Induction chemotherapy followed by long-course chemoradiotherapy versus short-course radiotherapy followed by consolidation chemotherapy for achieving complete response in patients with locally advanced rectal cancer: a propensity-score matching study.

PURPOSE

This study compared complete response (CR) outcomes between two total neoadjuvant therapy (TNT) strategies for locally advanced rectal cancer: induction chemotherapy followed by long-course chemoradiotherapy (INCT-LCCRT) versus short-course radiotherapy followed by consolidation chemotherapy (SCRT-CNCT).

METHODS

The subjects of this retrospective study were 234 patients with clinical stage T3-4NanyM0 low rectal cancer, treated between 2011 and 2022 with TNT and either total mesorectal excision or non-operative management (NOM). CR was defined as pathological CR after resection or sustained clinical CR in NOM. Propensity score matching was applied to adjust baseline differences, resulting in 38 matched pairs. We evaluated CR rates and survival outcomes.

RESULTS

There were 194 patients treated with INCT-LCCRT and 40 treated with SCRT-CNCT. The INCT-LCCRT group had more advanced disease features, including higher rates of clinical T4 (29.9% vs. 2.5%) and lateral pelvic node metastases (62.4% vs. 10%). The CR rates were comparable in the full cohort (30.9% vs. 30.0%, p = 1) and after matching (34.2% vs. 28.9%, p = 0.81). No significant differences were observed in 3-year relapse-free or local recurrence-free survival.

CONCLUSIONS

In the matched cohort of mainly intermediate-risk cases, INCT-LCCRT and SCRT-CNCT demonstrated comparable CR rates and oncological outcomes.