Combination treatment of rectal cancer using polyradiomodification and short courses of neoadjuvant radiotherapy

Objective: to improve the outcomes of combination treatment of patients with rectal cancer using polyradiomodification and short courses of neoadjuvant radiotheragy.

Materials and methods. A total of 905patients were included into this retrospective study based on the data retrieved from a prospective database. Of them, 241 patients underwent combination treatment with polyradiomodification (CT + PRM); 271 patients underwent combination treatment with preoperative radiotherapy alone (CT); 393patients underwent surgical treatment only (ST). Combination treatment with polyradiomodification included a course of radiotherapy with a total dose of 25 Gy delivered in 5 fractions (5 Gy each), rectal administration of biopolymer composition containing metronidazole at a dose of 10 g/m² (5-h exposure in the rectum on days 3 and 5), and chemotherapy with capecitabine at a dose of 2 g/m2 on days 1—14 followed by surgery within the next 4—6 weeks. We analyzed the incidence of postoperative complications, 5-year relapse-free survival, and frequency of relapses.

Results. The incidence of grade IIIB postoperative complications was significantly lower in patients who underwent combination treatment with polyradiomodification than in those who had surgery only (p = 0.0023) and those who had combination therapy without polyradiomodification (p = 0.0003). The 5-year relapse-free survival rate was 80.5 % in the group of CT + PRM compared to 64.9 % in the group of CT (p = 0.00315) and 60.1 % in the group of ST (p = 0.000001). The frequency of relapses was 0.4 %, 8.5 % (p = 0.00001), and 13.7 % (p = 0.00001) in the groups CT + PRM, CT, and ST respectively. There were no significant differences in the incidence of distant metastasis between the groups.

Conclusions. The developed variant of combination treatment with polyradiomodification did not increase the number of complications and ensured better relapse-free survival due to improved locoregional control.

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