Comparative study between daily and 5-days-a-week administration of oral 5-fluorouracil chemotherapy in mice: determining the superior regimen.

BACKGROUND: Oral administration of derivatives of 5-fluorouracil (5-FU) is currently used to treat colorectal cancer in the United States. Oral chemotherapy possesses certain advantages: it is simple, easy to administer, and has few side effects. We compared conventional daily oral administration of 5-FU (daily schedule) with administration on 5 consecutive days followed by 2 drug-free days (5-days-a-week schedule) in a mouse tumor model. METHODS: The maximal tolerated dose (MTD) in the 5-days-a-week schedule and in the daily schedule were determined in 6-week-old non-tumor-bearing CDF1 male mice. In antitumor experiments, CDF1 mice were inoculated subcutaneously with Colon26 cells (1x10(6) per mouse). Antitumor efficacy was evaluated in terms of the ratio of tumor size in treated to control mice (T/C ratio). RESULTS: The MTD of 5-FU in the 5-days-a-week schedule was 42 mg/kg, and in the daily schedule was 29 mg/kg. In the 5-days-a-week schedule dose escalation nearly 1.4 times that in the daily schedule was possible, although the total dose over 7 days was similar between the two schedules (203 mg/kg and 210 mg/kg, respectively). When the doses of 5-FU were compared under the condition of no body weight loss, the 5-days-a-week schedule produced a comparative dose escalation of 2.1 times per day (from 20 to 42 mg/kg), and 1.5 times per total weekly amount (from 140 to 210 mg/kg) compared to the daily schedule. With regard to the antitumor effect as indicated by the T/C ratio, the 5-days-a-week schedule produced over 70% tumor suppression, whereas the daily schedule produced only 50% suppression at the MTD. Therapeutic efficacy was calculated in terms of the ratio of body weight change to antitumor effect (T/C ratio), and revealed that the MTD of 42 mg/kg 5-FU in the 5-days-a-week schedule produced a therapeutic efficacy almost three times that of the MTD of 29 mg/kg 5-FU in the daily schedule (P<0.001). CONCLUSIONS: Using oral administration of 5-FU, we confirmed that the 5-days-a-week schedule allowed dose intensity escalation and was superior to the daily schedule in both enhancement of antitumor effect and protection against adverse effects.

p53 as an indicator of lymph node metastases in invasive early colorectal cancer.

We examined whether overexpression of p53 can be used as a new genetic marker to predict the presence of lymph node metastases of early invasive colorectal cancer. Forty-nine patients with primary colorectal adenocarcinomas invading to the submucosa (sm-CRC) were analyzed and 7 patients were found to have lymph node metastases. Immunostaining was used to detect the p53 overexpression; 43% of sm-CRC stained positive for p53 and all the cancer cells metastasized to lymph nodes were p53 positive. Both lymph node involvement and tumor budding were significantly more frequent in p53 positive than p53 negative tumors (p < 0.05, respectively), and multivariate analysis showed that p53 overexpression constituted a higher relative lisk for lymph node metastases of sm-CRC than either histologic type, level of sm invasion, macroscopic type, tumor budding or vascular invasion, although the difference was not significant (p = 0.086). We concluded that p53 overexpression is a useful biological marker of lymph node metastases of sm-CRC, and that p53 negative status may be an indicator for limited surgery, such as local excision of sm-CRC.

[Enhanced induction of apoptosis of human colorectal cancer cells after preoperative treatment with 5-fluorouracil its relationship to DNA ploidy pattern].

We examined the relationship between apoptosis induced by 5-fluorouracil (5-FU) that was given preoperatively to colorectal cancer patients and DNA ploidy pattern, and investigated the cell cycle changes, and the expression of Ki-67. Twenty-nine patients with advanced colorectal cancer were divided into four groups, 3 days, 5 days, 7 days, and 10 days. Groups received continuous intravenous 5-FU at 500 mg/body/day preoperatively. Then, patients were divided into two groups by DNA ploidy pattern, diploid(D) and aneuploid(A). Apoptotic cells were stained by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method. The expression of Ki-67 was examined by immunohistochemical staining. We used flow cytometry (FCM) for analysis of cell cycle distribution. Apoptosis of cancer cells was mostly increased in 7 days 5-FU administration in both D and A groups. The expression of Ki-67 was reduced according to the prolongation of the term of 5-FU administration in both D and A groups. We assessed S-phase fraction (SPF) to evaluate the cell cycle changes by 5-FU. Tumor samples of all patients after injection of 5-FU showed S-phase accumulation. The ratio of SPF (after 5-FU/before 5-FU) was the highest in the 5-day 5-FU administration group in both D and A groups. We concluded that apoptosis and S-phase accumulation were increased, and proliferative activity was decreased by preoperative 5-FU administration in colorectal cancer patients. However, there was no clear correlation between DNA ploidy pattern and these changes.

[DNA index as a significant prognostic indicator of colorectal cancer].

To investigate the prognostic significance of DNA ploidy pattern and DNA index (DI), DNA contents were measured by flow cytometer in 412 patients with colorectal cancer and correlation between their prognoses and DNA contents were analyzed on the same clinical stage. There were significant differences in the survival rate and the incidence of tumor recurrence between diploid and aneuploid tumors, especially the poor survival rate and frequent tumor recurrence in the aneuploid tumor with DI above 1.5. Cox's multiple regression proportional hazard model was used to investigate the prognostic value of DNA ploidy pattern, DI and clinicopathological findings. From these analyses, DI 1.5 was found to be the most significant prognostic factor. These results suggest that flow cytometrically evaluated DI values have a relevant independent power for predicting the clinical outcome of colorectal cancer patients.

[Flow cytometric measurement of p53 protein and DNA content in colorectal carcinomas with liver metastasis].

To investigate the possible relation between p53 protein, DNA content and liver metastasis of colorectal cancer, overexpression of p53 and DNA content were measured by flowcytometer in 113 primary lesions, which included 34 cases with simultaneous liver metastasis and 79 cases with curative resection, and 25 metastatic lesions of the liver. Overexpression of p53 and DNA aneuploidy were found in 44 (38.9%) and 77 (68.1%) of 113 primary lesions, respectively. However, p53 protein and DNA aneuploidy were unrelated to the clinicopathological findings, such as liver metastasis, venous invasion and lymph node metastasis. Comparing the overexpression of p53 protein between primary and metastatic lesions, p53 protein was recognized in 18 (72.0%) of 25 metastatic lesions of the liver. Incidence of p53 protein was significantly higher in metastatic lesions of the liver than in primary lesions (p < 0.01). On the other hand, p53 protein was found in 27 (60.0%) of 45 diploid lesions and in 35 (37.6%) of 93 aneuploid lesions. There was a significant difference in p53 protein between diploid and aneuploid tumors (p < 0.05). These results suggest that p53 protein may not correlate with the occurrence of liver metastasis and might be produced in the metastatic lesion of the liver after metastasis.

Relationship between the cell-proliferative activity of gastric cancers and that of the normal epithelium.

Samples of gastric carcinomas and of normal gastric mucosa adjacent to tumors from 104 patients with primary mucosal gastric cancer were analysed by flow-cytometry. These patients were divided into two groups according to the histologic type of their tumors (differentiated group and undifferentiated group). The pattern of DNA ploidy and the sizes of the S- and G2M-phase fractions (percentages of cells at each respective phase) were compared between these two groups. DNA aneuploidy was encountered in 25.4% of the cases in the differentiated group and in 21.2% of the cases in the undifferentiated group. The mean sizes of S- and G2M-phase fractions of carcinomas in the differentiated group were 8.85% and 3.75% and they were significantly higher than the mean sizes of S- and G2M-phase fractions of carcinomas in the undifferentiated group (6.97% and 2.92%). Moreover, the S-phase fraction of normal gastric mucosa adjacent to the differentiated adenocarcinoma was 5.75% and this value was significantly higher than that of normal gastric mucosa adjacent to undifferentiated adenocarcinoma (4.80%). These results suggest that the proliferative activity of mucosal gastric cancer cells, as described by flow-cytometry, is higher in cases of differentiated adenocarcinoma than in cases of undifferentiated adenocarcinoma, and that the proliferative activity of normal cells in the gastric mucosa close to where adenocarcinoma develops is higher in cases of differentiated adenocarcinoma than in cases of undifferentiated adenocarcinoma. Thus, differentiated adenocarcinoma seems to develop from gastric mucosa with high proliferative activity.

Prophylactic portal infusion chemotherapy as adjuvant therapy for the prevention of metachronous liver metastasis in colorectal cancer.

The DNA ploidy and DNA indices (DI) of 414 patients with colorectal cancer were analyzed, and the incidence of patients with metachronous liver metastasis was found to be significantly higher in those with aneuploid tumors and a DI above 1.5 than in those with aneuploid tumors and a DI below 1.4, or in those with diploid tumors and a DI equal to 1.0. Next, to confirm the effectiveness of administering prophylactic portal infusion chemotherapy (PPIC) as adjuvant therapy for the prevention of metachronous liver metastasis in colorectal cancer, a randomized controlled trial of PPIC was performed on 110 consecutive patients with primary colorectal cancer who had undergone curative resection. Although the incidence of patients with metachronous liver metastasis in the two study groups was not significantly different at 3.3% in the PPIC group and 10.3% in the control group, the incidence in the patients with aneuploidy and a DI above 1.5 was significantly lower in the PPIC group than in the control group. These findings suggest that colorectal cancer with aneuploidy and a DI above 1.5 may have a strong tendency to metastasize to the liver, and that prophylactic portal infusion chemotherapy may be effective for preventing metachronous liver metastasis in such patients.

[A case of Gardner's syndrome associated with thyroid carcinoma].

We report a 22-year-old female who was diagnosed as familial adenomatous polyposis (FAP) associated with thyroid carcinoma. Total thyroidectomy and bilateral neck lymph nodes dissection were performed. Gardner's syndrome was pointed out after an investigation of her family. Total colectomy and ileo-rectal anastomosis were carried out. Colon cancer was not found pathologically. We reviewed 10 cases of FAP with thyroid carcinoma in Japan. Ten out of 11 cases including this patient were female. Thus it is important to pay careful attention to the presence of thyroid carcinoma in the case of FAP or Gardner's syndrome.

[Relation between nuclear DNA content and lymph node metastasis in submucosal early gastric cancer].

To investigate a possible relation between the nuclear DNA content and lymph node metastasis of submucosal early gastric cancer, DNA content was analyzed for 46 patients with lymph node metastasis and 67 patients without nodal metastasis. DNA aneuploidy was found in 20 (43.5%) of 46 patients with lymph node metastasis and in 31 (46.3%) of 67 patients without it. There was no statistical difference in the incidence of aneuploidy between the 2 groups. Among the cases with DNA diploidy, the mean value of S phase fraction was 6.82% in patients with lymph node metastasis and 5.65% in those without metastasis. The mean value of S phase fraction was significantly higher in patients with nodal involvement (p < 0.05). Furthermore, among the cases with DNA aneuploidy, the mean value of G2/M phase fraction was 11.03% in patients with lymph node metastasis and 7.54% in patients without metastasis. The mean value of G2/M phase fraction was significantly higher in patients with nodal involvement (p < 0.05). These findings suggest the significant value of the S and G2/M phase fraction for the prediction of lymph node metastasis in patients with submucosal early gastric cancer.