Retrospective Study on the Effect of Preoperative Versus Postoperative Chemoradiation for Rectal Carcinoma

Abstract

Background: In the present, there are two types of giving radiotherapy together with chemotherapy for
treatment of rectal carcinoma: neoadjuvant chemoradiation (CRT) and adjuvant CRT. A study conducted
overseas has found that patients given neoadjuvant CRT had better disease-free survival rate than patients given
adjuvant CRT, with no difference in overall survival rate and distant metastasis rate. However, there is no study
comparing the efficacy of neoadjuvant CRT and to adjuvant CRT in Thai patients.
Materials & Methods: In this retrospective study, patients were divided into two groups: the group which
received neoadjuvant CRT (54 patients) and the group receiving adjuvant CRT (71 patients). The objective of
this study was to determine disease-free survival rate and overall survival rate of the treatment comparing
neoadjuvant and adjuvant CRT. Lastly, the correlation between the status of K-ras gene and outcome of the
treatment was analyzed.
Results: The group with neoadjuvant CRT had disease-free survival rate as follows: 1 year at 94.2%; 2
years at 81.8%; 3 years at 70.4%; and 5 years at 70.4% compared with the group with adjuvant CRT who had
disease-free survival rate as follows: 1 year at 82.4%; 2 years at 73.5%; 3 years at 57.1%; and 5 years at 46.1%.
The group which received neoadjuvant CRT had statistically significant better disease-free survival rate than the
group receiving adjuvant CRT (P=0.034). The group which received neoadjuvant CRT had overall survival
rate: 1 year at 96.2%; 2 years at 90.1%; 3 years at 82.1%; and 5 years at 64.5% compared with the adjuvant
chemoradiation group which had overall survival rate: 1 year at 89.7%; 2 years at 85.3%; 3 years at 69.9%; and
5 years at 55.4%. It was found that the group receiving neoadjuvant CRT did not have statistically significant
better overall survival rate than the adjuvant CRT group (P=0.147).
Conclusions: Patients who received neoadjuvant CRT had better outcome in term of disease-free survival
than those with adjuvant CRT.