The evidence supporting the use of this protocol comes from the GITSG-7175 trialr by the Gastrointestinal Tumour Study Group, in which patients were randomised to surgery alone or surgery plus post-op chemoradiation. Whilst a 5 year disease free survival benefit was demonstrated with combined treatment, no difference in overall survival was shown.
The GITSG-7175 trialr is one of the only trials comparing adjuvant chemoradiation with surgery alone that has demonstrated a benefit with the combined treatment arm improving 5 year disease free survival, 67% vs 45% (p=0.0005). The trial was ceased early due to a clear benefit. The study randomised 227 rectal patients following complete surgical resection of stages B2 and C rectal adenocarcinoma to four treatment arms:
- No adjuvant therapy n=58
- Chemotherapy only n=48
- Radiotherapy only n=50
- Radiotherapy and chemotherapy (combined modality) n=46 with a follow up period of 6.5 years.
However, overall survival was not significantly different when compared to the no adjuvant therapy group.r
A RCT by O'Connellr randomised 660 patients with stage II or III rectal cancer having undergone a potentially curative resection to receive either post-operative fluorouracil with/without semustine via bolus infusion (n= 332) or fluorouracil with/without semustine via continuous infusion (n=328) during concurrent post operative radiotherapy. Continuous fluorouracil infusion demonstrated a significant improvement in the time to relapse (p=0.001) with a decrease in tumour relapse rate by 27% and an increase in the 4 year overall survival rate from 60 to 70% (p=0.005).The study also reported a significant decrease in the overall rate of tumour relapse from 47 to 37% (p=0.01) and distant metastases from 40 to 31% (p=0.03) in the continuous infusion arm of the trial.