Outcomes of Neoadjuvant Chemotherapy without Radiation for Rectal Cancer

The efficacy of neoadjuvant chemotherapy without radiation (NAC) in the treatment of rectal cancer remains unclear. This retrospective study was aimed at determining the pathological complete response rate and short-term outcomes of NAC in patients with locally advanced rectal cancer.

We collected data on 159 consecutive patients treated for rectal cancer (cT3/cT4a, cN+, and cM0 status) at five tertiary referral hospitals between 2005 and 2010. Pathological complete response (pCR) and safety were assessed as the main outcomes in 124 eligible patients comprising 15 who received NAC (NAC group) and 109 who received no neoadjuvant chemotherapy (non-NAC group).

In the NAC group, 2 patients (13.3%) achieved a pCR (95% confidence interval: 1.7-40.5%) and 3 patients (20%) experienced grade 3/4 adverse events. No significant differences were found between the NAC and non-NAC groups in terms of short-term outcomes, including R0 proportion (100 vs. 96.3%, p = 0.45) and postoperative grade 3/4 complications (13.3 vs. 18.4%, p = 0.63).

Neoadjuvant systemic chemotherapy without radiation appears to be safe, without worsening short-term outcomes, in patients with locally advanced rectal cancer. A further study is needed to verify these findings in larger samples.