Improvement of Midpoint Imputation for Estimation of Median Survival Time for Interval-Censored Time-to-Event Data

BACKGROUND

Progression-free survival (PFS) is used to evaluate treatment effects in cancer clinical trials. Disease progression (DP) in patients is typically determined by radiological testing at several scheduled tumor-assessment time points. This produces a discrepancy between the true progression time and the observed progression time. When the observed progression time is considered as the true progression time, a positively biased PFS is obtained for some patients, and the estimated survival function derived by the Kaplan-Meier method is also biased.

METHODS

While the midpoint imputation method is available and replaces interval-censored data with midpoint data, it unrealistically assumes that several DPs occur at the same time point when several DPs are observed within the same tumor-assessment interval. We enhanced the midpoint imputation method by replacing interval-censored data with equally spaced timepoint data based on the number of observed interval-censored data within the same tumor-assessment interval.

RESULTS

The root mean square error of the median of the enhanced method is almost always smaller than that of the midpoint imputation regardless of the tumor-assessment frequency. The coverage probability of the enhanced method is close to the nominal confidence level of 95% in most scenarios.

CONCLUSION

We believe that the enhanced method, which builds upon the midpoint imputation method, is more effective than the midpoint imputation method itself.

Group sequential designs for cancer immunotherapy trial with delayed treatment effect

Cancer immunotherapy trials are frequently characterized by delayed treatment effects such that the proportional hazards assumption is violated and the log-rank test suffers a substantial loss of statistical power. To increase the efficacy of the trial design, a variety of weighted log-rank tests have been proposed for fixed sample and group sequential trial designs. However, in such a group sequential design, it is often not recommended for futility interim monitoring due to possible delayed treatment effect which could result a high false-negative rate. To resolve this problem, we propose a group sequential design using a piecewise weighted log-rank test which provides an event-driven approach based on number of events after the delayed time. That is, the interim looks will not be conducted until the planned number of events observed after the delay time. Thus, it avoids the possibility of false-negative rate due to the delayed treatment effect. Furthermore, with an event-driven approach, the proposed group sequential design is robust against the underlying survival, accrual and censoring distributions. The group sequential designs using Fleming-Harrington-(ρ , γ ) weighted log-rank test and a new weighted log-rank test are also discussed.

Sequential monitoring of cancer immunotherapy trial with random delayed treatment effect

Cancer immunotherapy trials are frequently characterized by a delayed treatment effect that violates the proportional hazards assumption. The log-rank test (LRT) suffers a substantial loss of statistical power under the nonproportional hazards model. Various group sequential designs using weighted LRTs (WLRTs) have been proposed under the fixed delayed treatment effect model. However, patients enrolled in immunotherapy trials are often heterogeneous, and the duration of the delayed treatment effect is a random variable. Therefore, we propose group sequential designs under the random delayed effect model using the random delayed distribution WLRT. The proposed group sequential designs are developed for monitoring the efficacy of the trial using the method of Lan-DeMets alpha-spending function with O'Brien-Fleming stopping boundaries or a gamma family alpha-spending function. The maximum sample size for the group sequential design is obtained by multiplying an inflation factor with the sample size for the fixed sample design. Simulations are conducted to study the operating characteristics of the proposed group sequential designs. The robustness of the proposed group sequential designs for misspecifying random delay time distribution and domain is studied via simulations.

Comorbidities were associated with cancer clinical trial discussion and participation: findings from the Health Information National Trends Survey-Surveillance, Epidemiology, and End Results Program (2021)

OBJECTIVES

Oncology clinical trials are recommended to better reflect real-world cancer patient populations and to increase patient access to new treatments in trials. The influence of comorbidities on trial participation is unclear. This study examined the association of having comorbidities and patients' experiences with clinical trial discussion or actual participation.

STUDY DESIGN AND SETTING

We included 958 cancer survivors from Health Information National Trends Survey-Surveillance, Epidemiology, and End Results Program. Trial discussion was defined as whether their medical team discussed cancer clinical trials, and trial participation was defined as whether they participated. Comorbidities included diabetes, hypertension, heart condition, chronic lung disease, and depression/anxiety disorder. Design-based logistic regression results were conducted.

RESULTS

Seventy-five percent of patients had one or more comorbidities, commonly having hypertension (56%) and diabetes (26%). Only 15% of participants reported trial discussion and 8% reported trial participation. Having one or more comorbidities was significantly associated with lower rates of trial discussion in univariate analysis (22.9% vs. 12.1%, odds ratio = 0.46, P = 0.001), and such association was pertained in adjusted logistic regression (20.5% vs. 12.8%, adjusted odds ratio = 0.54, P = 0.02).

CONCLUSION

Findings suggest patients with comorbidities were underrepresented in cancer clinical trials, implying a potential lack of representativeness among trial participants.

Oncologic patients' misconceptions may impede enrollment into clinical trials: a cross-sectional study

Background

Clinical trials are an essential source for advances in oncologic care, yet the enrollment rate is only 2-4%. Patients' reluctance to participate is an important barrier. This study evaluates patients' level of understanding and attitudes towards clinical trials.

Methods

This cross-sectional study was conducted in the oncology department and day care unit at the oncology division Tel Aviv Sourasky Medical Center, Israel. From January 2015 to September 2016. Two-hundred patients’ currently receiving active anti-cancer therapy at a large tertiary hospital completed an anonymous questionnaire comprised of demographic information, past experience in clinical research and basic knowledge on clinical trials.

Results

The majority of respondents did not meet the minimum knowledge level criteria. In those who replied they would decline to participate in a clinical trial, concern were related to potential assignment to the placebo arm, provision of informed consent and trust issues with their oncologist. Those with sufficient knowledge were significantly more interested in participating. Patients with past experience in clinical trials had a higher level of academic education, were less religious, had a better understanding of medical research and were inclined to participate in future research.

Conclusions

Misperceptions of clinical trials may contribute substantially to the unwillingness to participate in them.

Handling informative dropout in longitudinal analysis of health-related quality of life: application of three approaches to data from the esophageal cancer clinical trial PRODIGE 5/ACCORD 17

Background

Health-related quality of life (HRQoL) has become a major endpoint to assess the clinical benefit of new therapeutic strategies in oncology clinical trials. Typically, HRQoL outcomes are analyzed using linear mixed models (LMMs). However, longitudinal analysis of HRQoL in the presence of missing data remains complex and unstandardized. Our objective was to compare the modeling alternatives that account for informative dropout.

Methods

We investigated three alternative methods—the selection model (SM), pattern-mixture model (PMM), and shared-parameters model (SPM)—in relation to the LMM. We first compared them on the basis of methodological arguments highlighting their advantages and drawbacks. Then, we applied them to data from a randomized clinical trial that included 267 patients with advanced esophageal cancer for the analysis of four HRQoL dimensions evaluated using the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 questionnaire.

Results

We highlighted differences in terms of outputs, interpretation, and underlying modeling assumptions; this methodological comparison could guide the choice of method according to the context. In the application, none of the four models detected a significant difference between the two treatment arms. The estimated effect of time on HRQoL varied according to the method: for all analyzed dimensions, the PMM estimated an effect that contrasted with those estimated by the SM and SPM; the LMM estimated effects were confirmed by the SM (on two of four HRQoL dimensions) and SPM (on three of four HRQoL dimensions).

Conclusions

The PMM, SM, or SPM should be used to confirm or invalidate the results of LMM analysis when informative dropout is suspected. Of these three alternative methods, the SPM appears to be the most interesting from both theoretical and practical viewpoints.

Trial registration

This study is registered with ClinicalTrials.gov, number NCT00861094.

Evaluating Adaptation of a Cancer Clinical Trial Decision Aid for Rural Cancer Patients: A Mixed-Methods Approach

Rural-residing cancer patients often do not participate in clinical trials. Many patients misunderstand cancer clinical trials and their rights as participant. The purpose of this study is to modify a previously developed cancer clinical trials decision aid (DA), incorporating the unique needs of rural populations, and test its impact on knowledge and decision outcomes. The study was conducted in two phases. Phase I recruited 15 rural-residing cancer survivors in a qualitative usability study. Participants navigated the original DA and provided feedback regarding usability and implementation in rural settings. Phase II recruited 31 newly diagnosed rural-residing cancer patients. Patients completed a survey before and after using the revised DA, R-CHOICES. Primary outcomes included decisional conflict, decision self-efficacy, knowledge, communication self-efficacy, and attitudes towards and willingness to consider joining a trial. In phase I, the DA was viewed positively by rural-residing cancer survivors. Participants provided important feedback about factors rural-residing patients consider when thinking about trial participation. In phase II, after using R-CHOICES, participants had higher certainty about their choice (mean post-test = 3.10 vs. pre-test = 2.67; P = 0.025) and higher trial knowledge (mean percentage correct at post-test = 73.58 vs. pre-test = 57.77; P < 0.001). There was no significant change in decision self-efficacy, communication self-efficacy, and attitudes towards or willingness to join trials. The R-CHOICES improved rural-residing patients' knowledge of cancer clinical trials and reduced conflict about making a trial decision. More research is needed on ways to further support decisions about trial participation among this population.

Patient-reported outcomes for patients with metastatic castration-resistant prostate cancer receiving docetaxel and Atrasentan versus docetaxel and placebo in a randomized phase III clinical trial (SWOG S0421)

Background

SWOG S0421 was a large randomized trial comparing docetaxel/prednisone plus placebo (DPP) to docetaxel/prednisone plus atrasentan over 12 cycles for patients with metastatic castration-resistant prostate cancer (mCRPC). The current report presents the PRO results for this trial, an important secondary endpoint.

Methods

The trial specified two primary PRO endpoints. Palliation of worst pain was based on the Brief Pain Inventory (BPI), where a 2 point difference is defined as clinically meaningful. Improvement of functional status was based on the Functional Assessment of Cancer Therapy – Prostate Cancer Trial Outcome Index (FACT-P TOI); a 5-point difference has been defined as clinically meaningful. We compared rates by arm using chi-square tests. Longitudinal analyses using linear mixed models addressed changes by arm over time.

Results

Four-hundred eighty-nine patients on each arm were evaluable for PRO endpoint data. There were no differences by arm in clinically meaningful pain palliation (41.7% for DPP vs. 44.0% for DPA, p = .70) or functional status (24.2% for DPP vs. 28.7% for DPA, p = .13). Longitudinal comparisons indicated no differences over time by arm for BPI Worst Pain scores (0.13 points, p = .23). Patients on the DPA arm had improved functional status of 1.78 points on average, a statistically significant (p = .02) but not clinically meaningful difference.

Conclusions

The SWOG S0421 PRO data showed little evidence of clinically meaningful differences by arm in either pain palliation or functional status.

Electronic supplementary material

The online version of this article (10.1186/s41687-018-0054-5) contains supplementary material, which is available to authorized users.

Perceptions of Cancer Care and Clinical Trials in the Black Community: Implications for Care Coordination Between Oncology and Primary Care Teams

BACKGROUND

Despite efforts to ameliorate disparities in cancer care and clinical trials, barriers persist. As part of a multiphase community-engaged assessment, an exploratory community-engaged research partnership, forged between an academic hospital and a community-based organization, set out to explore perceptions of cancer care and cancer clinical trials by black Bostonians.

MATERIALS AND METHODS

Key informant interviews with health care providers and patient advocates in community health centers (CHCs), organizers from grassroots coalitions focused on cancer, informed the development of a focus group protocol. Six focus groups were conducted with black residents in Boston, including groups of cancer survivors and family members. Transcripts were coded thematically and a code-based report was generated and analyzed by community and academic stakeholders.

RESULTS

While some participants identified clinical trials as beneficial, overall perceptions conjured feelings of fear and exploitation. Participants describe barriers to clinical trial participation in the context of cancer care experiences, which included negative interactions with providers and mistrust. Primary care physicians (PCPs) reported being levied as a trusted resource for patients undergoing care, but lamented the absence of a mechanism by which to gain information about cancer care and clinical trials.

CONCLUSIONS

Confusion about cancer care and clinical trials persists, even among individuals who have undergone treatment for cancer. Greater coordination between PCPs and CHC care teams and oncology care teams may improve patient experiences with cancer care, while also serving as a mechanism to disseminate information about treatment options and clinical trials.

IMPLICATIONS FOR PRACTICE

Inequities in cancer care and clinical trial participation persist. The findings of this study indicate that greater coordination with primary care physicians (PCPs) and community health center (CHC) providers may be an important step for both improving the quality of cancer care in communities and increasing awareness of clinical trials. However, PCPs and CHCs are often stretched to capacity with caring for their communities. This leaves the oncology community well positioned to create programs to bridge the communication gaps and provide resources necessary to support oncologic care along the cancer continuum, from prevention through survivorship.

Patients' knowledge and perceived understanding - Associations with consenting to participate in cancer clinical trials

Recruitment to clinical trials is essential. The aims of the study were to investigate associations between patients' informed consent to participate in a cancer clinical trial and knowledge and perceived understanding of the trial. Furthermore, associations between demographic factors and consent to participate and knowledge and perceived understanding of information about the trial were studied.

Methods

The patients were recruited in connection to a visit at the oncology clinic for information about a drug trial. The Quality of Informed Consent questionnaire was mailed to the patients after they had decided about participation in the trial. The associations of demographic factors and "knowledge" and "perceived understanding" were analysed using linear regression models.

Results

A total of 125 patients were included. Higher levels of "knowledge" and "understanding" were found to be associated with consent to participate in a clinical trial, both in the univariate and multivariate analyses (p = 0.001). None of the tested demographic factors were related to consent to participate. No statistically significant associations between any of the demographic factors and knowledge or perceived understanding scores were found.

Conclusion

The results indicate that interventions that increase patients' knowledge and perceived understanding might improve participation rates in clinical trials.

Clinical trial insurance coverage for cancer patients under the Affordable Care Act

Background

Participation in cancer clinical trials has been shown to increase overall survival with minimal increase in cost, but enrollment in adult cancer clinical trials remains low. One factor limiting enrollment is lack of insurance coverage, but this barrier should be reduced under the 2010 Patient Protection and Affordable Care Act (ACA), which includes a provision requiring coverage for clinical trial participation as of 2014.

Methods

To assess the number of Kansas adults aged 19-64, newly covered with health insurance for participation in oncology clinical trials as a result of the ACA, a cross sectional design using extracted data from the 2012 American Community Survey, Public Use Microdata Sample to estimate the number of individuals covered by insurance and data from the 2014 Department of Health and Human Services Health Insurance Marketplace enrollment to estimate those newly enrolled through ACA.

Results

In 2014, there was an estimated increase of 3% (54,397; 95% CI: 44,149-64,244) for a total of 72% (1,171,041) of Kansans aged 19 to 64 with health insurance coverage for clinical trial participation.

Conclusion

Three main factors limit the effectiveness of the ACA provisions in expanding clinical trial coverage: 1) 'grandfathered' self-funded employer plans not subject to state Employee Retirement Income Security Act (ERISA) regulations, 2) Medicaid coverage limits not addressed under the ACA, 3) populations that remain uninsured. Kansas saw a negligible increase in insurance coverage as a result of the ACA thus lack of insurance coverage is likely to remain a concern for cancer patients.

Qualitative inquiry: a method for validating patient perceptions of palliative care while enrolled on a cancer clinical trial

Background

Palliative care is a vital component of patient-centered care. It has increasingly become central to the management and care of seriously ill patients by integrating physical, psychosocial, and spiritual supportive services. Through qualitative inquiry, this paper examines cancer patients’ perceptions of the process and outcomes of the pain and palliative care consultative services they received while enrolled in a clinical trial.

Methods

A qualitative analysis of open-ended questions was conducted from a sub-sample of patients (n = 34) with advanced cancers enrolled in a randomized controlled trial exploring the efficacy of a palliative care consult service. Two open-ended questions focused on patient perceptions of continued participation on their primary cancer clinical trials and their perceptions of interdisciplinary communication.

Results

Three overarching themes emerged when asked whether receiving pain and palliative care services made them more likely to remain enrolled in their primary cancer clinical trial: patients’ past experiences with care, self-identified personal characteristics and reasons for participation, and the quality of the partnership. Four themes emerged related to interdisciplinary communication including: the importance of developing relationships, facilitating open communication, having quality communication, and uncertainty about communication between the cancer clinical trial and palliative care teams.

Conclusions

Our findings suggest the importance of qualitative inquiry methods to explore patient perceptions regarding the efficacy of palliative care services for cancer patients enrolled in a cancer clinical trial. Validation of patient perceptions through qualitative inquiry regarding their pain and palliative care needs can provide insight into areas for future implementation research.

Trial registration

NIH Office of Human Subjects Research Protection OHSRP5443 and University of Pennsylvania 813365

A phase II flexible screening design allowing for interim analysis and comparison with historical control

Sargent and Goldberg [1] proposed a randomized phase II flexible screening design (SG design) which took multiple characteristics of candidate regimens into consideration in selecting a regimen for further phase III testing. In this paper, we extend the SG design by including provisions for an interim analysis and/or a comparison to a historical control. By including a comparison with a historical control, a modified SG design not only identifies a more promising treatment but also assures that the regimen has a clinically meaningful level of efficacy as compared to a historical control. By including an interim analysis, a modified SG design could reduce the number of patients exposed to inferior treatment regimens. When compared to the original SG design, the modified designs increase the sample size moderately, but expand the utility of the flexible screening design substantially.