Current Issues in Conduct and Reporting of Noninferiority Randomized Controlled Trials in Surgical Management of Cancer Patients

Interpreting the results of noninferiority trials-a review

Noninferiority trials are becoming increasing common, but are often poorly reported and misunderstood. A better understanding of the new components of a noninferiority trial and their interpretation is needed. Noninferiority trials are an extension of conventional superiority trials, which provide a basis for determining if a new treatment, which may have advantages other than efficacy, has sufficient efficacy to be useful in certain situations. A key feature is the need to specify a clinical noninferiority margin above which the lower boundary of the confidence interval for the difference between the new treatment and the conventional treatment must lie. In most cases a nontreated control arm is not included, and when the efficacy of the new treatment is less than that of the standard treatment, determining its efficacy versus no treatment can be a major challenge. Treatments meeting a clinical noninferiority requirement can be statistically significantly superior to standard treatment, of similar efficacy (i.e., no significant difference), or even significantly inferior in a conventional analysis. Noninferiority comparisons are an important addition to the reporting of clinical trials, but require prior consideration of several factors that conventional superiority analyses do not address.

Surgical clinical trials with non-inferiority design: a cross-sectional bibliometric analysis

Background

Wide-spread concerns have been raised about possible bias in published surgical non-inferiority trials. Therefore, we performed a comprehensive bibliometric analysis to identify the existence of bias, and provided recommendations for future non-inferiority trials.

Methods

Databases including MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were systematically searched (last update on 27 April 2020) to include published phase II and phase III non-inferiority surgical trials. We collected general information and parameters associated with trial design. The association between extracted factors and establishment of non-inferiority was then analyzed.

Results

A total of 347 trials were included in this study. Only 13 (3.7%) trials reported the pre-specified non-inferiority margin in registration, and 99 (28.5%) trials justified margin selection in ultimate trial publications. A significant association was found between industry funding and increased odds of achieving non-inferiority [odds ratio (OR): 1.17, 95% confidence interval (CI): 1.06 to 1.30, P=0.001]. Moreover, trials which had been presented in conferences were less likely to claim non-inferiority (OR: 0.83, 95% CI: 0.69 to 0.99, P=0.035).

Conclusions

Our study was the first quantitative analysis revealing the presence of biases in findings of existing surgical non-inferiority trials, which could possibly mislead surgeons’ clinical decision making. We suggest improving reporting of detailed study design especially funding sources as well as margin justification for future trials. We also encourage conference presentation of ongoing trials prior to the ultimate publication.

Re-evaluating "Success" as It Pertains to Surgical Trials

The objective of this article is to review the difficulties with the design and interpretation of surgical clinical trials. Few surgical procedures are evaluated in a randomized fashion. There are a number of factors that make the design of surgical trials diffiuclt, and many surgical questions cannot be answered with a clinical trial. Issues with standardization of the surgical procedure, variability of surgical skills, and changes in surgical expertise over time further complicate the design and implementation of surgical trials. Statistical methods for surgical trials often require a noninferiorty design and are more complicated to interpret than the more common superiority trial. Even when properly conducted, both superiority and noninferiority trials are often misinterpreted. Because of the relatively high success rate in surgery, trials require large numbers of patients and noninferiority trials are often inconclusive with respect to the primary outcome. Surgical trials are often misinterpreted or over interpreted, and there can be confusion in how the findings of these trials should be incorportated into clinical practice. The interpretation of the results of a surgical trial often differ significantly from the primary and secondary outcomes that were specified in the trial design.