I am sympathetic with Dr Silen's1 concern about the indications for resection of hepatic metastases, because I have been guided by such reservations for 30 years. However, I do not accept his condemnation of beliefs that have been acquired cautiously and rationally throughout these years. I think there is some validity where he has found none, and I am convinced that some people who have hepatic metastases will live much longer if their liver lesions are removed. There is a small, well-defined group of patients who must not be assigned to therapeutic trials that would deny half of them their only chance for extended survival. Thus, we have a difference of opinion that at first seems to be absolute. Nevertheless, I think that something good can come from an examination of this disagreement.
The uncertainties that we share relate to the nature of controls, the differences between total populations