Colorectal cancer (CRC) is one of the most common cancers worldwide. Stage II/III patients undergo curative-intent surgery yet still face the recurrence risk. Detecting recurrences early provides the best opportunity for optimal treatment. We aimed to develop a microsimulation model to evaluate CRC management-associated outcomes based on current guidelines, including the performance of guideline-recommended surveillance in detecting recurrences.

Two separate individual-level state transition (microsimulation) models for colon and rectal cancer were built with a lifetime horizon using monthly cycles. The models integrated treatment and surveillance strategies per current guidelines.

The currently recommended surveillance modalities by National Comprehensive Cancer Network guidelines for surveilling patients with CRC after curative-intent surgery.

65-year-old patients with stage II and stage III CRC who underwent curative-intent surgery in the USA.

Cumulative recurrences, detected recurrences, detection rate, overall survival and recurrence-free survival in a 5-year horizon, as well as average life expectancy, were the outcome measures used.

Over 5 years, disease recurrence was observed in 9.5% of patients with stage II–III colon cancer and in 38.0% of patients with stage II–III rectal cancer. Of these, 82.5% and 85.5% were detected via surveillance, respectively, within 5 years. The predicted 5-year overall survival was 86.0% for colon cancer and 69.3% for rectal cancer, with corresponding recurrence-free survival rates of 78.9% and 53.8%. Based on current guidelines-recommended surveillance, detecting one colon cancer recurrence requires 148 carcinoembryonic antigen (CEA) tests, 37 CT scans and 21 colonoscopies. In contrast, detecting one rectal cancer recurrence requires 31 CEA tests, 8 CT scans and 4 colonoscopies.

Our validated model suggests that relative to an optimal benchmark in which all recurrences are detected, recurrence detection under current guidelines may be suboptimal, indicating room for improvement. As new tests emerge, this model could be a valuable tool for evaluating existing clinical practices and the potential of new tests to enhance patient outcomes.

Epidemics pose significant challenges for fragile health systems, particularly in humanitarian emergencies. Recent responses to epidemics such as cholera in Yemen and Ebola virus disease in the Democratic Republic of the Congo have highlighted the lack of effective and integrated coordination. We review existing global models for addressing large-scale epidemics in humanitarian emergencies, identify gaps and inefficiencies, and propose operational recommendations to enhance response mechanisms.

A two-pronged approach was used to identify and critically assess current response coordination frameworks. Using the Arksey and O’Malley framework, a scoping review was undertaken, which was complemented by key informant interviews with humanitarian emergency response experts. The interviews focused on identifying the existing challenges and potential strategies to improve epidemic response in humanitarian contexts.

The scoping review included 51 documents (13 peer-reviewed articles and 38 grey literature documents). We conducted in-depth interviews with 28 respondents representing 17 different agencies and donors.

We focused on two major response architectures: the Incident Management System (IMS) and the cluster system. IMS is an important coordination and response instrument increasingly being used to respond to infectious disease threats.

Outcome measures of interest included the gaps in the current mechanisms to address infectious disease threats in complex humanitarian emergencies.

Unlike the cluster system model, which relies on consensus decision-making, IMS has a command-and-control approach, ensuring rapid decision-making. However, it can also lead to vertical responses that neglect the cross-sectoral and complex needs of affected communities. In addition, we found that the absence of context-specific response coordination mechanisms, with clear roles and responsibilities for involved stakeholders, was a common shortcoming. Fragmented response efforts that sidelined national and local stakeholders and a lack of reliable funding were also identified as important weaknesses.

We recommend the integration of coordination mechanisms into a sufficiently flexible framework that can be adapted to local contexts, while empowering national and local actors and ensuring the continuity of essential humanitarian services. We propose a paradigm shift towards mechanisms that respect humanitarian principles, effectively addressing the epidemic threats while remaining focused on deploying community-centric response efforts.