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In the last 50 years, 5-fluorouracil-based therapy has been the mainstay of adjuvant and palliative treatment for colorectal cancer but response rates and median survival have been dismal despite the introduction of thymidylate synthase modulators such as leucovorin. Recently, new therapeutic approaches have been introduced. These include oral 5-fluorouracil analogues, pure thymidylate synthase inhibitors, dihydropyrimidine dehydrogenase inhibitors, and agents with mechanism of action unrelated to thymidylate synthase such as irinotecan, a topoisomerase I inhibitor, and oxaliplatin, the only platinum derivative with significant activity in colorectal cancer. Current treatment strategies involve combination therapies because this approach is the most effective. For instance, responses observed with oxaliplatin and 5-fluorouracil indicate synergy between the two agents and the combination of capecitabine plus oxaliplatin or irinotecan has shown high activity both in chemotherapy-naive and in pretreated patients with advanced colorectal cancer. Additionally, it is likely that future therapeutic management of advanced colorectal cancer may include combination therapy of one of the new oral 5-fluorouracil analogues, because of the convenient oral regimens. The identification of colorectal cancer-specific prognostic factors will undoubtedly influence treatment decisions. For instance, patients overexpressing epidermal growth factor receptor and p53 with thymidylate synthase have a worse prognosis. To target these biomarkers, antibodies such as cetuximab, an anti-EGFR antibody, and angiogenesis inhibitors and tyrosine kinase inhibitors have been introduced and are undergoing clinical evaluation. Over the last 5 years the armamentarium to fight colorectal cancer has increased significantly, giving more hope for effective disease management.
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PMID:The role of oxaliplatin in the treatment of advanced metastatic colorectal cancer: prospects and future directions. 1242 6

Progress in the treatment of colon cancer depends on the development of target-based molecules built on an improved understanding of the molecular biology of the disease. Defining end points for chemotherapy resistance is needed as drug resistance develops quickly and patients demonstrate variation in response to chemotherapy. Many techniques that measure a marker's preponderance have been developed including biochemical, immunohistochemical, genomics, proteomics or a combination thereof. However, standardization of these techniques that measure either genes or their protein products is urgently needed. This article reviews several markers (TS,TP, DPD, FT, EGFR, VEGF, CD44v6, TRAIL, microsatellite instability, allelic deletions, oncogenes and suppressor genes [c-myc, Ki-Ras, p53, p21, Topo I, Topo IIalpha, Fos, hMLH1, Bcl-2/Bax and MDR1], MDR-related proteins [Pgp, MRP and LRP], genomic polymorphisms [XPD, ERCC1, GSTP1 and TS 3 -UTR] and COX-;2) that influence DNA metabolism, DNA damage, programmed cell death, the immune or vascular system, or lead to mutations. When combined together and tested by newly developed genomic and proteomic approaches, many of these markers provide a more sensitive indicative predictor of response than when evaluated separately or by older biochemical, immunohistologic or morphologic methods. A global approach involving the simultaneous testing of several predictive multimarkers will provide critical information for improving chemotherapy to alleviate suffering from this disease.
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PMID:Molecular markers that predict response to colon cancer therapy. 1593 13

Malignant gastrointestinal tumors are still worldwide a very common cause of death from cancer. Even though the surgical techniques and the neoadjuvant/adjuvant therapies have improved over the last years and multimodal concepts in cancer treatment have been established, these types of tumors remain a challenge. Therefore predictive/prognostic markers need to be established, to be able to tailor chemotherapies and therefore improve efficacy of neoadjuvant/adjuvant treatment. Over the last years potential predictive/prognostic factors have been characterized by molecular-biological technologies: the tumor suppressor gene p53, the cell-cycle regulatory proteins p21 and p27, the marker of proliferation Ki-67, the epidermal growth factor receptor, HER2/neu, angiogenetic factors (the vascular endothelial growth factor, cyclooxygenase 2, thymidine phosphorylase), enzymes involved in the DNA-repair-system (ERCC1), enzymes involved in the 5-fluorouracil-metabolism (thymidylate synthase, dihydropyrimidine dehydrogenase) or other genetic alterations, like the loss of heterozygosity or the microsatellite instability. The results of the mainly retrospective studies are promising but prospective studies are needed to validate those markers in the therapy of gastrointestinal tumors. The goal is that we will be able to predict when and with what to treat.
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PMID:[Predictive and prognostic factors in the neoadjuvant/adjuvant therapy of gastrointestinal tumors: wishful thinking or reality?]. 1661 82

The potential of gene expression profiles to predict the response to neoadjuvant chemotherapy in patients with advanced adenocarcinoma of the esophagus was analyzed. Paraffin-embedded endoscopic esophageal tumor biopsies of 38 patients with advanced esophageal adenocarcinoma (Barrett's adenocarcinoma) were included. All patients underwent two cycles of cisplatin and fluorouracil (5-FU) therapy with or without additional paclitaxel (taxol) followed by abdominothoracal esophagectomy. RNA expression levels of 5-FU-metabolism associated genes thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), methylenetetrahydrofolate reductase (MTHFR), MAP7, ELF3, as well as of platinum and taxane associated related genes caldesmon, excision cross-complementing genes (ERCC1 and ERCC4) HER2-neu, DNA damage-inducible gene 45 (GADD45) and multidrug resistance genes (MDR1, MRP1) were determined using real-time RT-PCR. Expression levels were correlated with the histopathological response to chemotherapy assessed in surgically resected specimens. Responding patients showed significantly higher pretherapeutic expression levels of MTHFR (p = 0.012), Caldesmon (p = 0.016), MRP1 (p = 0.007) and MDR1 (p = 0.025). In addition, patients with high pretherapeutic MTHFR and MRP1 levels had a survival benefit after surgery (p = 0.013 and p = 0.015, respectively). Additionally, intratumoral heterogeneity of gene expression of selected genes (TP, DPD, MTHFR, HER2-neu, Caldesmon, ERCC4, MRP1) was additionally verified in 9 untreated Barrett's adenocarcinoma by examination of 5 distinct tumor areas and was observed in 12.7% (5.6%-23.5%, CI 95%) of all cases analyzed. Our results indicate that determination of mRNA levels of a few genes may be useful for the prediction of the success of neoadjuvant chemotherapy in individual cancer patients with advanced adenocarcinoma of the esophagus.
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PMID:[Prediction of response to neoadjuvant chemotherapy in Barrett's carcinoma by quantitative gene expression analysis]. 1689 54

Molecular markers predicting the efficacy of CPT-11 based chemotherapies in patients with colorectal cancer (CRC) are unknown. Therefore, we investigated whether mRNA levels of drug targets (Topoisomerase I, TS), enzymes involved in 5-FU metabolism (DPD), in angiogenesis (EGFR, IL-8, VEGF) and in DNA-repair/drug detoxification (ERCC1, GST-P1) are associated with the clinical outcome of patients with CRC treated with first-line CPT-11 based chemotherapy. Thirty three patients with metastatic CRC were included in the study. Intratumoral gene expression levels were assessed from paraffin-embedded tissue samples, using laser capture microdissection and quantitative Real-Time PCR. Complete response was observed in 1 patient, partial response in 12 patients, stable disease in 13 patients and progressive disease in 6 patients. Response was inevaluable for 1 patient. Patients with complete response or partial response were classified as responders, while patients with stable disease or progressive disease were classified as nonresponders. High intratumoral mRNA levels of EGFR, ERCC1 and GSPT-P1 were each significantly associated with response to CPT-11 based chemotherapy. Recursive partitioning analysis showed that mRNA levels of EGFR and ERCC1 are primarily responsible for delineating responders from nonresponders. Also, the combination of high intratumoral gene expression levels of both EGFR and ERCC1 was significantly associated with progression-free survival. The mRNA levels of EGFR had a significant correlation with expression levels of ERCC1, GST-P1 and VEGF. This small retrospective study suggests that gene expression levels of EGFR, ERCC1 and GST-P1 may be useful in predicting the clinical outcome of patients with metastatic CRC treated with first-line CPT-11 based chemotherapy.
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PMID:Molecular determinants of irinotecan efficacy. 1689 65

Current choice of cancer therapy is usually empirical and relies mainly on the statistical prediction of the treatment success. Molecular research provides some opportunities to personalize antitumor treatment. For example, life-threatening toxic reactions can be avoided by the identification of subjects, who carry susceptible genotypes of drug-metabolizing genes (e.g. TPMT, UGT1A1, MTHFR, DPYD). Tumor sensitivity can be predicted by molecular portraying of targets and other molecules associated with drug response. Tailoring of antiestrogen and trastuzumab therapy based on hormone and HER2 receptor status has already become a classical example of customized medicine. Other predictive markers have been identified both for cytotoxic and for targeted therapies, and include, for example, expression of TS, TP, DPD, OPRT, ERCC1, MGMT, TOP2A, class III beta-tubulin molecules as well as genomic alterations of EGFR, KIT, ABL oncogenes.
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PMID:Molecular-based choice of cancer therapy: realities and expectations. 1730 83

Combined modality therapy is gaining acceptance for treating stage 3 and 4A thymic tumors. Also, specific subsets of stage 2 tumors deserve particular attention. Single-center experiences demonstrate that there are some advantages in selected groups of patients. The overall relatively low complete response rate, however, imposes the search for better systemic therapy to optimize results. In fact, although thymic tumors are responsive to different cytotoxic regimens, none has been demonstrated to be the ideal one. New therapies and strategies should be designed and tested in large-scale multicenter prospective trials. Among the others, epidermal growth factor receptor inhibitors have shown some clinical response, because EGFR is overexpressed in thymoma. c-KIT is overexpressed in thymic carcinoma. Although in a recent study a clinical response to imatinib has been reported, results of a prospective study in patients who have thymic carcinoma are pending. Clinical responses have been reported also to other tyrosine kinase inhibitors, such as dasatinib. Other reports have stressed the presence of an up-regulation of COX-2 with a potential separate therapeutic pathway. Other markers, such as the expression of thymidine synthase and dihydropyrimidine dehydrogenase, which predict sensitivity to 5-fluoruracil-based chemotherapy, were not correlated with the clinicopathological characteristics in a series of thymomas. These new therapies should be incorporated in a standardized approach that goes from a careful assessment of histology, staging, and lymph node status, and a constructive and nonempiric cooperation between the oncologist, radiotherapist, pathologist, and thoracic surgeon.
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PMID:Multimodality treatment of thymic tumors. 1928 22

We evaluated the usefulness of the level of thymidylate synthase(TS)and dihydropyrimidine dehydrogenase(DPD) activity as prognostic factors and indicators for selection of chemotherapy regimens. Between November 1997 and March 1999, fifty-seven patients with stages I - IIIa primary breast cancer were registered. Using recurrence risk categories, they were classified into TAM monotherapy, TAM+oral 5-FU, and TAM+CMF groups(each were standard regimens at the time), and underwent postoperative adjuvant chemotherapy. The relationship between prognosis and the TS level and DPD activity, in addition to conventional risk factors, was examined. The recurrence-free survival time curve showed significant differences when stratified by tumor diameter, ER expression, and TS levels, but not by menopausal status, nodal status, surgical method, p53 expression, DPD activity, or HER2 expression. These results suggest that the TS level is useful as a prognostic factor for breast cancer.
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PMID:[Clinical significance of intratumoral TS levels and DPD activity in breast cancer]. 1929 64

Recurrence after neoadjuvant chemo-radiotherapy (CRT) followed by surgery is high in patients with esophageal cancer. No standard second line therapy is currently available for patients with recurrence. This study aimed to evaluate the expression of chemo-radiosensitive genes after neoadjuvant CRT in residual tumor cells. Thirteen patients with esophageal squamous cell carcinoma underwent 5-fluorouracil (5-FU) and cisplatin (CDDP) based CRT followed by surgery. Total RNA was successfully obtained from 6 formalin-fixed paraffin-embedded (FFPE) specimens using proteinase K digestion and phenol chloroform extraction. TS and DPD as the 5-FU pathway gene, ERCC1 as the CDDP pathway gene, and EGFR, VEGF, HIF1a as radioresistant genes were measured using real-time reverse transcription polymerase chain reaction; comparing the mRNA level of each gene in pre-CRT biopsy with that in post-CRT FFPE specimens. Five patients had less than one-third residual tumor cells in resected specimens histopathologically; eight had more than two-thirds residual tumor cells. There were significant increases in TS (p=0.02) and DPD (p=0.01) levels in residual tumor cells after CRT. Significant decreases in ERCC1 (p=0.03), EGFR (p=0.01), VEGF (p=0.003) and HIF1a (p=0.003) levels were observed. 5-FU and CDDP based CRT up-regulated 5-FU pathway genes and down-regulated CDDP pathway and radioresistant genes. The expression of chemo-radiosensitive genes was significantly changed in residual tumor cells after CRT. Gene expression analysis of residual tumor cells in FFPE specimens may be useful when selecting a second line chemotherapy regimen for recurrent esophageal cancer after CRT.
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PMID:Clinical significance of the gene expression profile in residual tumor cells after neoadjuvant chemo-radiotherapy for esophageal cancer. 1942 28

Some general and specific, statutory, clinical and biological parameters have to be taken into account before beginning chemotherapy in colorectal cancer to ensure maximal safety. Statutorily the prescription is reserved to specialised or competent physicians in oncology in some accredited institutions. It is essential to conform to indications, contraindications and posology, and to have a good knowledge of safety measures, drug interactions and side effects. Patients, family members and general practitioners should be informed about side effects, without forgetting some thematics (sexuality, fertility, contraception, vaccines, driving). This information should be simple, adapted and "reassuring", but should focus on symptoms indicating a serious toxic side effect. The message can be optimized by nurse consultation, transmission of the individualized care plan and linkage notebook, such as oral chemotherapies (capecitabine, UFT). The computerized and standardized prescription is done after infusion line inspection, clinical examination (global health status, nutritional status and buccodental status) and review of relevant pathological, radiological and biological data. Management of side effects includes patient education, appropriate premedication and prescription of prophylactic supportive care. Some specific preventive measures can attenuate the cutaneous side effects of EGFR inhibitors and the oxaliplatine-induced sensory neurotoxicity. Life expectancy, comorbidities, level of dependence, and if possible the comprehensive geriatric assessment should be taken into account for elderly patients. Prescription should be individualized and adapted to liver biology (irinotecan), kidney function (capecitabine and raltitrexed) and cardiovascular status (bevacizumab, 5-FU, capecitabin). Some molecular biologic prerequisites are indicated: detection of tumor KRAS-BRAF mutation before anti-EGFR and tumor microsatelliteinstability status before 5-FU in stage II cancers. Clinical relevance of others pretherapeutic molecularparameters are still being evaluated: UGT1A1 genotyping before irinotecan and detection of dihydropyrimidine dehydrogenase deficiency before fluoropyrimidines.
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PMID:[Prerequisites to the administration and prevention of adverse effects of chemotherapy in colorectal cancer]. 2008 Apr 56


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