ERASur: Trial overview

Stage IV colorectal cancer includes a diverse group of patients, including patients with 1 liver metastasis, patients with <10 metastases in 2 organs, or metastases in many organs.

We know that patients with liver-only disease that can be treated with local therapy, such as surgery, do well and can even be cured in some situations. However, there are patients with slightly more disease involving 3 or even 4 sites in the body where we are unsure if local therapy including ablative radiation, surgery, or thermal ablation in addition to chemotherapy is helpful.

This trial aims to find out if patients with 4 or fewer sites of disease based on initial imaging at diagnosis and following 4-6 months of first line chemotherapy, benefit from local treatment with ablative radiation, surgery, or thermal ablation of all metastatic sites.

The primary objective of ERASur is to determine if adding local therapy to the usual treatment of chemotherapy for patients with limited metastatic disease can improve overall survival and prevent local recurrence or if this local treatment is not beneficial.


ERASur is a phase III clinical trial studying if the addition of total ablative therapy (TAT) to the usual treatment for metastatic colorectal cancer, chemotherapy, can lengthen survival compared to treatment with chemotherapy alone.

TAT means that all individual metastatic tumor spots are destroyed with high doses of radiation therapy, surgically removed, or destroyed with heat. For patients with metastatic disease in the liver only, these ablative local treatments have been shown to be beneficial. However, questions remain about the benefit of adding TAT to the standard approach of chemotherapy in patients with metastatic disease that is involving more than just the liver. The purpose of ERASur is to help clarify the role of adding TAT to chemotherapy in patients with limited disease involving more than just the liver, that persists after 4-6 months of chemotherapy.

Who is the trial for?

ERASur is for adults with newly-diagnosed metastatic colorectal cancer that is limited in spread. For this study, we have defined this as having 4 or fewer sites of disease based on pre-treatment imaging. These site(s) would need to persist after 4-6 months of chemotherapy.

A single site includes: each side of the liver (right and left), each lobe of the lungs, each adrenal gland, lymph nodes treatable with a single surgery or in a single radiation field or bone metastases treatable in a single radiation field.

To explain this further, for example, there is no limit to the number of metastases per side of the liver or lobe of the lungs – it still counts as 1. Three lesions in the right liver is 1 site, and 3 lesions in the left liver is a 2nd site, and 3 lesions in the right upper lobe of the lung is a 3rd site.

For lymph nodes, this means one lymph node or 2 or 3 lymph nodes next to each other which can be removed by 1 surgery or a few lymph nodes that can fit in 1 radiation field.

Patients are allowed to receive up to 6 months of first-line chemotherapy prior to registering for the study.

What is the main trial objective?

The primary goal of ERASur is to demonstrate superior overall survival in the patients treated with TAT plus chemotherapy compared to treatment with chemotherapy alone.

Interested? Here are the details

Phase: III ID number: NCT05673148

Enrollment status: Active, total expected enrollment = 364 patients

Trial sponsors: The National Cancer Institute and the National Clinical Trials Network, Alliance for Clinical Trials in Oncology