Clinical Trial in New York | Immunotherapy eliminates colorectal cancer… under certain conditions

Curing colon cancer without surgery, radiation or chemotherapy is now possible for some patients thanks to a team of doctors from the United States. The key to success ? immunotherapy.

Posted on June 14th

Alice Girard bosses

Alice Girard bosses
The press

“Immunotherapy is available in Canada and Quebec, but only for stage 4 cancer when there is metastasis to other organs,” said Barry Stein, CEO of Colorectal Cancer Canada and a survivor of the disease.

The clinical trial at Memorial Sloan Kettering Cancer Center (MSK) in New York aimed to determine for the first time whether immunotherapy can induce complete remission of rectal cancer that has not spread to other tissues.

Fourteen patients with stage 2 or 3 rectal cancer therefore received intravenous immunotherapy every three weeks for six months.

All of the patients had their cancer resolved after immunotherapy without resorting to standard treatments such as radiation therapy, surgery or chemotherapy.

The cancer has not returned in any of them, some of them for almost two years.

“We did not expect to see all patients responding completely. The probability of this was low,” exclaims the Dright Benoit Rousseau, medical oncologist at Memorial Sloan Kettering Cancer Center who participated in the clinical study.

A fundamental anomaly

However, for immunotherapy to be effective, patients must have a tumor that contains a specific genetic abnormality called micro satellite unstable (MSI). Between 5 and 10% of all rectal cancer patients have tumors with this abnormality.

“So it’s not a one-size-fits-all strategy,” says Dr.right Rousseau. Studies in the past have shown that immunotherapy has no effect in patients without this abnormality.


PHOTO SUPPLIED BY Dright Benoit Rousseau

Dright Benoit Rousseau, medical oncologist at Memorial Sloan Kettering Cancer Center (MSK)

Avoid side effects

Immunotherapy also makes it possible to limit the side effects caused by radiotherapy, chemotherapy and surgical interventions. “The rectum is adjacent to the bladder, the prostate in men and the gynecological system in women, so we have many implications in terms of quality of life for these patients,” explains the Dright Rousseau.

In fact, standard treatments can lead to a loss of fertility, the risk of a permanent stoma — an opening in the abdomen that allows stool to pass — and permanent indigestion.

Because immunotherapy completely cleared the cancer, patients were able to avoid chemotherapy, radiation therapy, and surgery.

rise among young people

The majority of patients in the study were under 40 years old. “It’s very young,” says the Dright Rousseau.

In recent years, the rate of colorectal cancer has increased in Canadians in their 20s and 30s, while it has decreased in adults 55 and older.

About 30% of early-stage colorectal cancer cases occur in people with a family history or genetic predisposition. In many cases, these young patients have the genetic abnormality that allows them to be susceptible to immunotherapy treatment, Stein says.

The idea is to educate young people not to ignore the symptoms – abdominal pain, blood in the stool – and to educate general practitioners not to ignore the symptoms of patients.

Barry Stein, CEO of Colorectal Cancer Canada and a survivor of the disease

Strong enthusiasm

A strong enthusiasm for immunotherapy has been felt since the publication of her article. “Some colleagues receive 300 calls a day. They have dedicated nurses who have been answering questions since the article came out,” says Dr.right Rousseau.

Some clinics in the United States are planning to give their patients access to treatment very quickly. “In Canada and Europe, there is a need to determine whether the data from a small study is sufficient to warrant reimbursement for the drug. Immunotherapy remains an expensive treatment,” says Dr.right Rousseau. An immunotherapy treatment costs around $11,000 in the United States, says the oncologist. Each patient received eight doses.

Although the study was conducted on a small number of patients, the results give a lot of hope, says Dr.right Rousseau. “That is extremely encouraging. It offers patients incredible perspectives and opens the door to new studies,” he concludes.

How does immunotherapy work?

The immune system doesn’t normally attack healthy cells, thanks to a protective device called a checkpoint. However, colon cancer cells have the ability to trigger this device, which prevents the immune system from locating and destroying the tumor. Immunotherapy can solve the problem by blocking the checkpoints, allowing the immune system to attack and destroy cancer cells.

Learn more

  • 67
    Number of Canadians diagnosed with colorectal cancer each day in Canada.

    Source: Canadian Cancer Society

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