Handling missing covariates in observational studies: an illustration with the assessment of prognostic factors of survival outcomes in soft-tissue or visceral sarcomas in irradiated fields (SIF).

Background: Missing covariates are common in observational research and can lead to bias and loss of statistical power. Limited data regarding prognostic factors of survival outcomes of sarcomas in irradiated fields (SIF) are available. Because of the long lag time between irradiation of first cancer and scarcity of SIF, missing data are a critical issue when analyzing long-term outcomes. We assessed prognostic factors of overall (OS), progression-free (PFS), and metastatic-progression-free (MPFS) survivals in SIF using three methods to account for missing covariates. Methods: We relied on the NETSARC French Sarcoma Group database, Cox (OS/PFS), and competitive hazards (MPFS) survival models. Covariates investigated were age, sex, histological subtype, tumor size, depth and grade, metastasis, surgery, surgical resection, surgeon's expertise, imaging, and neo-adjuvant treatment. We first applied multiple imputation (MI): observed data were used to estimate the missing covariate. With the missing-data modality approach, a category missing was created for qualitative variables. With the complete-case (CC) approach, analysis was restricted to patients without missing covariates. Results: CC subjects (N = 167; 33%) presented more often with soft-tissue sarcoma (versus visceral sarcoma) and grade I-II tumors as compared to the 504 eligible cases. With MI (N = 504), factors associated with the worst outcome included metastasis (p = 0.04) and R1/R2 resection (p < 0.001) for OS; higher grade/non-gradable tumors (p = 0.002) and R1/R2 resection (p < 0.001) for PFS; and metastasis (p = 0.01) for M-PFS. The 'missing-data modality' approach (N = 504) led to different associations, including significance reached due to variables with the modality 'missing'. The CC analysis led to different results and reduced precision. Conclusion: The CC population was not representative of the eligible population, introducing bias, in addition to worst precision. The 'missing-data modality method' results in biased estimates in non-randomized studies, as outcomes may be related to variables with missing values. Appropriate statistical methods for missing covariates, for example, MI, should therefore be considered.

[Contribution of whole-body MRI to the initial assessment of myxoid liposarcoma]. / Apport de l'IRM corps entier au bilan initial du liposarcome myxoïde.

INTRODUCTION: Myxoid liposarcoma is a soft tissue sarcoma associated with multifocal metastases at diagnosis. These metastases are asymptomatic and occult on CT and FDG-PET and can alter the therapeutic management and prognosis. In this context, we evaluated the contribution of whole-body MRI to the initial workup of patients with myxoid liposarcoma. METHOD: This retrospective study was conducted between January 2015 and December 2020 at the Oscar Lambret Center. We enrolled 22 patients who were diagnosed with myxoid liposarcoma and underwent whole-body MRI at diagnosis. The number of metastases at diagnosis, their location, and the visibility of these lesions on CT were evaluated. Associations between clinical features, presence of metastasis, and their impact on management were assessed. RESULTS: Sixteen patients (72.7%) had non-metastatic disease at the initial diagnosis, and 15 of these patients were managed using local treatment. Six patients (27.3%) had metastases at multiple locations and received chemotherapy. The main locations were the bones (n=5) and lungs (n=3). In five patients with metastases, whole-body MRI demonstrated additional lesions that were not visible on CT (bone and soft tissue lesions). Only the presence of a round cell contingent (P=0.009) was found as a criterion associated with the presence of metastases. CONCLUSION: The patients' young age, absence of reliable prognostic factors at diagnosis, asymptomatic nature of the lesions, and the benefits of early and targeted therapeutic management encourage the use of whole-body MRI as part of the initial work-up as it seems to provide a better initial staging compared with conventional imaging.

Anti-programmed death ligand 1 immunotherapies in cancer patients with pre-existing systemic sclerosis: A postmarketed phase IV safety assessment study.

OBJECTIVES: Cancer patients with pre-existing autoimmune disease, such as systemic sclerosis (SSc), are excluded from clinical trials, so the data on tolerability and efficacy of immune checkpoint inhibitors in these patients are limited. This study investigated the tolerability and efficacy of anti-programmed death ligand 1 (PD (L)1) immunotherapies in patients with pre-existing SSc. METHODS: Scleronco-01 was a multicentre, nationwide, open-label, phase IV observational study, from 2019 to 2021. RESULTS: Seventeen SSc patients receiving treatment for lung carcinoma (n = 13, 77%), head and neck cancer (n = 2, 12%), melanoma (n = 1, 6%), and colorectal carcinoma (n = 1, 6%) were included. The median (interquartile range) patient age was 60 (34-82) years. Fifteen (88%) patients received anti-PD1 (nivolumab and pembrolizumab) and two (12%) anti-PD-L1 (durvalumab). The median follow-up duration was 12 (range, 2-38) months. Four patients (24%) experienced flare-up of SSc symptoms. Ten patients (59%) developed an immune-related adverse event (grade I-II in 11 patients [65%], grade III-IV in one [6%]) without grade V. The overall response rate was 41% (7/17 patients). The median overall survival was 15.8 (95% confidence interval: 7.3 to not reached) months. CONCLUSION: Anti-PD1 or PD-L1 immunotherapies are suitable options for cancer patients with pre-existing SSc. Longer follow-up periods are required for long-term safety analyses.

Cost-Utility Analysis of Continuation Versus Discontinuation of First-Line Chemotherapy in Patients With Metastatic Squamous-Cell Esophageal Cancer: Economic Evaluation Alongside the E-DIS Trial.

OBJECTIVES: Continuous chemotherapy has been used to treat patients with metastatic esophageal squamous cell carcinoma (mESCC), despite weak evidence supporting a clinical benefit, associated side effects for the patients, and unjustified medical costs. In the French setting, we conducted a cost-utility analysis alongside the randomized E-DIS trial (NCT01248299), which compared first-line fluorouracil/platinum-based chemotherapy continuation (CT-CONT) to CT discontinuation (CT-DISC) in progressive-free patients after an initial 6-week treatment phase. METHODS: A partitioned survival analysis was performed using patient-level data collected during the trial for survival outcomes, quality of life (EQ-5D-3L), and medical costs. The mean quality-adjusted life-years (QALYs) and medical costs were estimated over an 18-month period to assess the incremental net monetary benefit and incremental cost-effectiveness ratio. Uncertainty was handled using the nonparametric bootstrap and univariate analysis. Sixty-seven patients with mESCC were randomized and included in the cost-utility analysis. RESULTS: On average, CT-CONT slightly decreased the number of QALYs (-0.038) and increased the cost per patient (+ €1177). At a willingness-to-pay threshold of €50 000/QALY, the incremental net monetary benefit was negative (-€3077 [95% confidence interval: -6564; 4359]), and the incremental cost-effectiveness ratio was -30 958€/QALY (CT-CONT dominated). The probability of the CT-CONT treatment option being cost-effective at a willingness-to-pay threshold of €50 000/QALY, compared to CT-DISC, was 29%. CONCLUSIONS: CT-DISC may be considered as an alternative therapeutic option to CT-CONT in patients with mESCC who have stable disease after an initial chemotherapy treatment phase. A continuous chemotherapy could indeed reduce the number of QALYs because of the disutility associated with the continuous treatment.

Determinants of the access to remote specialised services provided by national sarcoma reference centres.

BACKGROUND: Spatial inequalities in cancer management have been evidenced by studies reporting lower quality of care or/and lower survival for patients living in remote or socially deprived areas. NETSARC+ is a national reference network implemented to improve the outcome of sarcoma patients in France since 2010, providing remote access to specialized diagnosis and Multidisciplinary Tumour Board (MTB). The IGéAS research program aims to assess the potential of this innovative organization, with remote management of cancers including rare tumours, to go through geographical barriers usually impeding the optimal management of cancer patients. METHODS: Using the nationwide NETSARC+ databases, the individual, clinical and geographical determinants of the access to sarcoma-specialized diagnosis and MTB were analysed. The IGéAS cohort (n = 20,590) includes all patients living in France with first sarcoma diagnosis between 2011 and 2014. Early access was defined as specialised review performed before 30 days of sampling and as first sarcoma MTB discussion performed before the first surgery. RESULTS: Some clinical populations are at highest risk of initial management without access to sarcoma specialized services, such as patients with non-GIST visceral sarcoma for diagnosis [OR 1.96, 95% CI 1.78 to 2.15] and MTB discussion [OR 3.56, 95% CI 3.16 to 4.01]. Social deprivation of the municipality is not associated with early access on NETSARC+ remote services. The quintile of patients furthest away from reference centres have lower chances of early access to specialized diagnosis [OR 1.18, 95% CI 1.06 to 1.31] and MTB discussion [OR 1.24, 95% CI 1.10 to 1.40] but this influence of the distance is slight in comparison with clinical factors and previous studies on the access to cancer-specialized facilities. CONCLUSIONS: In the context of national organization driven by reference network, distance to reference centres slightly alters the early access to sarcoma specialized services and social deprivation has no impact on it. The reference networks' organization, designed to improve the access to specialized services and the quality of cancer management, can be considered as an interesting device to reduce social and spatial inequalities in cancer management. The potential of this organization must be confirmed by further studies, including survival analysis.

Development of a disease-specific graded prognostic assessment index for the management of sarcoma patients with brain metastases (Sarcoma-GPA).

BACKGROUND: Brain metastases from sarcomatous lesions pose a management challenge owing to their rarity and the histopathological heterogeneity. Prognostic indices such as the Graded Prognostic Assessment (GPA) index have been developed for several primary tumour types presenting with brain metastases (e.g. lung, breast, melanoma), tailored to the specifics of different primary histologies and molecular profiles. Thus far, a prognostic index to direct treatment decisions is lacking for adult sarcoma patients with brain metastases. METHODS: We performed a multicentre analysis of a national group of expert sarcoma tertiary centres (French Sarcoma Group, GSF-GETO) with the participation of one Canadian and one Swiss centre. The study cohort included adult patients with a diagnosis of a bone or soft tissue sarcoma presenting parenchymal or meningeal brain metastases, managed between January 1992 and March 2012. We assessed the validity of the original GPA index in this patient population and developed a disease-specific Sarcoma-GPA index. RESULTS: The original GPA index is not prognostic for sarcoma brain metastasis patients. We have developed a dedicated Sarcoma-GPA index that identifies a sub-group of patients with particularly favourable prognosis based on histology, number of brain lesions and performance status. CONCLUSIONS: The Sarcoma-GPA index provides a novel tool for sarcoma oncologists to guide clinical decision-making and outcomes research.

Brain Metastasis and Renal Cell Carcinoma: Prognostic Scores Assessment in the Era of Targeted Therapies.

AIM: This study aimed at exploring several brain metastatic prognostic scores in patients with renal cell carcinoma. PATIENTS AND METHODS: We retrospectively analyzed data of 93 metastatic renal cell carcinoma patients who were diagnosed with brain metastases between October 2005 and July 2016 who received targeted therapy. Potential prognostic factors (RTOG RPA, BS-BM, and a newly developed score CERENAL) were analyzed. RESULTS: A total of 75 patients received targeted therapy. All scores showed prognostic value in progression-free survival after first-line treatment with CERENAL being the sole independent prognostic factor associated with improved duration of first-line treatment. Both RTOG RPA and CERENAL were potential prognosticators for overall survival, whereas only the CERENAL score was associated with prolonged disease-specific survival. CONCLUSION: Several prognostic scores can be useful to predict survival of patients with brain metastases from renal cancer, especially the newly developed CERENAL score.

A phase I, open-label, single-arm study for QT assessment of eribulin mesylate in patients with advanced solid tumors.

BACKGROUND: Several cancer therapies can prolong cardiac repolarization. This study assessed the potential of eribulin to affect cardiac repolarization in patients with advanced solid tumors. METHODS: In this Phase I, open-label, single-arm study, patients received eribulin mesylate (1.4 mg/m(2); Days 1 and 8 of a 21-day cycle). The primary objective was to assess the effect of eribulin on the QTcF pre- and post-infusion; QTcF and QTcNi were compared for ability to remove heart-rate dependence of the QT interval. Relationship between concentration of eribulin and ΔQTc was explored using linear mixed-effects analysis. Secondary objectives explored pharmacokinetics, safety, and tolerability. RESULTS: Twenty-six patients were enrolled. QTcNi was more effective than QTcF in correcting for heart-rate dependency of the QT interval. On Day 1, mean ΔQTcNi were ~0 at all timepoints. An apparent time-dependent increase in ΔQTc was observed: on Day 8, changes from baseline were larger and more variable, without clear relation to plasma levels of eribulin. Day 8 predose ΔQTcNi was 5 ms, post-infusion mean values ranged from 2 to 9 ms (largest mean ΔQTcNi at 6 h). No new or unexpected toxicities were reported. CONCLUSION: Eribulin demonstrated an acceptable safety profile and a minor prolongation of QTc not expected to be of clinical concern in oncology patients.

A paradigm shift in tumour response evaluation of targeted therapy: the assessment of novel drugs in exploratory clinical trials.

PURPOSE OF REVIEW: To describe the difficulty in assessing the biological activity of a novel agent in phase II trials. RECENT FINDINGS: Two major fields of research provide interesting new potential endpoints: endpoints based on new imaging techniques (e.g. PET or spectral imaging that explore tumour metabolism, dynamic contrast enhanced (DCE) ultrasonography or DCE-MRI that explore tumour vascularization and tumour growth inhibition) and endpoints integrating assessment of tumour burden across time, such as the growth modulation index. SUMMARY: Most of the recently described techniques appear attractive, but require formal validation.

Predictors for establishing recommended phase 2 doses: analysis of 320 dose-seeking oncology phase 1 trials.

INTRODUCTION: For decades, determination of the recommended Phase 2 dose (RP2D) was based on the toxicity (especially the maximum tolerated dose or MTD) experienced by patients enrolled in dose-escalating Phase 1 trials investigating anti-cancer agents. Recent studies suggest that this toxicity-based strategy is not suitable for modern anti-cancer agents. We conducted a retrospective study to identify the risk factor(s) for failing to determine the RP2D according to the MTD. MATERIAL AND METHODS: We analyzed 320 recently published (1997-2008) Phase 1 trials using the maximum tolerated dose (MTD) to define the P2RD. We analyzed the current definitions of RP2D and then identified the risk factors for not establishing the RP2D using the odds ratio and 95% confidence intervals. Interactions between these risk factors were explored using the logistic regression model and CHAID algorithm. RESULTS: 18% of contemporary dose-seeking Phase 1 trials did not identify a RP2D. The logistic regression analysis showed that the risk factors for not identifying the RP2D were: investigation of molecular targeted therapies (RR = 3.0, p = 0.0017), lack of justification of the starting dose (RR = 5.9, p = 0.0121) and lack of definition of the MTD (RR = 8.4, p = 0.0006). The CHAID algorithm confirmed the importance of the methodological parameters. DISCUSSION: This study confirms the difficulty of determining the RP2D of molecular targeted therapy using conventional methods. However, it underlines the major importance of two methodological points: definition of the MTD and justification of the starting dose.

Vancomycin flush as antibiotic prophylaxis for early catheter-related infections: a cost-effectiveness analysis.

BACKGROUND: Early catheter-related infection (CRI) remains a severe complication in cancer patients. Some recent data suggest that vancomycin flush (VF) administered on the day of catheter insertion could reduce the CRI incidence, but VF could also induce infections by vancomycin-resistant Enterococcus sp. (VRE). MATERIALS AND METHODS: So, we had conducted a decision model analysis of the cost and the effectiveness of three preventive strategies: absence of VF, VF in all cases, and VF in high-risk patients. The main outcome was absence of CRI and absence of VRE. Inputs were extracted from literature data. Variable uncertainty was explored by one- and two-way sensitivity analyses and best/worst case analysis. Model uncertainty was explored by Monte Carlo probabilistic sensitivity analysis. RESULTS: In base case, compared to absence of VF, the VF strategy in high-risk patients was the best strategy, in terms of cost (reduction cost estimated at $190 per patient) and benefit (probability of infection estimated at 98.1% versus 96.6%). The VF strategy in all cases was strongly dominated. These findings were confirmed by sensitivity analysis. CONCLUSIONS: VF in high-risk patients, such as defined in literature, is beneficial and cost-saving. Nevertheless, further investigations are needed to define better the probability and the cost of VRE, which are the two variables driving the model.

Factors determining length of the postoperative hospital stay after major head and neck cancer surgery.

Hospital stays constitute the main component of costs of cancer treatment. We conducted a prospective study to identify the determinants of the length of stay (LOS) after head and neck cancer surgery (HNCS). Patients who underwent major HNCS with opening of mucosa and with curative intent were enrolled. Data were collected for patient characteristics, type of tumour, surgical procedures and postoperative outcome. LOS defined as the interval between the day of admission for surgery until hospital discharge or death was determined by the Kaplan-Meier method. Independent determinants of LOS were identified using a Cox model. All 260 patients were included. Median LOS was 26 days (range, 3-178). In the multivariate model, four variables remained associated with increased LOS: American Society of Anaesthesiologist's score equal to 3 (hazard ratio 1.62 [1.23-1.99]), duration of surgical procedure >220 min., (HR=1.37 [1.22-1.56]), SSI (HR=2.09 [2.02-2.54]), occurrence of SSI caused by multi-resistant pathogen (HR=2.92 [2.78-3.77]) and occurrence of PP (HR=2.09 [1.78-2.81]). The present results highlighted the long duration of LOS after head and neck cancer surgery. Two variables (duration of surgical procedure and occurrence of nosocomial infections) were associated with LOS and might be improved by appropriate strategies.

General practitioners assessment of a structured report on medical decision making by a regional multidisciplinary cancer committee.

The structured report (SR) summarizing the multidisciplinary decision making for referred cancer patient is a new opportunity to ameliorate communication between GPs and cancer specialists. The aim of this study was to investigate how GPs value this structured report. We carried out a questionnaire-audit on SR GPs assessment. The SR had included: the list of committee participants, short summary of clinical history and characteristics, tumour location and size, TNM classification, precise histological diagnosis, practice guidelines used, possibility of clinical trial, identification of specialist in charge of patient, and a short conclusion. The enrolled patients were treated for soft tissue sarcoma, melanoma or carcinoma with unknown primary. The response rate was 47% (52/110). 79% of GPs are satisfactory with the structured report. The analysis of responses suggest 3 amelioration axes: (i) accompany the report with a short summary of guidelines used, (ii) describe clearly the potential cancer treatment side effects and suggest some treatments of those side-effects, (iii) and send this structured report more rapidly during the clinical pathway. This SR appears clearly an opportunity of communication amelioration between care providers. This SR is appreciated by GPs. But, it is necessary to include more practical information.