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Biomedical subjects

A M Cohen

Publications and source records attributed to A M Cohen.

At least 37 records · Page 2Linked to original sources

Influence of hospital procedure volume on outcomes following surgery for colon cancer.

CONTEXT: Survival following high-risk cancer surgery, such as pancreatectomy and esophagectomy, is superior at hospitals where high volumes of these procedures are performed. Conflicting evidence exists as to whether the association between hospital experience and favorable health outcomes also applies to more frequently performed operations, such as those for colon cancer. OBJECTIVE: To determine whether hospital procedure volume predicts survival following colon cancer surgery. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of data from the Surveillance, Epidemiology and End Results-Medicare linked database on 27 986 colon cancer patients aged 65 years and older who had surgical resection for primary adenocarcinoma diagnosed between 1991 and 1996. MAIN OUTCOME MEASURES: Thirty-day postoperative mortality and overall and cancer-specific long-term survival, by hospital procedure volume. RESULTS: We found small differences in 30-day postoperative mortality for patients treated at low- vs high-volume hospitals (3. 5% at hospitals in the top-volume quartile vs 5.5% at hospitals in the bottom-volume quartile). However, the correlation was statistically significant and persisted after adjusting for age at diagnosis, sex, race, cancer stage, comorbid illness, socioeconomic status, and acuity of hospitalization (P<.001). The association was evident for subgroups with stage I, II, and III disease. Hospital volume directly correlated with survival beyond 30 days and also was not attributable to differences in case mix (P<.001). The association between hospital volume and long-term survival was concentrated among patients with stage II and III disease (P<.001 for both). Among stage III patients, variation in use of adjuvant chemotherapy did not explain this finding. CONCLUSION: Our data suggest that hospital procedure volume predicts clinical outcomes following surgery for colon cancer, although the absolute magnitudes of these differences are modest in comparison with the variation observed for higher-risk cancer surgeries.

Adenocarcinoma↗

Tumor necrosis factor (TNF)-alpha-induced interleukin-8 in human blood cultures discriminates neutralization by the p55 and p75 TNF soluble receptors.

The dose-dependent increase in mortality in patients with sepsis who are treated with tumor necrosis factor (TNF) p75 soluble receptor Fc conjugate (p75-Fc) remains unexplained. In this study, neutralization of TNF-alpha-induced interleukin (IL)-8 by p75-Fc in whole human blood exhibited a U-shaped inhibition curve, whereas the TNF-soluble p55 receptor, linked to polyethylene glycol (p55-PEG), exhibited a dose-dependent inhibition. Native soluble p75 increased TNF-alpha-induced IL-8, versus a 61% reduction by native p55. Spontaneous IL-8 production was increased by p75-Fc or native p75 but not by p55-PEG or native p55. Unexpectedly, TNF-alpha-stimulated IL-1 receptor antagonist was suppressed by p75-Fc but not by p55-PEG. Studies of binding to TNF trimer revealed that p75-Fc has an affinity 40-fold lower than that of p55-PEG and a faster off rate. Native and p75-Fc pass TNF-alpha to membrane receptors more readily than does native or p55-PEG, which may partly explain the increased mortality in patients with sepsis who are treated with p75-Fc.

Antigens, CD↗

High-dose-rate intraoperative brachytherapy for recurrent colorectal cancer.

PURPOSE: Management of locally recurrent colorectal adenocarcinoma represents a significant challenge. Many of these tumors adhere to or invade into vital pelvic structures rendering surgery or external beam radiotherapy (EBRT) as palliative treatment. Therefore, a treatment approach was developed to evaluate the role of high-dose-rate intraoperative brachytherapy (HDR-IORT) and surgery as a component of therapy in the management of locally recurrent colorectal cancer. This is an update of our preliminary report with longer follow-up and larger patient numbers. METHODS AND MATERIALS: Between January 1992 and September 1998, 74 patients with locally recurrent rectal cancer were treated with surgery and HDR-IORT. Additional EBRT was given to 29 patients, and 33 patients received 5-fluorouracil based chemotherapy. All patients underwent complete gross resection, and 21 of 74 had positive microscopic margin. The dose of HDR-IORT ranged from 10 to 18 Gy. RESULTS: With a median follow-up of 22 months, the 5-year local control, distant metastasis disease-free, disease-free, and overall survival rates were 39%, 39%, 23%, and 23%, respectively. The only predictor of improved local control was a negative margin of resection with a 5-year local control rate of 43%, compared to 26% in those with positive margin (p = 0.02). For overall survival, a negative microscopic margin (p = 0.04) and the use of IORT + EBRT (p = 0.04) were significant predictors of improved survival. The incidence of peripheral neuropathy was 16%. CONCLUSION: The results with HDR-IORT in this group of patients are encouraging. Further improvements in local and distant control are still needed.

Adenocarcinoma↗

Toxicity of three oil spill remediation techniques to the Australian bass Macquaria novemaculeata.

Australian bass, Macquaria novemaculeata, were exposed to the water accommodated fraction (WAF) of Bass Strait crude oil, dispersed crude oil, burnt crude oil, and 4-chlorophenol. The WAF of dispersed crude oil was the most toxic treatment with 96-h LC(50) values of 7. 15% (7.94% upper and 6.42% lower 95% CI) and 7.45% (8.26% upper and 6.71% lower 95% CI). The WAF of crude oil was less toxic, with 96-h LC(50) values of 43.72% (49.21% upper and 38.87% lower 95% CI) and 45.87% (51.51% upper and 40.97% lower 95% CI). The WAF of burnt crude oil was the least toxic treatment with 96-h LC(50) values of 49.81% (63.33% upper and 39.44% lower 95% CI) and 47.28% (59.72% upper and 37.62% lower 95% CI). Sublethal toxicity of the crude oil WAF and burnt crude oil WAF was observed at dilutions seven to eight times less than in the dispersed crude oil WAF.

Animals↗

Abdominal wall recurrence after colorectal resection for cancer.

PURPOSE: Disease recurrence in the abdominal wall from a primary colorectal cancer is a poorly studied and little understood phenomenon that has received renewed attention after the recognition of port site metastases in patients after laparoscopic colorectal resections. The purpose of the present study was to define the clinical, pathologic, and management issues in patients with abdominal wall metastases from colorectal cancer. METHODS: Patients presenting to Memorial Sloan-Kettering Cancer Center with a diagnosis of colorectal cancer were entered into a prospective database beginning in 1986. Review of this database showed that 31 patients presenting with recurrent disease in the abdominal wall were managed surgically at the institution between 1986 and 1998. RESULTS: A total of 31 patients (19 males) with a median age of 67 (range, 45-86) years presented with recurrent disease between 7 and 183 (median, 24) months after primary surgery. Primary tumors were located in the right colon in 17 patients, left colon in 2 patients, sigmoid colon in 7 patients, and rectum in 3 patients. Nineteen percent of primary tumors were perforated, 45 percent were poorly differentiated, 92 percent were transmural (T3 or T4), and 51 percent had lymph node metastases at presentation. Twenty-two patients presented with a symptomatic abdominal wall mass, whereas recurrence in the abdominal wall was found incidentally in 9 patients undergoing laparotomy. Four patients had isolated abdominal wall disease, whereas the remaining 27 were found to have associated intra-abdominal disease. Six patients who were left with residual intra-abdominal cancer after abdominal wall resection had a median survival time of four months. Twenty-five patients underwent a histologically complete resection of recurrence restricted to the abdominal wall alone (n = 4; median survival time, 18 months), abdominal wall and in continuity resection of adherent viscera (n = 15; median survival time, 12.5 months), or resection of abdominal wall and intra-abdominal recurrence at a distant site (n = 6; median survival time, 22 months, although only 1 patient remained alive with disease). The actual two-year and five-year disease-free survival rates were 16 and 3 percent, respectively. CONCLUSION: Abdominal wall metastases are often indicators of recurrent intra-abdominal cancer; however, aggressive resection in patients with disease restricted to the abdominal wall and associated adherent viscera can result in local disease control with little morbidity and no mortality.

Abdominal Muscles↗

Favorable short-term and long-term outcome after elective radical rectal cancer resection in patients 75 years of age or older.

PURPOSE: Because the elderly population in Western countries is rapidly increasing, as is their life expectancy, studies aimed at determining the impact of major surgery for primary rectal cancer in this group are warranted. The purpose of this study was to compare perioperative morbidity and mortality and long-term disease-specific and overall survival in primary rectal cancer patients, older and younger than 75 years of age, subject to major pelvic surgery. METHODS: From September 1986 to December 1996, the Prospective Colorectal Service Database identified 1,120 consecutive patients who underwent major pelvic surgery for primary rectal cancer. Of these, 157 (15 percent) were 75 years of age or older and comprise the elderly group. From the remaining 963 patients younger than 75 years of age, a representative random sample of 174 was selected and constitutes the younger group. Data were obtained from computerized databases and confirmed via chart review and telephone interviews. RESULTS: Perioperative complications were observed in 53 (34 percent) elderly and 63 (36 percent; P = not significant) younger patients. Perioperative deaths occurred in two (1.3 percent) elderly and one (0.6 percent; P = not significant) younger patient. The median follow-up time was 48 months. Although the overall survival was lower in the elderly group (P = 0.02; the 5-year overall survival rates were 51 and 66 percent), the disease-specific survival rate was similar in the two groups (P = 0.75; the 5-year disease-specific survival rates were 69 and 71 percent). CONCLUSION: In select individuals 75 years of age or older, major pelvic surgery for primary rectal cancer can be done with perioperative morbidity and mortality rates comparable to those obtained in younger individuals, while achieving excellent disease-specific and overall long-term survival.

Aged↗

Computer-based inpatient medical record in colorectal surgery: pilot study.

PURPOSE: Clinical guidelines and care maps are important tools for improving quality of care and reducing costs. However, problems of quantity, quality, and accessibility of data recorded in the inpatient medical record have not been solved by the implementation of clinical pathways. Variance or "charting by exception" improves legibility, in part. The aim of the present study was to design a computer-based medical record on a database platform to provide legible notes within a clinical guideline and variance charting framework. METHODS: A computerized database program was written, integrating pre-established clinical guidelines into a user-friendly interface according to modification of the charting by exception principles. Patient care guidelines were provided for each postoperative day. After an initial debugging process by entering data from old charts of patients, the software was installed and its function was evaluated on selected patients. The charting time was compared with the standard charting method. Functionality and user friendliness were assessed. RESULTS: After a brief introduction of ten minutes, all users were able to use the software without difficulties. It was found to be functional and user friendly. The charting time was shorter for the computer-based inpatient medical record compared with the charting time of the standard charts. Because all daily notes were printed on standardized forms on a laser printer, legibility was excellent. CONCLUSIONS: The results of this pilot study suggest that the idea of computer-based inpatient medical record integrating an on-line inpatient medical record in a database platform is feasible. Further development and integration with other hospital information systems and the other health-care providers is required.

Colectomy↗

Pancreatic or duodenal resection or both for advanced carcinoma of the right colon: is it justified?

PURPOSE: The role of extended resections for locally advanced carcinomas of the right colon infiltrating duodenum and pancreas remains unclear. This investigation was undertaken to review our experience with pancreatic head or duodenal resections for advanced right-sided colon cancer. METHODS: The clinical, pathologic, and follow-up details of eight patients with bulky primary carcinomas of the right colon infiltrating the duodenum (n = 4) or pancreatic head (n = 4) surgically managed at Memorial Sloan-Kettering Cancer Center between 1986 and 1998 were reviewed. RESULTS: Six patients presented with anemia, and one patient each with epigastric pain and an abdominal mass. All patients had T4 lesions, whereas five had lymph node metastases at presentation. All patients were resected with clear pathologic margins either by right colectomy and en bloc duodenectomy (n = 4), or en bloc pancreaticoduodenectomy (n = 4). The 30-day mortality rate was zero. Six patients remained alive and free of disease at a median follow-up of 26 months, and there was one long-term survivor who was alive and free of disease at 84 months after resection. CONCLUSION: Extended resection for localized primary colonic carcinoma invading pancreas or duodenum can be undertaken safely and is associated with prolonged survival time.

Aged↗

Prospective assessment of primary rectal cancer response to preoperative radiation and chemotherapy using 18-fluorodeoxyglucose positron emission tomography.

PURPOSE: The purpose of this prospective study was to determine the ability of fluorine-18 fluorodeoxyglucose positron emission tomography to assess extent of pathologically confirmed rectal cancer response to preoperative radiation and 5-fluorouracil-based chemotherapy. METHODS: Patients with primary rectal cancer deemed eligible for preoperative radiation and 5-fluorouracil-based chemotherapy because of a clinically bulky or tethered tumor or endorectal ultrasound evidence of T3 and/or N1 were prospectively enrolled. Positron emission tomography and CT scans were obtained before preoperative radiation and 5-fluorouracil-based chemotherapy (5,040 cGy to the pelvis and 2 cycles of bolus 5-fluorouracil with leucovorin) and repeated four to five weeks after completion of radiation and 5-fluorouracil-based chemotherapy. In addition to routine pathologic staging, detailed assessment of rectal cancer response to preoperative radiation and 5-fluorouracil-based chemotherapy was performed independently by two pathologists. Positron emission tomography parameters studied included conventional measures such as standardized uptake value (average and maximum), positron emission tomography-derived tumor volume (size), and two novel parameters: visual response score and change in total lesion glycolysis. RESULTS: Of 21 patients enrolled, prospective data (pretreatment and posttreatment positron emission tomography, and complete pathologic assessment) were available on 15 patients. All 15 demonstrated pathologic response to preoperative radiation and 5-fluorouracil-based chemotherapy. This was confirmed in 100 percent of the cases by positron emission tomography compared with 78 percent (7/9) by CT. In addition, one positron emission tomography parameter (visual response score) accurately estimated the extent of pathologic response in 60 percent (9/15) of cases compared with 22 percent (2/9) of cases with CT. CONCLUSIONS: This pilot study demonstrates that fluorine-18 fluorodeoxyglucose positron emission tomography imaging adds incremental information to the preoperative assessment of patients with rectal cancer. However, further studies in a larger series of patients are needed to verify these findings and to determine the value of fluorine-18 fluorodeoxyglucose positron emission tomography in a preoperative strategy aimed at identifying patients suitable for sphincter-preserving rectal cancer surgery.

Adenocarcinoma, Mucinous↗

Prokinetic effect of erythromycin after colorectal surgery: randomized, placebo-controlled, double-blind study.

PURPOSE: Nausea and vomiting three to seven days after an elective operation on the colon and rectum remain a persistent clinical problem. Erythromycin, a safe, inexpensive drug that stimulates intestinal motilin receptors, has previously been shown to accelerate gastric emptying significantly after upper gastrointestinal surgery. We aimed to evaluate the effect of postoperative intravenous erythromycin on postoperative ileus in patients undergoing elective surgery for primary colorectal cancer. METHODS: Between May 1998 and April 1999, 150 patients undergoing primary resection of colon or rectal cancer were enrolled in this prospective, randomized, placebo-controlled trial. One hundred thirty-four patients completed the study. Patients were excluded if they had extensive metastatic disease, were taking medications known to interact with erythromycin, or if they required an ileostomy. Patients received either 200 mg of intravenous erythromycin or placebo every six hours. Clinical endpoints were recorded and continuous end-points are presented as mean +/- standard deviation. RESULTS: There were no significant complications related to erythromycin. The erythromycin (n = 65) and placebo (n = 69) groups were comparable regarding demographic and operative factors. The erythromycin group had a slightly shorter length of time to passage of flatus (4.1 +/- 1.3 vs. 4.4 +/- 1.1 days; P = 0.03). There was no significant difference between erythromycin and placebo in time to first solid food (5.6 +/- 1.9 vs. 5.4 +/- 1.8 days), time to first bowel movement (5.2 +/- 1.9 vs. 5.4 +/- 1.3 days), or time to discharge from hospital (7.5 +/- 2.0 vs. 7.6 +/- 2.8 days). There was no difference in the rate of clinically significant nausea (26 vs. 26 percent; P = 0.99), vomiting (17 vs. 16 percent; P = 0.88), or nasogastric tube placement (9 vs. 7 percent; P = 0.68). CONCLUSIONS: Erythromycin does not seem to alter clinically important outcomes related to postoperative ileus in patients undergoing resection for colorectal cancer.

Aged↗

Lymph node micrometastases do not predict relapse in stage II colon cancer.

BACKGROUND: Over one third of patients with stage II colonic adenocarcinoma experience tumor recurrence. Because effective adjuvant therapy is now available, it is important to identify subsets of patients at higher risk for relapse who may benefit from early treatment. Immunohistochemistry has been used to detect microscopic metastases in histologically uninvolved mesenteric lymph nodes, but the prognostic significance of minimal nodal involvement has not been established. METHODS: Hematoxylin and eosin (H&E)-stained recuts of 900 mesenteric lymph nodes from 55 patients (range, 2-47; mean, 16.4 nodes per case) with resected pT3 or pT4, N0, M0 (TNM stage II) colonic adenocarcinomas were re-examined for the presence of metastases and then stained immunohistochemically for keratin using the AE1:AE3 antibody. Twenty-seven patients did not experience recurrence of tumor within 5 years following resection (no evidence of disease [NED]); 28 patients relapsed during the same time frame. Lymph nodes from 10 patients having colonic resections for nonneoplastic disorders also were stained as controls. Keratin-positive cells and cell clusters were quantified in the lymph nodes, and comparisons were made between patients with and without tumor relapse. RESULTS: In the relapse group, four patients had positive nodes already identified on the H&E-stained recuts and had to be excluded from further analysis. Sixteen additional patients had keratin-positive cells; thus, 16 of 24 (67%) had micrometastases. In the NED group, one patient had a positive node on H&E staining and 22 additional patients had keratin-positive cells, so 22 of 26 (84%) patients had micrometastases. In the patients who had micrometastases, there was a mean of 3.5 and 4.6 positive nodes in the relapse and NED groups, respectively, and a mean of 11.3 and 12.4 keratin-positive cells or clusters in the relapse and NED groups, respectively. No keratin-positive cells were found in the 1 to 21 (mean, 9.1) nodes per case studied in the control patients. CONCLUSIONS: Micrometastases to histologically uninvolved mesenteric lymph nodes commonly are detected in patients with pT3 or pT4 colonic adenocarcinomas on recuts stained immunohistochemically for keratin. Nodal micrometastases detected by immunohistochemical staining are not useful for identifying stage II patients at higher risk for relapse.

Adenocarcinoma↗

Effect of cardiopulmonary bypass on pulmonary gas exchange: a prospective randomized study.

BACKGROUND: Conventional coronary artery bypass surgery is associated with postoperative pulmonary dysfunction. Inflammation due to cardiopulmonary bypass has been regarded as one of the main causes. In this study, we investigated the effect of coronary revascularization with or without cardiopulmonary bypass on pulmonary function. METHODS: Fifty-two patients (40 male, mean age 60.1 years) were prospectively randomized to undergo coronary revascularization via median sternotomy, with or without normothermic cardiopulmonary bypass. Alveolar-arterial oxygen gradients were measured before and after induction of anesthesia, postoperatively in the intensive care unit during mechanical ventilation and 6 hours after tracheal extubation. The techniques of anesthesia and mechanical ventilation were standardized throughout. RESULTS: Patient characteristics were similar in the two groups. The alveolar-arterial oxygen gradients increased progressively throughout the perioperative period, with no significant differences in the two groups at any time during the study. CONCLUSIONS: Myocardial revascularization with or without cardiopulmonary bypass caused a similar degree of pulmonary dysfunction, as assessed by alveolar-arterial oxygen gradient. Our study suggests that the deterioration in pulmonary gas exchange associated with cardiac surgery is due to factors other than the use of cardiopulmonary bypass.

Body Temperature↗

Management of patient skin dose in fluoroscopically guided interventional procedures.

PURPOSE: To simulate dose to the skin of a large patient for various operational fluoroscopic conditions and to delineate how to adjust operational conditions to maintain skin dose at acceptable levels. MATERIALS AND METHODS: Patient entrance skin dose was estimated from measurement of entrance air kerma (dose to air) to a 280-mm water phantom for two angiographic fluoroscopes. Effects on dose for changes in machine floor kVp, source-to-skin distance, air gap, electronic magnification, fluoroscopic dose rate control settings, and fluorographic dose control settings were examined. RESULTS: Incremental changes in operational parameters are multiplicative and markedly affect total dose delivered to a patient's skin. For long procedures, differences in doses of 8 Gy or more are possible for some combinations of operational techniques. CONCLUSIONS: Effects on skin dose from changes in operational parameters are multiplicative, not additive. Doses in excess of known thresholds for injury can be exceeded under some operating conditions. Adjusting operational parameters appropriately will markedly reduce dose to a patient's skin. Above all other operational factors, variable pulsed fluoroscopy has the greatest potential for maintaining radiation exposure at low levels.

Angiography↗

Reduced cerebral embolic signals in beating heart coronary surgery detected by transcranial Doppler ultrasound.

Cerebral emboli detected by transcranial Doppler imaging were recorded in 20 patients undergoing multiple-vessel coronary artery bypass surgery, either with or without cardiopulmonary bypass, in a prospective unblinded comparative study. Emboli were recorded continuously from the time of pericardial incision until 10 min after the last aortic instrumentation. The numbers of coronary grafts and of aortic clampings were also documented. Patients undergoing revascularization with cardiopulmonary bypass had more emboli (median 79, range 38-876) per case compared with patients having off-pump surgery (median 3, range 0-18). No clinically detectable neurological deficits were seen in either group. Beating heart surgery is associated with fewer emboli than coronary surgery with cardiopulmonary bypass. Further research is necessary to determine whether a smaller number of emboli alters the incidence of neurological deficit after cardiac surgery.

Aged↗