Neoadjuvant chemotherapy in the combination treatment for locally advanced rectal cancer: currently available options

Abstract

Objective: to analyze treatment outcomes in patients with locally advanced rectal cancer that received various combinations of neoadjuvant chemotherapy and chemoradiotherapy.Materials and methods. In this retrospective study, we analyzed a cohort of prospectively recruited patients with stage mrT3(CRM+)/ T4N0–2M0 locally advanced rectal cancer. Participants were divided into three groups. Patients in Group 1 received preoperative longcourse radiotherapy given concurrently with capecitabine, followed by 2–6 cycles of consolidation chemotherapy with capecitabine and oxaliplatin (CapOx). In Group 2, patients initially received 1–2 cycles of induction chemotherapy with CapOx, followed by radiotherapy + capecitabine, and then consolidation chemotherapy with CapOx (“sandwich” method). Participants in Group 3 were treated with 1–3 cycles of induction CapOx chemotherapy with subsequent long-course chemoradiotherapy. After the combination treatment, all patients underwent surgery. The primary endpoint of this study was therapeutic pathomorphosis. Secondary endpoints included complete clinical response, toxicity, local recurrence, distant metastasis, and relapse-free survival.Results. This study included 155 patients (98 in Group 1, 44 in Group 2, and 13 in Group 3). Grade III toxicity was documented in 6.12 %, 4.55 %, and 23.08 % of cases in Groups 1, 2, and 3 respectively. None of the patients had grade IV toxicity. Grade III therapeutic pathomorphosis was achieved in 33.7 %, 22.7 %, and 23.1 % of patients in Groups 1, 2, and 3 respectively. Grade IV therapeutic pathomorphosis was observed in 14.3 %, 15.9 %, and 7.69 % of patients in Groups 1, 2, and 3 respectively. Complete clinical response was registered in 16.3 %, 11.4 %, and 0 % of cases in Groups 1, 2, and 3 respectively. Median follow-up was 47.2 months with no signs of progression. Relapses were observed in 1.02 % and 2.27 % of patients from Group 1 and Group 2 respectively, whereas Group 3 demonstrated no relapses. A total of 11.22 %, 13.64 %, and 23.1 % of participants from Groups 1, 2, and 3 respectively developed distant metastasis.Conclusion. Polychemotherapy used within the consolidation and «sandwich» treatment regimens is a promising option for the treatment of locally advanced rectal cancer. The efficacy of induction chemotherapy should be further studied with a larger sample.

Keywords

• locally advanced rectal cancer
• chemoradiotherapy
• neoadjuvant chemotherapy
• consolidation chemotherapy
• induction chemotherapy
• “sandwich” therapy
• pathomorphosis