Biomedical subjects

Jordan M Winter

Publications and source records attributed to Jordan M Winter.

12 recordsLinked to original sources

PubMed2006

Genomic copy number changes affecting the thymidylate synthase (TYMS) gene in cancer: a model for patient classification to aid fluoropyrimidine therapy.

Thymidylate synthase (TS) is an important target for 5-fluorouracil (5FU)-based therapy. The TS polymorphic 5'-untranslated region tandem repeat sequence is under investigation to guide 5FU treatment, yet current protocols omit consideration of copy number changes at the TS locus. We surveyed the TS tandem repeat sequence and found copy number changes in gastrointestinal cancers. Ten of 12 informative cases had loss of heterozygosity (LOH), whereas two others and an additional cell line had a novel TS genotype, allelic imbalance at the TS locus due to polysomy. Experimentally, we studied a diploid colorectal cancer line heterozygous at TS to mimic three common TS genotypes of cancers. Using genetic engineering, we deleted the short tandem repeat (two repeats) allele and retained the long (three repeats) allele to produce artificial LOH at the TS gene; the TS(+/-) line had a reduced TS protein expression and was hypersensitive to 5FU and 5-fluoro-2'-deoxyuridine in vitro as compared with syngeneic control lines. We linked this sensitivity directly to the reduced TS expression by introducing exogenous TS cDNA expression into the TS(+/-) line (i.e., increased TS copies). Our model predicts that the 5FU sensitivity of a tumor is modified by aneuploidy producing copy number changes of TS alleles by one or more of the following: LOH, amplification, and, as presented here, copy number changes due to polysomy. The data suggest that TS copy number in a patient's tumor may be a dominating variable affecting 5FU responsiveness.

5' Untranslated Regions↗

PubMed2006

Resected periampullary adenocarcinoma: 5-year survivors and their 6- to 10-year follow-up.

BACKGROUND: Many studies have reported 5-year survival data after pancreaticoduodenectomy for periampullary adenocarcinoma. This study evaluates 10-year survival in patients surviving 5 years after initial surgery. METHODS: We reviewed all patients undergoing pancreaticoduodenectomy for periampullary adenocarcinoma from April 1970 to July 1999 at a single institution. All 5-year survivors were identified, and their subsequent 5-year survival was compared with the actuarial survival of the general population starting at 70 years of age. RESULTS: Nine hundred fifteen patients underwent pancreaticoduodenectomy for periampullary adenocarcinoma. Follow-up was complete on 890 patients. There were 201 (23%) 5-year survivors with a median age of 65 years at initial surgery; 51% were male and 92% were Caucasian. For the 5-year survivors, the carcinoma origin was pancreatic in 46%, ampullary in 25%, distal bile duct in 17%, and duodenal in 12%. For all 5-year survivors, the subsequent 5-year actuarial survival rate was 65%, with a median survival after achieving the 5-year landmark of 7.9 additional years. The subsequent 5-year survival by site of tumor origin was 55% for pancreatic, 66% for ampullary, 74% for bile duct, and 85% for duodenal cancer. For the age-matched population, the 5-year survival rate was 87% (P<.001 when compared with those with all periampullary cancers). CONCLUSIONS: While the 5-year survival rate for all patients with resected periampullary adenocarcinoma is only 23%, these data imply that attainment of the 5-year survival landmark carries with it an improved survival for the subsequent 5 years. While the survival rate was less than that of the age-matched population, 65% of 5-year survivors survived 5 more years, bringing them to the 10-year postresection landmark.

Adenocarcinoma↗

PubMed2006

Elegance, silence and nonsense in the mutations literature for solid tumors.

A third of highly cited clinical studies are subsequently contradicted, and there are statistical reasons for why many published research findings may be false. The subjective impression of many experts in cancer genetics is that much of the tumor mutation literature may also be erroneous or deeply flawed. For example, there exist many reports of false somatic mutations attributable entirely to the choice of analytic method. This pattern of mis-reporting may divert the investment of limiting resources for cancer research into fundamentally flawed directions. We provide here a review of the basic theoretic principles and observed patterns within the literature of solid tumors and inherited tumor-susceptibility syndromes. These patterns provide support for a systematic approach to the critical analysis of the somatic mutation literature offered in the accompanying paper.

Animals↗

PubMed2006

Multiple-criterion evaluation of reported mutations: a proposed scoring system for the intragenic somatic mutation literature.

In an accompanying paper, we review the theoretical principles of tumor mutations and the observed patterns of mutations in the cancer literature. These patterns are discussed in the context of a perceived dichotomy in quality that exists among mutation reports. Due to the frequency of mis-reporting, a systematic approach to the somatic mutation literature in human cancer is needed. We propose a multiple-criterion numerical tool, referred to as the scoring SISTM (System for Intragenic Somatic Tumor Mutations), which effectively discriminates promising and unpromising somatic mutation reports in human cancer. Reports are assessed on 12 criteria, and are given a final score of 15 or less. Scores in the range of 10 to 15 are suggestive of well-presented reports of disease-inducing somatic mutations. Reports with scores less than 10 should be viewed with skepticism.

Biomarkers, Tumor↗

PubMed2006

Pancreaticoduodenectomy in the very elderly.

It is estimated that by 2050, there will be a 300% increase in the elderly population (> or =65 years) and a corresponding increase in elderly patients presenting for surgical evaluation. Surgical decision-making in this population can be difficult because outcomes in the elderly are poorly defined. We reviewed 2698 consecutive pancreaticoduodenectomies (PDs) at our institution over a 35-year period (April 1970 through March 2005), with the last 1000 resections being done in the last 4 years. Data collected included surgical indication, mortality (defined as 30-day or in-hospital mortality), complications, and survival. Patients were divided by age into three groups (<80, 80-89, and > or =90 years) and evaluated using multiple logistic regression. Two hundred seven patients > or =80 years old underwent a PD (7.7% of 2698). Patients 80-89 years of age had a mortality rate of 4.1% (8 of 197) and a complication rate of 52.8% (99 of 197), whereas patients < or =79 years of age had a mortality of 1.7% and a complication rate of 41.6% (P < 0.05). There were no perioperative deaths among the 10 patients > or =90 years of age, and their complication rate was 50% (5 of 10). One-year survival for patients 80-89 years of age was 59.1%, and that for patients > or =90 years was 60%. Age was not an independent risk factor for perioperative mortality and morbidity following PD after adjusting for preoperative comorbidities. We demonstrate that PD can be safely performed in patients over 80 years of age and conclude that age alone should not be a contraindication to pancreatic resection. The advent of improved surgical outcomes and an aging population will likely result in a significant increase in the number of PDs performed in the next few decades.

Age Factors↗

PubMed2006

Does pancreatic duct stenting decrease the rate of pancreatic fistula following pancreaticoduodenectomy? Results of a prospective randomized trial.

Pancreatic duct stenting remains an attractive strategy to reduce the incidence of pancreatic fistulas following pancreaticoduodenectomy (PD) with encouraging results in both retrospective and prospective studies. We performed a prospective randomized trial to test the hypothesis that internal pancreatic duct stenting reduces the development of pancreatic fistulas following PD. Two hundred thirty-eight patients were randomized to either receive a pancreatic stent (S) or no stent (NS), and stratified according to the texture of the pancreatic remnant (soft/normal versus hard). Four patients were excluded from the study; in three instances due to a pancreatic duct that was too small to cannulate and in the other instance because a total pancreatectomy was performed. Patients who randomized to the S group had a 6-cm-long segment of a plastic pediatric feeding tube used to stent the pancreaticojejunostomy anastomosis. In patients with a soft pancreas, 57 randomized to the S group and 56 randomized to the NS group. In patients with a hard pancreas, 58 randomized to the S group and 63 randomized to the NS group. The S and NS groups for the entire study population, as well as for the subgroup of high-risk patients with soft pancreata, were similar as regard to demographics, past medical history, preoperative symptoms, preoperative procedures, and intraoperative data. The pancreatic fistula rate for the entire study population was 9.4%. The fistula rates in the S and NS subgroups with hard pancreata were similar, at 1.7% and 4.8% (P = 0.4), respectively. The fistula rates in the S and NS subgroups with soft pancreata were also similar, at 21.1% and 10.7% (P = 0.1), respectively. A nonstatistically significant increase in the pancreatic fistula rate in the S group persisted after adjusting for the operating surgeon and technical details of the operation (e.g., anastomotic technique, anastomotic orientation, pancreatic duct size, and number of intra-abdominal drains placed). In patients with soft pancreata, 63% percent of the pancreatic fistulas in stented patients required adjustment to the clinical pathway (including two deaths), compared to 47% of the pancreatic fistulas in patients in the NS group (P = 0.3). Internal pancreatic duct stenting does not decrease the frequency or the severity of postoperative pancreatic fistulas.

Adult↗

PubMed2006

Hospital readmission after pancreaticoduodenectomy.

Data exist on the morbidity and mortality of patients undergoing pancreaticoduodenectomy (PD), but there are few reports about hospital readmissions after this procedure. Our aim was to evaluate the number of and reasons for readmission after PD and the factors influencing readmission. We reviewed the initial hospitalization and readmissions for 1643 patients undergoing PD compared patients requiring readmission to patients that did not require readmission. Twenty-six percent of patients were readmitted a total of 678 times after PD. Patients readmitted were younger than those not readmitted (61.8 versus 64.6 years, P < 0.0001). Vessel resection, abscess formation, wound infection, postoperative percutaneous biliary stents, estimated blood loss >1000 ml, and age < or =65 years were independently associated with readmission. The length of stay for all patients decreased over time, from 10.5 days in 1996 to 7 days in 2003. The percentage of patients being readmitted also decreased from 33% in 1996 to 20% (P = 0.004) in 2003. The readmission rate after PD was 26%. Younger age, blood loss, postoperative complications, and vessel resection were independent risk factors for readmission. The early hospital readmission rate has not increased in association with a decreased LOS, supporting the idea that reduction in LOS did not lead to increased readmission rates.

Aged↗

PubMed2006

1423 pancreaticoduodenectomies for pancreatic cancer: A single-institution experience.

Pancreaticoduodenectomy (PD) with the possible addition of neoadjuvant or adjuvant therapy is the standard of care in the United States for adenocarcinoma originating in the pancreatic head, neck, and uncinate process. We reviewed 1423 patients who underwent a PD for a malignancy originating in the pancreas at our institution between 1970 and 2006. We examined 1175 PDs for ductal adenocarcinomas in greater detail. Eighteen different histological types of pancreatic cancer were identified; the most common diagnoses included ductal adenocarcinoma, neuroendocrine carcinoma, and IPMN with invasive cancer. Patients with ductal adenocarcinoma were analyzed in detail. The median age was 66 years, with patients in the present decade significantly older (68 years), on average, than patients in the three prior decades (e.g., 60 years in 1970, P = 0.02). The median tumor diameter was 3 cm; 42% of the resections had positive margins and 78% had positive lymph nodes. The perioperative morbidity was 38%. The median postoperative stay declined over time, from 16 days in the 1980s to 8 days in the 2000s (P < 0.001). The perioperative mortality declined from 30% in the 1970s to 1% in the 2000s (P < 0.001). The median survival for all patients with ductal adenocarcinoma was 18 months (1-year survival = 65 %, 2-year survival = 37%, 5-year survival = 18%). In a Cox proportional hazards model, pathological factors having a significant impact on survival included tumor diameter, resection margin status, lymph node status, and histologic grade. This is the largest single-institution experience with PD for pancreatic cancer. Patients who have cancers with favorable pathological features have a statistically significant improved long-term survival.

Adult↗

PubMed2006

Periampullary and pancreatic incidentaloma: a single institution's experience with an increasingly common diagnosis.

BACKGROUND: While incidental masses in certain organs have received particular attention, periampullary and pancreatic incidentalomas (PIs) remain poorly characterized. METHODS: We reviewed 1944 consecutive pancreaticoduodenectomies (PD) over an 8-year period (April 1997 to October 2005). A total of 118 patients (6% of all PDs) presented with an incidental finding of a periampullary or pancreatic mass. The PI patients were analyzed and compared with the rest of the cohort (NI, nonincidentaloma group, n = 1826). RESULTS: Thirty-one percent of the PI patients (n = 37) had malignant disease (versus 76% of the NI patients, P < 0.001), 47% (n = 55) had premalignant disease, and the remaining 22% (n = 26) had little or no risk for malignant progression. The 3 most common diagnoses in the PI group were IPMN without invasive cancer (30%), cystadenoma (17%), and pancreatic ductal adenocarcinoma (10%). The PI group had a higher overall complication rate (55% versus 43%, P = 0.02), due in part to a significantly increased rate of pancreatic fistulas (18.4% PI versus 8.5% NI, P < 0.001). Patients in the PI group with malignant disease had a superior long-term survival (median, 30 months, P = 0.01) compared with patients in the NI group with malignant disease (median, 21 months). CONCLUSIONS: Incidentally discovered periampullary and pancreatic masses comprise a substantial proportion of patients undergoing PD. Roughly three fourths of these lesions are malignant or premalignant, and amenable to curative resection. Resected malignant PIs have favorable pathologic features as compared with resected malignant NIs, and resection of these early lesions in asymptomatic individuals is associated with improved survival, compared with patients with symptomatic disease.

Adolescent↗

PubMed2006

Assessment of complications after pancreatic surgery: A novel grading system applied to 633 patients undergoing pancreaticoduodenectomy.

OBJECTIVE: To define a simple and reproducible classification of complications following pancreaticoduodenectomy (PD) based on a therapy-oriented severity grading system. BACKGROUND: While mortality is rare after PD, morbidity rates remain high. The lack of standardization in evaluating morbidity after PD has severely hampered meaningful comparisons over time and among centers. We adapted a novel classification of complication to stratify morbidity by severity after PD, to test whether the incidence of pancreatic fistula has changed over time, and to identify risk factors in a single North American center. METHODS: The classification was applied to a consecutive series of 633 patients undergoing PD between February 2003 and August 2005. Another series of 141 patients treated between 1987 and 1990 was also analyzed to identify changes in the incidence and severity of fistula. Univariate and multivariate analyses were performed to link respective complications with preoperative and intraoperative parameters, length of hospital stay, and long-term survival. RESULTS: A total of 263 (41.5%) patients did not develop any complication, while 370 (58.5%) had at least one complication; 62 (10.0%) patients had only grade I complications (no need for specific intervention), 192 patients (30.0%) had grade II (need for drug therapy such as antibiotics), 85 patients (13.5%) had grade III (need for invasive therapy), and 19 patients (3.0%) had grade IV complications (organ dysfunction with ICU stay). Grade V (death) occurred in 12 patients (2.0%). A total of 57 patients (9.0%) developed pancreatic fistula, of which 33 (58.0%) were classified as grade II, 17 (30.0%) as grade III, 5 (9.0%) as grade IV, and 2 (3.5%) as grade V. Delayed gastric emptying was documented in 80 patients (12.7%); half of them were scored as grade II and the other half as grade III. A significant decrease in the incidence of fistula was observed between the 2 periods analyzed (14.0% vs. 9.0%, P < 0.001), mostly due to a decrease in grade II fistula. Cardiovascular disease was a risk factor for overall morbidity and complication severity, while texture of the gland and cardiovascular disease were risk factors for pancreatic fistula. CONCLUSION: This study demonstrates the applicability and utility of a new classification in grading complications following pancreatic surgery. This novel approach may provide a standardized, objective, and reproducible assessment of pancreas surgery enabling meaningful comparison among centers and over time.

Adult↗

PubMed2005

Novel genotoxicity assays identify norethindrone to activate p53 and phosphorylate H2AX.

Norethindrone is a commonly used drug for contraception and hormone replacement therapy, whose carcinogenic potential is still controversial. We applied a novel and particularly sensitive method to screen for DNA damage with special attention to double-strand breaks (DSBs) and identified norethindrone to be likely genotoxic and therefore potentially mutagenic: a p53-reporter assay served as a first, high-throughput screening method and was followed by the immunofluorescent detection of phosphorylated H2AX as a sensitive assay for the presence of DSBs. Norethindrone at concentrations of 2-100 microg/ml activated p53 and phosphorylated H2AX specifically and in a dose-dependent manner. No p53 activation or H2AX phosphorylation was detected using a panel of structurally/functionally related drugs. The overall amount of DNA damage induced by norethindrone was low as compared with etoposide and ionizing radiation. Consistently, norethindrone treatment did not cause a cell cycle arrest. DSBs were not detected with the neutral comet assay, a less sensitive method for DSB assessment than H2AX phosphorylation. Our findings in the p53-reporter and gamma-H2AX assays could not be ascribed to common DSB-causing artifacts in standard genotoxicity screening, including drug precipitation, high cytotoxicity levels and increased apoptosis. Therefore, our study suggests that norethindrone induces DSBs in our experimental setting, both complementing and adding a new aspect to the existing literature on the genotoxic potential of norethindrone. As the effective concentrations of norethindrone used in our assays were approximately 100- to 1000-fold higher than therapeutical doses, the significance of these findings with regard to human exposure still remains to be determined.

Animals↗

PubMedDate not supplied

Retroperitoneal paraganglioma: single-institution experience and review of the literature.

Paragangliomas are rare tumors arising from extra-adrenal chromaffin cells. We examined the clinical characteristics of all patients at our institution having paragangliomas resected from 1984 through 2005. Of 253 resections, 22 (9%) were retroperitoneal and were selected for further study. The ratio of males to females was 1.3:1, and the median age was 39 years. The average size, rate of metastasis (i.e., malignancy), and rate of function was 7.4 cm, 9.5%, and 57.1%, respectively. Tumors larger than 7 cm were more likely to require adjacent organ resection (P = 0.01). The overall 5-year survival was 73%. Survival was significantly worse after metastasis (P = 0.0023) but did not depend on the tumor diameter, the secreting function of the tumor, the status of surgical margins of resection, or status of the resected lymph nodes.

Digestive System Surgical Procedures↗