prevalence of abdominal aortic aneurysms was 5.9%, affecting predominantly males, with a notorious increase with advanced age.

Age Distribution↗

PubMed2002

[Morphological prognostic elements in gallbladder cancer].

BACKGROUND: The exact survival rates and prognostic factors of gallbladder cancer are still incompletely known. AIM: To report the actuarial survival of patients with gallbladder cancer. MATERIAL AND METHODS: Six hundred thirty seven women, aged 59 years old as a mean and 108 men, aged 64 years old as a mean, with gallbladder cancer are reported. Patients were followed for up to 150 months. RESULTS: Two hundred twenty four patients had an early and 521 had an advanced carcinoma. Overall survival was 38% at ten years. Sex or ethnic origin did not influence survival. Early tumors had a 92% survival at 10 years whereas the survival of advanced tumors was 16% at 5 years. Subserous tumors had a 5 years survival of 32% whereas serous tumors had a 5 years survival of 11%. Well-differentiated advanced tumors had a significantly better survival than moderately or poorly differentiated tumors. Vascular or lymphatic infiltration was also associated to a lower survival. All patients with advanced tumors and vascular infiltration died before 5 years. CONCLUSIONS: Tumor infiltration and differentiation degree were the most important prognostic independent factors in gallbladder cancer.

Adenocarcinoma↗

PubMed2002

[Mesenteric acute ischemia caused by spontaneous and isolated dissection of the superior mesenteric artery].

Spontaneous dissection of the superior mesenteric artery is an unusual cause of mesenteric ischemia. Diagnosis can be based on findings of the belicoidal computed tomography or selective angiography of the superior mesenteric artery. We report two male patients, aged 47 and 50 years, who were admitted for abdominal pain. Isolated superior mesenteric artery dissection was confirmed by angiography. Both patients were treated with anticoagulation, conservative measures and recovered uneventfully.

Acute Disease↗

PubMed2002

[Is gallbladder cancer a disease with bad prognosis?].

Gallbladder cancer is frequent in Chile, but it is not uniformly mortal. The diagnosis is usually made after a cholecystectomy, indicated for a symptomatic cholelithiasis. Global survival of gallbladder cancer can be as high as 40% at five years. In 69% of women of less than 30 years old, the tumor is detected in early stages. In these cases, cholecystectomy is the curative procedure, with a 90% survival at five years. According to our experience, cholecystectomies should be performed between 40 and 50 years of age in men and between 30 and 40 years in women. The prognostic factors that should be considered are symptoms associated to lithiasis, age, parity, obesity, size of stones and the size of the gallbladder. If the tumor is detected in early stages, the survival is good. The natural history of the disease would change significantly if all women with symptomatic stones were operated.

Adult↗