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Colorectal cancer (CRC) is one of the most common malignancies in the western world. The majority of patients who develop this tumour will ultimately die from metastatic disease. The fluorinated pyrimidine 5 fluorouracil (5-FU) is at present the most active drug available for first-line therapy of this disease. Randomised studies have consistently demonstrated a survival advantage from early treatment with 5-FU in advanced CRC, which can be achieved without deterioration in quality of life. Despite over 30 years of use, the optimal 5-FU schedule remains controversial with a wide range of response rates reported in the literature. Single agent activity is in the order of 10 - 11% [1,2]. In an attempt to improve response rates, modulation of 5-FU with a variety of agents has been intensively investigated.This article examines the role of interferon-α in the treatment of advanced CRC.

BACKGROUND. The results of chemotherapy for patients with esophagogastric carcinoma have generally been modest but regimens developed more recently have produced higher response rates, and rekindled interest in neoadjuvant chemotherapy. One such regimen is epirubicin, cisplatin, and 5-fluorouracd (ECF). This study evaluates its efficacy, toxicity, impact on quality of life (QL), and impact on survival in a large consecutive series of patients with metastatic and locally advanced disease (LAD). METHODS. Patients with histologically confirmed esophagogastric carcinoma were treated with ECF (epirubicin 50 mglm' and cisplatin 60 mglm' every 3 weeks with continuous infusion of 5-fluorouracil (5-FU) 200 mg/m'/d). Responses were evaluated with computed tomography (CTJ scan and endoscopy. QL was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire. RESULTS. A total of 235 patients were treated, 173 with metastatic disease and 62 with LAD. The mean number of cycles delivered was 6 (range: 1-11) and patients were followed-up for a median of 8 months. Response was observed in 135 of 220 (61%) evaluable patients, with a complete response (CR), 11% of the patients and a partial response in 50% of the patients. Patients with moderately differentiated adenocarcinomas and LAD responded most favorably. Symptomatic improvement was achieved in the majority of cases (63-78% depending on the symptom). Toxicity was generally only mild to moderate, with severe non hematologic toxicity in less than 12% of the patients and only 6 (2.5%) treatment related deaths. QL assessment showed no significant negative impact on emotional functioning and good symptomatic control. Surgery following response to ECF was performed in 29 of the LAD patients, and in 19 cases (66%) a potentially curative resection was possible, with histologic CR in 32% of the patients. CONCLUSIONS. ECF is a highly active regimen with acceptable toxicity in patients with esophagogastric adenocarcinoma. In a proportion of patients with LAD, chemotherapy enabled potentially curative surgery to be performed. The results justify further investigation of this regimen in a neoadjuvant setting. Cancer 1996; 721978-85. 0 1996 Americari Cancer Society.

The administration of anti-cancer agents is currently associated with significant toxicity and lack of tumour specificity. Prodrugs are being designed to favourably alter the therapeutic index of these agents by improving their efficacy and reducing toxicity. Progress in the development of prodrugs including the cytotoxic agents most commonly used in cancer treatments namely 5-fluorouracil (5-FU), the anthracyclines, paclitaxel and platinum will be described. Many of these agents are at an early stage of development: however, this article will also describe those which have already made an impact in the clinic. It is likely that future improvements in care will come from refinement of the drugs already well established in clinical practice. In addition, this technology could be applied to novel agents with alternative cellular targets such as those involved in angiogenesis or in conferring metastatic potential. Thus, lessons learned with standard drugs may be applicable across a wider spectrum of therapeutics.

Aberrations in the components of cell-cycle checkpoints are a common feature of many tumours and several have been shown to have prognostic significance in colorectal cancer. In this study, seven components of cell-cycle control [cyclin D1, retinoblastoma (pRb), p21, p27, p16, p53, and proliferating cell nuclear antigen (PCNA)] were examined in a large series of well-characterized colorectal adenocarcinomas using immunohistochemistry to ascertain co-regulation and influence on survival. The majority (92%) of the tumours had abnormal staining ofor =2 cell-cycle control factors. Expression of cyclin D1 protein was correlated with both p21 (p0.001) and p27 (p=0.033), suggesting co-regulation of these proteins in colorectal tumours. Only cyclin D1 (p=0.048) and p53 (p=0.025) were directly associated with PCNA levels, suggesting a more important role in the proliferative capacity of tumour cells. Significant associations between cell cycle-related proteins and clinicopathological data were observed: cyclin D1 and p53 proteins were correlated with patient age (p=0.042 and p0.001, respectively) and p53 (p=0.01) and p21 (p=0.024) proteins were associated with tumour site. Expression of cyclin D1 protein was the only protein examined that was related to improved outcome in these patients (p=0.0266), but it was not an independent predictor of survival. These results suggest that loss of control of cell-cycle checkpoints is a common occurrence in colorectal tumours and may be an important therapeutic target.

A wide range of tumor response is seen amongst patients with the same stage of colorectal cancer, even with the use of uniform chemotherapy. The significant economic and personal impact of chemotherapy provides the impetus for the identification of markers of response for use in guiding patient treatment. However, practical constraints prevent evaluation of all putative markers in a definitive manner. In this study, the enrichment approach was evaluated by examining the expression of a panel of putative response markers in selected patient populations with advanced colorectal cancer (i.e., those demonstrating the best and the poorest clinical response to a standardized 5-fluorouracil/folinic acid chemotherapy regimen). Patients showing a good response had a significantly increased survival when compared with poor responders (P=0.0013). Markers were then ranked for clinical importance based on differences in expression between the two groups. This allows for the relatively rapid and inexpensive investigation of multiple markers, using defined patient groups. Bcl-2 overexpression in primary colorectal tumor specimens was found to correlate with clinical response of metastatic deposits to chemotherapy (P=0.044), as did the site of the primary tumor (P=0.011). However, no clear association was observed between response status and the other examined factors (p53, PCNA, TP, MMPs 1, 2 or 9, TIMPs 1 or 2, TS, Dukes' stage at initial diagnosis, histological grade, sex or age). This approach has allowed prioritization of markers of clinical response on which larger, statistically definitive studies will be performed.

PURPOSE: To determine the effect of eniluracil on colorectal tumor dihydropyrimidine dehydrogenase (DPD) activity. PATIENTS AND METHODS: Patients who were to undergo primary colorectal tumor resection received oral eniluracil 10 mg/m2 twice daily for 3 days before surgery. Mononuclear cells were obtained before the start of eniluracil and on the morning of surgery, to measure DPD activity, protein, and mRNA. Plasma uracil was also measured at these two time points to assess the effect of eniluracil on pyrimidine accumulation. DPD activity, protein, and mRNA were also assessed in colorectal tumors and adjacent normal mucosa of patients who received eniluracil and untreated control patients. RESULTS: DPD activity in tumors from 10 untreated patients ranged from 30 to 92 pmol/min/mg of protein. In contrast, there was no detectable tumor DPD activity in 10 patients who received eniluracil. A similar pattern was observed in mononuclear cells, where median pretherapy activity was 366.5 pmol/min/mg of protein (range, 265 to 494 pmol/min/mg of protein) and was undetectable immediately before surgery. Plasma uracil changed from a median less than 0.2 μmol/L before therapy to 27.76 μmol/L before surgery. No difference in DPD protein or mRNA was observed between pretherapy and presurgery mononuclear cell samples or between treated and untreated tumor samples. CONCLUSION: This study provides definitive evidence that eniluracil completely inactivates DPD activity in human solid tumors. The increased plasma uracil and decreased DPD activity are consistent with systemic inactivation of the enzyme. The mechanism of inactivation is at the catalytic level, because no changes in DPD protein or mRNA were observed. Treatment with eniluracil will eliminate DPD activity as a source of pharmacokinetic fluorouracil variability or resistance in human colorectal cancer.