A decade of breast cancer clinical investigation: results as reported in the Program/Proceedings of the American Society of Clinical Oncology

Abstract

Purpose: To test the hypothesis that clinical research results have driven changes in recent breast cancer management recommendations.

Methods: All breast cancer abstracts in the Program/Proceedings of the American Society of Clinical Oncology (ASCO) from 1984 to 1993 were prospectively reviewed in 31 areas and categorized by study type, study question, whether statistical significance was claimed, and whether the abstract was presented.

Results: Of 1,372 abstracts, 54% reported on prospective clinical trials (PCTs) and 17% on randomized clinical trials (RCTs). The total number of published abstracts progressively increased (from 87 in 1984 to 221 in 1993) and author citations nearly quadrupled (from 430 in 1984 to 1,642 in 1993, P < .01); however, RCTs have come to represent a smaller proportion of reports: 37% (33 of 89) in 1986 versus 10% (22 of 221) in 1993 (P < .001). The size of adjuvant-therapy RCTs has progressively increased (mean +/- SEM subjects/trial, 237 +/- 43 in 1984 to 874 +/- 374 in 1993), but has remained small in advanced-disease RCTs (mean +/- SEM subjects/trial, 145 +/- 25 in 1984 to 146 +/- 34 in 1993). For adjuvant therapy, 14 of 90 RCTs (with 51,207 patients) reported a significant (P < .05) survival benefit for investigational therapies (16%). For advanced-disease therapy, only three of 141 RCTs (with 26,281 patients) reported a significant (P < .05) survival benefit for investigational therapies (2%). Randomization was rarely used in trials of dose-intensity with blood-product support (zero of 86 trials) or locally advanced disease.

Conclusion: For breast cancer ASCO abstracts in the past decade, we determined the following: (1) adjuvant trials have not infrequently supported study hypotheses; and (2) advanced-disease trials have consistently failed to identify new approaches with a significant impact on survival. These results suggest that a critical process evaluation of current policy and procedures involved in directing breast cancer research is warranted, especially for strategies in advanced disease.