Abstract 244P
Background
Total neoadjuvant therapy is increasingly utilized in rectal cancer patients. We assessed the benefit of consolidation chemotherapy after long course neoadjuvant chemoradiotherapy (CRT) compared to neoadjuvant CRT alone in non-metastatic rectal cancer patients.
Methods
We recruited non-metastatic rectal cancer patients with clinical Stage T2 N1-2, T3N0-2, T4 N0-2 from 3 hospitals in Saudi Arabia. They were randomised to either neoadjuvant CRT followed by consolidation chemotherapy including 4 cycles of FOLFOX6 or 3 cycles of XELOX (experimental arm) or CRT alone (control arm). Patients with pT0-2 N0 after rectal surgery should not receive adjuvant chemotherapy in both arms while adjuvant chemotherapy should be given in case of higher pathological stage. The primary endpoint was pathological complete response (pCR) rate.
Results
Between 11-2017 and 1-2022, 108 patients were recruited. Baseline characteristics were balanced between the two arms with 57.4% and 35.2% of patients had cT3 and cT4 tumours, respectively. The great majority were node-positive and 52.7% had cN2 disease. pCR rate was numerically higher in the experimental compared to the control arm in intent to treat analysis (ITT) (50.0% vs. 30.2%, p=0.07) and per protocol analysis (48.6% vs 27.5%, p=0.06). Patients in the experimental arm had significantly higher major pathological tumour regression grade (TRG), defined as complete and near complete response, in ITT (76.3% vs 48.8%, p=0.011) and per protocol analysis (74.3% vs 47.5%, p=0.018). After a median follow up of 32.1 months, 3-year-disease free survival (DFS) was numerically in favour of consolidation chemotherapy arm in ITT (90.6% vs. 75.9%, HR=0.48, 95% CI= 0.17-1.35, p= 0.17) and per protocol analysis (91.5% vs 74%, HR=0.38, 95% CI=0.12-1.18, p= 0.09). No significant difference in adverse events was found between the two arms.
Conclusions
We demonstrated a strong trend of improving pCR and 3-year DFS with consolidation chemotherapy after long course CRT compared to CRT alone, with significant improvement in major pathological TRG. Longer follow up is needed for mature survival data.
Clinical trial identification
NCT03957733.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.