Recent advances in the management of carcinoma of the rectum.

In the last two decades rectal cancer has changed from a surgically managed disease into a multidisciplinary treatment model resulting in considerable improvements in the survival and outcome. This has been made possible by better understanding of the tumor biology and oncogenesis, advances in diagnostic and staging investigations, and the changing concepts in surgical excision; from the days of abdominoperineal resection to the concept of "zone of upward spread" and low anterior resection to the era of total mesorectal excision and transanal excision. Efforts are on the way to risk stratification and identification of predictors of nonoperative management. Impressive advances in the adjuvant therapies have seen a sea change in the form of postoperative radiotherapy to preoperative radiotherapy to preoperative chemoradiotherapy and postoperative adjuvant chemotherapy. This multidisciplinary approach is the key to impressive local control rates, decreased metastatic rates, overall survival, and enhancement in quality of life. Newer ideas in the understanding of genetic differences in rectal cancers have stemmed from the observation that these cancers differ in their response to the adjuvant treatment. The present day research has focused these areas of biologic differences in cancers and aims to target the specific loci in malignant cells with monoclonal antibodies directed against various growth factors, key enzyme inhibition, and genetic manipulation. The future research lies in the study of gene expression, micro-array techniques, molecular markers, and better understanding of the predictors of tumor response to therapy.