Activity and safety of oxaliplatin with weekly 5-fluorouracil bolus and low-dose leucovorin as first-line treatment for advanced colorectal cancer

A Markov model assessing the effectiveness and cost-effectiveness of FOLFOX compared with FOLFIRI for the initial treatment of metastatic colorectal cancer

OBJECTIVE

To analyze the efficacy and cost-effectiveness of FOLFOX compared with FOLFIRI for patients with metastatic colorectal cancer.

METHOD

We developed a Markov decision model using a hypothetical cohort of patients with metastatic colorectal cancer to compare beginning chemotherapy with FOLFOX or FOLFIRI. Probabilities of toxicities, including neutropenia, diarrhea, and neuropathy, were based on published literature for FOLFOX and FOLFIRI. Costs for physician and hospital services unadjusted for geographic location were estimated using Centers for Medicare and Medicaid services reimbursement data. Drug costs were estimated using Medicare B reimbursement and the Federal Supply Schedule. Health outcomes were measured in quality-adjusted life years (QALYs). Univariate and probabilistic sensitivity analyses were performed to address uncertainty in the model parameters.

RESULTS

The FOLFOX strategy provided 1.003 QALYs at a cost of $29,865, whereas FOLFIRI provided 0.921 QALYs at a cost of $24,551. The incremental cost-effectiveness ratio for FOLFOX treatment was $65,170/QALY. In 10,000 probabilistic Monte Carlo simulations, FOLFOX was cost-effective in 48.59% of trials using a $50,000/QALY threshold. The most influential variables in univariate sensitivity analysis were the expected years of survival associated with each chemotherapy regimen.

CONCLUSIONS

FOLFOX and FOLFIRI are similar in terms of costs and benefits. The slight QALY benefits associated with FOLFOX are within the range of $100,000/QALY, an accepted threshold in oncology.

cDNA array analysis for prediction of hepatic metastasis of colorectal carcinoma

PURPOSE

Distant metastasis is a significant prognostic factor of colon carcinoma. Adjuvant chemotherapy has been shown to decrease its recurrence. However, there are no definitive methods for the diagnosis of hepatic recurrence after potentially curative surgery. The aim of this study was to evaluate the accuracy of mRNA expression profiling using samples obtained from primary tumors to predict hepatic recurrence.

METHODS

Patients with stage III colorectal carcinoma without any recurrence for at least 5 years (group A: n = 9) and patients with stage IV carcinoma with hepatic metastasis (group B: n = 10) were included in this study. Tissue samples were collected from the primary tumor and adjacent normal colonic mucosa at the time of surgery in each patient. Total RNA was extracted and the mRNA expression profile was examined using a cDNA macroarray.

RESULTS

A hierarchical clustering analysis revealed a dendrogram in which the patients were divided into two clusters. One cluster consisted of seven patients in group A and two in group B. The other consisted of two patients in group A and eight in group B. Therefore, the positive and negative predictive value of hierarchical clustering analysis for hepatic metastasis was 80.0% and 78.8%, respectively. Fifteen genes were revealed to be upregulated and 12 were downregulated in group B. The upregulated genes included CCNA2, TP53, and MDM2, while the downregulated genes included CDH1, GADD45A, and BCL2L2.

CONCLUSIONS

mRNA expression profiling by a cDNA array analysis of specimens obtained from primary tumors was found to be useful for distinguishing patients with and without hepatic metastasis. This method is expected to contribute to the identification of patients at high risk for hepatic recurrence, while also helping in the administration of intensive adjuvant chemotherapy for such high risk patients.

Current Status of Clinical Studies for Colorectal Cancer in Taiwan

The incidence and age-adjusted mortality of colorectal cancer (CRC) has drastically increased in the past 2 decades in Taiwan. Fortunately, chemotherapy for metastatic CRC also showed improvement in terms of tumor response rate and survival in the corresponding time period. For its low toxicity profile and high objective response rate (17.5%-31.9% in patients who received low-dose 5-fluorouracil [5-FU] that failed and 53.3%-61.5% in patients who were chemotherapy-naive), weekly 24-hour infusion of high-dose 5-FU and leucovorin (LV) has been a favorable regimen for advanced CRC for medical oncologists in Taiwan. Investigators also put their effort in exploring the mechanisms of high efficacy and low toxicity profile of this regimen, as well as the prognostic factors in predicting tumor response to this regimen. With the emergence of new, active compounds for metastatic CRC, a simple 2-hour infusion of oxaliplatin plus 46-hour infusion of 5-FU/LV every 2 weeks has become a favorable regimen, with an overall response rate (ORR) of 40%-50% and overall survival of 18.2 months in chemotherapy-naive patients. Conversely, there were also studies to suggest that biweekly oxaliplatin plus weekly or biweekly bolus 5-FU/LV was shown to achieve a comparable tumor response and survival in 5-FU-refractory metastatic CRC. In patients who had been treated with oxaliplatin plus infusional 5-FU/LV that failed, salvage biweekly irinotecan plus bolus and infusional 5-FU/LV could achieve an ORR of 22.2% with a median duration of response of 8 months. As for oral fluoropyrimidine analogues, oral tegafur/uracil and capecitabine are available in Taiwan. In addition, a clinical trial of dendritic cell-based immunotherapy for chemotherapy-refractory metastatic CRC has also been initiated and is in progress.