The results of 5-Fu blood concentration analysis in the control group and the experimental group during the 6 cycles showed that the proportion of the 37 patients in the control group who fell within the therapeutic window (AUC:20-30 mg·h/L) for a total of 23 times during the 6 cycles was 16.67% (23/138), and most of the patients had a 5-Fu AUC value lower than the therapeutic window range. In the experimental group, after BSA-based administration, the distribution of 5-Fu blood concentration was also more dispersed, and the proportion of patients falling within the therapeutic window was 21.6% (8/37) with a coefficient of variation (CV) of 48.77% in cycle 1, and after dose adjustment from cycle 2 to 6, the proportion increased to 67.74% (23/34) with a CV of 22.75% in cycle 6. The difference between the two groups was statistically significant (χ² = 20.04, P < 0.01).

Figure 1 AUC distribution of 5-Fu over 6 cycles in control and experimental patients

Note, A, the majority of patients in the control group had 5-Fu AUC values below the therapeutic window range; B, there was an increase in the number of patients in the experimental group whose 5-Fu AUC fell within the therapeutic window range, with a tendency to concentrate.

Compared with the control group [70.3% (26/37)], the incidence of toxic side effects ( ≥ grade 3) in the experimental group [32.4% (12/37)] showed a statistically significant difference (χ2 = 10.60, P < 0.01). Further analysis of the specific toxic side effects showed that the differences in diarrhea, oral mucositis and other toxic side effects were statistically significant (P < 0.05), while the differences in nausea, vomiting, hand-foot syndrome, loss of appetite, loss of body weight and leukopenia were not statistically significant (P > 0.05).

Table 2 Relationship between toxic side effects in control and experimental groups [n (%)]

Discussion