About SAGITTARIUS
Why is this research being done?
One of the most important ways of improving outcomes in colon cancer is by identifying and treating it as early as possible. In the early stages, when the disease is local (which means the cancer affects only the colon and has not spread to other organs), it can often be successfully treated and cured via surgery.
For people with either high-risk stage colon cancer (whose cancer has crossed the colon intestine wall) or stage III colon cancer (whose cancer has spread to neighbouring lymph nodes), surgery treatment with chemotherapy is recommended. Post-surgery chemotherapy is also known as ‘adjuvant’ chemotherapy.
The purpose of giving chemotherapy after surgery is to remove any traces of cancer that may be remaining in the body (known as minimal residual disease (MRD) to stop the cancer from coming back.
Currently, all patients with high-risk stage II or stage III colon cancer indiscriminately receive chemotherapy after surgery because, until now, it has not been possible to know who is at risk of having minimal residual disease and who is not
That means many patients might currently receive chemotherapy unnecessarily, gaining little or no benefit while experiencing significant and unpleasant side effects and long-lasting impact on their lives. Meanwhile, many patients who might benefit from other, more targeted treatments, do not receive them
1. European Cancer Information System [Internet]. Available from: https://ecis.jrc.ec.europa.eu/
The patient perspective – living with the long-term impact of chemotherapy
“For me, chemotherapy affected me significantly. I had a lot of side effects during the course, including crippling fatigue and peripheral neuropathy. Years later, I'm still living with consequences. I was fit, doing regular cycle rides. I used to reach dance. I had to stop all of that because of the chemotherapy, not the cancer. It affects your self-confidence as well. Then there’s the impact on your loved ones; during the chemo, my wife became a full-time nurse for me. The impact is immense. Preventing unnecessary chemo after surgery will be life-changing for so many people.”
Stephen Rowley, UK
What is the purpose of SAGITTARIUS?
A liquid biopsy is a blood test that detects DNA that is circulating in the blood, called “circulating tumour DNA” or “ctDNA.” ctDNA is DNA released by the tumour cells into the blood and therefore it carries the same characteristics as the tumour of origin. ctDNA has been shown to be a strong indicator of minimal residual disease, of cancer cells remaining in the body. If the liquid biopsy test is positive, it means that there might be other cancer cells somewhere in the body, even though the primary tumour has been removed.
The genetic profile of the primary tumour will be analysed and then used to create a tailor-made liquid biopsy test for each patient participating in SAGITTARIUS. This liquid biopsy will then be able to detect tumour DNA in their blood, and to help doctors understand which personalised treatment strategies should be used.
Why run SAGITTARIUS is crucial?
In the SAGITTARIUS trial, the newly tailored pathway under evaluation is experimental, leaving uncertainties about its superiority over the standard method. Each group presents advantages and disadvantages.
Participants in the standard group benefit from established treatments with a proven track record of effectiveness over many years. However, there's a risk of receiving unnecessary treatment if minimal residual disease is absent, potentially leading to secondary effects. Moreover, the standard treatment might not entirely align with the genetic profile of the tumour.
Those in the experimental group have the potential to receive a treatment better suited to their specific case post-surgery, avoiding unnecessary treatments and their associated side effects. Nonetheless, this approach is experimental. Liquid biopsy, although promising, hasn't yet been validated as a clinical diagnostic tool, raising the possibility of undetected minimal residual disease.
Hence, conducting the clinical trial is crucial to accurately determine the potential of liquid biopsy as a validated clinical diagnostic tool in the future.
What will be the outcome and impact of SAGITTARIUS?
SAGITTARIUS could help to transform the way people with colon cancer are treated after surgery.
It is hoped that based upon the results of a liquid biopsy test and the genetic profile of the primary tumor, the best treatment approach will be known for each patient. This will ensure patients get the best treatment for them at the earliest possible stage (including precision therapies for certain patients), while also ensuring they don’t receive unnecessary treatments in the meantime. For example, patients who do not need chemotherapy will not receive it, meaning many patients will avoid unnecessary side effects and the long-term impacts associated with chemotherapy.
Ultimately, by helping to ensure that each patient receives the treatment most suited to them, SAGITTARIUS will help to improve outcomes for patients with colon cancer, helping them to lead longer, healthier lives.
At the same time, using the right treatment for the right patient at the right time will lead to more efficient use of essential health system resources and finances, contributing to a substantial reduction in the socio-economic burden of colon cancer care.