关键词:

中低位直肠癌, 静态调强放疗, 动态调强放疗, 序贯化疗, 全程新辅助治疗, 剂量学差异

Abstract:

Objective　To explore the preoperative static intensity-modulated radiation therapy (sIMRT) or dynamic intensity-modulated radiation therapy (dIMRT) of total neoadjuvant therapy (TNT) for patients with stage Ⅱ/Ⅲ middle-low rectal cancer and dosimetry comparison. Methods　A total of 87 patients with stage Ⅱ/Ⅲ middle-low rectal cancer treated at Shaanxi Provincial People's Hospital from February 2021 to February 2024 were selected as the study objects. According to the preoperative TNT methods, the patients were divided into two groups. Among the 44 patients in the sIMRT group, there were 26 males and 18 females; they were (62.58±6.43) years old; they were given sequential sIMRT chemotherapy. Among the 43 patients in the dIMRT group, there were 23 males and 20 females; they were (60.87±6.41) years old; they were given sequential dIMRT chemotherapy. The clinical efficacies, radiation dosimetry, and safety were compared between the two groups. χ² and t tests were used for the statistical analysis. Results　The objective response rate and disease control rate in the sIMRT group were 56.82% (25/44) and 84.09% (37/44), and those in the dIMRT group 67.44% (29/43) and 93.02% (40/43), respectively, with no statistical differences (χ²=1.043 and 1.706; P=0.307 and 0.192). After the treatment, there were no statistical differences in the levels of soluble cytokeratin 19 fragment antigen 21-1 (CYFRA21-1), carbohydrate antigen 242 (CA242), and CA72-4 between the sIMRT group and the dIMRT group (all P>0.05). The 2% of the planning target volume dose (D₂)[(2 677.43±3.58) cGy vs. (2 678.54±3.26) cGy], D₉₈ [(2 506.47±5.24) cGy vs. (2 511.43±5.33) cGy], and conformity index (CI) (0.72±0.08 vs. 0.78±0.09) of the sIMRT group were lower than those of the dIMRT group, and the maximum dose (D_max) [(2 763.74±7.41) cGy vs. (2 760.44±7.32) cGy], minimum dose (D_min) [(2 287.41±34.67) cGy vs. (2 264.75±36.42) cGy], and homogeneity index (HI) (0.15±0.04 vs. 0.13±0.03) were higher, with statistical differences (t=2.872, 4.377, 3.288, 2.089, 2.973, and 2.634 ; all P<0.05). The monitor units [(1 314.58±54.77) MU vs. (1 268.73±52.86) MU] and safety [9.30% (4/43) vs. 27.27% (12/44)] in the dIMRT group were better than those in the sIMRT group (t=3.973 and χ²=4.679; both P<0.05). Conclusions　TNT of sIMRT or dIMRT sequential chemotherapy has good efficacy in the clinical treatment of stage Ⅱ/Ⅲ middle-low rectal cancer, and can control tumor progression. Compared with sIMRT sequential chemotherapy, dIMRT sequential chemotherapy can better control the target dose and has higher clinical safety.

Key words:

Middle-low rectal cancer, Static intensity-modulated radiation therapy, Dynamic intensity modulated radiation therapy, Sequential chemotherapy, Total neoadjuvant therapy, Dosimetric difference