Neoadjuvant chemotherapy (CAPOX) alone for low- and intermediate-risk stage II/III rectal cancer: Long-term follow-up of a prospective single-arm study

Abstract

BackgroundStratified treatment has been recommended for rectal cancer. Our previous multicenter randomized trial showed that low-/intermediate-risk rectal cancer patients did not benefit much from neoadjuvant chemoradiotherapy. In our phase II study, we found that stage II/III rectal cancer patients with low-/intermediate risks can be managed by neoadjuvant chemotherapy alone and achieve a good response. The current study aimed to report the long-term survival outcomes in the expanded phase II trial. MethodConsecutive patients diagnosed with mid-low stage II/III rectal cancer with low/intermediate risk factors were included. Four cycles of neoadjuvant chemotherapy (CAPOX) were given, and MRI was used for tumour response detection. The primary endpoint was disease-free survival. The secondary endpoints were tumour response to NCT, tumour-related death, and overall survival. ResultsThis study enrolled 121 eligible patients. The good tumour response rate based on MRI was 82.6 %, with a pathological complete response (pCR) rate of 18.3 %. The disease-free survival rate was 82.6 %, and the overall survival rate was 96.7 % after a median follow-up time of 40 months. Two patients (1.7 %) suffered local recurrence, and 15 patients (12.4 %) suffered distant metastasis. The median disease-free survival and overall survival were 37 (9–60) and 40 (16–60) months, respectively. Tumour longitudinal length reduction and tumour regression grade on MRI were identified as predictors for poor tumour response to neoadjuvant chemotherapy. ConclusionIn stage II/III rectal cancer patients with low-/intermediate risks, neoadjuvant chemotherapy alone may result in an acceptable tumour response and disease-free survival. Tumour response might be predicted early.