Stuart Mercer

Cancer cell adaptation to chemotherapy.

BackgroundTumor resistance to chemotherapy may be present at the beginning of treatment, develop during treatment, or become apparent on re-treatment of the patient. The mechanisms involved are usually inferred from experiments with cell lines, as studies in tumor-derived cells are difficult. Studies of human tumors show that cells adapt to chemotherapy, but it has been largely assumed that clonal selection leads to the resistance of recurrent tumors.MethodsCells derived from 47 tumors of breast, ovarian, esophageal, and colorectal origin and 16 paired esophageal biopsies were exposed to anticancer agents (cisplatin; 5-fluorouracil; epirubicin; doxorubicin; paclitaxel; irinotecan and topotecan) in short-term cell culture (6 days). Real-time quantitative PCR was used to measure up- or down-regulation of 16 different resistance/target genes, and when tissue was available, immunohistochemistry was used to assess the protein levels.ResultsIn 8/16 paired esophageal biopsies, there was an increase in the expression of multi-drug resistance gene 1 (MDR1) following epirubicin + cisplatin + 5-fluorouracil (ECF) chemotherapy and this was accompanied by increased expression of the MDR-1 encoded protein, P-gp. Following exposure to doxorubicin in vitro, 13/14 breast carcinomas and 9/12 ovarian carcinomas showed >2-fold down-regulation of topoisomerase IIα (TOPOIIα). Exposure to topotecan in vitro, resulted in >4-fold down-regulation of TOPOIIα in 6/7 colorectal tumors and 8/10 ovarian tumors.ConclusionThis study suggests that up-regulation of resistance genes or down-regulation in target genes may occur rapidly in human solid tumors, within days of the start of treatment, and that similar changes are present in pre- and post-chemotherapy biopsy material. The molecular processes used by each tumor appear to be linked to the drug used, but there is also heterogeneity between individual tumors, even those with the same histological type, in the pattern and magnitude of response to the same drugs. Adaptation to chemotherapy may explain why prediction of resistance mechanisms is difficult on the basis of tumor type alone or individual markers, and suggests that more complex predictive methods are required to improve the response rates to chemotherapy.

Outcome of ATP-based tumor chemosensitivity assay directed chemotherapy in heavily pre-treated recurrent ovarian carcinoma

BackgroundWe wished to evaluate the clinical response following ATP-Tumor Chemosensitivity Assay (ATP-TCA) directed salvage chemotherapy in a series of UK patients with advanced ovarian cancer. The results are compared with that of a similar assay used in a different country in terms of evaluability and clinical endpoints.MethodsFrom November 1998 to November 2001, 46 patients with pre-treated, advanced ovarian cancer were given a total of 56 courses of chemotherapy based on in-vitro ATP-TCA responses obtained from fresh tumor samples or ascites. Forty-four patients were evaluable for results. Of these, 18 patients had clinically platinum resistant disease (relapse < 6 months after first course of chemotherapy). There was evidence of cisplatin resistance in 31 patients from their first ATP-TCA. Response to treatment was assessed by radiology, clinical assessment and tumor marker level (CA 125).ResultsThe overall response rate was 59% (33/56) per course of chemotherapy, including 12 complete responses, 21 partial responses, 6 with stable disease, and 15 with progressive disease. Two patients were not evaluable for response having received just one cycle of chemotherapy: if these were excluded the response rate is 61%. Fifteen patients are still alive. Median progression free survival (PFS) was 6.6 months per course of chemotherapy; median overall survival (OAS) for each patient following the start of TCA-directed therapy was 10.4 months (95% confidence interval 7.9–12.8 months).ConclusionThe results show similar response rates to previous studies using ATP-TCA directed therapy in recurrent ovarian cancer. The assay shows high evaluability and this study adds weight to the reproducibility of results from different centres.

Implementation of a specialist-led service for the management of acute gallstone disease

The ‘gold standard’ treatment for acute cholecystitis and biliary colic requiring hospital admission is urgent laparoscopic cholecystectomy. This is not routinely available in all hospitals.

Selective MRCP in the management of suspected common bile duct stones

BACKGROUND It is controversial whether selective endoscopic sphincterotomy or routine laparoscopic bile duct exploration is the optimal treatment for choledocholithiasis. Magnetic resonance cholangio-pancreatography (MRCP) is a safe and accurate imaging modality; this study evaluated its use in a clinical algorithm for the management of suspected choledocholithiasis. PATIENTS AND METHODS Consecutive patients presenting with suspected common bile duct (CBD) stones were managed according to an algorithm involving the selective use of MRCP to identify patients who required endoscopic sphincterotomy and bile duct clearance. Following radiological demonstration of a clear CBD, all patients were considered for cholecystectomy. RESULTS From 157 consecutive patients, 68 proceeded straight to endoscopic sphincterotomy, which was therapeutic in 59. Of 89 who underwent MRCP, choledocholithiasis was demonstrated in 29; subsequent endoscopic sphincterotomy was therapeutic in 22. MRCP demonstrated a clear CBD in the remaining 60 patients. Seventy-four patients subsequently underwent cholecystectomy, with a conversion rate of 9% and a median postoperative stay of 1 day. There were no instances of post-sphincterotomy pancreatitis or haemorrhage requiring transfusion. CONCLUSION An algorithm involving selective MRCP with endoscopic sphincterotomy is a safe, effective means of managing suspected choledocholithiasis, particularly where the expertise, equipment or theatre time for laparoscopic bile duct exploration is not routinely available.

Ex vivo reversal of chemoresistance by tariquidar (XR9576).

The expression of P-glycoprotein (P-gp) has been demonstrated to confer resistance to several anticancer drugs, including anthracyclines, taxanes and vinca alkaloids. Tariquidar is a novel inhibitor of P-gp that has been shown to reverse resistance to cytotoxic drugs in tumor cell lines and mouse xenografts. We have used an ATP-based chemosensitivity assay (ATP-TCA) to compare the activity of cytotoxic drugs in combination with tariquidar against a variety of solid tumors (n=37). The expression of P-gp was determined in a subset of solid tumor samples by immunohistochemistry (n=16). Resistance was seen in 20 of 37 (54%) tumors tested with doxorubicin, in 27 of 34 (79%) samples tested with paclitaxel and 17 of 31 (55%) with vinorelbine. Tariquidar alone showed no activity over a wide range of concentrations up to 2 μM (n=14). The median IC90s for doxorubicin, paclitaxel and vinorelbine, alone were 2.57, 27.4 and 15.5 μM. These decreased to 1.67 (p<0.0005), 20.6 (p<0.05) and 9.5 μM (p<0.001), respectively, in combination with tariquidar. Tariquidar also significantly decreased resistance in 14 of 20 (70%), six of 27 (22%) and six of 17 (35%) samples tested with doxorubicin, paclitaxel and vinorelbine, respectively. Immunohistochemical staining for P-gp was positive in nine of 16 (56%) samples and in all of these cases addition of tariquidar improved the activity of the cytotoxic. The results show that tariquidar is able to decrease resistance in a number of solid tumors resistant to cytotoxic drugs known to be P-gp substrates. These data support the introduction of tariquidar in combination with chemotherapy to clinical trials of patients expressing P-gp.

Open and laparoscopically assisted oesophagectomy: a prospective comparative study.

OBJECTIVES Although a number of studies have examined minimally invasive approaches for oesophagectomy, these procedures have typically been offered only to selected patients with the limited long-term follow-up data. The purpose of this prospective study was to assess the feasibility of performing laparoscopically assisted oesophagectomy (LAO) for all-comers and to compare the short- and long-term clinical outcomes of this surgical strategy with a matched cohort of patients who had undergone open surgery. METHODS From November 2009, all patients referred for trans-thoracic resection of an oesophageal cancer underwent a two-stage laparoscopically assisted Ivor-Lewis oesophagectomy. This consisted of laparoscopic mobilization of the stomach and distal oesophagus, followed by open thoracotomy, thoracic lymphadectomy and intrathoracic anastomosis. The clinical and oncological outcomes of the first 39 consecutive LAO patients were compared with those of the preceding 31 consecutive patients who had undergone open surgery. RESULTS Of the 39 LAO cases, 37 cases were completed laparoscopically and 2 were converted to an open surgery. LAO was associated with a decreased incidence of postoperative complications (specifically cardiac and infectious complications) when compared with open surgery (54 vs 77%, P = 0.04). In addition, the initial intensive care unit stay (2 vs 4 days; P = 0.04) and overall length of hospital stay (14 vs 18 days; P = 0.02) were shorter in the LAO group. In terms of pathological outcomes, the lymph node yield and R0 resection rate of the LAO and open groups were comparable, as were the 1-year survival rates (62 vs 61%, P = 0.97). CONCLUSIONS LAO can be offered to an unselected cohort of all-comers with a reduced postoperative complication rate and comparable oncological and long-term survival outcomes when compared with open surgery.

Rapid up-regulation of cyclooxygenase-2 by 5-fluorouracil in human solid tumors.

Inhibition of cyclooxygenase (COX)-2 has been associated with reduced growth of malignant cells. Current therapy of gastrointestinal carcinomas involves the use of 5-fluorouracil (5-FU)-based chemotherapy and we have therefore studied the effect of this agent on the expression of COX-2. COX-2 expression was measured by quantitative RT-PCR in biopsies from a series of 14 esophageal carcinomas, six of which had paired samples taken before and after chemotherapy, and in tumor-derived cells exposed to 5-FU in vitro from a series of 44 tumors, including breast, ovarian, esophageal and colonic carcinomas. COX-2 expression was increased by exposure to 5-FU or 5-FU combination chemotherapy in all the tumor types studied, whether measured in biopsies taken before and after 5-FU-based chemotherapy (4-fold increase, p<0.015) or in primary cells exposed to drugs in vitro (24-fold increase, p<0.001). A modest increase of COX-2 mRNA was also seen after in vitro treatment of cells with cisplatin. In contrast, doxorubicin and paclitaxel caused no up-regulation in vitro, while irinotecan caused inhibition of COX-2 (2.7-fold decrease, p<0.01). These data provide a molecular rationale for clinical trials of combination chemotherapy with COX-2 inhibitors.

Combination chemotherapy in advanced gastrointestinal cancers: ex vivo sensitivity to gemcitabine and mitomycin C.

Advanced or metastatic disease is common in both oesophagogastric and colorectal cancers, with poor 5-year survival despite palliative chemotherapy. We have investigated the sensitivity of gastrointestinal tumours to gemcitabine in combination with mitomycin C (GeM), using a modified ex vivo ATP-based tumour chemosensitivity assay (ATP-TCA). Tumour material from 41 colorectal and 22 oesophagogastric cancers were assessed. The GeM combination showed variable but definite activity in most of the samples tested. The results show that GeM achieves >95% inhibition at concentrations within the range achievable clinically in 60% of colorectal tumours (21 out of 35) and 38% of oesophagogastric tumours (five out of 13) tested. We did not identify any significant difference in sensitivity using concurrent or sequential exposure of tumour-derived cells to these two drugs. The results from this study suggest that GeM may be a useful combination in the treatment of advanced gastrointestinal malignancy.

Defining Benchmarks for Transthoracic Esophagectomy: A Multicenter Analysis of Total Minimally Invasive Esophagectomy in Low Risk Patients

Objective: To define “best possible” outcomes in total minimally invasive transthoracic esophagectomy (ttMIE). Background: TtMIE, performed by experts in patients with low comorbidity, may serve as a benchmark procedure for esophagectomy. Patients and Methods: From a cohort of 1057 ttMIE, performed over a 5-year period in 13 high-volume centers for esophageal surgery, we selected a study group of 334 patients (31.6%) that fulfilled criteria of low comorbidity (American Society of Anesthesiologists score ⩽2, WHO/ECOG score ⩽1, age ⩽65 years, body mass index 19–29 kg/m2). Endpoints included postoperative morbidity measured by the Clavien-Dindo classification and the comprehensive complication index. Benchmark values were defined as the 75th percentile of the median outcome parameters of the participating centers to represent best achievable results. Results: Benchmark patients were predominantly male (82.9%) with a median age of 58 years (53–62). High intrathoracic (Ivor Lewis) and cervical esophagogastrostomy (McKeown) were performed in 188 (56.3%) and 146 (43.7%) patients, respectively. Median (IQR) ICU and hospital stay was 0 (0–2) and 12 (9–18) days, respectively. 56.0% of patients developed at least 1 complication, and 26.9% experienced major morbidity (≥grade III), mostly related to pulmonary complications (25.7%), anastomotic leakage (15.9%), and cardiac events (13.5%). Benchmark values at 30 days after hospital discharge were ⩽55.7% and ⩽30.8% for overall and major complications, ⩽18.0% for readmission, ⩽3.1% for positive resection margins, and ≥23 for lymph node yield. Benchmarks at 30 and 90 days were ⩽1.0% and ⩽4.6% for mortality, and ⩽40.8 and ⩽42.8 for the comprehensive complication index, respectively. Conclusion: This outcome analysis of patients with low comorbidity undergoing ttMIE may serve as a reference to evaluate surgical performance in major esophageal resection.

Ex vivo characterization of XR11576 (MLN576) against ovarian cancer and other solid tumors.

XR11576 (MLN576) is a novel monophenazine with a mechanism of action that includes interaction with both topoisomerase (Topo) I and II. The aim of this study was to evaluate its cytotoxicity against fresh tumor cells taken from patients with a variety of solid tumors. Cells were obtained from 89 patients and exposed for 6 days to XR11576 alone, or in combination with doxorubicin, cisplatin, treosulfan, paclitaxel or vinorelbine. Cell survival was measured using the ATP-Tumor Chemosensitivity Assay (ATP-TCA). Immunohistochemical staining of Topo I, Topo II&agr; and MDR1 was performed on paraffin-embedded blocks in those tumors for which tissue was available (n=49). Overall, the median IC90 and IC50 values of XR11576 in tumor-derived cells were 242 and 110 nM, respectively. In all samples XR11576 was more potent than the other cytotoxics tested. Breast and gynecological malignancies were most sensitive to XR11576, while the potency of this compound was slightly attenuated in gastrointestinal tumors, in which the median IC90 and IC50 values were 308 and 212 nM, respectively. Cases of synergism were identified when combining XR11576 with vinorelbine (nine of 30 samples) and doxorubicin (12 of 38 samples), while the addition of paclitaxel resulted in an antagonistic effect (CI50>1.2) in 38 of 42 tumors. A very modest correlation by linear regression analysis was found between the intensity of MDR1 staining and the IC50 of XR11576 (r=0.311, p=0.0312), but not with the IC90 (r=0.247, NS). These data support the rapid introduction of XR11576 to clinical trials and suggest that it may be effective against a broad spectrum of tumor types.