Hierarchical changepoint modeling of post-radiotherapy prostate-specific antigen (PSA) series in men with prostate cancer

Prostate-specific antigens (PSA) help monitor the post-therapy course of prostate cancer. If radiotherapy is successful, levels reach a nadir, and remain low or possibly rise very slowly. A sustained steep increase indicates biochemical failure.Serial PSA measurements are rarely perfectly monotonic. The American Society for Therapeutic Radiology and Oncology (ASTRO) consensus panel defines biochemical failure as three consecutive PSA increases. I examined the sensitivity and specificity of the ASTRO criterion using simulations of realistic, sophisticated data sets, that accurately reflect the systematic and random variations observed in PSA series.In a preliminary analysis, I estimated the underlying PSA trajectories in a cohort of 470 men treated with radiotherapy for localized prostate cancer. I exploited the flexibility of Bayesian hierarchical regression models to describe the individual PSA series, each with its own changepoint, and non-constant variance.The estimates provided by the hierarchical model allowed me to simulate a large set of true PSA series. From these, I generated observed PSA series: each underlying PSA value was distorted by adding a realistic amount of 'noise'. To evaluate the performance of rules for biochemical failure, including the ASTRO criterion, I then compared the generated observed PSA series to the underlying true PSA series. My results suggest that another rule might outperform ASTRO. This simulation-based approach can be applied to evaluate other rules that purport to rapidly and accurately detect up (down) turns in noisy series, such as in other medical data, and in data series used to monitor economic trends.Finally, I present a practical charting paper for physicians to record post-treatment PSA values of individual patients. The plotted serial values provide rapid and accurate estimates of the PSA doubling time, without any difficult computations

Breast cancer care compared with clinical Guidelines: an observational study in France

International audienceBACKGROUND: Great variability in breast cancer (BC) treatment practices according to patient, tumour or organisation of care characteristics has been reported but the relation between these factors is not well known. In two French regions, we measured compliance with Clinical Practice Guidelines for non-metastatic BC care management and identified factors associated with non-compliance at clinical and organisational levels. METHODS: Eligible patients had invasive unilateral BC without distant metastases and at least two contacts with one of the two regional healthcare systems (2003-2004) in the first year after diagnosis. Medical data were collected from patient medical records in all public and private hospitals (99 hospitals).The care process was defined by 20 criteria: clinical decisions for treatment and therapeutic procedures. Each criterion was classified according to level of compliance ("Compliant", "Justifiable" and "Not Compliant") and factors of non-compliance were identified (mixed effect logistic regression). RESULTS: 926 women were included. Non-compliance with clinical decisions for treatment was associated with older patient age (OR 2.1; 95%CI: 1.3-3.6) and region (OR 3.0; 95%CI: 1.2-7.4). Non-compliance with clinical decisions for radiotherapy was associated with lymph node involvement or the presence of peritumoural vascular invasion (OR 1.5; 95%CI: 1.01-2.3) and non-compliance with overall treatment (clinical decisions for treatment + therapeutic procedures) was associated with the presence of positive lymph nodes (OR 2.0; 95%CI: 1.2-3.3), grade III versus grade I (OR 2.9; 95%CI: 1.4-6.2), and one region of care versus another (OR 3.5; 95%CI: 1.7-7.1). Finally, heterogeneity of compliance in overall treatment sequence was identified between local cancer units (p < 0.05). CONCLUSION: This study provides interesting insights into factors of non-compliance in non-metastatic BC management and could lead to quality care improvements

Randomized phase 2 trial of intravenous oncolytic virus JX-594 combined with low-dose cyclophosphamide in patients with advanced soft-tissue sarcoma

JX-594 is an oncolytic vaccinia virus genetically modified to replicate selectively in tumor cells. Metronomic chemotherapy has shown preclinical synergy with oncolytic viruses. We report here the results of the METROMAJX which is a randomized phase II clinical trial investigating the combination of JX-594 combined with metronomic cyclophosphamide (arm 1) or metronomic cyclophosphamide (arm 2) in patients with advanced STS. A two-stage Simon design was used. JX-594 was administered intra-venously at the dose 1.109 every 2 weeks for the first 3 injections and then every 3 weeks. Cyclophosphamide was given orally at the dose of 50 mg BID 1 week on 1 week off. The primary endpoint was the 6-month non progression rate. 20 patients were included (arm 1:15, arm 2:5). The two most frequent toxicities were grade 1 fatigue and fever and grade 2 fatigue and grade 2 lymphopenia in arms 1 and 2, respectively. In arm 1, 12 patients were assessable for the efficacy analysis. None of them were progression-free at 6 months indicating that the first stage of the Simon's design was not satisfied. One patient out 4 assessable for efficacy was progression-free at 6 months in arm 2. High throughput analysis of sequential plasma samples revealed an upregulation of protein biomarkers reflecting immune induction such as CXCL10 and soluble CD8 antigen in arm 1. Systemic treatment with JX-594 is safe in patients with advanced STS. Further investigations are needed to improve immune response to oncolytic viruses and define their therapeutic potential in patients with STS

Assessing patient-reported outcomes (PROs) and patient-related outcomes in randomized cancer clinical trials for older adults: Results of DATECAN-ELDERLY initiative

As older adults with cancer are underrepresented in randomized clinical trials (RCT), there is limited evidence on which to rely for treatment decisions for this population. Commonly used RCT endpoints for the assessment of treatment efficacy are more often tumor-centered (e.g., progression-free survival). These endpoints may not be as relevant for the older patients who present more often with comorbidities, non–cancer-related deaths, and treatment toxicity. Moreover, their expectation and preferences are likely to differ from younger adults. The DATECAN-ELDERLY initiative combines a broad expertise, in geriatric oncology and clinical research, with interest in cancer RCT that include older patients with cancer. In order to guide researchers and clinicians coordinating cancer RCT involving older patients with cancer, the experts reviewed the literature on relevant domains to assess using patient-reported outcomes (PRO) and patient-related outcomes, as well as available tools related to these domains. Domains considered relevant by the panel of experts when assessing treatment efficacy in RCT for older patients with cancer included functional autonomy, cognition, depression and nutrition. These were based on published guidelines from international societies and from regulatory authorities as well as minimum datasets recommended to collect in RCT including older adults with cancer. In addition, health-related quality of life, patients' symptoms, and satisfaction were also considered by the panel. With regards to tools for the assessment of these domains, we highlighted that each tool has its own strengths and limitations, and very few had been validated in older adults with cancer. Further studies are thus needed to validate these tools in this specific population and define the minimum clinically important difference to use when developing RCTs in this population. The selection of the most relevant tool should thus be guided by the RCT research question, together with the specific properties of the tool

Prognostic Value of Routinely Measured Inflammatory Biomarkers in Older Cancer Patients: Pooled Analysis of Three Cohorts

BACKGROUND: The prognostic assessment of older cancer patients is complicated by their heterogeneity. We aimed to assess the prognostic value of routine inflammatory biomarkers. METHODS: A pooled analysis of prospective multicenter cohorts of cancer patients aged >/=70 was performed. We measured CRP and albumin, and calculated Glasgow Prognostic Score (GPS) and CRP/albumin ratio. The GPS has three levels (0 = CRP /= 35 g/L, i.e., normal values; 1 = one abnormal value; 2 = two abnormal values). One-year mortality was assessed using Cox models. Discriminative power was assessed using Harrell's C index (C) and net reclassification improvement (NRI). RESULTS: Overall, 1800 patients were analyzed (mean age: 79 +/- 6; males: 62%; metastases: 38%). The GPS and CRP/albumin ratio were independently associated with mortality in patients not at risk of frailty (hazard ratio [95% confidence interval] = 4.48 [2.03-9.89] for GPS1, 11.64 [4.54-29.81] for GPS2, and 7.15 [3.22-15.90] for CRP/albumin ratio > 0.215) and in patients at risk of frailty (2.45 [1.79-3.34] for GPS1, 3.97 [2.93-5.37] for GPS2, and 2.81 [2.17-3.65] for CRP/albumin ratio > 0.215). The discriminative power of the baseline clinical model (C = 0.82 [0.80-0.83]) was increased by adding GPS (C = 0.84 [0.82-0.85]; NRI events (NRI+) = 10% [2-16]) and CRP/albumin ratio (C = 0.83 [0.82-0.85]; NRI+ = 14% [2-17]). CONCLUSIONS: Routine inflammatory biomarkers add prognostic value to clinical factors in older cancer patients

BMC Med

BACKGROUND: Overall survival (OS) is the gold standard endpoint to assess treatment efficacy in cancer clinical trials. In metastatic breast cancer (mBC), progression-free survival (PFS) is commonly used as an intermediate endpoint. Evidence remains scarce regarding the degree of association between PFS and OS. Our study aimed to describe the individual-level association between real-world PFS (rwPFS) and OS according to first-line treatment in female patients with mBC managed in real-world setting for each BC subtype (defined by status for both hormone-receptor [HR] expression and HER2 protein expression/gene amplification). METHODS: We extracted data from the ESME mBC database (NCT03275311) which gathers deidentified data from consecutive patients managed in 18 French Comprehensive Cancer Centers. Adult women diagnosed with mBC between 2008 and 2017 were included. Endpoints (PFS, OS) were described using the Kaplan-Meier method. Individual-level associations between rwPFS and OS were estimated using the Spearman's correlation coefficient. Analyses were conducted by tumor subtype. RESULTS: 20,033 women were eligible. Median age was 60.0 years. Median follow-up duration was 62.3 months. Median rwPFS ranged from 6.0 months (95% CI 5.8-6.2) for HR-/HER2 - subtype to 13.3 months (36% CI 12.7-14.3) for HR + /HER2 + subtype. Correlation coefficients were highly variable across subtypes and first-line (L1) treatments. Among patients with HR - /HER2 - mBC, correlation coefficients ranged from 0.73 to 0.81, suggesting a strong rwPFS/OS association. For HR + /HER2 + mBC patients, the individual-level associations were weak to strong with coefficients ranging from 0.33 to 0.43 for monotherapy and from 0.67 to 0.78 for combined therapies. CONCLUSIONS: Our study provides comprehensive information on individual-level association between rwPFS and OS for L1 treatments in mBC women managed in real-life practice. Our results could be used as a basis for future research dedicated to surrogate endpoint candidates

Variables with time-varying effects and the Cox model: Some statistical concepts illustrated with a prognostic factor study in breast cancer

International audienceBACKGROUND: The Cox model relies on the proportional hazards (PH) assumption, implying that the factors investigated have a constant impact on the hazard - or risk - over time. We emphasize the importance of this assumption and the misleading conclusions that can be inferred if it is violated; this is particularly essential in the presence of long follow-ups. METHODS: We illustrate our discussion by analyzing prognostic factors of metastases in 979 women treated for breast cancer with surgery. Age, tumour size and grade, lymph node involvement, peritumoral vascular invasion (PVI), status of hormone receptors (HRec), Her2, and Mib1 were considered. RESULTS: Median follow-up was 14 years; 264 women developed metastases. The conventional Cox model suggested that all factors but HRec, Her2, and Mib1 status were strong prognostic factors of metastases. Additional tests indicated that the PH assumption was not satisfied for some variables of the model. Tumour grade had a significant time-varying effect, but although its effect diminished over time, it remained strong. Interestingly, while the conventional Cox model did not show any significant effect of the HRec status, tests provided strong evidence that this variable had a non-constant effect over time. Negative HRec status increased the risk of metastases early but became protective thereafter. This reversal of effect may explain non-significant hazard ratios provided by previous conventional Cox analyses in studies with long follow-ups. CONCLUSIONS: Investigating time-varying effects should be an integral part of Cox survival analyses. Detecting and accounting for time-varying effects provide insights on some specific time patterns, and on valuable biological information that could be missed otherwise

Consensus guidelines for the definition of time-to-event end points in image-guided tumor ablation: results of the SIO and DATECAN initiative

International audienceThere is currently no consensus regarding preferred clinical outcome measures following image-guided tumor ablation or clear definitions of oncologic end points. This consensus document proposes standardized definitions for a broad range of oncologic outcome measures with recommendations on how to uniformly document, analyze, and report outcomes. The initiative was coordinated by the Society of Interventional Oncology in collaboration with the Definition for the Assessment of Time-to-Event End Points in Cancer Trials, or DATECAN, group. According to predefined criteria, based on experience with clinical trials, an international panel of 62 experts convened. Recommendations were developed using the validated three-step modified Delphi consensus method. Consensus was reached on when to assess outcomes per patient, per session, or per tumor; on starting and ending time and survival time definitions; and on time-to-event end points. Although no consensus was reached on the preferred classification system to report complications, quality of life, and health economics issues, the panel did agree on using the most recent version of a validated patient-reported outcome questionnaire. This article provides a framework of key opinion leader recommendations with the intent to facilitate a clear interpretation of results and standardize worldwide communication. Widespread adoption will improve reproducibility, allow for accurate comparisons, and avoid misinterpretations in the field of interventional oncology research. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Liddell in this issue

Detecting heritability of brain structure using magnetic resonance imaging

A method is described that allows one to assess heritability of brain structures using magnetic resonance images (MRI). We have obtained MRI images for a group of identical twins and another group of fraternal twins. Each MRI image was segmented into white and gray matter then smoothed to estimate white and gray matter density at each 3D image element or voxel. At each voxel, we use the intraclass correlations of the two groups in order to compute a 3D image of a measure of heritability, as well as a test statistic for detecting those regions with significant heritability. To our knowledge the genetic variability of white and gray matter density has not been investigated on a voxel basis previously

J Biopharm Stat

In epidemiology and clinical research, recurrent events refer to individuals who are likely to experience transient clinical events repeatedly over an observation period. Examples include hospitalizations in patients with heart failure, fractures in osteoporosis studies and the occurrence of new lesions in oncology. We provided an in-depth analysis of the sample size required for the analysis of recurrent time-to-event data using multifrailty or multilevel survival models. We covered the topic from the simple shared frailty model to models with hierarchical or joint frailties. We relied on a Wald-type test statistic to estimate the sample size assuming either a single or multiple endpoints. Simulations revealed that the sample size increased as heterogeneity increased. We also observed that it was more attractive to include more patients and reduce the duration of follow-up than to include fewer patients and increase the duration of follow-up to obtain the number of events required. Each model investigated can address the question of the number of subjects for recurrent events. However, depending on the research question, one model will be more suitable than another. We illustrated our methodology with the AFFIRM-AHF trial investigating the effect of intravenous ferric carboxymaltose in patients hospitalised for acute heart failure