Intensification of neoadjuvant therapy in patients with locally advanced rectal cancer

The aim of the study: to increase the frequency of achieving pathologic complete response and increase disease-free survival in the investigational group of patients with locally advanced rectal cancer T3(MRF+)–4N0–2M0 by developing a new strategy for neoadjuvant therapy.
Materials and methods. In total, 414 patients were assigned to treatment. Control group I included 89 patients who underwent radiotherapy (RT) 52–56 Gy/26–28 fractions with concurrent capecitabine twice daily 5 days per week. Control group II included 160 patients who underwent RT 52–56 Gy/26–28 fractions with concurrent capecitabine twice daily 5 days per week and oxaliplatin once a week, during the course of RT. Study group III consisted of 165 patients. This group combined RT 52–56 Gy/26–28 fractions with concurrent capecitabine twice daily 5 days per week and additional consecutive CapOx cycles. This group was divided into 2 subgroups: subgroup IIIa included 106 patients with consolidating chemotherapy (after CRT); subgroup IIIb included 59 patients who underwent “sandwich” treatment. Therapy consisted of conducting from 1 to 2 cycles of induction CapOx (up to CRT) and from 1 to 2 cycles of consolidating CapOx with an interval of 7 days. In the interval between the courses of drug therapy, RT 52–56 Gy/26–28 fractions was performed. According to the results of the control examination, further treatment tactics were determined. The primary end points were 5-year disease-free survival and the achievement of a pathologic complete response.
Results. Pathologic complete response was significantly more often recorded in patients in the investigational group III (17.48 %; p = 0.021) compared with control groups (7.95 % in the I group and 8.28 % in the II group). 5-year disease-free survival in patients in the study groups was: 71.5 % in the III group, 65.6 % in the II group and 56.9 % in the I group.
Conclusion. The shift in emphasis on strengthening the neoadjuvant effect on the tumor and improving approaches to drug therapy regimens have significantly improved disease-free survival of patients with locally advanced rectal cancer.

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