Abstract 414P
Background
No broad consensus exists for the adjuvant management of patients with rectal cancer (RC) who are down-staged following neoadjuvant chemoradiotherapy (nCRT) and total mesorectal excision (TME). This study evaluated clinical outcomes of adjuvant chemotherapy (AC) versus surveillance(S) in a real-world setting across multiple sites.
Methods
We retrospectively evaluated the records of radically resected RC patients who had nCRT, were downstaged and then offered either S or AC based on clinician’s judgement. Data was extracted from the electronic patient records from 4 NHS trusts in Kent, UK that covers a population of 1.8 million people.
Results
589 patients with rectal cancer between 1 Jan 2014 and 31 Dec 2019 were identified. Of these, 149 who had M0 disease and were later downstaged at TME were assessed. Median age was 67 (24-89). All patients had nCRT (45Gy/25 + Capecitabine (Cape)/5FU or 25Gy/5). They then had TME. 94 (63%) had AC, (Cape/5FU, CAPOX or FOLFOX) while 55 (37%) were kept under surveillance. Patients with AC had a lower age (median 62 vs 68, p=0.0045); higher baseline tumour stage (p=0.012); longer time between RT and TME (89 vs 86 days, p=0.027); higher EMVI (70 vs 41%, p=0.00345); higher rates of threatened/positive CRM (83 vs 65%, p=0.01481), and post op tumour stage (p<0.0001). There was no significant difference in tumour grade, distance from anal verge,TRG, post RT staging, and resection margin status. Overall, there was no significant survival difference between AC & S with RFS of 70% vs 75%(p=0.1233) and 2-year OS of 91% vs 98% (p=0.1661), table1. Higher tumour grade at diagnosis(p=0.014), post op stage (p=0.042) & resection margin(p=0.003) were associated with risk of death. Table: 414P
Patient characteristics
| Adjuvant | Surveillance | Sig difference | p-value | |
| n | 94 (63%) | 55(37%) | ||
| Age | 62 | 68 | ** | 0.0045 |
| Grade( 1-3) | 2 (median) | 2 (median) | ns | 0.6391 |
| Baseline Stage (2 & 3) | 2: 5 (5.3%) 3: 89 (94.7%) | 2: 11(20%) 3: 44 (80%) | * | 0.0120 |
| EMVI ( + or -) | 70% (43/61) | 41% (15/37) | ** | 0.00345 |
| CRM ( + or -) | 83% (73/88) | 65% (33/51) | * | 0.01481 |
| Anal verge(<5cm or >5cm) | 40% (33/82) | 50% (26/52) <5cm | ns | 0.58265 |
| Post RT staging 2: 45 3: 46 | 2: 30 3: 33 | 2: 15 3: 13 | ns | 0.6212 |
| Post op staging 2: 52 3: 38 | 2: 39 3: 31 | 2: 13 3: 7 | *** | <0.0001 |
| Resection margin (R1/R2 vs R0) | 3.5% (2/57) | 12.5% (11/89) | ns | 0.0795 |
| Time btw RT and surgery | 89 days | 86 days | * | 0.0270 |
| Recurrence free survival (RFS) | 70% | 75% | ns | 0.1233 |
| OS 1 year | 95.6% | 98% | ns | 0.6505 |
| OS 2 year | 91.1% | 98% | ns | 0.1661 |
Conclusions
Results in our real-world cohort did not find any significant benefit of AC following nCRT and TME. Surveillance may avoid chemotherapy related toxicities without compromising survival. Randomised trials are necessary to address this important issue.
Clinical trial identification
Editorial acknowledgement
We acknowledge the contributions of the below members of the multidisciplinary teams that either led in clinical decision making or provided direct care to the patients in this study but due to author list number limitations were not listed as authors. EKHUFT Pradeep Basnyat Mr Sudhakar Mangam Mr Ashish Shrestha Mr Amjad Khushal Mr Mansoor Akhtar Mr Mohan Harilingam Mr Biju Aravind Mr George Tsavellas DVH Rakesh Bhardwaj Mr Petr Hanek Mr Piero Nastro Mr Jacek Adamek Medway Henk Wegstapel Mr Neil Kukreja Ms Shirley Chan Mr Pankaj Gandhi Mr William Garrett MTW Chris Wright Mr Charles Bailey Mr Raza Moosvi Mr Simon Bailey Mr Daniel Lawes Ms Helen Lloyd.
Legal entity responsible for the study
Maidstone and Tunbridge Wells NHS Trust.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.