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R Rosell

Publications and source records attributed to R Rosell.

At least 37 records · Page 2Linked to original sources

Phase I study of weekly CPT-11 (irinotecan)/docetaxel in patients with advanced solid tumors.

Based on the synergistic cytotoxicity demonstrated in vitro by topoisomerase I inhibitors followed by docetaxel and the feasibility of giving both drugs on a weekly schedule avoiding overlapping toxicities, we designed a phase I trial of weekly CPT-11 (irinotecan)/docetaxel to determine the dose-limiting toxicities (DLT) and the maximum-tolerated dose (MTD) of this combination. Eighteen patients with advanced solid tumors treated with at least one prior chemotherapy regimen were included in this trial. CPT-11 was administered as a 90-min (intravenous) IV infusion followed immediately by docetaxel as a 30-min IV infusion. Both drugs were given on days 1, 8 and 15 in 4-week cycles. Four escalating dose levels of CPT-11/docetaxel (level I: 60/20 mg/m(2), level II: 60/25 mg/m(2), level III: 70/25 mg/m(2), and level IV: 70/30 mg/m(2)) were studied. Forty-seven cycles were administered (range, 1-5 courses) with a median number of 2.6 cycles per patient. Grade 4 leukopenia was the DLT reached at dose-level IV (CPT-11/docetaxel 70/30 mg/m(2)). Four patients had grade 3 anemia at dose levels III (two patients) and IV (two patients), while grade 3/4 thrombocytopenia was not seen. Grade 3/4 non-hematologic toxicities included grade 3 diarrhea in two patients (dose levels II and IV), grade 3 asthenia in one patient (dose level II) and grade 3 stomatitis in one patient (dose level I). The recommended dose of this weekly schedule is CPT-11 70 mg/m(2) and docetaxel 25 mg/m(2). DLT of this regimen is leukopenia, although toxicity is manageable at the recommended dose level. The activity of this regimen is being evaluated in a phase II study in previously treated patients with advanced non-small cell lung cancer.

Adult↗

Use of 201Tl SPECT imaging to assess the response to therapy in patients with high grade gliomas.

PURPOSE: To assess the potential role of 201Tl single photon emission tomography (201-Thallium SPECT) when compared to other imaging modalities in the evaluation of the response to therapy in high grade gliomas. MATERIALS AND METHODS: Twenty patients with histologically proved high grade glioma have been included: 15 with glioblastoma (GBM), 3 with anaplastic astrocytoma (AA) and 2 with anaplastic oligoastrocytoma (AOA). Patients were assessed by 201Tl SPECT, computed tomography (CT) and magnetic resonance imaging (MRI) at (a) either at the moment of maximum response to first line chemotherapy, or after the completion of radiotherapy and chemotherapy if post-surgical residual disease was present, and (b) after the completion of second line chemotherapy if disease persisted, or either a relapse or disease progression was confirmed. Final response was evaluated according to the McDonald criteria, and by comparing SPECT, CT and MRI results. RESULTS: According to the McDonald criteria, clinical response after first line chemotherapy was 5 partial response, 7 stable disease and 8 progressive disease. Evaluation by 201Tl SPECT was in agreement with such criteria in nearly all patients (90%). MRI findings closely agreed with the clinical follow-up. CT findings clearly differed from those observed by SPECT and MRI. After second line therapy, 10 patients progressed, 3 had stable disease and 7 had partial response. 201Tl SPECT agreed with the clinical status in 89% cases, whereas MRI and, specially CT, fared significantly lower. CONCLUSION: Compared to conventional neuroimaging, 201Tl SPECT added valuable information in the assessment of the response to therapy in our patient population; whenever findings were not conclusive and in the case of disagreement between CT and MRI findings.

Adult↗

Phase III randomised trial comparing paclitaxel/carboplatin with paclitaxel/cisplatin in patients with advanced non-small-cell lung cancer: a cooperative multinational trial.

BACKGROUND: The combination of paclitaxel with cisplatin or carboplatin has significant activity in non-small-cell lung cancer (NSCLC). This phase III study of chemotherapy-naïve advanced NSCLC patients was designed to assess whether response rate in patients receiving a paclitaxel/carboplatin combination was similar to that in patients receiving a paclitaxel/cisplatin combination. Paclitaxel was given at a dose of 200 mg/m(2) (3-h intravenous infusion) followed by either carboplatin at an AUC of 6 or cisplatin at a dose of 80 mg/m(2), all repeated every 3 weeks. Survival, toxicity and quality of life were also compared. PATIENTS AND METHODS: Patients were randomised to receive one of the two combinations, stratified according to centre, performance status, disease stage and histology. The primary analyses of response rate and survival were carried out on response-evaluable patients. Survival was also analysed for all randomised patients. Toxicity analyses were carried out on all treated patients. RESULTS: A total of 618 patients were randomised. The two treatment arms were well balanced with regard to gender (83% male), age (median 58 years), performance status (83% ECOG 0-1), stage (68% IV, 32% IIIB) and histology (38% squamous cell carcinoma). In the paclitaxel/carboplatin arm, 306 patients received a total of 1311 courses (median four courses, range 1-10 courses) while in the paclitaxel/cisplatin arm, 302 patients received a total of 1321 courses (median four courses, range 1-10 courses). In only 76% of courses, carboplatin was administered as planned at an AUC of 6, while in 96% of courses, cisplatin was given at the planned dose of 80 mg/m(2). The response rate was 25% (70 of 279) in the paclitaxel/carboplatin arm and 28% (80 of 284) in the paclitaxel/cisplatin arm (P = 0.45). Responses were reviewed by an independent radiological committee. For all randomised patients, median survival was 8.5 months in the paclitaxel/carboplatin arm and 9.8 months in the paclitaxel/cisplatin arm [hazard ratio 1.20, 90% confidence interval (CI) 1.03-1.40]; the 1-year survival rates were 33% and 38%, respectively. On the same dataset, a survival update after 22 months of additional follow-up yielded a median survival of 8.2 months in the paclitaxel/carboplatin arm and 9.8 months in the paclitaxel/cisplatin arm (hazard ratio 1.22, 90% CI 1.06-1.40; P = 0.019); the 2-year survival rates were 9% and 15%, respectively. Excluding neutropenia and thrombocytopenia, which were more frequent in the paclitaxel/carboplatin arm, and nausea/vomiting and nephrotoxicity, which were more frequent in the paclitaxel/cisplatin arm, the rate of severe toxicities was generally low and comparable between the two arms. Overall quality of life (EORTC QLQ-C30 and LC-13) was also similar between the two arms. CONCLUSIONS: This is the first trial comparing carboplatin and cisplatin in the treatment of advanced NSCLC. Although paclitaxel/carboplatin yielded a similar response rate, the significantly longer median survival obtained with paclitaxel/cisplatin indicates that cisplatin-based chemotherapy should be the first treatment option.

Adult↗

Kirsten ras mutations in patients with colorectal cancer: the 'RASCAL II' study.

Researchers worldwide with information about the Kirsten ras (Ki-ras) tumour genotype and outcome of patients with colorectal cancer were invited to provide that data in a schematized format for inclusion in a collaborative database called RASCAL (The Kirsten ras in-colorectal-cancer collaborative group). Our results from 2721 such patients have been presented previously and for the first time in any common cancer, showed conclusively that different gene mutations have different impacts on outcome, even when the mutations occur at the same site on the genome. To explore the effect of Ki-ras mutations at different stages of colorectal cancer, more patients were recruited to the database, which was reanalysed when information on 4268 patients from 42 centres in 21 countries had been entered. After predetermined exclusion criteria were applied, data on 3439 patients were entered into a multivariate analysis. This found that of the 12 possible mutations on codons 12 and 13 of Kirsten ras, only one mutation on codon 12, glycine to valine, found in 8.6% of all patients, had a statistically significant impact on failure-free survival (P = 0.004, HR 1.3) and overall survival (P = 0.008, HR 1.29). This mutation appeared to have a greater impact on outcome in Dukes' C cancers (failure-free survival, P = 0.008, HR 1.5; overall survival P = 0.02, HR 1.45) than in Dukes' B tumours (failure-free survival, P = 0.46, HR 1.12; overall survival P = 0.36, HR 1.15). Ki-ras mutations may occur early in the development of pre-cancerous adenomas in the colon and rectum. However, this collaborative study suggests that not only is the presence of a codon 12 glycine to valine mutation important for cancer progression but also that it may predispose to more aggressive biological behaviour in patients with advanced colorectal cancer.

Adolescent↗

Phase II trial of paclitaxel plus gemcitabine in patients with locally advanced or metastatic non-small-cell lung cancer.

PURPOSE: Given the cisplatin-related myelotoxicity and nonhematologic toxicities, we were prompted to undertake a study of the noncisplatin combination of paclitaxel plus gemcitabine to evaluate the efficacy, tolerance, and survival of this combination in patients with locally advanced and metastatic non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients received gemcitabine 2,000 mg/m(2) and paclitaxel 150 mg/m(2) on days 1 and 15 of a 28-day cycle, for a maximum of eight cycles. RESULTS: Between December 1997 and June 1998, 89 untreated NSCLC patients were enrolled; 30 (34%) had stage IIIB disease (23 with malignant pleural effusion and seven without), and 59 (66%) had stage IV disease. Eighty-six percent of patients had a performance status of 0 or 1. The median number of cycles administered was four (range, one to eight cycles). The mean dose-intensity for both paclitaxel and gemcitabine was nearly 100%. Hematologic and nonhematologic toxicities were mild. Thirty-eight patients received second-line chemotherapy after completion of the study. The overall intent-to-treat response rate was 32.2%, with a higher response rate for stage IIIB patients (43.3%) than for stage IV patients (26.3%). Overall median survival was 9.9 months, and 1-year survival was 38.8% (14.2 months for stage IIIB and 7.7 months for stage IV; P =.007). Median survival was 10.2 months for patients with a performance status of 0 or 1 and 4.8 months for patients with a performance status of 2 (P =.007). CONCLUSION: A biweekly paclitaxel/gemcitabine regimen was well tolerated, with an acceptable response rate and a reasonable median survival time, especially in patients with good performance status. It merits further exploration in future studies.

Adult↗

Chromosomal alterations in lung adenocarcinoma from smokers and nonsmokers.

The etiology of lung tumors arising in nonsmokers remains unclear. Although mutations in the K-ras and p53 genes have been reported to be significantly higher in smoking-related lung carcinomas, in the present study we performed a more comprehensive analysis in search of additional genetic changes between lung adenocarcinoma from tobacco- and non-tobacco-exposed patients. We selected a matched cohort of 18 lifetime nonsmoking and 27 smoking patients diagnosed with primary adenocarcinoma of the lung and searched for chromosomal alterations in each tumor by testing normal and tumor tissue with 54 highly polymorphic microsatellite markers located on 28 different chromosomal arms. Allelic losses or gains at chromosomal arms 3p (37 versus 6%), 6q (46 versus 12%), 9p (65 versus 22%), 16p (28 versus 0%), 17p (45 versus 11%), and 19p (58 versus 16%) were present significantly more often in adenocarcinomas from smokers than from nonsmokers. Chromosomal arms showing allelic imbalance in lung tumors from nonsmokers were rare but occurred more often at 19q (22%), 12p (22%), and 9p (22%). The FAL (fractional allelic loss or gain) is defined as the percentage of chromosomal arm losses/gains among the total informative chromosomal arms. Tumors from smokers harbored higher levels of FAL (13 (48%) of 27 showed FAL > or = 0.3) compared with the lung tumors from the nonsmoker patients (2 (11%) of 18 showed FAL > or = 0.3; P = 0.02; odds ratio, 0.13; 95% confidence interval, 0.01-0.79). Our data demonstrate that widespread chromosomal abnormalities are frequent in lung adenocarcinoma from smokers, whereas these abnormalities are infrequent in such tumors arising in nonsmokers. These observations support the notion that lung cancers in nonsmokers arise through genetic alterations distinct from the common events observed in tumors from smokers.

Adenocarcinoma↗

Prognostic value of K-ras mutations and allelic imbalance on chromosome 18q in patients with resected colorectal cancer.

PURPOSE: We designed this study to assess the frequency of K-ras mutations in patients with resected colorectal tumors and their association with survival. A second objective was to analyze the prognostic value of different K-ras genotypes. In a subgroup of patients we also investigated the presence of allelic imbalance on chromosome 18q and its relationship to clinical outcome. METHODS: One hundred fourteen colorectal tumors resected between 1983 and 1986 were analyzed to detect K-ras point mutations at codons 12, 13, and 61 by polymerase chain reaction followed by allele specific oligonucleotide hybridization. A subgroup of 77 tumors was further screened to detect loss of heterozygosity on chromosome 18q using three polymorphic microsatellite markers (D18S67, D18S474 and D18S58). RESULTS: K-ras mutations were detected in 29 percent (33/114) of patients. K-ras mutations correlated with age and preoperative carcinoembryonic antigen levels, and there was some indication that they may be linked to poor survival, especially in Stage II tumors, where a subgroup of patients with aspartic and serine mutations showed significantly reduced survival (P = 0.03) compared with K-ras-negative patients. 18q loss of heterozygosity was present in 39 percent (25/63) of tumors. A multivariate analysis of Stage II tumors showed that 18q loss of heterozygosity was significantly associated with a worse prognosis (P = 0.006). A significant decrease in survival was identified in ten patients harboring both genetic alterations (K-i mutations and 18q loss of heterozygosity; P = 0.02). CONCLUSIONS: In colorectal tumors, K-ras mutations and 18q loss of heterozygosity are two genetic markers which may identify patients with more aggressive behavior, mainly in Stage II tumors. These findings warrant further research, because they can be useful in customizing adjuvant chemotherapy.

Allelic Imbalance↗

Predicting response to paclitaxel/carboplatin-based therapy in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a systemic illness. The majority of newly diagnosed patients depend on systemic chemotherapy to improve outcome. Among the new chemotherapeutic agents recently tested, paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has shown convincing single-agent activity in advanced NSCLC. The two initial phase II studies using paclitaxel alone showed a 1-year survival rate of 40%, comparable to that seen with combination regimens. Paclitaxel/carboplatin is one of several standard regimens for patients with stage IIIB to IV disease. It is as effective as any other new agent/platinum combination studied to date; it is easy to administer and well tolerated. Identification of the molecular and genetic events involved in each step of tumor progression seems to be crucial both to understanding lung cancer and for the development of new pharmacologic compounds that target specific cellular processes affecting growth and proliferation. An innovative strategy is to combine established chemotherapy with these new compounds. Resistance to available chemotherapy drugs is the major obstacle to effective chemotherapy. Genetic abnormalities could play a role in outlining some patterns of chemoresistance. Acquired resistance to paclitaxel can be mediated by several mechanisms, including overexpression of p-glycoprotein, altered expression of beta-tubulin isotypes, intrinsic or acquired mutations in beta-tubulin, and expression of novel genes. Beta-tubulin mutations were recently identified in 33% of 49 NSCLC patients, none of whom had an objective response to paclitaxel treatment. Cisplatin resistance is associated with several molecular alterations, including overexpression of metallothionein and the mRNA level of the excision repair cross-complementing (ERCC1) gene. Early detection of circulating cancer cells in peripheral blood would enable more accurate lung cancer staging. Furthermore, sequential measurements of DNA concentration may be used to monitor the effects of therapy. Serum DNA can be used as a surrogate for detecting genetic abnormalities and as a potential guide for customizing treatment. We analyzed the presence of beta-tubulin mutations in serum DNA from NSCLC patients and from healthy individuals. Beta-tubulin mutations were detected in 42% of the 131 patients and in none of the control group. Several clinical studies are proposed to develop more customized approaches in lung cancer.

Antineoplastic Agents↗

Types and localisation of p53 gene mutations: a report on 332 non-small cell lung cancer patients.

Mutations of p53 suppressor gene are among the most common molecular abnormalities in human malignancies. We demonstrated earlier significant differences in mutational profiles between NSCLC patients from Poland and Spain. These differences were most probably related to ethnic and/or geographical factors. In the present study we analyzed the types and location of p53 gene mutations in a large group of 332 operated NSCLC patients from two institutions in Northern Poland. Within the last decades this region has been characterized by the highest incidence of lung cancer in Poland. We used both frozen and paraffin-embedded tumor samples and the screened region included exons from 5 to 8. A total of 96 samples (29%) were positive for p53 gene mutation. The proportion of mutations in particular exons was as follows: exon 5-33%, exon 6-22%, exon 7-16%, and exon 8-29%. Three 'hot spots' were located in codons 176,245 and 248. Evolutionary conserved domains were much more frequently affected than the regions outside domains. The majority of mutations (73%) were missense type, followed by null and silent mutations (21 and 6%, respectively). In all six silent mutations substituted was the third base in codon. There were no major differences in the types and locations of mutations between patients from the two institutions. This homogeneity, together with our earlier findings, may confirm the impact of ethnic and geographical factors on the mutational profile of p53 gene in NSCLC.

Aged↗

Drug resistance in non-small cell lung cancer.

There is an underlying feeling in the oncology community that chemotherapy has reached a therapeutic glass ceiling in non-small cell lung cancer (NSCLC) and that we will never attain the acceptable survival rates that are just beyond our reach. Multiple clinical trials have tested doublets, triplets and sequential chemotherapy in what is often regarded as a futile attempt to break through this ceiling. Recent large randomized trials have not demonstrated that any of these combinations is superior to any of the others. Nevertheless, the analysis of DNA or RNA from patients can permit us to assess genes that may be specific targets of certain cytotoxic agents and others that may be markers of multidrug resistance. With this in mind, the Spanish Lung Cancer Group has designed a trial to test the involvement of various genes in resistance to gemcitabine and cisplatin.

Adult↗

The role of chemotherapy in early non-small-cell lung cancer management.

Great advances have been made in chemotherapy in advanced and metastatic non-small-cell lung cancer (NSCLC), and a major milestone was reached with the administration of neoadjuvant chemotherapy in stage IIIA N2 disease. The systemic nature of lung cancer has been confirmed by many genetic analyses documenting micrometastases in negative lymph nodes and bone marrow, and mRNA gene overexpression as a surrogate of cancer cells has been identified in peripheral blood. Furthermore, serum or plasma cell-free tumor DNA has been observed even in tumors with a diameter of less than 2 cm. Pharmacogenetic screening can lead to tailored chemotherapy even in patients with early disease through the use of a genetic tool kit that will allow us to optimize the use of chemotherapy by using serial measurements of serum DNA that can help to detect residual disease and re-assess the chemosensitivity of sub-clinical micrometastatic disease. The ongoing (neo)adjuvant taxol/carboplatin hope (NATCH) trial is testing the value of three cycles of chemotherapy given pre- or post-operatively compared with surgery alone and will analyze genetic abnormalities in serum DNA at three different points during patient follow-up. Our major concern in this review is to analyze the pros and cons of chemotherapy in NSCLC. Although this review is not a formal meta-analysis, we have discussed the most relevant published studies in this field. We conclude that not only is there no evidence of detrimental effects of chemotherapy, in fact, there are many indications that chemotherapy induces response in up to 80% of patients and downgrades N2 disease in up to 50% of patients. This translates into significantly better survival when accompanied by complete resection. Since at least 50% of patients with stage IB disease develop distant metastases, it seems logical to explore the role of chemotherapy in early disease.

Antineoplastic Combined Chemotherapy Protocols↗

Risk factors and prognostic indicators of bacterial meningitis in a cohort of 3580 postneurosurgical patients.

In order to identify the incidence, risk factors and prognostic indicators of postneurosurgical bacterial meningitis, a 9-y retrospective cohort study was performed. The cohort comprised 3580 individuals who underwent neurosurgical operations at the Department of Neurosurgery of Catholic University, Rome, a 1,700-bed university hospital. We observed 52 episodes of postneurosurgical meningitis, with infection rates of 1.4/100 patients, 0.8/100 operations for craniotomies and 2.6/100 operations for internal cerebrospinal fluid (CSF) shunt or ventriculostomy with external drainage. The overall infection rate decreased from 2.5/100 operations in 1989 to 0.9/100 in 1997 (p = 0.03). Logistic regression analysis indicated that duration of ventriculostomy with external drainage [p < 0.01; odds ratio (OR) = 9.67; 95% confidence interval (CI) = 2.44-38.321 and increasing value of the APACHE III score (p <0.01; OR = 8.51; 95% CI = 2.15-33.68) were independent risk factors for development of meningitis. The overall case fatality rate was 8%. Predictors of mortality were low ( < 1.66 mmol/l) CSF glucose concentration (p = 0.001), increasing value of the APACHE IIl score (p = 0.002) and Gram-negative aetiology (p = 0.003).

APACHE↗

Predictive molecular markers in non-small cell lung cancer.

Recent biotechnologic knowledge has enabled the discovery of a cornucopia of genetic abnormalities commonly involved not only in cancer but also in other diseases ranging from the plague to arteriosclerosis. The wealth of possibilities uncovered by this knowledge inspires the hope that today's dream of a unified concept of common treatment for multiple diseases could become a future reality. This review arbitrarily categorizes recent findings into five major areas. First, cisplatin resistance associated with the nucleotide excision repair pathway can help clinical oncologists to choose between cisplatin and noncisplatin combinations. Second, the relevant role of nuclear factor-kappa B as a predictor of chemosensitivity can lead to the development of new drugs abrogating nuclear factor-kappa B expression. Third, the presence of tubulin mutations, which are directly involved in resistance to microtubule-interactive drugs, can guide chemotherapy based on taxane or nontaxane combinations. In addition, certain chromosomal deletions affect genes involved in deoxyribonucleotide synthesis, like ribonucleotide reductase, that intervene in gemcitabine metabolism; this raises interest in investigating deletion at chromosome 11p15.5 as a potential mechanism of gemcitabine resistance. Finally, an overwhelming number of publications have analyzed genes involved in cell cycle regulation and development as predictive markers of survival; however, where these pieces fit into the puzzle of cancer management is still unclear.

Biomarkers, Tumor↗

New strategies in the treatment of resectable non-small cell lung cancer.

Non-small cell lung cancer is a systemic illness. Given the systemic nature of lung cancer, it seems that chemotherapy should play an essential role. In stage IIIA disease neoadjuvant chemotherapy plus surgical resection improves survival when compared with surgical resection alone. However, randomized trials using postoperative adjuvant chemotherapy with 'older' drugs has shown no substantial improvement in survival. Since new chemotherapeutic agents may provide additional benefits, there are various studies incorporating new agents in the resectable disease treatment setting. One focus for ongoing research is to find better treatment approaches in earlier stages of disease. Some data suggest that induction chemotherapy in stage I-II is feasible and appears not to compromise surgery. Another promising more individual approach is to tailor chemotherapy according to the pattern of genetic variants or abnormalities found in DNA and/or RNA extracted from the bloodstream. Furthermore, at present many types of new agents are available for testing as 'consolidation treatment' following induction treatment, including, angiogenesis inhibitors, antibodies to growth factor receptors, gene therapy and vaccines.

Antineoplastic Agents↗

Advances in the treatment of non-small cell lung cancer: molecular markers take the stage.

Increasing evidence that non-small cell lung cancer is a systemic disease from the outset confirms the rationale for adjuvant chemotherapy. However, clinical trial evidence of benefit is still awaited. The position is clearer in the case of neoadjuvant therapy because long-term follow up of two trials now shows that patients randomized to chemotherapy before surgery were significantly more likely to survive to 5 years than patients treated with surgery alone. Early data suggest that neoadjuvant chemotherapy based on docetaxel (Taxotere; Aventis, Antony, France) (possibly used sequentially with other agents) may be as effective as older regimens and better tolerated. Because p53 status influences the expression of microtubule-associated proteins and hence the sensitivity of a tumor to taxanes, it is possible that molecular markers could be used to customize chemotherapy to individual patients. Generally, it is becoming clearer that molecular staging is a more sensitive means of demonstrating tumor dissemination than light microscopy. The Cancer and Leukemia Group B is undertaking a prospective study using reverse transcriptase-polymerase chain reaction to detect MUC-1 RNA in bone marrow and hilar and mediastinal lymph nodes removed at resection with the aim of distinguishing between stage I patients likely to remain disease-free for long periods and those at high risk of relapse. A study of small cell lung cancer is using automated fluorescence microscopy to detect keratin-positive cells in the marrow and blood of patients who have a complete response to initial therapy but are nevertheless at high overall risk of relapse. The identification of genetic lesions in a high proportion of patients with non-small cell lung cancer may guide the development of new therapies aimed at increasing rates of apoptosis among tumor cells.

Antineoplastic Agents↗

Novel approaches in the treatment of non-small-cell lung cancer.

A wealth of data indicates that certain genetic abnormalities can target specific cytotoxic drugs and intervene at an early step as a mechanism of resistance in the treatment of non-small-cell lung cancer. Therefore prescribing certain combinations of cytotoxic anticancer agents to a vast majority of these patients is futile. Genetic abnormalities have been found to be useful surrogate markers for response, particularly in colorectal cancer: thymidylate synthase mRNA and ERCC1 mRNA levels. In addition, beta-tubulin mutations may also confer paclitaxel resistance in patients. An important target to be explored for gemcitabine resistance is the assessment of a particular region in chromosome 11p15.5 wherein lies the ribonucleotide reductase gene that could affect gemcitabine metabolism. Shedding light on this genetic framework, several proposed customized chemotherapy studies could help validate the relevance of these markers.

Antineoplastic Combined Chemotherapy Protocols↗