Doctors have successfully cured rectal cancer in patients thanks to an experimental drug trial.
Oncologists at Memorial Sloan Kettering Cancer Center (MSK) in New York found that the latest tests of patients showed no evidence of cancer.
Tea treatment uses immunotherapy which harnesses the body’s own immune system as an ally against cancer.
Sascha Roth, the first patient in the clinical trial involving immunotherapy had undergone six months of treatment.
For the first time, the MSK clinical trial was investigating if immunotherapy alone could cancer rectal beat that had not spread to other tissues, in a subset of patients whose tumor contained a specific genetic mutation.
As the first patient to enroll in the trial, the research team was anxious that Roth’s experience might prove to be an outlier but the same remarkable result was repeated in all 14 people in the trial.
In every case, the rectal cancer disappeared after immunotherapy—without the need for the standard treatments of radiation, surgery, or chemotherapy—and cancer has not returned in any of the patients, who have been cancer-free for up to two years.
‘It’s incredibly rewarding to get these happy tears and happy emails from the patients in this study who finish treatment and realize, “Oh my God, I get to keep all my normal body functions that I feared I might lose to radiation or surgery,” ‘ said Dr. Andrea Cercek, a medical oncologist working on the trial.
The patients in the study had tumors with a specific genetic makeup known as mismatch repair-deficient (MMRd) or microsatellite instability (MSI).
There are 45,000 Americans diagnosed a year with rectal cancer. Between 5% and 10% of all rectal cancer patients are thought to have MMRd tumors.
‘Immunotherapy has proven successful in treating a subset of patients with colon and rectal cancer that has metastasized, meaning spread to other tissues,’ explained Dr Luis Diaz, Jr., a co-investigator on the trial.
The clinical trial also focused on avoiding the toxicity often associated with treatment for rectal cancer as the standard treatment for rectal cancer with surgery, radiation, and chemotherapy can be particularly hard on people because of the location of the tumour.
‘They can suffer life-altering bowel and bladder dysfunction, incontinence, infertility, sexual dysfunction, and more,’ said Dr Diaz.
To avoid these toxicities, many approaches to rectal cancer try to shrink the tumor as much as possible with chemotherapy and radiation to facilitate surgery.
Dr Diaz says this decision by Dr Cercek was ‘a world-class moment’ that promised to change the lives of patients if it worked.
All patients in the trial must have stage 2 or 3 rectal tumors that are MMRd making their cancer particularly sensitive to immunotherapy. The patients were given a drug intravenously every three weeks, for six months.
Their tumors were closely tracked, Dr Diaz explains, ‘using imaging, visualization such as endoscopy, as well other methods’.
‘The immunotherapy shrank the tumors much faster than I expected,’ said Dr Cercek.
‘My research nurse Jenna Sinopoli would tell me, “The patient has only received one treatment and already they’re not bleeding anymore and their terrible pain has gone away”.’
‘One young man and his family just sat in stunned silence when I told them his cancer had disappeared,’ said Dr Cercek. ‘Then they thanked us over and over.’
The fascinating part of the trial is that every single one of the patients had only needed immunotherapy with no need for radiation or surgery.
‘They have preserved normal bowel function, bladder function, sexual function, fertility. Women have their uterus and ovaries. It’s remarkable,’ said Dr Cercek.
Bowel cancer is one of the most common types of cancer diagnosed in the UK. Most people diagnosed with it are over the age of 60. However, there has been a disturbing rise in the number of people under 50 who are diagnosed with colorectal cancer, particularly rectal cancer.
Dr Cercek says: ‘We are seeing more and more young people with rectal cancer, including people in their 20s in our trial. Immunotherapy might be an important new option for them.’
The result of the trial has been published in The New England Journal of Medicine and featured at the nation’s largest gathering of clinical oncologists in June 2022.