Colorectal cancer: chemotherapy treatment overview.

Fluorouracil (5-FU) has remained the standard therapy for the treatment of advanced colorectal cancer for over 40 years. Unfortunately, only a minority of patients experience objective clinical response. Discussed herein are attempts to improve on the activity of 5-FU by biochemically modulating its action. In addition, novel agents for the treatment of advanced colorectal cancer (oral fluoropyrimidines, oxaliplatin, and irinotecan) are discussed. Oral fluoropyrimidines (UFT plus leucovorin, capecitabine, eniluracil plus oral 5-FU) provide the convenience of oral delivery with a marked reduction in febrile neutropenia and mucositis. Recent randomized trials with these agents have demonstrated therapeutic activity that is comparable with intravenous schedules of 5-FU plus leucovorin. Compared to 5-FU, both oxaliplatin and irinotecan have uniquely different mechanisms of action and have demonstrated clinical activity in patients whose disease has progressed with 5-FU treatment. Combinations of either irinotecan or oxaliplatin plus 5-FU/leucovorin have demonstrated that the addition of these agents to 5-FU/leucovorin improves response rates and time to progression compared to 5-FU/leucovorin alone. Combination chemotherapy regimens with these novel agents are rapidly being introduced into the adjuvant setting.

Fluoropyrimidines: a critical evaluation.

After nearly four decades of clinical experience with the fluoropyrimidines, 5-fluorouracil (5-FU) remains an integral part of chemotherapy for colorectal cancer. A range of 5-FU treatment regimens with or without biochemical modulation are currently used and toxicity appears to be schedule dependent. The use of oral 5-FU was abandoned because of erratic absorption caused by varying levels of dihydropyrimidine dehydrogenase (DPD) found in the gastrointestinal tract. This effect may be overcome by administering agents that are converted to 5-FU or by inhibiting or inactivating DPD. Xeloda((R)) (capecitabine) was designed as an orally administered, selectively tumoractivated(TM) cytotoxic agent which achieves higher levels of 5-FU in the primary tumor than in plasma or other tissues. The United States Food and Drug Administration (FDA) has approved Xeloda for use in patients with metastatic breast cancer resistant to paclitaxel and in whom further anthracycline therapy is contraindicated. Xeloda is also registered in Canada, Switzerland, Thailand and Argentina. In phase II clinical trials in colorectal cancer, Xeloda produced response rates of 21-24% and median time to disease progression of 127-230 days. Other oral agents in development for the treatment of colorectal cancer include tegafur/uracil plus oral leucovorin, S-1 and eniluracil plus oral 5-FU.

Autoimmune conditions associated with primary biliary cirrhosis: response to ursodeoxycholic acid therapy.

OBJECTIVES: A variety of autoimmune conditions occur in association with primary biliary cirrhosis. Among these conditions are sicca syndrome, Raynaud's phenomenon, arthritis, and Hashimoto's thyroiditis. Information is sparse regarding the prevalence and natural history of these conditions when associated with primary biliary cirrhosis and their response to ursodeoxycholic acid treatment. We evaluated the prevalence, natural history, and response to ursodeoxycholic acid therapy of these conditions coassociated with primary biliary cirrhosis. METHODS: One hundred-eighty patients with primary biliary cirrhosis, enrolled in a prospective randomized controlled trial of ursodeoxycholic acid (13-15 mg/ kg/day), were included. Patients were assessed at study entry and annually. RESULTS: At entry, 77/180 patients (43%) had one of the four conditions, and 18/180 patients (10%) had two or more conditions. Sicca syndrome was the most common, occurring in 58/180 patients (32%). After 2 yr, there was no difference between the treatment groups with regard to resolution or spontaneous onset of these autoimmune features. Sicca syndrome was the most common spontaneously developing condition (9% per yr). Sicca syndrome was the most common associated autoimmune condition, present in one-third of our patients. The associated conditions tended to improve over time, with a low rate of spontaneously developing these conditions. Although ursodeoxycholic acid therapy leads to improvement in the underlying liver disease, it did not appear to influence either the development or resolution of these autoimmune features. CONCLUSIONS: Although ursodeoxycholic acid is beneficial in the treatment of primary biliary cirrhosis, it had no measurable effect on the autoimmune conditions coassociated with the disease.