Oxaliplatin-based adjuvant chemotherapy rather than fluorouracil-based chemotherapy in rectal cancer is more efficient to decrease distant metastasis and increase survival after preoperative chemoradiotherapy and surgery: a meta-analysis.

PURPOSE: The standard treatment of stage II-III rectal cancer is preoperative chemoradiotherapy (CRT), followed by total mesorectal excision (TME). However, the rate of metastasis is still high following this treatment. Therefore, several adjuvant chemotherapy studies have been conducted on reducing subsequent metastases and increasing survival, although there are still no definite conclusions. METHODS: We searched for published prospective randomized controlled trials comparing adjuvant chemotherapy regimens following standard preoperative CRT and curative surgery in stage II-III rectal cancer. We systematically searched Medline, Embase, and the Cochrane Library for relevant trials done from January 2004 to January 2021. Review Manager (RevMan, version 5.3) was used to analyze the data. RESULTS: We initially searched 1955 studies. We screened and carefully selected four randomized controlled trials with 2897 patients. Compared to the 5-FU-based regimen group, the oxaliplatin-added regimen group attained a higher 3-year locoregional control rate (relative risk [RR] of 0.64, 95% confidence interval [CI], 0.48-0.86; p = 0.003) and 3-year distant metastasis control rate (RR of 0.82, 95% CI, 0.71-0.95; p = 0.007). The oxaliplatin-added regimen group had significantly increased 3-year disease-free survival with a hazard ratio (HR) of 0.85 (95% CI: 0.74-0.97, p = 0.020), but not overall survival (p = 0.740). Grade 3 or higher acute toxicity rates did not differ between the two groups (p = 0.190). CONCLUSION: The addition of oxaliplatin to adjuvant therapy for stage II-III rectal cancer following preoperative CRT and TME may increase disease-free survival without significant increases in toxicity, but not overall survival.

Effect of a Shortened Duration of FOLFOX Chemotherapy on the Survival Rate of Patients with Stage II and III Colon Cancer.

BACKGROUND: FOLFOX chemotherapy is widely used as an adjuvant treatment for advanced colon cancer. The duration of adjuvant chemotherapy is usually set to 6 months, which is based on a former study of 5-fluorouracil/leucovorin chemotherapy. However, the FOLFOX regimen is known to have complications, such as peripheral neuropathy. The aim of this study was to compare the survival rates and complications experienced by patients receiving either 4 or 6 months of FOLFOX chemotherapy. METHODS: Retrospective data analysis was performed for stage II and III patients who underwent radical resection of colon cancer. We compared the 5-year survival rates and the occurrence of complications in patients who completed only 8 cycles of FOLFOX chemotherapy with patients who completed 12 cycles of chemotherapy. RESULTS: Among 188 patients who underwent adjuvant FOLFOX chemotherapy for stage II or III colon cancer, 83 (44.1%) completed 6 months of FOLFOX chemotherapy and 64 (34.0%) patients discontinued after 4 months of chemotherapy. The 5-year overall survival and disease-free survival rates did not show a significant difference. Patients in the 6-month group had peripheral neuropathy more frequently (p = 0.028). CONCLUSIONS: Five-year overall and disease-free survival were not significantly different between the 2 groups. Large-scale prospective studies are necessary for the analysis of complications and survival rates.

Clinical Significance of 5-Fluorouracil Chemosensitivity Testing in Patients with Colorectal Cancer.

AIM: To evaluate whether the results of chemosensitivity testing were associated with prognosis of colorectal cancer patients after adjuvant 5-fluorouracil (FU)/ leucovorin chemotherapy. PATIENTS AND METHODS: Eighty-nine patients who received 5-FU/leucovorin adjuvant chemotherapy for colorectal cancer were enrolled. Chemosensitivity tests were performed and tumor growth inhibition rate was calculated using the MTT (3-(4,5-dimethylthiazol-2-yl)02,5-diphenyl-2H tetrazolium bromide) assay. RESULTS: Fifty-one patients (57.3%) were sensitive to 5-FU according to the chemosensitivity test. After a median follow-up of 64 months, there was a significant difference between the 5-year disease-free survival rates of the chemo-sensitive and chemo-resistant groups. However, there was no significant difference in the overall 5-year survival between the chemo-sensitive and chemo-resistant groups. CONCLUSION: A positive 5-FU sensitivity test with in vitro histoculture drug response assay (HDRA) was associated with better disease-free survival. Chemosensitivity may be a prognostic factor for colorectal cancer patients undergoing adjuvant 5-FU/leucovorin chemotherapy.