The frequency of medical reversals in a cross-sectional analysis of high-impact oncology journals, 2009-2018

Differential Treatment Effects of Subgroup Analyses in Phase 3 Oncology Trials From 2004 to 2020

Importance

Subgroup analyses are often performed in oncology to investigate differential treatment effects and may even constitute the basis for regulatory approvals. Current understanding of the features, results, and quality of subgroup analyses is limited.

Objective

To evaluate forest plot interpretability and credibility of differential treatment effect claims among oncology trials.

Design, Setting, and Participants

This cross-sectional study included randomized phase 3 clinical oncology trials published prior to 2021. Trials were screened from ClinicalTrials.gov.

Main Outcomes and Measures

Missing visual elements in forest plots were defined as a missing point estimate or use of a linear x-axis scale for hazard and odds ratios. Multiplicity of testing control was recorded. Differential treatment effect claims were rated using the Instrument for Assessing the Credibility of Effect Modification Analyses. Linear and logistic regressions evaluated associations with outcomes.

Results

Among 785 trials, 379 studies (48%) enrolling 331 653 patients reported a subgroup analysis. The forest plots of 43% of trials (156 of 363) were missing visual elements impeding interpretability. While 4148 subgroup effects were evaluated, only 1 trial (0.3%) controlled for multiple testing. On average, trials that did not meet the primary end point conducted 2 more subgroup effect tests compared with trials meeting the primary end point (95% CI, 0.59-3.43 tests; P = .006). A total of 101 differential treatment effects were claimed across 15% of trials (55 of 379). Interaction testing was missing in 53% of trials (29 of 55) claiming differential treatment effects. Trials not meeting the primary end point were associated with greater odds of no interaction testing (odds ratio, 4.47; 95% CI, 1.42-15.55, P = .01). The credibility of differential treatment effect claims was rated as low or very low in 93% of cases (94 of 101).

Conclusions and Relevance

In this cross-sectional study of phase 3 oncology trials, nearly half of trials presented a subgroup analysis in their primary publication. However, forest plots of these subgroup analyses largely lacked essential features for interpretation, and most differential treatment effect claims were not supported. Oncology subgroup analyses should be interpreted with caution, and improvements to the quality of subgroup analyses are needed.

Trends in use of radiation therapy, chemotherapy, and combination chemoradiotherapy in advanced uterine cancer before, during, and after GOG 258

OBJECTIVE

To explore the use of Gynecologic Oncology Group 258 (GOG 258) study regimens before, during, and after the study.

METHODS

Patients aged 18 years or older with endometrial cancer between 2004-2019 were identified in the National Cancer Database. Inclusion criteria were stage III or IVA of any histology and stage I-IVA clear cell or serous histologies with positive washings that received adjuvant therapy. Adjuvant therapy use was examined in the pre-GOG 258 era (before 2009), during GOG 258 enrollment and maturation (2010-2017), and after results presentation in 2017 (2018-2019). Two-sided Cochran-Armitage tests, Wilcoxen rank sum tests, and χ2 tests were used for continuous and categorical variables. Multi-variable logistic regression assessed factors associated with the receipt of chemoradiotherapy compared with chemotherapy only or radiation therapy only.

RESULTS

From 2004 to 2019, 41 408 high-risk endometrial cancer patients received adjuvant therapy (12% radiation therapy, 38% chemotherapy, 50% chemoradiotherapy). Chemoradiotherapy increased over the GOG 258 study period (40% before study opening, 54% during enrollment, and 59% after results). Serous (OR 0.6, 95% CI 0.6 to 0.7) and clear cell histology (0.7, 0.6 to 0.8), higher grade (0.8, 0.7 to 0.9), and lymph node positivity (0.8, 0.7 to 0.9) were negatively associated with receipt of chemoradiotherapy compared with single-modality treatment. Non-Hispanic Black ethnicity (0.8, 0.8 to 0.9) and residing ≥50 miles from the treatment facility (0.8, 0.7 to 0.9) were also negatively associated with chemoradiotherapy. Private insurance (1.2, 1.0 to 1.4) and treatment at community hospitals (1.2, 1.2 to 1.3) were positively associated with chemoradiotherapy.

CONCLUSION

Despite the lack of benefit in the GOG 258 experimental arm, chemoradiotherapy use increased during study enrollment and after results publication.

Frequency and Characteristics of Trials Using Medical Writer Support in High-Impact Oncology Journals

IMPORTANCE

The practice of using medical writers to communicate scientific information has gained popularity, but it may affect how and what information is communicated.

OBJECTIVE

To assess characteristics of oncology trials that use medical writers and whether there is an association between the use of medical writers and trial success or the primary outcome evaluated.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included oncology trials testing a tumor-targeting intervention that were published in The Lancet, The Lancet Oncology, JAMA, JAMA Oncology, Journal of Clinical Oncology, and The New England Journal of Medicine between May 1, 2021, and May 1, 2022.

EXPOSURES

Assistance of medical writers or no assistance.

MAIN OUTCOMES AND MEASURES

The main outcomes were the percentage of studies with medical writers, the percentage of trial successes reported with medical writers, the association between trial success and medical writer use, and the association between a primary end point and medical writer use.

RESULTS

Among 270 studies, 141 (52.2%) included a medical writer and 129 (47.8%) did not include a medical writer. Of the studies that included a medical writer, 83 (58.9%) were successful. Of the studies that did not include a medical writer, 64 (49.6%) were successful (P = .16 for difference). Studies with medical writers were less likely than studies without medical writers to have the end point of overall survival (15 [10.6%] vs 17 [13.2%]) and disease-free or event-free survival (16 [11.3%] vs 29 [22.5%]), whereas studies with a medical writer were more likely to have the end point of progression-free survival (32 [22.7%] vs 17 [13.2%]). Use of medical writer was associated with the conclusions being presented favorably in all studies (113 [80.1%] vs 89 [69.0%]; odds ratio [OR], 1.81 [95% CI, 1.04-3.19]), but when adjusted for other variables, there was no association (OR, 1.84 [95% CI, 0.92-3.72]).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, trials using medical writers were more likely to report surrogate end points, such as progression-free survival, and favorable conclusions, but when adjusted for trial phase, randomization, and study funding, there was no association with favorable conclusions. These findings suggest that journals need heightened scrutiny for studies with medical writers and that authorship should be properly acknowledged.

All-cause mortality as the primary endpoint for the GRAIL/National Health Service England multi-cancer screening trial

A randomized trial of the GRAIL Galleri^TM multi-cancer screening test is being planned for the National Health Service in England, and will have 140,000 healthy participants aged 50-79: 70,000 exposed to screening and 70,000 unexposed. The test reportedly detects 50 different cancers and is expected to reduce all-cancer mortality by approximately 25%. Given this effect size-and that cancer deaths constitute a large fraction of all deaths-the trial is sufficiently large to test the effect on all-cause mortality. Because most patients believe cancer screening "saves lives", the GRAIL/National Health Service collaboration could set the evaluation standard for multi-cancer screening.