Benjamin R Tan

Washington University in St. Louis, San Luis, Missouri, United States

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Publications (25)159.61 Total impact

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    ABSTRACT: Objectives Adjuvant gemcitabine with or without chemoradiation is a standard therapeutic option for patients with resected pancreatic cancer. The feasibility and toxicity of gemcitabine with docetaxel before and after 5-fluorouracil (5FU)-based chemoradiation in the adjuvant pancreatic and biliary cancer setting were investigated.Methods After a curative-intent resection, eligible patients with pancreaticobiliary cancers were treated with two cycles of gemcitabine and docetaxel followed by 5FU-based chemoradiation. Four weeks after completing chemoradiation, two cycles of gemcitabine and docetaxel were administered. The primary endpoint was the incidence of severe toxicities. Secondary endpoints included disease-free survival (DFS) and overall survival (OS).ResultsFifty patients with pancreaticobiliary cancers were enrolled. Twenty-nine patients had pancreatic cancer whereas 21 patients had biliary tract or ampullary cancers. There was one death as a result of pneumonia, and 15% of patients experienced grade 3 or greater non-haematological toxicities. The median DFS and OS for patients with pancreatic cancer were 9.6 and 17 months, respectively, and for those with resected biliary tract cancer were 12 and 23 months, respectively.Conclusions This combination of gemcitabine and docetaxel with chemoradiation is feasible and tolerable in the adjuvant setting. Future studies utilizing a different gemcitabine/taxane combination and schedule may be appropriate in the adjuvant treatment of both pancreatic cancer and biliary tumours.
    No preview · Article · Mar 2015 · HPB
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    ABSTRACT: Background Retrospective studies indicate associations between TSER (thymidylate synthase enhancer region) genotypes and clinical outcomes in patients receiving 5-FU based chemotherapy, but well-controlled prospective validation has been lacking. Methods In this phase II study (NCT00515216 registered through ClinicalTrials.gov, http://clinicaltrials.gov/show/NCT00515216), patients with “good risk” TSER genotypes (at least one TSER*2 allele) were treated with FOLFOX chemotherapy to determine whether prospective patient selection can improve overall response rates (ORR) in patients with gastric and gastroesophageal junction (GEJ) cancers, compared with historical outcomes in unselected patients (estimated 43%). Results The ORR in genotype-selected patients was 39.1% (9 partial responses out of 23 evaluable patients, 95% CI, 22.2 to 59.2), not achieving the primary objective of improving ORR. An encouraging disease control rate (DCR, consisting of partial responses and stable diseases) of 95.7% was noted and patients with homozygous TSER*2 genotype showed better tumor response. Conclusions In this first prospective, multi-institutional study in patients with gastric or GEJ cancers, selecting patients with at least one TSER*2 allele did not improve the ORR but led to an encouraging DCR. Further studies are needed to investigate the utility of selecting patients homozygous for the TSER*2 allele and additional genomic markers in improving clinical outcomes for patients with gastric and GEJ cancers. Trial Registration ClinicalTrials.gov NCT00515216
    Full-text · Article · Sep 2014 · PLoS ONE
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    ABSTRACT: Objective Oxaliplatin, a component of chemotherapy for colorectal carcinoma liver metastases, can result in hepatic sinusoidal injury; rarely, the injury is fatal. The manifestations of injury are variable. There are no known predictors of susceptibility and outcome. A semi-quantitative system for assessing histological features in non-tumor liver was designed to compare with clinical short-term and long-term outcomes. MethodsA review of 47 patients with metastatic colorectal carcinoma who received liver resection utilizing a system for an aggregate liver injury score (0-4) included hepatocellular and sinusoidal features. Immunohistochemistry (IHC) for aberrant capillarization was included. The proliferation of hepatocytes and sinusoidal lining cells was evaluated with Ki-67 stain. ResultsIn total, 32 (68.1%) cases showed light microscopic lesions of oxaliplatin-induced liver injury, in which 26 were moderate to severe. Elevated preoperative aspartate aminotransferase (AST) and alkaline phosphatase levels were noted with higher injury scores (P=0.01). Patients with higher injury scores had no significant increase in short-term postoperative complications, with one notable exception, who died of liver failure 10 months postoperatively. Increased CD34 expression was associated with higher injury scores (P=0.00004), and abnormal AST levels (P=0.04). Preoperative use of bevacizumab was not associated with lower injury scores. Steatosis was correlated with body mass index (P=0.052) but not with exposure to oxaliplatin, bevacizumab or irinotecan. Conclusions The proposed liver injury scoring system encompasses the spectrum of sinusoidal and hepatocellular lesions in oxaliplatin-induced liver injury and is correlated with serum liver enzyme levels in this group. Most patients recovered without complications during the 93-month follow-up, indicating that these lesions are reversible.
    No preview · Article · Jul 2014 · Journal of Digestive Diseases
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    ABSTRACT: Small bowel adenocarcinoma is an uncommon gastrointestinal malignancy with limited data on effective chemotherapy in the adjuvant setting, as well as for advanced disease. We present a case report of a patient with recurrent duodenal adenocarcinoma after resection and adjuvant chemotherapy who experienced a complete response to bevacizumab with oxaliplatin and 5FU (FOLFOX) followed by bevacizumab/capecitabine maintenance therapy for 2 years. The patient continues to be disease-free 8 years after his recurrence. This case highlights the potential of vascular endothelial growth factor (VEGF) inhibitors to enhance chemotherapeutic regimens for advanced small bowel adenocarcinoma.
    No preview · Article · Feb 2014 · Journal of gastrointestinal oncology
  • Daniel K Mullady · Benjamin R Tan
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    ABSTRACT: Management of patients with gastrointestinal stromal tumor (GIST) typically involves a combination of surgical, pathologic, and pharmacologic interventions. Gastroenterologists are often the first specialists to encounter patients presenting with GIST and are therefore responsible for facilitating early intervention strategies. Although patients with gastric or small-bowel GISTs typically present with symptoms, a diagnosis of GIST should be considered whenever a submucosal lesion is seen endoscopically. Visualization by standard endoscopy often can determine tumor location and size, although endoscopic ultrasound (EUS) is the most accurate imaging technique for submucosal lesions. Biopsy techniques that yield sufficient tumor samples for diagnostic studies, such as EUS-guided fine needle aspiration, are essential, although other approaches such as EUS-guided core needle biopsy may increase diagnostic yield for subepithelial lesions. Pathology assessment should include immunohistochemical staining for KIT and possibly DOG1 expression, and mutational analysis can have prognostic and predictive value for certain patients. R0 resection is the goal for patients with localized or potentially resectable tumors, which often can be accomplished by laparoscopic resection, even for larger tumors. Medical oncologists play a key role in assessing risk of recurrence after resection and optimizing tyrosine kinase inhibitor therapy in the adjuvant or metastatic setting. Cytoreductive surgery may have value for patients with recurrent or metastatic GIST who exhibit stable disease or respond to tyrosine kinase inhibitor therapy. A coordinated multidisciplinary approach over the course of the disease will serve to enhance communication among GIST team members, reduce risk of progression, and optimize outcomes.
    No preview · Article · Jun 2013 · Journal of clinical gastroenterology
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    ABSTRACT: Combination chemotherapy with FOLFIRINOX (oxaliplatin, irinotecan, fluorouracil, and leucovorin) was shown to be effective in a large phase III trial. The purpose of this study was to examine the tolerance and effectiveness of FOLFIRINOX as practiced outside of the confines of a clinical trial and to document any dose modifications used by practicing oncologists. Data on patients with all stages of pancreatic adenocarcinoma treated with FOLFIRINOX at three institutions was analyzed for efficacy, tolerance, and use of any dose modifications. Total of 61 patients was included in this review. Median age was 58 years (range: 37 to 72 years), 33 were male (54.1%) and majority had ECOG performance of 0 or 1 (86.9%, 53 patients). Thirty-eight (62.3%) had metastatic disease, while 23 (37.7%) were treated for locally advanced or borderline resectable disease. Patients were treated with a median number of four cycles of FOLFIRINOX, with dose modifications in 58.3% (176/302) of all cycles. Ten patients had stable disease (16.4%), four had a partial response (6.6%) while eight had progressive disease (13.1%) on best imaging following therapy. Median progression-free survival and overall survival were 7.5 months and 13.5 months, respectively. The most common grade 3-4 adverse event was neutropenia at 19.7% (12 cases), with 4.9% (3 cases) rate of febrile neutropenia. Twenty-one patients (34.4%) were hospitalized as a result of therapy but there were no therapy-related deaths. Twenty-three (37.7%) had therapy eventually discontinued as a result of adverse events. Despite substantial rates of adverse events and use of dose modifications, FOLFIRINOX was found to be clinically effective in both metastatic and non-metastatic patients. Regimen toxicity did not detract from overall response and survival.
    No preview · Article · Sep 2012 · JOP: Journal of the pancreas
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    ABSTRACT: The purpose of this study was to assess the efficacy and safety of 5-fluorouracil (5FU) and gemcitabine administered concurrently with radiation in patients with locally advanced, nonmetastatic pancreatic cancer. Eligible patients had histologically confirmed pancreatic adenocarcinoma deemed locally unresectable without evidence of metastatic disease. In addition, all patients underwent laparoscopy or laparotomy before study entry to rule out peritoneal carcinomatosis. Patients received radiation therapy (50.4 Gy) with concurrent infusional 5FU (200 mg/m(2) 5 days/week) and weekly gemcitabine (200 mg/m(2) ). After a 3-week break, patients received weekly gemcitabine at 1000 mg/m(2) for 3 of 4 weeks, for 4 cycles. The primary endpoint of the trial was the proportion of patients surviving 9 months from study entry. Secondary endpoints included objective tumor response, CA19-9 response, overall survival (OS) time to progression (TTP), and toxicity. Between November 2001 and October 2004, 81 patients were enrolled, 78 of whom were eligible for analysis. With a median follow-up of 55.2 months, the median OS was 12.2 months (95% confidence interval [CI], 10.9-14.9) and the median TTP was 10 months (95% CI, 6.4-12.0). An objective tumor response was seen in 19 patients (25%), and among 56 patients with an elevated CA19-9 at baseline, 29 (52%) had a sustained CA19-9 response. Overall, 41% of patients had grade 3 or greater treatment-related gastrointestinal adverse events. The combination of 5FU, gemcitabine, and radiation is well tolerated. Survival is comparable with the best results of other recent studies of 5FU and radiation or gemcitabine and radiation.
    Full-text · Article · Jun 2011 · Cancer
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    ABSTRACT: UCN-01 (7-hydroxystaurosporine) is a multi-targeted protein kinase inhibitor that exhibits synergistic activity with DNA-damaging agents in preclinical studies. We conducted a Phase I study to determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), pharmacokinetic, and pharmacodynamic effects of UCN-01 and irinotecan in patients with resistant solid tumors. Patients received irinotecan (75-125 mg/m(2) IV on days 1, 8, 15, 22) and UCN-01 (50-90 mg/m(2) IV on day 2 and 25-45 mg/m(2) on day 23 and subsequent doses) every 42 days. Blood for pharmacokinetics of UCN-01 and irinotecan, and blood, normal rectal mucosa, and tumor biopsies for pharmacodynamic studies were obtained. Twenty-five patients enrolled to 5 dose levels. The MTD was irinotecan 125 mg/m(2) on days 1, 8, 15, 22 and UCN-01 70 mg/m(2) on day 2 and 35 mg/m(2) on day 23. DLTs included grade 3 diarrhea/dehydration and dyspnea. UCN-01 had a prolonged half-life and a low clearance rate. There was a significant reduction in SN-38 C(max) and aminopentanocarboxylic acid (APC) and SN-38 glucuronide half-lives. Phosphorylated ribosomal protein S6 was reduced in blood, normal rectal mucosa, and tumor biopsies at 24 h post-UCN-01. Two partial responses were observed in women with ER, PgR, and HER2-negative breast cancers (TBNC). Both tumors were defective for p53. Twelve patients had stable disease (mean duration 18 weeks, range 7-30 weeks). UCN-01 and irinotecan demonstrated acceptable toxicity and target inhibition. Anti-tumor activity was observed and a study of this combination in women with TNBC is underway.
    Full-text · Article · Jun 2011 · Cancer Chemotherapy and Pharmacology
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    ABSTRACT: Downstaging (DS) of rectal cancers is achieved in approximately 45% of patients with neoadjuvant fluorouracil (FU) -based chemoradiotherapy (CRT). Polymorphisms in the thymidylate synthase gene (TYMS) had previously defined two risk groups associated with disparate tumor DS rates (60% v 22%). We conducted a prospective single-institution phase II study using TYMS genotyping to direct neoadjuvant CRT for patients with rectal cancer. Patients with T3/T4, N0-2, M0-1 rectal adenocarcinoma were evaluated for germline TYMS genotyping. Patients with TYMS *2/*2, *2/*3, or *2/*4 (good risk) were treated with standard chemoradiotherapy using infusional FU at 225 mg/m²/d. Patients with TYMS *3/*3 or *3/*4 (poor risk) were treated with FU/RT plus weekly intravenous irinotecan at 50 mg/m². The primary end point was pathologic DS. Secondary end points included complete tumor response (ypT0), toxicity, recurrence rates, and overall survival. Overall, 135 patients were enrolled, of whom 27.4% (37 of 135) were considered poor risk. The prespecified statistical goals were achieved, with DS and ypT0 rates reaching 64.4% and 20% for good-risk and 64.5% and 42% for poor-risk patients, respectively. To our knowledge, this is the first study to prospectively use TYMS genotyping to direct neoadjuvant CRT in patients with rectal cancer. High rates of DS and ypT0 were achieved among both risk groups when personalized treatment was based on TYMS genotype. These results are encouraging, and further evaluation of this genotype-based strategy using a randomized study design for locally advanced rectal cancer is warranted.
    Full-text · Article · Feb 2011 · Journal of Clinical Oncology
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    ABSTRACT: Polymorphisms in the 5' regulatory region of the thymidylate synthase gene (TYMS) have been shown to modulate thymidylate synthase expression and are associated with resistance to fluoropyrimidine-based therapies. These polymorphisms include a two repeat (2R) or three repeat (3R) of a 28-bp sequence and a G>C SNP in the second repeat of the 3R allele (TSER*3 G>C). Genotyping methods for the TYMS 5'-UTR polymorphisms have typically involved visualizing PCR and RFLP products on agarose gels. This article describes the use of a robust capillary electrophoresis assay for TYMS 5'-UTR genotyping. As part of pharmacogenetic studies, we performed TYMS genotyping for the 5'-UTR polymorphisms in 314 colorectal cancer patients. A gel-based capillary electrophoresis method, employing a high-resolution gel cartridge on a QIAxcel(®) system, was developed to detect PCR products and RFLP fragment sizes. The high resolution of the capillary electrophoresis technique allowed identification of a 6-bp insertion in the second repeat of the 3R allele in three patients. The frequency of the insertion allele was 0.4% in Caucasians and 1.3% in African-Americans. We also found 3.3% of Caucasian patients were heterozygous for a G>C SNP in the first repeat of the 2R allele, but this allele was not observed in the African-American patients. We describe a robust RFLP genotyping technique that employs size discrimination by capillary electrophoresis to genotype the TYMS TSER*3 G>C SNP. The technique also allows identification of a 6-bp insertion in the 3R allele, and we report the allelic frequencies for two uncommon TSER alleles.
    Full-text · Article · Dec 2010 · Pharmacogenomics
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    Preview · Dataset · Aug 2010
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    ABSTRACT: Only recently has a standard chemotherapy regimen, gemcitabine plus cisplatin, been established for advanced biliary tract cancers (BTCs) based on a phase III randomized study. The aim of this phase II single-institution trial was to assess the efficacy and safety of gemcitabine combined with carboplatin in the first-line treatment of patients with advanced BTCs. Patients with histologically proven BTCs, including cholangiocarcinoma or gallbladder and ampullary carcinomas, were treated with a maximum of nine cycles of intravenous (i.v.) gemcitabine at 1000 mg/m(2) over 30 min on days 1 and 8 with i.v. carboplatin dosed at an area-under-the-curve (AUC) of 5 over 60 min on day 1 of a 21-day cycle. A total of 48 patients with advanced BTCs (35 cholangiocarcinoma, 12 gallbladder and 1 ampullary cancer) were enrolled. A median of four cycles were administered (range: 1-9). The overall response rate for evaluable patients was 31.1%. Median progression-free survival, overall survival and 6-month survival rates are 7.8 months, 10.6 months and 85.4%, respectively. The most common grade 3-4 toxicities include neutropenia and thrombocytopenia. Grade 3 or 4 non-haematological toxicities were rare. Gemcitabine combined with carboplatin has activity against advanced BTCs. Our results are comparable to other gemcitabine-platinum or gemcitabine-fluoropyrimidine combinations in advanced BTCs.
    Preview · Article · Aug 2010 · HPB
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    ABSTRACT: Mesothelin is a glycoprotein expressed on normal mesothelial cells and is overexpressed in several histologic types of tumors including pancreatic adenocarcinomas. A soluble form of mesothelin has been detected in patients with ovarian cancer and malignant mesothelioma, and has prognostic value. Mesothelin has also been considered as a target for immune-based therapies. We conducted a study on the potential clinical utility of mesothelin as a biomarker for pancreatic disease and therapeutic target pancreatic cancer. Tumor cell-bound and soluble mesothelin in patients was evaluated by immunohistochemistry and ELISA, respectively. The in vitro cellular immune response to mesothelin was evaluated by INF gamma ELISA and intracellular cytokine staining for IFN gamma in CD4(+) and CD8(+) T cells. The level of circulating antibodies to mesothelin was measured by ELISA. All tumor tissue from patients with pancreatic adenocarcinoma expressed mesothelin (n = 10). Circulating mesothelin protein was detected in patients with pancreatic adenocarcinoma (73 of 74 patients) and benign pancreatic disease (5 of 5) but not in healthy individuals. Mesothelin-specific CD4(+) and CD8(+) T cells were generated from peripheral blood lymphocytes of patients with pancreatic cancer in 50% of patients compared with only 20% of healthy individuals. Antibodies reactive to mesothelin were detected in <3% of either patients or healthy individuals. Circulating mesothelin is a useful biomarker for pancreatic disease. Furthermore, mesothelin-specific T cells can be induced in patients with pancreatic cancer. This suggests that mesothelin is a potential target for immune-based intervention strategies in pancreatic cancer.
    Full-text · Article · Nov 2009 · Clinical Cancer Research
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    ABSTRACT: Gastrointestinal stromal tumour is the most common sarcoma of the intestinal tract. Imatinib mesylate is a small molecule that inhibits activation of the KIT and platelet-derived growth factor receptor alpha proteins, and is effective in first-line treatment of metastatic gastrointestinal stromal tumour. We postulated that adjuvant treatment with imatinib would improve recurrence-free survival compared with placebo after resection of localised, primary gastrointestinal stromal tumour. We undertook a randomised phase III, double-blind, placebo-controlled, multicentre trial. Eligible patients had complete gross resection of a primary gastrointestinal stromal tumour at least 3 cm in size and positive for the KIT protein by immunohistochemistry. Patients were randomly assigned, by a stratified biased coin design, to imatinib 400 mg (n=359) or to placebo (n=354) daily for 1 year after surgical resection. Patients and investigators were blinded to the treatment group. Patients assigned to placebo were eligible to crossover to imatinib treatment in the event of tumour recurrence. The primary endpoint was recurrence-free survival, and analysis was by intention to treat. Accrual was stopped early because the trial results crossed the interim analysis efficacy boundary for recurrence-free survival. This study is registered with ClinicalTrials.gov, number NCT00041197. All randomised patients were included in the analysis. At median follow-up of 19.7 months (minimum-maximum 0-56.4), 30 (8%) patients in the imatinib group and 70 (20%) in the placebo group had had tumour recurrence or had died. Imatinib significantly improved recurrence-free survival compared with placebo (98% [95% CI 96-100] vs 83% [78-88] at 1 year; hazard ratio [HR] 0.35 [0.22-0.53]; one-sided p<0.0001). Adjuvant imatinib was well tolerated, with the most common serious events being dermatitis (11 [3%] vs 0), abdominal pain (12 [3%] vs six [1%]), and diarrhoea (ten [2%] vs five [1%]) in the imatinib group and hyperglycaemia (two [<1%] vs seven [2%]) in the placebo group. Adjuvant imatinib therapy is safe and seems to improve recurrence-free survival compared with placebo after the resection of primary gastrointestinal stromal tumour. US National Institutes of Health and Novartis Pharmaceuticals.
    Full-text · Article · Mar 2009 · The Lancet
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    ABSTRACT: To evaluate the factors associated with disease control and morbidity after radiotherapy for anal carcinoma. Between 1975 and 2005, 194 patients with localized epidermoid anal carcinoma underwent radiotherapy. Treatment evolved from radiotherapy with or without surgery, to preoperative chemoradiotherapy, to definitive chemoradiotherapy (CRT). The radiotherapy techniques also evolved. With a median follow-up of 61 months, 57 patients had persistence or recurrence, 9 of whom were successfully salvaged, resulting in 146 (75%) ultimately free of disease (UNED). Univariate analysis for UNED survival showed a strong association with the T and N stage (5-year UNED rate, 88.5% +/- 3.4% for those with Stage T1-T2N0; 70.1% +/- 4.2% for Stage T3N0; and 52.7% +/- 6.6% for Stage III; p > .001) and mobility on palpation (5-year UNED rate, 89.2% +/- 4.6% for those with mobile tumors vs. 59.3% +/- 6.1% for those with tethered/fixed tumor; p > .001). No association was found with gender, age, preoperative vs. definitive CRT, or human immunodeficiency virus status. The 20 human immunodeficiency virus+ patients all received CRT. The radiotherapy factors associated with Grade 3 or greater late morbidity included anorectal morbidity with tumor dose (29% with a dose > or =55 Gy vs. 9% otherwise), small bowel injury with technique (9% with anteroposterior-posteroanterior supine vs. 0.7% with multiple fields prone), and bone injury with femoral head dose (9% with a dose of > or =44 Gy vs. 0.7% otherwise). Of the 194 patients, 56 had 68 additional malignancies, mainly either antedating the anal cancer or outside the radiation fields. Our results have confirmed that CRT is an effective approach. Patients with human immunodeficiency virus can be treated with CRT. Tumor mobility significantly predicts the outcome; the implications for management are discussed. We also discuss the treatment planning implications of the late morbidity findings. The substantial incidence of additional malignancies underscores the importance of full oncologic screening during follow-up.
    No preview · Article · Feb 2009 · International journal of radiation oncology, biology, physics
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    ABSTRACT: This is a phase II, single-center, single-arm study of patients with resectable adenocarcinoma of the pancreas who were treated with adjuvant interferon-based chemoradiation followed by gemcitabine. The primary end point was 2-year overall survival, with secondary endpoints being 2-year disease-free survival, and the frequency of grade 3 or 4 toxicity. From April 2002 to September 2005, 53 patients with adenocarcinoma of the pancreas underwent curative resection at a single institution, and subsequently received interferon- and gemcitabine-based adjuvant therapy consisting of external-beam irradiation at a dose of 5040 cGy (25 fractions per 5 weeks) and simultaneous 3-drug chemotherapy consisting of (1) continuous infusion 5-fluorouracil (175 mg/m2); (2) weekly intravenous bolus cisplatin (25 mg/m2); and (3) interferon-alpha (3 million units subcutaneously 3 times per week) during the 6 weeks of radiation. This was followed by two 4-week courses of weekly intravenous infusion of gemcitabine (1000 mg/m2, 3 of 4 weeks). Median follow-up is 38 months. Seventy-seven percent of patients had node-positive disease. Sixteen patients (30%) failed to complete adjuvant therapy, due to disease progression (7 patients), toxicity (7 patients), and consent withdrawal (2 patients). No patients completed planned therapy without dose modification. Median overall survival was 25 months (confidence interval [CI] = 21.5-48.5 months). Actuarial overall survival for the 1-, 2- and 3-year periods were 75% (CI = 61-85%), 56% (CI = 41-69%), and 41% (26-55%), respectively. This phase II trial demonstrated increased patient survival compared with historical controls, and equivalent survival compared with the regimen combining interferon-alpha with 5-fluorouracil-based chemoradiation. Despite these encouraging results, significant concerns regarding dose- and treatment-limiting toxicities remain.
    No preview · Article · Aug 2008 · Annals of surgery
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    ABSTRACT: To determine the maximum tolerated dose, dose-limiting toxicity (DLT), and pharmacokinetics of weekly docosahexaenoic acid-paclitaxel (DHA-paclitaxel), a taxane fatty acid conjugate. Docosahexaenoic acid-paclitaxel was administered by 2-hour i.v. infusion weekly for three out of four weeks. DHA-paclitaxel 200 mg/m(2) was dose escalated by 100 mg/m(2) per cohort to 600 mg/m(2). Blood samples for pharmacokinetics of DHA-paclitaxel and paclitaxel derived from DHA-paclitaxel were collected. Twenty-one patients received 42 cycles of treatment over five dose levels. Grade 3/4 neutropenia occurred in five patients but was not dose limiting. Grade 3 hyperbilirubinemia, a DLT, and grade 1 sensory neuropathy occurred at the highest dose level. PK analyses demonstrated dose proportional C (max) and AUC(0-24). Limited accumulation of DHA-paclitaxel or paclitaxel occurred with weekly treatment. Increased DHA-paclitaxel and paclitaxel AUC(0-24) were associated with increased neutropenia. Of the 19 patients evaluable for response, three patients with esophageal, melanoma and colon carcinoma had stable disease for 11, 16, and 17 weeks, respectively. Docosahexaenoic acid-paclitaxel administered weekly to a maximum dose of 600 mg/m(2) was well-tolerated. The slow release of paclitaxel from DHA-paclitaxel and the weekly schedule approximates continuous infusion paclitaxel which may be more active than every 3 week or weekly taxanes.
    No preview · Article · May 2008 · Cancer Chemotherapy and Pharmacology
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    ABSTRACT: The antiepidermal growth factor receptor (EGFR) antibody cetuximab shows activity in multiple epithelial tumor types; however, responses are seen in only a subset of patients. This study was conducted to identify markers that are associated with disease control in patients treated with cetuximab. One hundred ten patients with metastatic colorectal cancer were enrolled onto a cetuximab monotherapy trial. Transcriptional profiling was conducted on RNA from mandatory pretreatment metastatic biopsies to identify genes whose expression correlates with best clinical responses. EGFR and K-ras mutation analyses and EGFR gene copy number analyses were performed on DNA from pretreatment biopsies. Gene expression profiles showed that patients with tumors that express high levels of the EGFR ligands epiregulin and amphiregulin are more likely to have disease control with cetuximab (EREG, P = .000015; AREG, P = .000025). Additionally, patients whose tumors do not have K-ras mutations have a significantly higher disease control rate than patients with K-ras mutations (P = .0003). Furthermore, patients with tumors that have high expression of EREG or AREG also have significantly longer progression-free survival (PFS) than patients with low expression (EREG: P = .0002, hazard ratio [HR] = 0.47, and median PFS, 103.5 v 57 days, respectively; AREG: P < .0001, HR = 0.44, and median PFS, 115.5 v 57 days, respectively). Patients with tumors that have high gene expression levels of epiregulin and amphiregulin and patients with wild-type K-ras are more likely to have disease control on cetuximab treatment. The identified markers could be developed further to select patients for cetuximab therapy.
    Preview · Article · Aug 2007 · Journal of Clinical Oncology
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    ABSTRACT: PURPOSE Hepatic Artery Chemoembolization (HACE) is an accepted treatment for neuroendocrine liver metastases. Long-term outcomes data is limited. We present our experience treating patients with HACE for neuroendocrine liver metastases. METHOD AND MATERIALS 46 patients with proven carcinoid (n=31) or islet cell (n=15) tumors were treated. Overall survival (OS) and progression free survival (PFS) were calculated from the date of first treatment. Factors affecting survival including presence of extrahepatic disease and resection of the primary lesion were studied. Improvement in symptoms was determined for biologically active tumors. RESULTS The 46 patients underwent 93 HACE sessions. Mean and median OS for the group was 1273 +/- 185 and 978 days. Mean OS for the carcinoid (1243 +/- 163 days) and the islet cell tumor (1311 +/- 403 days) subgroups was similar (p=0.66). PFS for carcinoid (602 +/- 144 days) and islet cell tumor subgroups (501 +/- 107 days) was similar (p=0.72). Survival of patients without known extrahepatic metastases (1571 +/- 291 days, n=18) trended towards significance when compared to patients with known extrahepatic disease (770 +/- 112 days, n= 26, p=0.08). Resection of the primary tumor in 19/46 patients did not affect survival (resection survival 1558 +/- 400 days vs. non-resection survival 1000 +/ 179 days, p=0.44). 20/25 patients with hormonally active tumors experienced relief of symptoms after one cycle of HACE including 13/16 patients with extrahepatic metastases. Complications occurred following 12.9% of procedures and 30-day mortality was 4.3%. CONCLUSION OS following HACE of neuroendocrine tumors is approximately 3.5 years. PFS approaches 1.5 years. OS and PFS with different tumor types are similar. The presence of extrahepatic metastases may result in decreased survival but symptom relief from hormonal syndromes is obtained in the majority of treated patients. The presence of extrahepatic metastases or an unresected primary tumor should not limit application of HACE. CLINICAL RELEVANCE/APPLICATION In contrast to hepatocellular carcinoma, long-term outcomes data for chemoembolization of neuroendocrine metastases is scant and our experience represents one of the largest treated groups to date.
    No preview · Conference Paper · Nov 2006
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    Gustavo Alvarez · Arie Perry · Benjamin R Tan · Hanlin L Wang
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    ABSTRACT: Immunohistochemical detection of expression of the epidermal growth factor receptor (EGFR) has been utilized to identify eligible patients with solid malignant tumors, including colorectal adenocarcinoma, for monoclonal antibody therapy (eg, cetuximab). The EGFR status in squamous cell carcinoma of the anal canal, an uncommon malignancy traditionally treated with chemoradiation, has not been well investigated. In this study, 38 primary squamous cell carcinomas of the anal canal were immunohistochemically examined for EGFR expression and analyzed by fluorescence in situ hybridization (FISH) for EGFR gene copy numbers. The results showed a variable degree of EGFR expression in 21 (55%) tumors, among which 13 (62%) cases exhibited a 2+ to 3+ staining pattern according to the Dako EGFR phamDx interpretation guide. There were no significant differences among tumors stratified by stage, degree of keratinization, or tissue block storage times. FISH analysis showed that none of the 34 cases with interpretable results had EGFR gene amplification. Increased gene copy numbers due to polysomy 7 were seen in seven of 18 (39%) cases that expressed EGFR protein and four of 16 (25%) cases that did not (P=0.3876). Ten (56%) tumors with positive EGFR staining showed a balanced disomy 7 pattern and one case with monosomy 7 exhibited strong EGFR expression (3+). These results demonstrate that EGFR is overexpressed in more than one-half of the squamous cell carcinomas of the anal canal through mechanisms other than gene amplification. These observations may have important therapeutic implications since EGFR-based targeted therapies have shown promise for other malignant neoplasms.
    Preview · Article · Aug 2006 · Modern Pathology