ABSTRACT

The value of radiation therapy is well established in improving local control with surgery, but cumulative data on normal tissue toxicities associated with external beam raise concerns in the present era of total mesorectal excision (TME). There are two different types of toxicity: acute and late on normal tissues. This chapter discusses the factors involved with timing of the treatment, role of chemotherapy, treatment volumes, dose fractionation, new radiation technologies and possible alternatives to improve the therapeutic index. Radiation technologies have evolved from 2-D to 3-D modalities with the introduction of computerised planning systems and new generations of linear accelerators. TME surgery provides optimal tumour bed resection together with the perirectal nodes within the mesorectal fascia. TME surgery carries its share of morbidity with a 40% post-operative complications rate and late morbidity burden both with a permanent colostomy and also with the low anterior resection syndrome after sphincter preservation.