- We conducted a clinical audit of the recurrence-free rates and absolute survival of 146 patients who presented with T1-T3 glottic cancer and received primary radiotherapy treatment at the Nova Scotia Cancer Centre between 1984 and 1990. The outcomes are compared with a review of published results from other centres. We used stage T3 glottic cancer as an example to illustrate concepts of effectiveness research which are used to determine at what level interventions operate in the day to day practice of medicine. The actuarial recurrence-free rates at 5 years are: T1 91%, T2 73%, and T3 44%. The actuarial absolute survival rates are: T1 84%, T2 68%, and T3 52%. Effectiveness research may utilize efficacy research, clinical audit, quality of life assessment and decision making theory. Its objective is to aid the implementation of appropriate clinical management for specific individuals and defined communities. Expert computer systems may be necessary to synthesize the data and to enhance communication and decision making.