Comparative Effectiveness of Up To Three Lines of Chemotherapy Treatment Plans for Metastatic Colorectal Cancer

Treatment of Patients With Late-Stage Colorectal Cancer: ASCO Resource-Stratified Guideline

PURPOSE

To provide expert guidance to clinicians and policymakers in resource-constrained settings on the management of patients with late-stage colorectal cancer.

METHODS

ASCO convened a multidisciplinary, multinational Expert Panel that reviewed existing guidelines, conducted a modified ADAPTE process, and used a formal consensus process with additional experts for two rounds of formal ratings.

RESULTS

Existing sets of guidelines from four guideline developers were identified and reviewed; adapted recommendations from five guidelines form the evidence base and provided evidence to inform the formal consensus process, which resulted in agreement of ≥ 75% on all recommendations.

RECOMMENDATIONS

Common elements of symptom management include addressing clinically acute situations. Diagnosis should involve the primary tumor and, in some cases, endoscopy, and staging should involve digital rectal exam and/or imaging, depending on resources available. Most patients receive treatment with chemotherapy, where chemotherapy is available. If, after a period of chemotherapy, patients become candidates for surgical resection with curative intent of both primary tumor and liver or lung metastatic lesions on the basis of evaluation in multidisciplinary tumor boards, the guidelines recommend patients undergo surgery in centers of expertise if possible. On-treatment surveillance includes a combination of taking medical history, performing physical examinations, blood work, and imaging; specifics, including frequency, depend on resource-based setting.

Additional information is available at www.asco.org/resource-stratified-guidelines.

Simulating Progression-Free and Overall Survival for First-Line Doublet Chemotherapy With or Without Bevacizumab in Metastatic Colorectal Cancer Patients Based on Real-World Registry Data

BACKGROUND

Simulation models utilizing real-world data have potential to optimize treatment sequencing strategies for specific patient subpopulations, including when conducting clinical trials is not feasible. We aimed to develop a simulation model to estimate progression-free survival (PFS) and overall survival for first-line doublet chemotherapy with or without bevacizumab for specific subgroups of metastatic colorectal cancer (mCRC) patients based on registry data.

METHODS

Data from 867 patients were used to develop two survival models and one logistic regression model that populated a discrete event simulation (DES). Discrimination and calibration were used for internal validation of these models separately and predicted and observed medians and Kaplan-Meier plots were compared for the integrated DES. Bootstrapping was performed to correct for optimism in the internal validation and to generate correlated sets of model parameters for use in a probabilistic analysis to reflect parameter uncertainty.

RESULTS

The survival models showed good calibration based on the regression slopes and modified Hosmer-Lemeshow statistics at 1 and 2 years, but not for short-term predictions at 0.5 years. Modified C-statistics indicated acceptable discrimination. The simulation estimated that median first-line PFS (95% confidence interval) of 219 (25%) patients could be improved from 175 days (156-199) to 269 days (246-294) if treatment would be targeted based on the highest expected PFS.

CONCLUSIONS

Extensive internal validation showed that DES accurately estimated the outcomes of treatment combination strategies for specific subpopulations, with outcomes suggesting treatment could be optimized. Although results based on real-world data are informative, they cannot replace randomized trials.

Health Economic Models for Metastatic Colorectal Cancer: A Methodological Review

OBJECTIVE

The aim of this systematic review was to provide a comprehensive and detailed review of structural and methodological assumptions in model-based cost-effectiveness analyses of systemic metastatic colorectal cancer (mCRC) treatments, and discuss their potential impact on health economic outcome estimates.

METHODS

Five databases (EMBASE, MEDLINE, Cochrane Library, Health Technology Assessment and National Health Service Health Economic Evaluation Database) were searched on 26 August 2019 for model-based full health economic evaluations of systemic mCRC treatment using a combination of free-text terms and subject headings. Full-text publications in English were eligible for inclusion if they were published in or after the year 2000. The Consolidated Health Economic Evaluation Reporting Standards checklist was used to assess the reporting quality of included publications. Study selection, appraisal and data extraction were performed by two reviewers independently.

RESULTS

The search yielded 1418 publications, of which 54 were included, representing 51 unique studies. Most studies focused on first-line treatment (n = 29, 57%), followed by third-line treatment (n = 13, 25%). Model structures were health-state driven (n = 27, 53%), treatment driven (n = 19, 37%), or a combination (n = 5, 10%). Cohort-level state-transition modelling (STM) was the most common technique (n = 33, 65%), followed by patient-level STM and partitioned survival analysis (both n = 6, 12%). Only 15 studies (29%) reported some sort of model validation. Health economic outcomes for specific strategies differed substantially between studies. For example, survival following first-line treatment with fluorouracil, leucovorin and oxaliplatin ranged from 1.21 to 7.33 years, with treatment costs ranging from US$8125 to US$126,606.

CONCLUSIONS

Model-based cost-effectiveness analyses of systemic mCRC treatments have adopted varied modelling methods and structures, resulting in substantially different outcomes. As models generally focus on first-line treatment without consideration of downstream treatments, there is a profound source of structural uncertainty implying that the cost-effectiveness of treatments across the mCRC pathway remains uncertain.