To investigate the efficacy of bevacizumab combined with 5- fluorouracil+calcium folinate+irinotecan (FOLFIRI) chemotherapy in the treatment of advanced colon cancer and its impact on the vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor 2 (VEGFR2) signaling pathway.

The patients with advanced colon cancer admitted to our hospital were divided into control group and experimental group according to the random number table method. The control group was given FOLFIRI chemotherapy regimen: on the first day, irinotecan injection 180 mg·m^-2 + 500 mL normal saline was given by intravenous drip ; calcium folinate 400 mg·m^-2 + 250 mL normal saline, intravenous infusion, 2 h infusion completed; fluorouracil injection 400 mg·m^-2, intravenous injection ; fluorouracil 2 400 mg·m^-2,46 h intravenous pumping. The experimental group was treated with bevacizumab on the basis of the control group: after the completion of chemotherapy, bevacizumab 5 mg·kg^-1 + 500 mL normal saline was intravenously administered. Both groups were treated for 2 cycles with 14 days as a cycle. The therapeutic effect, tumor markers [colon cancer specific antigen-2 (CCSA-2 ), carcinoembryonic antigen (CEA), thymidine kinase (TK1), carbohydrate antigen 199 (CA199)], vascular endothelial growth factor (VEGF) / VEGF receptor 2 (VEGFR2) signaling pathway factors, immune function (peripheral blood CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺), quality of life [cancer treatment function assessment-colorectal cancer scale (FACT-C) score] and adverse reactions were compared between the two groups, and followed up for 1 year, the 1-year survival rate was compared between the two groups.

In this study, 98 patients were screened, all of whom completed the treatment and were followed up for one year. Two patients in the experimental group were lost to follow-up, and one patient in the control group was lost to follow-up. After 2 cycles of treatment, the disease remission rate and disease control rate of the experimental group (55.10%, 69.39%) were higher than those of the control group (34.69%, 44.90%) (P<0.05). After 2 cycles of treatment, the peripheral blood CD3⁺ in the experimental group and the control group were (60.75±3.29)% and (58.81±3.10)%; CD4⁺/CD8⁺ were (1.76±0.40)%, (1.29±0.38)%; CD4⁺ were (38.65±3.05)%, and (33.12±2.86)% ; the serum CEA was (18.71±4.10) and (23.69±3.68) ng·mL^-1; the serum VEGF levels were (236.28±55.79) and (380.44±81.32) pg·mL^-1; the serum CA199 levels were (22.48±4.26) and (37.19±4.55) U·mL^-1; serum VEGFR2 were (1 131.16±142.53) and (1 514.79±215.41) pg·mL ^-1 ; serum TK1 was (1.15±0.23) and (1.92±0.31) pmol·L^-1, the serum CCSA-2 levels were (15.13±3.06) and (19.04±3.25) ng·mL^-1. Peripheral blood CD8⁺ were (22.02±2.15)%, (25.68±2.62)% ; the peripheral blood CD3⁺, CD4⁺/CD8⁺ and CD4⁺ in the experimental group were higher than those in the control group, and the serum CEA, VEGF, CA199, VEGFR2, TK1, CCSA-2 and peripheral blood CD8⁺ were lower than those in the control group (P<0.05). After 2 cycles of treatment, the physical status scores of FACT-C in the experimental group and the control group were (21.35±2.39) and (18.07±3.16) scores; the scores of social / family status were (24.27±1.31) and (20.94±1.75) scores; the scores of emotional status were (18.56±1.81) and (16.17±2.03) scores; the functional status scores were (22.42±1.64) and (19.78±2.18) scores; the specific module scores of colorectal cancer were (30.52±2.18) and (27.16±2.35) scores; the above indexes in the experimental group were higher than those in the control group (P<0.05). The incidence of leukopenia and gastrointestinal reactions in the experimental group (34.69%, 16.33%) was lower than that in the control group (61.22%, 36.73%) (P<0.05). After 1 year of follow-up, the survival rate of the experimental group (80.85%) was higher than that of the control group (62.50%) (P<0.05).

The combination therapy of FOLFIRI chemotherapy and bevacizumab for patients with advanced colon cancer can effectively regulate the VEGF/VEGFR2 signaling pathway, reduce tumor marker levels, improve immune function, decrease the occurrence of adverse reactions, enhance treatment efficacy, improve patients’ quality of life, and increase survival rates.