Novel oral fluoropyrimidines in the treatment of metastatic colorectal cancer.

The evolution of and rationale for fluorouracil-based strategies in the treatment of metastatic colorectal cancer are discussed, and the role of the new oral fluoropyrimidines is described. Although fluorouracil is one of the most widely used drugs in the United States for colorectal, head and neck, bladder, and breast cancer, response rates and survival times have been disappointing. Dihydropyrimidine dehydrogenase (DPD), a rate-limiting enzyme in the catabolism of fluorouracil, indirectly determines the drug's anticancer efficacy by regulating the availability of fluorouracil for anabolism. Recently, investigators have identified at least five compounds -capecitabine, UFT (tegafur plus uracil), eniluracil, S-1, and BOF-A2-that inhibit, destroy, inactivate, or bypass DPD's activity. Capecitabine, a prodrug of fluorouracil, circumvents DPD. UFT, S-1, and BOF-A2 contain prodrugs of fluorouracil in combination with compounds that alter DPD's activity. Fluorouracil must be administered in combination with eniluracil, an inactivator of DPD. These compounds, classified as fluoropyrimidines, can be administered orally. Oral fluoropyrimidines appear to be at least as active against metastatic colorectal cancer as conventionally administered intravenous fluorouracil, with significantly less toxicity, improved quality of life, and less expense. New oral fluoropyrimidines may ultimately provide enhanced antitumor activity to fluorouracil-containing regimens for advanced colorectal cancer.

Docetaxel in anthracycline-resistant metastatic breast cancer.

Docetaxel is a taxane that disrupts the equilibrium in the polymerization and depolymerization of microtubules, thus inhibiting cell growth. This agent is indicated for the treatment of anthracycline-resistant metastatic breast cancer. The dose-limiting adverse effect is neutropenia, but febrile neutropenia is uncommon. Like paclitaxel, docetaxel is very active in patients with both chemotherapy-resistant and refractory metastatic breast cancer. Although the mechanism of action, spectrum of activity, and side effect profile of this agent are similar to those of paclitaxel, docetaxel may be efficacious in patients with metastatic breast cancer who have become resistant or refractory to paclitaxel therapy. However, more studies are warranted before the role of docetaxel is defined in patients with paclitaxel-resistant breast cancer.

Granisetron.

Granisetron is the second agent in the 5-HT3 receptor antagonist class to be approved for the prophylaxis of acute emesis caused by cancer chemotherapy. It is equally effective to ondansetron as a first-line agent in the prevention of acute chemotherapy-induced emesis and has a similar low toxicity profile. Granisetron will be marketed in early 1994, according to SmithKline Beecham. Additional studies will be needed to determine the role of granisetron in the current management of chemotherapy-induced emesis.

Parenteral nutrition support in patients with cancer.

In the patient with cancer, malnutrition may result from the disease itself or from its treatment. Total parenteral nutrition (TPN) has been used for many years to treat or prevent malnutrition in the patient with cancer. There have been few studies, however, that demonstrate significant benefit from TPN therapy in these patients. Patients receiving high-dose chemotherapy (as in bone marrow transplantation), and patients with solid tumors who have documented malnutrition (cachexia, weight loss) prior to cancer surgery, may benefit from TPN. No other groups of patients with cancer appear to derive significant benefit from TPN, and some groups may actually be harmed by its use. Practical considerations in the use of TPN include periodic calorie-protein assessment, electrolyte management, and monitoring for drug-TPN interactions.

A randomized trial of continuous intravenous versus hepatic intraarterial floxuridine in patients with colorectal cancer metastatic to the liver: the Northern California Oncology Group trial.

In 1983, the Northern California Oncology Group (NCOG) instituted a randomized trial of intravenous (IV) versus intraarterial (IA) floxuridine (FUDR) administered via an implantable pump for patients with colorectal cancer metastatic to the liver. The study objectives were to compare the hepatic response rate, time to hepatic progression, and toxicity for the two treatment arms. The study design, which allowed patients failing IV FUDR to crossover to the IA arm, prevents a meaningful comparative analysis of survival. Patients with liver-only metastases (N = 143) were randomized, 76 to the IV arm and 67 to the IA arm, and 115 patients (65 IV, 50 IA) were fully evaluable. Of the 65 patients in the IV arm, 28 crossed over to IA treatment after failing IV FUDR. The dose-limiting toxicity of IV FUDR was diarrhea, whereas biliary toxicity limited both the dose and duration of IA FUDR therapy. Of the first 25 patients treated with IA FUDR at a dose of .3 mg/kg/day, 10 developed radiographically evident biliary strictures, and three developed permanent jaundice. With reduction of the initial IA FUDR dose to .2 mg/kg/day, and adoption of a policy of early dosage reduction, treatment interruption, or termination of therapy for persistent elevations in alkaline phosphatase, only two further cases of serious biliary toxicity occurred. However, 26 of the 50 IA FUDR patients ultimately had therapy terminated because of drug toxicity rather than disease progression. When compared with systemic infusion, infusion into the hepatic artery greatly enhanced the antitumor activity of FUDR against colorectal liver metastases. Although biliary toxicity is the most serious limitation of this form of therapy, biliary stricture and jaundice usually can be averted through careful monitoring of liver enzymes and early dosage reduction.

Toxicities and complications of implanted pump hepatic arterial and intravenous floxuridine infusion.

Toxicities and complications were prospectively analyzed in patients with liver metastases receiving hepatic intra-arterial (IA) and systemic intravenous (IV) floxuridine (FUDR) with the Infusaid (Intermedics-Infusaid Corp., Norwood, MA) implantable pump. Among 55 patients treated with IA FUDR (0.3-0.1 mg/kg/day X 14, every 28 days), elevations in liver enzyme values, not attributable to disease progression, developed in 96% of patients. Serious biliary toxicity occurred in 31 patients (56%). In 16, biliary sclerosis was documented radiographically and was diagnosed clinically in 15 additional patients. Ten patients were hospitalized for biliary toxicity, including five who required cholecystectomy for acalculous cholecystitis. Because of the high reported incidence of serious gastroduodenal toxicity after IA FUDR infusion, our procedure for hepatic arterial cannulation was designed to eliminate misperfusion of the stomach and duodenum with drug; none of our patients experienced FUDR-associated gastroduodenal ulceration or bleeding. Cyclic IV FUDR (0.05-0.15 mg/kg/day X 14, every 28 days) was administered to 31 participants of the Northern California Oncology Group trial (3L-82-1) of IV versus IA FUDR. Dose-limiting toxicity was diarrhea. Serious toxicities were: protracted diarrhea (three), dermatitis (two), tear duct stenosis (two), and stomatitis (two). Three patients were hospitalized for toxicity. No hematologic or biliary toxicity occurred. The optimal route for treatment of hepatic metastases with continuous FUDR infusion has not yet been established. Systemic IV infusion has low morbidity, but preliminary response data need to be substantiated in controlled clinical trials before there can be widespread clinical application. High response rates for IA infusion have been previously documented. Morbidity due to acalculous cholecystitis and gastroduodenal ulceration can now be avoided. Despite significant progress in characterization of hepatobiliary toxicity, it remains dose-limiting. Continuous IA FUDR infusion should remain under the aegis of dedicated treatment centers until standardized protocols with diminished toxicity are established.

Phase II study of sequential methotrexate and 5-FU plus mitomycin and leucovorin in patients with disseminated large bowel cancer: a Northern California Oncology Group study.

Sequential methotrexate (MTX) and 5-FU plus leucovorin and mitomycin (MMC) was given to 52 patients with disseminated, measurable colorectal cancer. Complete and partial responses were seen in 19 of 49 (39%) evaluable patients. Nine additional patients achieved a minimal response. Median overall survival was 8.8 months, while that for patients objectively responding was 13.6 months. This study utilized a MTX exposure period of 12 hours prior to 5-FU. In comparison to other trials utilizing sequential MTX and 5-FU, the addition of MMC to the regimen may improve the response rate but increases the incidence of adverse effects, particularly myelosuppression and renal toxicity. This phase II trial suggests that sequential MTX and 5-FU plus leucovorin and MMC is an active combination therapy and warrants further comparative trial in patients with large bowel cancer.