Combination chemotherapy for advanced colorectal cancer. A pilot study

Effect of gold on survival of tumor-bearing mice

Sodium aurothiomalate (monogold monosodium mono-hydrogen sulfidobutanedioate), an anti-rheumatoid gold agent, was injected s.c. every other day for three times or given in drinking water daily for two weeks to Balb/C mice that were inoculated with syngeneic Meth/A cells i.p. As the control, cisplatinum was injected s.c. Survival curve was then observed and significance was determined by Wilcoxon's method. Statistically significant effects on survivals was obtained by 30 mg/kg/day s.c. or 75 mg/kg/day p.o. of gold. A dose of less than 12.5 mg/kg/day s.c. adversely affected the survival. Cisplatinum was significantly effective at the dose of 12.5 mg/kg/day, but markedly toxic at the dose of 125 mg/kg and adversely effective at 6 mg/kg/day s.c. The range of dose effectiveness of cisplatinum on survival was narrower than that of gold. Gold was effective when given s.c. or p.o. No significant toxicity of gold was observed at doses up to 125 mg/kg/day.

Antitumor effect of gold as revealed by growth suppression of cultured cancer cells

Gold agents have been widely used for the treatment of rheumatoid arthritis. We studied the growth inhibiting effect of such an agent on malignant cells in vitro. HCT-15, AGS cells derived from a human malignancy, and Meth/A cells from a malignant lymphoma of Balb/C mice were cultured separately with gold agent at concentrations of 2 micrograms/ml. Four days after the cultures had been incubated in a 5% CO2 incubator at 37 degrees C, cell counts were made; and significance of differences was analyzed by Student's t test. Additionally, HCT-15 cells were cultured with gold for two days, and then the cells were analyzed by flow cytometry. The growth of HCT-15, AGS, and Meth/A cells was suppressed by gold. Fifty percent suppression was observed at a concentration between 50 micrograms/ml and 10 micrograms/ml for HCT-15 cells, between 125 micrograms/ml and 50 micrograms/ml for AGS cells, and between 125 micrograms/ml and 50 micrograms/ml for Meth/A cells. Fifty percent suppression of HCT-15 cell growth by cisplatinum was found between 50 micrograms/ml and 10 micrograms/ml. Flow cytometric findings showed a significant rise in the tetraploid peak, a mild rise in the resion between diploid and tetraploid peaks, and an increase in cells with a ploidy greater than four. These data suggest that gold blocks the S phase, G2 to M phase, and M phase as well. To observe the cytotoxicity of gold, each of 10 of 4 week-old Balb/C mice was injected s.c. at a dose of 10 mg/kg or 2 mg/kg every other day for a total of 3 injections, or was administered the gold at 30 mg/kg/day p.o. for 10 days. All mice were still alive after 20 days of observation. Cisplatinum at a dose of 10 mg/kg was also injected s.c. one time into each of 10 mice, and 60% of the animals died within 10 days after the injection.

Carboplatin in patients with advanced colorectal cancer pretreated with fluoropyrimidines

The activity of carboplatin (CBDCA) was tested in 21 consecutive patients with advanced colorectal cancer that had progressed during fluoropyrimidine therapy. CBDCA was chosen in view of the favourable results obtained in previous phase II studies. We were unable to find any activity of the agent which was given every 21 days at a dose of 400 mg/m2. The main toxicity was haematological. CBDCA is not recommended in pretreated patients with colorectal cancer.

Regional treatment of hepatic metastases and hepatocellular carcinoma

Hepatic metastases represent a common site of dissemination for a number of primary malignancies related in part to the dual blood supply, large blood flow, and receptive environment of the hepatic parenchyma. Although this review focuses on regional therapy, we have included sections on systemic therapy to better interpret the results with intrahepatic therapy. We will also discuss the efficiency of hepatic arterial ligation, embolization, and radiotherapy of hepatic metastases. Primary gastrointestinal neoplasms are particularly prone to produce hepatic metastases. Because colorectal carcinoma metastasizes to the liver in up to 70% of patients with advanced disease, the treatment of hepatic metastases is a relevant topic. We will discuss the systemic and regional therapy of colorectal, gastric, and gallbladder cancers. Breast carcinoma and malignant melanoma frequently metastasize to the liver, and we have described systemic and regional treatments of these diseases. Because sarcomas are often treated by regional therapy, we have included a section on the treatment of hepatic sarcomas. Neuroendocrine tumors (carcinoid and islet cell), although often slow growing, frequently metastasize to the liver and then cause symptomatic problems. Much of the work done with embolization and hepatic ligation in the treatment of hepatic metastases has been performed in neuroendocrine tumors, and these studies, as well as the systemic and regional chemotherapy of hepatic metastases, will be described. The last section concerns the treatment of hepatocellular carcinoma. We have outlined the staging systems used. We then detail the results of systemic and intrahepatic therapy, embolization, and hepatic ligation in the treatment of hepatocellular carcinoma. Because hepatic metastases are a frequent problem, many patients are available for clinical investigation. It is hoped that newer strategies for the treatment of liver metastases will lead to higher response rates and perhaps control of local disease. These therapeutic approaches may also give us leads to the treatment of systemic disease.

Role of chemotherapy in the treatment of colorectal carcinoma

Large bowel cancer afflicts more patients in the United States than any other malignancy excluding skin cancer. Fifty percent of patients who undergo resection of colorectal carcinoma have positive lymph nodes, and approximately 18% have liver metastases at initial presentation. To improve survival, more effective treatment than surgical resection of the primary must be developed. The most active single agent in the treatment of colorectal carcinoma is 5-fluorouracil (5-FU). To increase the response rate obtained with this agent, work has been done on the modulation of 5-FU by other agents, using drugs that are synergistic with 5-FU and manipulating the method of 5-FU administration. Combination chemotherapy has improved response rates in some situations, though generally it has not been shown to improve survival. Studies using direct hepatic infusion clearly demonstrate an increase in response rates, but again, it is too early to say whether this type of treatment increases survival. Early adjuvant chemotherapy trials used inadequate doses of chemotherapy for short periods of time and demonstrated no added efficacy to surgery alone. Later studies with more aggressive therapy suggested some benefit to treating patients with rectal carcinoma; however, there is still little evidence that adjuvant chemotherapy improves survival in patients with colon carcinoma. To compare and understand the various chemotherapy trials, more stringent reporting of baseline laboratory values, performance status, and estimation of tumor involvement are needed.