ADJUVANT CHEMOTHERAPY FOR RECTAL CANCER 

Hello. I am David Kerr, Professor of Cancer Medicine at University of Oxford, and past President of the European Society for Medical Oncology. Today I want to talk about adjuvant chemotherapy for rectal cancer. This has been an area in which we have been poorly served by the data, a result of many small clinical trials that are underpowered. None of these trials has been able to demonstrate a clear survival benefit [associated with adjuvant chemotherapy]. Now, theAnnals of Oncology has published a paper by 2 good friends of mine, Lars Påhlman and Bengt Glimelius,^[1] who have used the Swedish Cancer Registry data to look at routine use of adjuvant chemotherapy for patients with stage III rectal cancer. Because of the high quality of the data linkage between treatment delivered and outcomes, these authors have given us a fascinating insight into the potential survival benefits of radiotherapy.

They have shown that of the roughly 450 patients they studied, those who received adjuvant chemotherapy had 5-year survival rates of around 65%, compared with 45% for those who did not [receive adjuvant chemotherapy]. This was not a randomized study, so there are potential biases, although it is difficult to imagine a bias that would lead to a survival difference of that sort. But you could argue it both ways. Perhaps you would choose patients for adjuvant chemotherapy who are healthier and may have a better prognosis, or the converse: that those patients with a more phenotypically aggressive tumor might be selected for more aggressive treatment. The potential for bias is real but unlikely to play a major role. The only other large major European study that has shown a survival benefit was our own Quasar trial,^[2] a randomized trial [of patients with predominantly stage II rectal cancer at low risk for recurrence]. Again, we saw an overall survival benefit for the subgroup of patients [who received adjunctive chemotherapy vs those who received observation]. Putting these data together provides useful evidence of the survival benefits of a 6-months series of fluorouracil and folinic acid-based adjuvant chemotherapy for patients with stage III rectal cancer.

Thanks for listening.