Abstract 98P
Background
The previous standard of care (SOC) for LARC was NA CCRT or short course RT followed by surgery with or without adjuvant chemotherapy. Since the read out of multiple phase III clinical trials for TNT in LARC and its wide-scale adoption globally, real-world data from Asia has been limited. Here, we compare the clinical outcomes of patients (pts) who received TNT against NA CCRT.
Methods
All pts diagnosed with LARC or oligometastatic rectal cancer at National University Cancer Institute, Singapore (NCIS) were discussed at a multi-disciplinary tumour board. From 2020, pts at NCIS were eligible for TNT if they had cT2/3N+ or cT4Nany, threatened circumferential resection margin and adequate organ function.
Results
Between 2011 and 2023, 403 pts were diagnosed. The median age was 62 (range: 28-89), 68.5% male, 72.5% Chinese, 12.1% had stage 4 disease, 17.9% cT4 tumours, 73.9% node positive and 44.4% had CRM involvement. Median tumour distance from anal verge was 6cm on colonoscopy and magnetic resonance imaging (range: 1-15 cm and 1-12 cm). 11.7% (n = 47) pts received TNT and 83.1% (n = 335) received NA CCRT. The rest received adjuvant therapy only. Of pts who underwent surgery after TNT (n=36), 77.8% had sphincter-preserving surgery, 88.9% achieved R0 resection and 5.6% (n=2) achieved pathological complete response (pCR). Among pts who had NA CCRT before surgery (n = 335), 85.3% had sphincter-preserving surgery, 91.3% had R0 resection and 9.0% (n=30) achieved pCR. In the TNT group, after a median follow up of 34.5 months (range: 20.6 – 53.0 months), 21.3% had disease recurrence (2.1% local, 19.2% systemic) and 14.9% demised. 1-year DFS rate was 88.7% (95% CI 75.0% - 95.2%). In the NA CCRT group, median follow-up was 94.3 months (range: 30.9 – 161.7 months). 33.1% had disease (1.8% local, 31.3% systemic) and 31.0% demised. 1-year DFS rate was 90.4% (95% CI 86.5% - 93.3%).
Conclusions
The high disease recurrence rates with previous SOC justifies the intensification of neoadjuvant therapy with TNT for LARC. pCR rates of both TNT and NA CCRT are lower than what has been reported in phase III clinical trials and further analysis are ongoing to determine the causes.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.