Prospective adjuvant therapy with mitomycin C and carmofur (HCFU) for colorectal cancer, 10-year follow-up: Tokai HCFU Study Group, the first study for colorectal cancer

Versatile use of Carmofur: A comprehensive review of its chemistry and pharmacology

Carmofur, 1-hexylcarbamoyl-5-fluorouracil (HCFU) is an antineoplastic drug, which has been in clinics in Japan since 1981 for the treatment of colorectal cancer. Subsequently, it was also introduced in China, Korea, and Finland. Besides colorectal cancer, it has also shown antitumor activity in other cancers such as breast, head and neck, pancreatic, gastrointestinal, and solid brain tumors. A prodrug of 5-fluorouracil (5-FU), carmofur has shown better gastrointestinal stability and superior antiproliferative activity compared to its active counterpart 5-FU. Recently, carmofur has gained attention as an acid ceramidase inhibitor and as a potential lead compound against several noncancerous diseases such as coronavirus disease 2019, Krabbe disease, acute lung injury, Parkinson's disease, dementia, childhood ependymoma etc. Carmofur has also been reported to have antifungal, and antimicrobial properties. Nevertheless, no comprehensive review is available on this drug. Herein, we summarized the chemistry, pharmacokinetics, and pharmacology of carmofur based on the literature published between January 1976 and March 2022 as identified from PubMed and Google Scholar search engines.

Significance of histologic type of primary lesion and metastatic lymph nodes as a prognostic factor in stage III colon cancer

PURPOSE

This study was designed to investigate whether the histologic types of the primary lesion and of metastatic lymph nodes in Stage III colon cancer are useful as prognostic factors. The usefulness of adjuvant chemotherapy in a randomized, controlled trial by using these prognostic factors as stratification criteria was also investigated.

METHODS

Stage III colon cancer patients were enrolled and were divided into two groups: Group W, in which the histologic type of both primary tumors and metastatic lymph nodes was well-differentiated adenocarcinoma; and Group U, in which the primary tumors and the metastatic lymph nodes were of any type other than well-differentiated. Group W patients were assigned to Treatment Arm A (surgery alone) or Arm B (surgery, then 1-hexylcarbamoyl-5-fluorouracil); and Group U patients, to Treatment Arm C (same as B), and Arm D (surgery + 1-hexylcarbamoyl-5-fluorouracil + mitomycin C).

RESULTS

The Group W five-year survival rate was significantly superior to that in Group U (P = 0.0035). There was a better survival rate in Treatment Arm A than Arm B (P = 0.0321), but no difference between Treatment Arms C and D.

CONCLUSIONS

In Stage III colon cancer, the prognosis of cases whose primary lesion and lymph node tissues are both well differentiated is extremely good. In such cases, it is possible for adjuvant chemotherapy to have a deleterious effect, and therefore, it is not recommended.

Randomized trial of the efficacy of adjuvant chemotherapy for colon cancer with combination therapy incorporating the oral pyrimidine 1-hexylcarbamoyl-5-fluorouracil

BACKGROUND AND AIMS

The purpose of the present trial was to clarify the efficacy of postoperative adjuvant chemotherapy including an oral fluoropyrimidine anticancer drug, the 1-hexylcarbamoyl-5-fluorouracil (HCFU), for the treatment of colon cancer.

METHOD

Patients with clinical stage Dukes' B and C colon cancer, who had been treated surgically, were assigned to a chemotherapy group treated with mitomycin C, 5-fluorouracil (5-FU), and HCFU and to a control group that received no postoperative adjuvant chemotherapy.

RESULTS

Of the 1,001 patients registered for the study, 17 (1.7%) were ineligible. The incidence of toxicity was significantly higher in the chemotherapy group than in the control group. However, there were few severe side effects and no deaths related to the treatment. Overall survival showed no significant difference between the groups. The disease-free survival or the recurrence-free intervals was significantly higher in the chemotherapy group than in the control group. The incidence of hepatic recurrence was significantly (P=0.003) lower in the chemotherapy group than in the control group.

CONCLUSION

The results of this study demonstrated the efficacy of adjuvant chemotherapy for colon cancer, i.e., combined chemotherapy that included the 5-FU oral anticancer drug HCFU.

An Individual Patient Data Meta-analysis of Adjuvant Therapy with Carmofur in Patients with Curatively Resected Colon Cancer

BACKGROUND

Oral carmofur, either as a single or in combination with other chemotherapeutic agents, has been used as adjuvant chemotherapy for curatively resected colon cancer patients. Past trials and meta-analyses indicate that it is somewhat effective in extending survival of patients with this cancer. The objective of this study was to perform a reappraisal of randomized clinical trials conducted in this regard.

METHODS

We designed an individual patient-based meta-analysis of relevant clinical trials to examine the benefit of oral carmofur for curatively resected colon cancer in terms of overall survival (OS) and disease-free survival (DFS).

RESULTS

We analyzed individual patient data of three randomized clinical trials, which met the predetermined inclusion criteria. These three trials had a combined total of 2152 patients, carmofur as adjuvant chemotherapy compared with surgery-alone, 5 years follow-up, intention-to-treat-based analytic strategy and similar end points (OS and DFS). In a pooled analysis, 5 year OS rates were 80.4 and 76.4%, and 5 year DFS rates 76.9 and 71.0%, respectively, in carmofur and surgery-alone group. Oral carmofur had significant advantage over surgery-alone in terms of both OS [pooled hazard ratio, 0.82; 95% confidence interval (CI) = 0.68-0.99; P = 0.043] and DFS (pooled hazard ratio, 0.77; 95% CI = 0.65-0.91; P = 0.003).

CONCLUSIONS

This individual patient-based meta-analysis demonstrated that oral carmofur significantly improves both OS and DFS in patients with curatively resected colon cancers.

Comparative detection of lymph node micrometastases of stage II colorectal cancer by reverse transcriptase polymerase chain reaction and immunohistochemistry

PURPOSE

Inconsistent conclusions have been drawn about the clinical significance of micrometastases in lymph nodes (LNs) of node-negative colorectal cancer (CRC) patients. We performed a comparative study of detection of micrometastases using immunohistochemistry (IHC) by anti-cytokeratin antibody and carcinoembryonic antigen (CEA)-specific reverse-transcriptase polymerase chain reaction (RT-PCR) in the same patients, in an attempt to move closer to their clinical application.

PATIENTS AND METHODS

Sixty-four CRC patients, with RNA of good quality available from paraffin-embedded LN specimens, were selected from 84 stage II patients who underwent curative surgery between 1988 and 1996. We investigated associations between the presence of micrometastases by each method and prognosis.

RESULTS

Micrometastases were detected in 19 (29.6%) of 64 patients by RT-PCR and in 35 (54.7%) of 64 patients by IHC. By RT-PCR analysis, patients exhibiting a positive band for CEA mRNA had a significantly worse prognosis than those who were RT-PCR-negative, with respect to both disease-free and overall survival (P =.027 and.015, respectively). By IHC analysis, the presence of micrometastasis did not predict patient outcome in terms of either disease-free or overall survival. Infiltrating pattern of tumor growth characteristic was significantly associated with shorter disease-free survival among various clinical or pathologic factors. By multivariate Cox regression analysis, micrometastasis detected by RT-PCR and the Crohn's-like lymphoid reaction were both independent prognostic factors.

CONCLUSION

Micrometastases detected by RT-PCR, but not IHC, may be of clinical value in identifying patients who may be at high risk for recurrence of CRC and who are therefore likely to benefit from systemic adjuvant therapy.

Alcohol consumption enhances liver metastasis in colorectal carcinoma patients

BACKGROUND

It is important to identify risk factors for liver metastasis in patients with colorectal carcinoma because the liver is the most common site of recurrence. Alcohol consumption reportedly is associated with hematogenous metastasis in certain animal models. Furthermore, some studies have shown that carmofur, a derivative of 5-fluorouracil, is particularly effective as adjuvant chemotherapy for colorectal carcinoma, and may even suppress liver metastasis, although the mechanism by which this occurs remains unknown. In addition, carmofur is known to inhibit alcohol metabolism. To the authors' knowledge, the relation between liver metastasis in colorectal carcinoma and alcohol consumption has not been examined previously. Therefore, the authors studied the relations between liver metastasis in colorectal carcinoma and various clinicopathologic factors including alcohol consumption status.

METHODS

This study was comprised of 133 colorectal carcinoma patients with invasion beyond the submucosal layer who had undergone surgical resection. The subjects were examined and divided into two groups according to the occurrence or absence of liver metastasis. The relations between liver metastasis and other clinicopathologic factors were analyzed by univariate and multivariate statistical methods.

RESULTS

Univariate analysis showed alcohol consumption (P=0.0021) and blood vessel invasion (P=0.0045) were correlated with liver metastasis. Multivariate analysis showed both to be independent risk factors for liver metastasis.

CONCLUSIONS

Alcohol consumption is an independent risk factor for liver metastasis in colorectal carcinoma patients. Therefore, patients with colorectal carcinoma who drink alcohol require intensive examination and follow-up with respect to liver metastasis. Further study is necessary to confirm the effect of adjuvant chemotherapy using carmofur in colorectal carcinoma patients.

Oral adjuvant chemotherapy with carmofur (HCFU) for colorectal cancer: five-year follow-up. Tokai HCFU Study Group--third study on colorectal cancer

BACKGROUND

A joint study was performed by the Tokai HCFU study group, which included seven institutions, to examine the value of oral administration of Carmofur (HCFU), a 5-fluorouracil (5-FU) derivative, for postoperative adjuvant chemotherapy in patients with colorectal cancer undergoing curative resection.

METHODS

The patients were divided into two groups, a control group receiving no HCFU and a group administered HCFU for 1 year, using a centralized registration system by telephone. Among 173 patients entered into this study, 159 evaluable cases were analyzed for evaluation of the drug.

RESULTS

The cumulative 5-year disease-free rate of patients who received HCFU was significantly increased compared with the control group. In particular, the rate was much higher in patients with colon cancer. No severe side effects arose from adjuvant chemotherapy with HCFU.

CONCLUSION

Adjuvant chemotherapy with oral HCFU appears to provide a useful and safe postoperative treatment.