The Clinical Research Of The Individual Treatment Of Non-Small Cell Lung Cancer With Gemcitabine Plus Platinum

Lung cancer remains the leading cause of cancer death in the world. About 80% Of lung cancer diagnosed were non-small cell lung cancer(NSCLC). Apart from a small number of patients via surgical resection, most patients have been in advanced stage (Ⅲ,Ⅳstage) when diagnosed and would experience a poor prognosis. Gemcitabine (2,2'-difluorodeoxycytidine), a new pyrimidine antimetabolite, is a novel deoxycytidine analog. On 1998, Gemcitabine was permitted to use as the front-line treatment of advanced NSCLC by FDA. Furthermore, combination of gemcitabine and platinums, paclitaxel, anthracycline and pyrimidine is widely used regimen for its acceptable high efficiency and lower toxicity.The serum concentration is often measured in patients clinically, to find the best chemotherapy to reduce side effects caused by chemotherapy and to provide provide the basis for individual administration. Pharmacogenomics is a kind of "individual" treatment according to the patient/tumor-specific genetic characteristics.It is a breakthrough in the current NSCLC chemotherapy.To investigate the relationship between peak concentration(Cmax)of fixed-dose-rate gemcitabine and hematological toxicity profile in patients with advanced NSCLC. The study was performed on patients, who were administered gemcitabine at a fixed dose rate (1200 mg/m2,over 120 min) with carboplatin. Plasma concentrations of gemcitabine were measured by ion-pair reversed-phase high-performance liquid chromatography.With the analysis of hematological toxicities, the relationship between Cmax and toxicity profile could supports gemcitabine administration with individuation in order to decrease the occurrence of ADR.Furthermore, the paper aims to study the expression of ribonucleotide reductase (RRM1), one of the gemcitabine targets, and breast cancer susceptibility gene (BRCA1), which also plays an important role on the NSCLC, in peripheral blood of NSCLC patients, and to discuss the relationship between the gene expression and gemcitabine/ platinum chemotherapy.SYBR real-time fluorescence quantitative PCR was used to assay gene expression level in tissue and peripheral blood of non-small cell lung cancer patients in this study. The quality control standards were established by optimizing the SYBR real-time fluorescence quantitative PCR working conditions, and the detection accuracy, precision and reproducibility were charactered. After construction of housekeeping gene p-actin plasmid standard, and SYBR real-time fluorescence quantitative PCR analysis, the standard curve was prepared. Following, the RRM1 (AF107045), BRCA1 (U14680) and the housekeeping gene p-actin (AY582799) mRNA were detected in peripheral blood of 20 cases of non-small cell lung cancer. The difference and relativity of expression levels in RRM1 and BRCA1 in tumor tissue, peripheral blood and/or adjacent tissues were evaluated. At the same time, 37 cases of NSCLC patients were selected randomly and subjetcted gemcitabine 1200 mg/m2 (d1, d8) combined carboplatin (AUC5; d1) as he standard first-line NSCLC chemotherapy, whose RRM1 and BRCA1 expression level in peripheral blood were detected, and clinical significances were estimated.The data was analysied by SPSS 15.0 statistical software. Gene expression differences in tumor tissue, normal tissue, lymph tissue and peripheral blood were analysed by independent sample ONE-WAY ANOVA test. RRM1 and BRCA1 expression in peripheral blood were analyzed by linear correlation analysis and X2 test. Overall survival comparison used the Kaplan-Meier survival curve and log-rank test analysis. Related factors that affecting patients with advanced NSCLC survival were analyzed by COX regression analysis method. Twenty-one patients were enrolled in the study with advanced NSCLC to evaluate the efficacy and safety of gemcitabine in combination with carboplatin at a fixed dose rate (gemcitabine 1,200 mg/m2 over 120 min). Of the 21 eligible patients, the best response to treatment was assessed as a partial response (PR) in 10 patients, for an overall objective response rate of 47.6%,and a stable disease in 7 patients. The estimated median time to tumor progression (TTP) was 7 months (95% CI 4-10 months), median overall survival (OS) was 12 months (95% CI 11.2-12.8 months). The mean value of Cmax of eligible patients was 4.95±2.42μg/ml. The main hematological toxicities were transient grade III-IV thrombocytopenia and neutropenia. The Cmax of gemcitabine and the percentage of reduction in WBC showed a significant correlation (r2=0.4575,p<0.05). A significant correlation (r2=0.5671,p<0.05) was also observed between the percentage of reduction of PLTC and Cmax of gemcitabine.RRM1 expression in tumor tissue was significantly higher than those in normal tissues and lymphoid tissue (P<0.05), while the expressions of BRCA1 in tumor tissues, normal tissues and lymphoid tissues were no significant difference (P>0.05). RRM1 and BRCA1 expression in peripheral blood was significantly lower than that in tissue(P<0.05). This suggests that RRM1 expression and tumor proliferation activity is closely related, even with the possibility of that drug resistance is correlated with chemotherapy. BRCA1 expression and tumor activity does not seem very closely related. That are yet to be confirmed by further studies.The survival of patients with clinical and pathological factors was assessed. The results show that the chemotherapy sensitivity of different groups (CR+PR Vs SD+PD) had a significant effect on the survival (19.50 Vs 12.88, log-rank 8.392, P= 0.004), but the survival difference of groups with different gender, TNM stage, smoking status, pathological type, PS grade (P values were 0.833,0.943,0.927, 0.487,0.803) was not statistically significant.RRM1 and BRCA1 expression and survival were correlated. RRM1 expression of the low group had a longer survival time than the high group (16.95 Vs 12.76, log-rank 3.989, P=0.046). although survival curves of BRCA1 Low expression group were above the high expression group, the difference was not statistically significant (16.80 Vs 13.77, log-rank 0.830, P=0.362). The patient's gender, TNM stage, smoking status, PS score, histological type and RRM1,BRCA1 expression were analysed using COX regression analysis model. It was found that though it is not sure that RRM1 is the independent factor impacting prognostic (hazard ratio: 2.586; 95% CI:0.967～6.916; p=0.058) through peripheral blood evaluation.Above all, Patients with advanced NSCLC were given gemcitabine by 120 min infusion (at a fixed dose rate) on days 1 and 8 and combination with carboplatin. Of the 21 eligible patients, an overall objective response rate is 47.6%. The main hematological toxicities were transient grade III-IV thrombocytopenia and neutropenia. RRM1 expression in peripheral blood isn't the independent factor impacting prognostic, however, RRM1 also can be used as a reference for clinic since its prognostic trend. In advanced NSCLC, Low expression of RRM1 had a longer survival than the high expression group, which is helpful for selecting patients to receive gemcitabine plus platinum as first-line chemotherapy, and provide a scientific basis for clinical treatment.