Evaluation of Treatment Successes: Outcome Measures
In a series of phase 3 RCTs completed between 1955 and 2000, new cancer treatments were found to be statistically superior in 24% of comparisons, while standard treatments were superior in 6%. The original researchers concluded that new treatments were better in 41% of comparisons. Quantitative pooling of data revealed a 5% relative reduction in the death rate for new treatments compared to standard treatments (HR, 0.95; 99% CI, 0.93-0.98).
Factors Affecting Outcomes
Factors such as publication bias, methodologic quality, and the choice of control intervention were identified as key influences on the results of clinical trials. The study also highlighted the importance of the ethical principle of equipoise, which underlies the design and conduct of RCTs, suggesting that treatment successes are a consequence of the predictable relationship between this principle and the outcomes of RCTs.
Pattern of Treatment Successes Over Time
The study found that the main advances in cancer treatment have occurred in the management of gastrointestinal cancer and hematologic malignant neoplasms, largely due to the introduction of adjuvant and intensive chemotherapies. The pattern of treatment successes has become more consistent over time, with the probability of treatment success remaining within a constant but limited range of plausible values.
Efficiency of the Clinical Trial System
The current system of RCTs in cancer is efficient within certain limits, with an estimated 25% to 50% of new cancer treatments that reach the stage of assessment in RCTs proving to be successful. The study suggests that the absolute number of discoveries might be improved if the proportion of inconclusive trials is reduced, highlighting the need for a more efficient clinical trial system.
Conclusion
The study concludes that society has received a good return on its investment in the COG system, with a consistent pattern of treatment successes over time. However, there is potential for improvement in the absolute number of discoveries by reducing the proportion of inconclusive trials.
