There are a number of reasons why radiotherapy is better given before rather than after radical surgery for rectal cancer. When this policy is adopted, however, two related problems arise. First, how are patients requiring radiotherapy to be selected? Second, how are irradiated patients to be compared with unirradiated patients stage by stage in clinical trials?
It is suggested that the Dukes' staging system is in-appropriate for both, and that a clinical staging system for rectal cancer is urgently required to solve both these problems. The way in which such a staging system might be developed is indicated.
In the meantime trials of adjuvant radiotherapy for carcinoma of the rectum should be interpreted with caution for two reasons. First, a reduction in local recurrence may not necessarily be reflected in a reduction in death rates. Second, since the origin of local recurrence is obscure the radiation dose to the regional lymph nodes should be recorded carefully.