Biomedical subjects

Mark J Krasna

Publications and source records attributed to Mark J Krasna.

27 records · Page 2Linked to original sources

PubMed2003

Operative techniques for lung volume reduction surgery.

Recently, LVRS has received renewed public interest. Various surgical approaches and techniques exist, and each has challenges, advantages, and disadvantages. Stapled techniques have been used more commonly than plication techniques or lasers. The choice of staple buttressing material has not been shown to affect outcome. For most patients who are suitable for LVRS, a bilateral procedure is appropriate. Minimally invasive techniques are gaining in popularity and have demonstrated good results. Of the approaches discussed above, bilateral thoracoscopy in the supine position is likely to be the most expeditious with the lowest incision-related morbidity and dysfunction.

Humans↗

PubMed2003

Thoracoscopic approach for spine deformities.

BACKGROUND: We reviewed our experience using anterior thoracoscopic procedures in the correction of severe idiopathic scoliosis and kyphotic deformities to evaluate the feasibility and effectiveness of such procedures. STUDY DESIGN: Twenty-four patients who underwent thoracoscopic surgical correction of the spine between March 1995 and December 2001 were retrospectively reviewed. A team consisting of one orthopaedic surgeon and one thoracic surgeon performed anterior thoracoscopic soft tissue release, disc excision, and bone grafting followed on the same day with posterior instrumentation and correction of deformity. RESULTS: There were 16 female and 8 male patients, with a median age of 16 years (range 11 to 47 years) with idiopathic scoliosis (20 patients) or kyphotic deformity (4 patients). The average time for the thoracoscopy was 125 minutes (range 60 to 175 minutes). Blood loss averaged 135 mL (range 20 to 350 mL), and a median number of five discs (range two to eight) were excised. The median ICU time was 2 days (range 1 to 8 days), and the median length of hospital stay was 6 days (range 4 to 11 days). One patient required conversion to an open procedure because of arterial bleeding from the cancellous bone (T5). Postoperative complications occurred in four patients (atelectasis, pneumothorax, pneumonia, and wound infection in one patient each). All patients had an uneventful hospital course after treatment. CONCLUSIONS: Thoracoscopic anterior procedures can be used safely and effectively in the treatment of idiopathic scoliosis and kyphotic deformity. This minimally invasive approach might decrease procedure-related trauma, operative time, blood loss, and length of hospitalization and may also alleviate postthoracotomy pain.

Adolescent↗

PubMed2003

Bleomycin-induced chromosome breaks as a risk marker for lung cancer: a case-control study with population and hospital controls.

Environmental exposure to carcinogens and individual susceptibility play significant roles in cancer risk. Suboptimal DNA repair capability, measured by quantifying mutagen-induced chromosome breaks, might explain variable host susceptibility to environmental carcinogens. In an ongoing lung cancer case-control study, we compared individual sensitivity to bleomycin-induced chromosome breaks in 152 non-small cell lung cancer patients with 94 population controls and 85 hospital controls with no history of cancer. Mutagen sensitivity was measured by mean number of chromatid breaks per cell in cultured peripheral blood lymphocytes treated with bleomycin. Non-parametric tests and chi(2) tests were used to determine the statistical significance of the crude case-control comparisons, followed by logistic regression to adjust for important covariates. The mean number of bleomycin-induced breaks per cell was 1.01 for the cases compared with 0.86 for hospital controls (P < 0.01) and 0.89 for population controls (P < 0.01). The mean number of breaks per cell was 1.01 for those >65 years old and 0.81 for those < or = 65 years old (P < 0.01) among population controls. Defining bleomycin sensitive as >0.84 break/cell (the median level in population controls), 67% of the cases were bleomycin sensitive compared with 49% of the hospital controls [adjusted odds ratio (OR) = 2.69, 95% confidence interval (CI) = 1.44, 5.04], and 51% of the population controls (adjusted OR = 2.18, 95% CI = 1.13, 4.21). Our data indicate that the increased number of bleomycin-induced chromosome breaks was significantly associated with an increased risk of lung cancer in the first 331 subjects.

Aged↗

PubMed2002

Artificial neural networks and gene filtering distinguish between global gene expression profiles of Barrett's esophagus and esophageal cancer.

cDNAmicroarrays, combined with bioinformatics analyses, are becomingincreasingly used in current medical research. Existing analytic methods,particularly those that are unsupervised, often have difficulty recognizing subtle differences among predefined subgroups. In contrast, supervised methods, such as Artificial Neural Networks (ANNs), are able to recognize subtly different biological entities. We applied ANNs in a proof-of-principle study of cDNA microarray data in esophageal cancer (CA) and premalignancy. cDNA microarrays, each containing 8064 clones, were hybridized to RNAs from 22 esophageal lesions, including 14 Barrett's esophagus (BA) metaplasias and 8 esophageal carcinomas (3 squamous cell carcinomas and 5 adenocarcinomas). Scanned cDNA microarray data were analyzed using the bioinformatics software Cluster/TreeView, Significance Analysis of Microarrays (SAM), and ANNs. Cluster analysis based on all 8064 clones on the microarrays was unable to correctly distinguish BA specimens from CA specimens. SAM then selected 160 differentially expressed genes between Barrett's and cancer. Cluster analysis based on this reduced set still misclassified 2 Barrett's as cancers. The ANN was trained on 12 samples and tested against the remaining 10 samples. Using the 160 selected genes, the ANN correctly diagnosed all 10 samples in the test set. Finally, the 160 genes selected by SAM may merit further study as biomarkers of neoplastic progression in the esophagus, as well as in elucidating pathological mechanisms underlying BA and CA.

Adenocarcinoma↗

PubMed2002

Clinical significance of micrometastasis in lung and esophageal cancer: a new paradigm in thoracic oncology.

In the past decade, detection of micrometastatic disease in different clinical samples including pleural lavage, lymph node, bone marrow, and blood has become a rapidly growing area of interest in research of non-small cell lung cancer and esophageal cancer. The results of these studies support the concept that, just as in many other solid malignancies, systemic spread may happen at an early stage in non-small cell lung cancer and esophageal cancer. Such systemic spread is often occult (micrometastases) at the time of primary diagnosis, which may have adverse effects on survival. Improved staging can be expected with information on micrometastases, and a subgroup of patients who will benefit most from adjuvant therapy might be identified. Although reliable and standard methods need to be developed before detection of micrometastasis is incorporated in the routine clinical practice, we suggest that it be considered an important correlate in clinical trials in non-small cell lung cancer and esophageal cancer.

Bone Marrow Neoplasms↗

PubMed2002

Thoracoscopic and laparoscopic lymph node staging in esophageal cancer: do clinicopathological factors affect the outcome?

BACKGROUND: This study was performed to evaluate the pattern of lymphatic metastases found by combined thoracoscopic (TS) and laparoscopic (LS) lymph node staging in esophageal cancer, and ascertain whether clinicopathologic factors may be used to guide the clinical practice of combined TS and LS staging. METHODS: A retrospective study was performed in a series of 76 esophageal cancer patients who had undergone both TS and LS staging before treatment. The correlation of TS and LS lymph node metastases with clinicopathologic factors was analyzed, including the clinical T stage, clinical N stage, tumor location, and histology. RESULTS: Thirty-one patients (40.8%) were found to have lymphatic metastasis by TS and LS staging. Among them, 22 patients had abdominal lymph node metastases, 7 patients had mediastinal lymph node metastases, and 2 patients had both. Patients with advanced T stage (T3 to T4) or adenocarcinoma had a higher frequency of abdominal lymphatic metastases than patients with early T stage (T1 to T2) (39% vs 16%; p = 0.04) or squamous cell carcinoma (39% vs 20%; p = 0.079), respectively. Patients with clinical abdominal N1 stage had a higher incidence of positive laparoscopic finding than patients with clinical abdominal N0 stage (67% vs 23%; p = 0.001). There was no significant correlation between lymphatic metastases and the location of the primary tumor. CONCLUSIONS: Clinicopathologic factors, including the histologic type, the clinical T stage, and abdominal N stage, may affect the outcome of TS and LS lymph node staging in esophageal cancer patients. This clinicopathologic impact may play a role for the selection of candidates for TS and LS staging, and also allows surgeons to focus their attention on the most likely high-yield biopsy targets.

Adult↗

PubMed2002

An analysis of multiple staging management strategies for carcinoma of the esophagus: computed tomography, endoscopic ultrasound, positron emission tomography, and thoracoscopy/laparoscopy.

BACKGROUND: This study compares the health care costs and effectiveness of multiple staging options for patients with esophageal cancer. Techniques studied included computed tomographic (CT) scan, endoscopic ultrasound with fine-needle aspiration biopsy (EUS-FNA), positron emission tomography (PET), thoracoscopy/laparoscopy, and combinations of these. METHODS: A decision-analysis model was constructed to compare different staging strategies. Costs were derived from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases and from other Medicare reimbursement rates. Life expectancies were obtained from the 1973-1996 SEER database and adjusted for quality of life. Cost and effectiveness measures were discounted at 0% and 3% per year. Sensitivity and specificity measures were obtained from the published literature and a parallel prospective clinical trial, and all key variables were subjected to sensitivity analyses. RESULTS: Under baseline assumptions, CT + EUS-FNA was the most inexpensive strategy and offered more quality-adjusted life-years, on average, than all other strategies with the exception of PET + EUS-FNA. The latter was slightly more effective but also more expensive. The marginal cost-effectiveness ratio for PET + EUS-FNA was $60,544 per quality-adjusted life-year. These findings were robust and changed very little in all of the sensitivity analyses. CONCLUSIONS: The combination of PET + EUS-FNA should be the recommended staging procedure for patients with esophageal cancer, unless resources are scarce or PET is unavailable. In these instances, CT + EUS-FNA can be considered the preferred strategy.

Biopsy, Needle↗

PubMed2002

Multimodality therapy for esophageal cancer.

Esophageal cancer is undergoing a major shift in its epidemiology. Its incidence is dramatically growing and it more commonly affects younger and healthier patients. Based on the published data, there is no strong evidence to recommend routine preoperative chemotherapy for the treatment of surgically resectable esophageal carcinoma. It might be that a large-scale randomized study-which will be published in the near future-will shed some different light on this subject. The role of preoperative CRT remains undetermined. To settle this issue, larger, clinical, controlled trials are needed. Improvement in the preoperative regimen and use of new drugs should be evaluated. Concomitant CRT should be considered for potential benefit in survival and local control in patients who have localized disease and are candidates for radical non-surgical treatment. Patients with pCR following neoadjuvant therapy have a consistent, substantial survival benefit. Biologic markers can be used to predict response to therapy and might allow designation of treatment based on the individual tumor. Pretreatment staging is necessary for standardization of patients undergoing treatment protocols and for outcome evaluation. Pretreatment staging will be even more important in the future for adjusting treatment to individual patient. Video-assisted thoracoscopy and laparoscopy have been found to be the most accurate lymph node staging techniques.

Chemotherapy, Adjuvant↗

PubMed2002

Thoracoscopy/laparoscopy in the staging of esophageal cancer: Maryland experience.

Precise clinical staging of esophageal cancer before treatment is important. Thoracoscopic/laparoscopic (Ts/Ls) staging has been proposed as a promising staging method. This study was conducted to evaluate the potential benefits of Ts/Ls staging over conventional noninvasive clinical staging in patients with esophageal cancer. From 1991 to 1999, 111 patients with esophageal cancer underwent Ts/Ls staging by the University of Maryland Medical System. Pretreatment staging workup included computed tomography, magnetic resonance imaging, and esophageal ultrasonography, followed by Ts/Ls surgical staging. Thoracoscopy was successfully performed in 102 patients and was aborted in 4 patients because of pleural adhesions. Laparoscopy was successfully done in 76 patients and was aborted in 1 patient because of peritoneal adhesion. Sixty-seven patients had both Ts and Ls staging, whereas 35 patients and 9 patients, respectively, had only Ts or Ls staging. Thirteen of 19 patients with clinical T4 disease were downstaged to T3 disease, and 8 patients with clinical T3 disease were upstaged to T4 by Ts/Ls staging. No clinical T1-2 disease was found to be associated with local invasion (T4) by Ts/Ls. Forty-eight and 19 patients had mediastinal and celiac lymph node metastases clinically diagnosed, respectively. Nine (18.8%) and 12 (63.2%) of them were proved by Ts and Ls, respectively. An additional 5 and 16 patients were found to have unexpected mediastinal and celiac lymph node metastases, respectively, by Ts/Ls. Biopsy specimens of pleura, lung, or liver were obtained by Ts/Ls procedures in 17 patients because of suspicious findings of routine imaging studies or unexpected findings during the staging operation. Five patients were found to have distant metastasis, and the presence of metastases in others was excluded. The correlation between Ts/Ls staging and conventional noninvasive clinical staging in the diagnosis of T4 disease, mediastinal lymph node metastasis, celiac lymph node metastasis, and M1 disease was 18.8%, 14.5%, 25.5%, and 20.0%, respectively. Ts/Ls provides more accurate information for evaluating local invasion, lymph node metastasis, and distant metastasis. The poor correlation of staging diagnosis between Ts/Ls and conventional noninvasive clinical examinations suggests that the accuracy of current noninvasive clinical staging is questionable and needs to be improved.

Adenocarcinoma↗