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

Woong Bae Ji, Jun Won Um, Je Seock Ryu, Kwang Dae Hong, Jung Sik Kim, Byung Wook Min, Sung Yeop Joung, Ju Han Lee, Young Sik Kim


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.

Keywords: 5-fluorouracil; Colorectal cancer; chemosensitivity; chemotherapy; survival.