Statistical fundamentals on cancer research for clinicians: Working with your statisticians

Increasing Power in Phase III Oncology Trials With Multivariable Regression: An Empirical Assessment of 535 Primary End Point Analyses

PURPOSE

A previous study demonstrated that power against the (unobserved) true effect for the primary end point (PEP) of most phase III oncology trials is low, suggesting an increased risk of false-negative findings in the field of late-phase oncology. Fitting models with prognostic covariates is a potential solution to improve power; however, the extent to which trials leverage this approach, and its impact on trial interpretation at scale, is unknown. To that end, we hypothesized that phase III trials using multivariable PEP analyses are more likely to demonstrate superiority versus trials with univariable analyses.

METHODS

PEP analyses were reviewed from trials registered on ClinicalTrials.gov. Adjusted odds ratios (aORs) were calculated by logistic regressions.

RESULTS

Of the 535 trials enrolling 454,824 patients, 69% (n = 368) used a multivariable PEP analysis. Trials with multivariable PEP analyses were more likely to demonstrate PEP superiority (57% [209 of 368] v 42% [70 of 167]; aOR, 1.78 [95% CI, 1.18 to 2.72]; P = .007). Among trials with a multivariable PEP model, 16 conditioned on covariates and 352 stratified by covariates. However, 108 (35%) of 312 trials with stratified analyses lost power by categorizing a continuous variable, which was especially common among immunotherapy trials (aOR, 2.45 [95% CI, 1.23 to 4.92]; P = .01).

CONCLUSION

Trials increasing power by fitting multivariable models were more likely to demonstrate PEP superiority than trials with unadjusted analysis. Underutilization of conditioning models and empirical power loss associated with covariate categorization required by stratification were identified as barriers to power gains. These findings underscore the opportunity to increase power in phase III trials with conventional methodology and improve patient access to effective novel therapies.

Nomogram-based prognostic tool for stage IIIB/IV non-small cell lung cancer patients undergoing traditional Chinese medicine treatment

Objective

Given the significant impact of long-term traditional Chinese medicine (TCM) treatment on the prognosis of patients with non-small cell lung cancer (NSCLC), we aimed to develop nomograms, with or without consideration of TCM treatment duration, to accurately predict the overall survival (OS) of patients with stage IIIB/IV NSCLC treated with TCM.

Methods

Nomograms were developed from a training cohort comprised of 292 patients diagnosed with NSCLC, using univariate and multivariate Cox regression analyses to screen for various prognostic factors with and without TCM treatment. The nomograms were evaluated using the concordance index (C-index), calibration curve, and decision curve analysis (DCA), after which they were validated, using the bootstrap self-sampling method for internal validation, and a validation cohort comprised of 175 patients for external validation. Bootstrap validation is a resampling technique that involves randomly selecting and replacing data from the original dataset to make statistical inferences, thereby circumventing the issue of sample reduction that can arise from cross-validation.

Results

We identified seven significant prognostic factors for OS. For nomogram A (excluding TCM treatment time), the C-indexes (95 % confidence interval [CI]) were 0.674 (0.635-0.712) and 0.660 (0.596-0.724) for the training and validation cohorts, respectively. For nomogram B (including TCM treatment time), the C-indices (95 % CI) were 0.846 (0.822-0.870) and 0.783 (0.730-0.894), for the training and validation cohorts, respectively, indicating that nomogram B was superior to nomogram A. Both the calibration curves and DCA results exhibited favorable clinical concordance and usefulness.

Conclusion

The nomogram B yielded precise prognostic predictions for patients with advanced NSCLC treated with TCM.

The Clinicopathological Characteristics of Young-Onset Versus Adult-Onset Colorectal Cancer: A Tertiary Hospital-Based Study

Background

The prevalence of colorectal cancer (CRC) among young individuals is rising worldwide, especially in Malaysia. Investigations are currently employed to distinguish the features of young-onset CRC (YOCRC) from adult-onset CRC (AOCRC). This study aimed to compare the characteristics of patients with YOCRC and AOCRC diagnosed at Hospital Universiti Sains Malaysia (HUSM).

Methods

This was a retrospective study of CRC cases from January 2013 to December 2021. The details of YOCRC (< 50 years old) and AOCRC (≥ 50 years old) patients were retrieved from the laboratory system and medical records. The Pearson's chi-square test, Fisher's exact test and multiple logistic regression were used to compare the AOCRC and YOCRC cases. Statistical significance was defined at a P-value of ≤ 0.05.

Results

The AOCRC (254/319, 79.6%) was more prevalent than YOCRC (65/319, 20.4%), with a predominance of males (53.9%) and Malay sub-population (90.2%). AOCRC and YOCRC shared similarities in left-sided location, high occurrence of adenocarcinoma with moderately differentiated histology and advanced stage of diagnosis. More patients with YOCRC (23.1%) had a family history of cancer than patients with AOCRC. YOCRC also differed from AOCRC by having more specific histological subtypes, such as mucinous adenocarcinoma (15.4%) and signet ring carcinoma (6.2%). In addition, patients with YOCRC commonly presented with a low density of tumour-infiltrating lymphocytes (TILs) (60%). Multiple logistic regression showed a family history of CRC (adjusted odds ratio [AOR] = 3.75, P = 0.003) and histological type (AOR = 15.21, P < 0.001) are more likely to cause YOCRC than diabetes (AOR = 0.06, P < 0.001) and hypertension (AOR = 0.14, P < 0.001) comorbidities, which are associated with AOCRC.

Conclusion

Our descriptive study presented the epidemiological and histopathological characteristics of AOCRC and YOCRC in HUSM, providing current information on distinguishing features between the groups.

Cytotoxic Effects of Common Irrigation Solutions on Chondrosarcoma and Giant Cell Tumors of Bone

BACKGROUND

Irrigation is commonly used as an adjuvant treatment during the intralesional curettage of bone tumors. The goal of the present study was to analyze the in vitro cytotoxicity of commonly used irrigation solutions on chondrosarcoma and giant cell tumor (GCT) cells as there is no consensus on which solution leads to the greatest amount of cell death.

METHODS

An in vitro evaluation was performed by exposing human GCT and human chondrosarcoma cell lines to 0.9% saline solution, sterile water, 70% ethanol, 3% hydrogen peroxide, 0.05% chlorhexidine gluconate (CHG), and 0.3% povidone iodine solutions independently for 2 and 5 minutes. A low-cytotoxicity control (LCC) and a high-cytotoxicity control (HCC) were established to determine the mean cytotoxicity of each solution and each solution's superiority to LCC and non-inferiority to HCC.

RESULTS

The present study demonstrated that 0.05% CHG was non-inferior to the HCC when chondrosarcoma was exposed for 5 minutes and when GCT was exposed for 2 and 5 minutes (mean cytotoxicity, 99% to 102%) (p < 0.003 for all). Sterile water was superior to the LCC when chondrosarcoma was exposed for 5 minutes and when GCT was exposed for 2 minutes (mean, 28% to 37%) (p < 0.05). Sterile water (mean, 18% to 38%) (p < 0.012) and 3% hydrogen peroxide (mean, 7% to 16%) (p < 0.001) were both inferior to the HCC. The 3 other solutions were non-superior to the LCC (mean, -24% to -5%) (p < 0.023).

CONCLUSIONS

In vitro irrigation in 0.05% CHG provided high cytotoxicity, comparable with the HCC. Therefore, the use of a 0.05% CHG solution clinically could serve as a potential chemical adjuvant during intralesional curettage of chondrosarcoma and GCT.

CLINICAL RELEVANCE

In an effort to reduce the burden of residual tumor cells, irrigation solutions are often utilized as adjuvant local therapy. Use of a 0.05% CHG solution clinically could serve as a potential chemical adjuvant to intralesional curettage of chondrosarcoma and GCT. Further in vivo studies may be indicated to assess clinical outcomes and safety associated with the use of 0.05% CHG in the treatment of chondrosarcoma and GCT.