MRI prognostic parameters in tailoring treatment for locally advanced rectal cancer

This study investigated the use of MRI predictive results to decide the best treatment for patients with locally advanced rectal cancer (LARC). Researchers suggested that early MRI results should be used in the treatment decision making.

Colorectal cancer is the third most common cancer in the world. Patients with LARC have a localized tumor that has spread to the lymph nodes. The standard treatment for this is chemotherapy and radiation therapy followed by surgery. However, each case is different, and treatment should be personalized to each patient. Patients with a good response to the treatment would receive less invasive therapy. While the ones likely to show poor response would receive a more aggressive treatment.

MRI is a non-invasive imaging method that allows measurements of the tumor such as size and volume. Tumor volume is a strong predictor of tumor response and outcome. However, how MRI can help personalize treatment for patients with LARC is still not clear.

This study included 133 patients with LARC. These patients underwent rectal MRI before treatment, 4 weeks after first-line chemotherapy and after completion of treatment. Factors like tumor size, volume, and margins (when cancer cells are left behind after surgery) were evaluated. The average follow-up period was 41.4 months. 23.3% (31) had a recurrence (when the tumor comes back).

After the first-line treatment, a larger tumor volume, a shrinkage of 60% or less and poor margins were associated with poorer outcomes. After completion of the treatment partial response, poor shrinkage and vascular invasion were associated with shorter disease-free survival. Disease-free survival is the time from treatment to disease progression.

Some factors associated with recurrence were, a tumor shrinkage of 60% or less after first-line treatment and vascular invasion. 

This study concluded that MRI results are associated with prognosis in LARC and should be used in the treatment decision making. 

This study included a limited number of participants. Further studies with a bigger population are needed.