Recent applications of chemosensitivity tests for colorectal cancer treatment

Summary To characterize somatic alterations in colorectal carcinoma (CRC), we conducted genome-scale analysis of 276 samples, analyzing exome sequence, DNA copy number, promoter methylation, mRNA and microRNA expression. A subset (97) underwent low-depth-of-coverage whole-genome sequencing. 16% of CRC have hypermutation, three quarters of which have the expected high microsatellite instability (MSI), usually with hypermethylation and MLH1 silencing, but one quarter has somatic mismatch repair gene mutations. Excluding hypermutated cancers, colon and rectum cancers have remarkably similar patterns of genomic alteration. Twenty-four genes are significantly mutated. In addition to the expected APC, TP53, SMAD4, PIK3CA and KRAS mutations, we found frequent mutations in ARID1A, SOX9, and FAM123B/WTX. Recurrent copy number alterations include potentially drug-targetable amplifications of ERBB2 and newly discovered amplification of IGF2. Recurrent chromosomal translocations include fusion of NAV2 and WNT pathway member TCF7L1. Integrative analyses suggest new markers for aggressive CRC and important role for MYC-directed transcriptional activation and repression.

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, has shown promising preclinical and clinical activity against metastatic colorectal cancer, particularly in combination with chemotherapy. Of 813 patients with previously untreated metastatic colorectal cancer, we randomly assigned 402 to receive irinotecan, bolus fluorouracil, and leucovorin (IFL) plus bevacizumab (5 mg per kilogram of body weight every two weeks) and 411 to receive IFL plus placebo. The primary end point was overall survival. Secondary end points were progression-free survival, the response rate, the duration of the response, safety, and the quality of life. The median duration of survival was 20.3 months in the group given IFL plus bevacizumab, as compared with 15.6 months in the group given IFL plus placebo, corresponding to a hazard ratio for death of 0.66 (P<0.001). The median duration of progression-free survival was 10.6 months in the group given IFL plus bevacizumab, as compared with 6.2 months in the group given IFL plus placebo (hazard ratio for disease progression, 0.54; P<0.001); the corresponding rates of response were 44.8 percent and 34.8 percent (P=0.004). The median duration of the response was 10.4 months in the group given IFL plus bevacizumab, as compared with 7.1 months in the group given IFL plus placebo (hazard ratio for progression, 0.62; P=0.001). Grade 3 hypertension was more common during treatment with IFL plus bevacizumab than with IFL plus placebo (11.0 percent vs. 2.3 percent) but was easily managed. The addition of bevacizumab to fluorouracil-based combination chemotherapy results in statistically significant and clinically meaningful improvement in survival among patients with metastatic colorectal cancer. Copyright 2004 Massachusetts Medical Society

On the basis of a previous meta-analysis, the International Adjuvant Lung Cancer Trial was designed to evaluate the effect of cisplatin-based adjuvant chemotherapy on survival after complete resection of non-small-cell lung cancer. We randomly assigned patients either to three or four cycles of cisplatin-based chemotherapy or to observation. Before randomization, each center determined the pathological stages to include, its policy for chemotherapy (the dose of cisplatin and the drug to be combined with cisplatin), and its postoperative radiotherapy policy. The main end point was overall survival. A total of 1867 patients underwent randomization; 36.5 percent had pathological stage I disease, 24.2 percent stage II, and 39.3 percent stage III. The drug allocated with cisplatin was etoposide in 56.5 percent of patients, vinorelbine in 26.8 percent, vinblastine in 11.0 percent, and vindesine in 5.8 percent. Of the 932 patients assigned to chemotherapy, 73.8 percent received at least 240 mg of cisplatin per square meter of body-surface area. The median duration of follow-up was 56 months. Patients assigned to chemotherapy had a significantly higher survival rate than those assigned to observation (44.5 percent vs. 40.4 percent at five years [469 deaths vs. 504]; hazard ratio for death, 0.86; 95 percent confidence interval, 0.76 to 0.98; P<0.03). Patients assigned to chemotherapy also had a significantly higher disease-free survival rate than those assigned to observation (39.4 percent vs. 34.3 percent at five years [518 events vs. 577]; hazard ratio, 0.83; 95 percent confidence interval, 0.74 to 0.94; P<0.003). There were no significant interactions with prespecified factors. Seven patients (0.8 percent) died of chemotherapy-induced toxic effects. Cisplatin-based adjuvant chemotherapy improves survival among patients with completely resected non-small-cell lung cancer. Copyright 2004 Massachusetts Medical Society