Radio-chemotherapy in rectal cancer

Abstract

The benefit of adjuvant chemotherapy in colon cancer has now been demonstrated in several trials. In fact, at least in stage III disease there is a consensus that it is now no longer considered acceptable to perform trials of chemotherapy versus none. In earlier stage disease it is more controversial. The absolute margin of benefit shown in each individual trial in this setting is small. In the MOSAIC trial using oxaliplatin in combination with 5-fluorouracil and folinic acid, a 6% improvement in disease-free survival at 3 years was demonstrated. It is also very likely that any benefits in adjuvant therapy of rectal cancer would be of the same sort of magnitude as in colon cancer. Attempts to define benefits for post-operative chemotherapy in rectal cancer have been even more difficult. This partly reflects the natural history of the disease with local relapse being (at least historically) a much more important problem in rectal cancer than in colonic cancer. But a number of other variables make it more complex to design and complete trials in this setting. Firstly, the surgical approach to rectal cancer has changed very dramatically in the last decade or so with more widespread adoption of the principles of total mesorectal excision as popularised by Heald et al. This has led to a marked reduction in local relapse rates in most literature reported series. Secondly, the potential influence of radiotherapy on local control and perhaps also in the eradication of disease may be important. There is also the question of preversus post-