Consolidation Chemotherapy May Improve Pathological Complete Response For Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiotherapy: Evidence From Real-World Data

Patients with locally advanced rectal cancer (LARC) have an improved prognosis if achieved pathological complete response (pCR) on account of neoadjuvant chemoradiation therapy (nCRT). However, the proportion of patients achieving pCR is only 15-20%. The purpose of this study was to explore whether the adding of consolidation chemotherapy to nCRT could improve pCR rate in patients with LARC. Subjects were 144 individuals with clinical stage II (T3–4, N0) or III (any T, N1–2) LARC who had received neoadjuvant CRT followed by total mesorectal excision (TME). 60 patients in the consolidation chemotherapy group received two cycles XELOX between CRT and TME, while 84 patients in the standard treatment group without consolidation chemotherapy. Two groups were matched according to age, gender, TNM staging, and ECOG grade. The pCR (ypT0N0), tumor downstaging (ypT0-2N0) after TME and adverse events (AEs) during and post treatment were compared between the treatment groups using multivariable logistic regression analysis. The consolidation chemotherapy group improved pCR rate (19.3% versus 4.9%, p = 0.01) and tumor downstaging rate (45.8% versus 24.6%, p = 0.009) compared to the standard treatment group. After adjustment for clinical tumor stage, clinical nodal stage and time interval to surgery, patients with consolidation chemotherapy were more likely to reach pCR (adjusted odds ratio 4.91, 95%CI 1.01- 23.79, p = 0.048). adverse events (AEs) during and post treatment in the two groups were 54.1% versus 49.3% (p = 0.57), respectively. In addition, the incidence of any grade 1-2 AEs in the two groups was 93.4% versus 95.1% (p = 0.93), while the incidence of grade 3 adverse events was 1.6% versus 2.4% (p = 0.74), respectively. No grade 4 AEs were occurred in two groups Adding neoadjuvant consolidation chemotherapy after CRT significantly improved the pCR rate without increasing during and post treatment in patients with LARC.