Colon cancer: new treatment reduces tumors by 95%

This is good news which was announced on September 11 at the annual congress of the European Society for Medical Oncology. A team from the Netherlands Cancer Institute in Amsterdam has indeed presented the results of a new treatment: according to their first results, the combination of two immunotherapy treatments could produce an unprecedented response rate by shrinking the tumor in place. by 95%. An interesting alternative when the current treatment for this cancer is based on major surgery, whether or not followed by chemotherapy.

Very encouraging results

To be able to present such a result, the team of scientists tested its treatment on 112 patients aged around 60, 74% of whom had high-risk stage III radiological disease (the tumor had crossed the wall of the colon or rectum and reaches the lymph nodes). Each received a combination of ipilimumab and nivolumab (two immunotherapy treatments), then nivolumab for the next two weeks, before being operated on.

According to their analyses, almost 95% of the tumors regressed by 90%, and 99% of the tumors were reduced by more than 50%. Another interesting fact, in the postoperative follow-up of 13 months, no case of recurrence was identified, while generally, the recurrence rates “shave ranged between 20% and 40%, even when standard chemotherapy is administered” said Myriam Chalabi, lead author of the research.

10 to 15% of colon cancers concerned

However, the study requires further research and does not apply to everyone: the advance only concerns 10 to 15% of non-metastatic colon cancers, targeted cancers that present “an anomaly of the genome causing a failure of the DNA repair system”.

In addition, although they are rare, side effects appeared in 4 of the 112 participants in the study: hepatitis, rash, as well as muscle weakness after taking the treatment. In his patients, surgery had to be rescheduled.

The place of surgery could tomorrow be discussed

For Dr. Antoine Hollebecque, oncologist in the gastrodigestive committee of the Gustave Roussy center, the study is promising. “We already knew that patients with a genomic abnormality called microsatellite instability (MI), (10-15% of colon cancer cases) were more sensitive to immunotherapy. But here, the combination tested tells us that the vast majority of patients show a strong or even complete response at the time of surgery” he rejoices, making the link with a similar study on rectal cancer presented in June.

With this promising study, we can hope that in some cases (in 10 to 15% of colon cancers), preoperative immunotherapy could simply be enough to make the cancer disappear, without going through any surgery. “Let’s wait for the results of randomized studies to reach us, but in the future, the question of surgery will probably be discussed again,” he confirms.

As a reminder, in France, more than 43,000 new cases of colon cancer are detected each year.