Refining Adjuvant Treatment Options for Colorectal Cancer

Elena Elez, MD, PhD, Vall d'Hebron University Hospital, Barcelona, Spain, explains how to refine the selection of adjuvant treatment for stage II colorectal cancer at 2019 World Congress on Gastrointestinal Cancer.

Transcript:

Hello, my name is Elena Elez, a medical oncologist working at Vall d’ Hebron Institute of Oncology in Barcelona. I'm focused on colorectal cancer. We are going to discuss today how to refine the treatment in stage II adjuvant colorectal cancer.

Actually, this is a matter of interest, as colorectal cancer is an illness that is increasing. It's the third most common cause of death related with cancer worldwide. The fact is that the change of lifestyle and diet patterns and so on, has made this illness to increase.

It's important, also, to take into consideration that colorectal screening has been very well established. Probably, the number of patients that will be diagnosed with an early stage will increase. Hence, stage II colon cancer probably will also increase.

The way how we define the treatment for this population is based on a TNM-stage system, but also certain risk factors like the pathological stage, T4, the differentiation of the tumor, the lymph nodes that are surgically resected and affected in the surgery, but also the occurrence of obstruction, of perforations.

This helps us to identify a population that may have a higher risk. Also, the microsatellite instability status help us to identify a certain subset of patients that probably will have a good prognosis, and that don't need systemic treatment with chemotherapy.

Nevertheless, we still have a percentage of populations that have recurrence so it’s our responsibility to design strategies in order to better identify this population. Now, we have data coming from different biomarkers that have been developed, like the BRAF mutational status.

KRAS, we don't have very current data across CDX, but what we can say is that BRAF may be actor of bad prognosis for this population. Nevertheless, in the routine clinical practice, we only test BRAF when we have an MSI instability.

Moreover, it also has been tested SMAD4 or the 18q LOH loss and other factors that have not been proven as bad prognosis factors. For example, for CDX2, we have also data in around five percent of the population. For this population that do not have expression of this factor, the consideration of chemotherapy could be recommended in stage II.

Also it’s important, this new line of research focused on looking at biopsy. We have now data about the importance of minimal residual disease. If we are able to detect free ctDNA in patients that have undergone surgery, the probability for these patients to recur is pretty high.

So there are several trials ongoing that are recruiting for stage II and stage III colon cancer, that aim to identify patients with ctDNA positive in blood. We wonder if this detection and adding an early treatment for this population may add a benefit, identifying these patients of higher risk.

We have also data from gene expression platforms for Immunoscore, that may help at least to identify patients with bad prognosis. We have also to take into consideration that, to have a bad prognosis does not imply to obtain a benefit in chemo.

So there is a lot of data that we have to integrate. We need prospective trials in order to demonstrate each one of these factors, to elucidate which aims will help us, finally, in the routine clinical practice.

For sure, in the near future, we will have very interesting data coming from several studies that are now ongoing. Probably we will be able to identify and treat these patients in a most appropriate manner.