The good results obtained by chemoradiotherapy as neoadjuvant therapy in the treatment of rectal cancer have included it as a routine procedure in order to improve resectability and sphincter preservation. Recent studies suggest a non operative approach in cases of complete tumour response and demonstrate the need of a better definition for prognosis of tumour response to neoadjuvant therapy as individual therapeutic approach. There are now evidences that this responsiveness is related to biomolecular tumour profile. Tissue expression of several proteins such as p53 and thymidylate synthase have shown significant correlation with tumour regression, although its predictive value has been insufficient to influence clinical decision. On the other hand, studies using microarray techniques to analyze a specific subsets of gene expressions have shown very encouraging results, with predictive values for tumour regression close to 100%, as a consistent possibility for clinical application in defining a more precise and individual indication for neoadjuvant therapy.
Rectal cancer; radiotherapy; molecular biology