Chemotherapy in colorectal carcinoma

Covering the colon anastomoses with amniotic membrane prevents the negative effects of early intraperitoneal 5-FU administration on anastomotic healing

PURPOSE

This study investigated whether covering the colonic anastomoses with amniotic membrane (AM) protects the anastomotic healing from the adverse effects of immediate 5-fluorouracil (5-FU) administration.

METHODS

One hundred twenty wistar albino rats were randomized to one of four groups (I-IV, 30 rats in each) and underwent a standardized left colon resection and anastomoses. The anastomoses of the rats in groups II (AM) and IV (5-FU + AM) were covered with AM. Saline solution (2 ml/day; groups I (control) and II) or 5-FU (20 mg/kg/day; groups III (5-FU) and IV) was administered to the rats intraperitoneally once daily from the day of operation until sacrificed. Half of each group was sacrificed on the postoperative day 4 (IA, IIA, IIIA, and IVA) and other half on the postoperative day 8 (IB, IIB, IIIB, and IVB), and their anastomoses were evaluated when sacrificed.

RESULTS

The dehiscence rate of anastomotic dehiscence and adhesion formation were significantly higher in groups IIIA and IIIB compared with groups IVA and IVB, respectively. Bursting pressure was significantly higher in the 5-FU + AM groups than in the 5-FU groups. The inflammatory cell infiltration was significantly lower in groups IIIA and IVA compared with group IA, in groups IIIB and IVB compared with group IB, and in group IVA compared with group IIIA. Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline levels were significantly higher in the 5FU + AM groups compared with control and 5-FU groups. Malondialdehyde levels were significantly higher in the 5-FU groups than in the 5-FU + AM groups.

CONCLUSION

Covering colon anastomoses with AM protects them, preventing leakage and reversing the negative effects of 5-FU administration.

Effect of early preoperative 5-fluorouracil on the integrity of colonic anastomoses in rats

AIM: To determine the effect of chemotherapy on wound healing by giving early preoperative 5-fluorouracil (5-FU) to rats with colonic anastomoses.

METHODS: Sixty Albino-Wistar male rats (median weight, 235 g) were used in this study. The rats were fed with standard laboratory food and given tap water ad libitum. The animals were divided into three groups: Group 1: Control group (chemotherapy was not administered), Group 2: Intraperitoneally (IP) administered 5-FU group (chemotherapy was administered IP to animals at a dose of 20 mg/kg daily during the 5 d preceeding surgery), Group 3: Intravenously (IV) administered 5-FU group. Chemotherapy was administered via the penil vein, using the same dosing scheme and duration as the second group. After a 3-d rest to minimize the side effects of chemotherapy, both groups underwent surgery. One centimeter of colon was resected 2 cm proximally from the peritoneal reflection, then sutured intermittently and subsequently end-to-end anastomosed. In each group, half the animals were given anaesthesia on the 3rd postoperative (PO) day and the other half on the 7th PO day, for in vivo analytic procedures. The abdominal incisions in the rats were dissected, all the new and old anastomotic segments were clearly seen and bursting pressures of each anastomotic segment, tissue hydroxyproline levels and DNA content were determined to assess the histologic tissue repair process.

RESULTS: When the IV group was compared with the IP group, bursting pressures of the anastomotic segments on the 3rd and 7th PO days, were found to be significantly decreased, hydroxyproline levels at the anastomotic segment on the 7th PO day were significantly decreased (P < 0.01).

CONCLUSION: In this study, we conclude that early preoperative 5-FU, administered IV, negatively affects wound healing. However, IP administered 5-FU does not negatively affect wound healing.

The effect of octreotide on healing of injured colonic anastomosis with immediate postoperative intraperitoneal administration of 5-Fluorouracil

PURPOSE

This study was designed to investigate the effect of octreotide on side effects of immediate usage of 5-fluorouracil after colonic anastomosis.

METHODS

Forty male Wistar rats were randomly assigned into four groups and underwent standardized left colonic anastomosis. The rats served as control or received intraperitoneal 5-fluorouracil (20 mg/kg daily), subcutaneous octreotide (20 mug/kg daily), or both. Diarrhea and wound complications were noted during the experiment. The colonic anastomoses were assessed for healing on postoperative Day 7 by determining the anastomotic bursting pressure, performing histologic examination, and measuring the tissue hydroxyproline content, serum malondialdehyde, and nitric oxide levels. Intraperitoneal adhesions and anastomotic leakage were also noted.

RESULTS

No statistical significant difference was found between the control and octreotide groups for each of the parameters measured. Immediate 5-fluorouracil use resulted with higher adhesion score (P = 0.002), significant depression in anastomotic bursting pressure (P = 0.0001), histopathologic score (P = 0.0001), hydroxyproline content (P = 0.0001), and increasing nitric oxide (P = 0.0001) and malondialdehyde levels (P = 0.0001) compared with the control group. Diarrhea was seen in 80 percent of the 5-fluorouracil group but in neither the control nor octreotide groups (P = 0.0001 for each comparison). However, all these parameters were ameliorated by use of concomitant octreotide and 5-fluorouracil (P = 0.019, P = 0.023, P = 0.0001, P = 0.006, P = 0.0001, and P = 0.013, respectively). In addition, diarrhea was found to be prevented (P = 0.0001).

CONCLUSIONS

The results of this study showed that concomitant octreotide use might prevent the side effects of 5-fluorouracil, such as diarrhea, postoperative adhesion, and delaying the anastomotic healing parameters. In addition, it might reduce tissue damage and inflammation.

Results of a Phase II Open-Label Study of Capecitabine in Combination with Irinotecan as First-Line Treatment for Metastatic Colorectal Cancer

BACKGROUND

Between July 2001 and September 2002, 49 eligible patients were enrolled in an open-label phase II study to assess the efficacy and safety of first-line treatment with capecitabine/irinotecan in metastatic colorectal cancer.

PATIENTS AND METHODS

Patients received capecitabine (1000 mg/m2 twice daily) on days 1-14 and irinotecan (240 mg/m2) on day 1 of a 21-day cycle. Patients enrolled had a median age of 64.5 years, and 6% of patients had an Eastern Cooperative Oncology Group performance status of 2. Fifty-seven percent of patients were male.

RESULTS

Forty-two patients were evaluable for response. There was 1 complete response (2%), 18 partial responses (43%), 20 cases of stable disease (48%), and 3 cases of disease progression (7%), for an overall response rate of 45% (95% CI, 30%-60%). The median duration of response was 5.7 months (range, 2.5-II.3 months). Median survival was 13.4 months (range, 1.2-28.8 months) and median progression-free survival was 6.2 months (range, 1.2-17.5 months). At 1 year, the estimated survival rate was 54% and the estimated progression-free survival rate was II%. The median number of cycles received was 6 (range, 1-18 cycles), and most patients (80%) required a dose modification because of diarrhea, nausea, and/or neutropenia. Grade 1/2 hand-foot syndrome occurred in 8 patients (16%). Grade 3/4 toxicities experienced by > or = 5% of patients included diarrhea (20%), neutropenia (12%), dehydration (10%), nausea (10%), anemia (6%), fatigue (6%), pain (6%), and vomiting (6%).

CONCLUSIONS

First-line capecitabine/ irinotecan is an active combination for the treatment of metastatic colorectal cancer and feasible for use in the community-based setting. Despite significant toxicity with the regimen, the treatment was manageable with dose reduction or delay and should be investigated in phase III trials.

Adjuvant chemotherapy in colorectal carcinoma: results of a meta-analysis

Despite the National Institutes of Health consensus regarding use of adjuvant chemotherapy in colorectal carcinoma, many general surgeons question the efficacy of this approach when considering costs involved for both the individual patient and society at large.

PURPOSE

This study was designed to determine the real impact of adjuvant chemotherapy on five-year survival rates of patients.

METHOD

A qualitative and quantitative meta-analysis of results from 39 randomized clinical trials published from 1959 to 1993 is described.

RESULTS

Design quality of clinical trials had a mean score of 48.6 percent (+/-6.2 standard deviation). A small benefit of therapy in terms of overall survival was noted, with a mortality odds ratio (OR) of 0.91 (confidence interval (CI) 95 percent, 0.83-0.99). For the group of colon carcinomas, the OR was 0.81 (CI 95 percent, 0.69-0.94) with an OR of 0.64 (CI 95 percent, 0.48-0.85) for the group of rectal carcinomas. The effect size was 0.09 for the colon group and 0.20 for the rectal group. For those patients who receive chemotherapy, this effect size implies that we can expect an increase of 5 percent in the survival rate in the group with colon carcinoma and a 9 percent increase in the survival rate in the group with rectal carcinoma.

CONCLUSION

Given the high incidence of colorectal carcinoma, the small benefit observed for those patients receiving chemotherapy is far from negligible. However, indications for adjuvant chemotherapy warrant further discussion.

Carcinoma of the rectum in children

Two cases of carcinoma of the rectum in children (10 and 11 years old) are presented. Both cases presented as acute intestinal obstruction with the history of bleeding per rectum, constipation, abdominal distention, and loss of weight and appetite. Carcinoma of the colon and rectum in children is rare. Its clinical, pathologic, and biological characteristics are different than those of adults. The prognosis is poorer in children, the reason for which is explained, and its management is briefly discussed.

Progress toward hormonal therapy of gastrointestinal cancer

OBJECTIVE

The authors discuss ongoing research to determine the mechanisms by which peptide hormones regulate growth of gastrointestinal cancer and ways in which this information might be used to develop noncytotoxic therapy.

SUMMARY BACKGROUND

Approximately 100,000 people die of cancer of the gastrointestinal (GI) tract each year. Surgery is curative only when the tumor is localized. Chemotherapy and radiotherapy have limited efficacy for locally advanced or widespread disease. Various peptide hormones regulate the growth of these tumors. As for breast and prostate cancer, the growth regulatory effect of these hormones is being studied as a potential mechanism of hormonal therapy.

CONCLUSION

Gut peptide hormones regulate the growth of GI malignancies through all-specific receptors and signal transduction pathways. Interruption or modification of these growth regulatory mechanisms may lead to specific noncytotoxic therapy. In combination with surgical extirpation, such hormonally based treatment may be curative of advanced GI cancer.

Regulation by vascular endothelial growth factor of human colon cancer tumorigenesis in a mouse model of experimental liver metastasis

To investigate the relationship between angiogenesis and hepatic tumorigenesis, we examined the expression of vascular endothelial growth factor (VEGF) in 8 human colon carcinoma cell lines and in 30 human colorectal cancer liver metastases. Abundant message for VEGF was found in all tumors, localized to the malignant cells within each neoplasm. Two receptors for VEGF, KDR and flt1, were also demonstrated in most of the tumors examined. KDR and flt1 mRNA were limited to tumor endothelial cells and were more strongly expressed in the hepatic metastases than in the sinusoidal endothelium of the surrounding liver parenchyma. VEGF monoclonal antibody administration in tumor-bearing athymic mice led to a dose- and time-dependent inhibition of growth of subcutaneous xenografts and to a marked reduction in the number and size of experimental liver metastases. In hepatic metastases of VEGF antibody-treated mice, neither blood vessels nor expression of the mouse KDR homologue flk-1 could be demonstrated. These data indicate that VEGF is a commonly expressed angiogenic factor in human colorectal cancer metastases, that VEGF receptors are up-regulated as a concomitant of hepatic tumorigenesis, and that modulation of VEGF gene expression or activity may represent a potentially effective antineoplastic therapy in colorectal cancer.

[Developments up to now and current status of adjuvant chemo- and radiotherapy in colonic and rectal carcinoma]

A review is given of the historical and current concepts of adjuvant chemo- and radiotherapy of colorectal cancer. Early studies analyzing the use of single drug regimens were followed by a second study generation investigating adjuvant chemotherapeutic combinations. 5-FU proved to be the most efficient single drug investigated and 5-FU/MeCCNU/vincristin the most efficient chemotherapeutic combination, but no significant improvement in 5-year survival rates was achieved. Clear progress was noted with the introduction of levamisol (LEV) for modulation of 5-FU. A 33% improval in the 5-year survival rate in patients with stage III colon carcinoma was documented. It was therefore recommended (NIH consensus conference 1990) that all patients with stage III colon carcinoma be treated with this regimen unless admitted to other trials of adjuvant therapy. Preoperative radiotherapy with a dosage of 35-45 Gy can lead to downstaging of rectal cancer. Nevertheless, significant improvement in patient survival has not been proved convincingly using either isolated pre- or postoperative adjuvant radiotherapy. However, combined radiochemotherapy has been shown to improve both patient survival and local tumor control compared to surgical resection alone. It is therefore recommended that all stage II and III rectal cancer patients be treated with adjuvant combined radiochemotherapy. 5-FU/MeCCNU is currently expected to be the most efficient chemotherapy in combination with radiotherapy. Early data point out that MeCCNU could possibly be omitted. Intraoperative radiotherapy (IORT) allows further dosage escalation in order to improve local tumor control without affecting radiosensitive structures. Available data are still sparse and mostly based on the treatment of advanced carcinoma. A general validation of IORT is not yet possible, but current data are promising.

Rolling review: gastrointestinal malignancy

The chemotherapy of gastrointestinal malignancies remain mostly investigational, although several adjuvant protocols in colorectal cancer and anal cancer are beginning to be accepted as standards against which newer regimens are to be compared. Chemotherapy regimens are best understood and appreciated with a basic understanding of cancer biology, tumour cell kinetics, and drug toxicities. An appreciation of chemotherapy-induced toxicity and an awareness of their management will help the gastroenterologist be an active participant in the multidisciplinary team caring for the patient with gastrointestinal malignancies.