Bowel cancer tumours disappear in 100% of patients after taking new drug in small trial

Bowel cancer is one of the UK's most common forms of cancer. Credit: PA

Bowel cancer patients who participated in a small clinical trial saw their tumours disappear after receiving a new drug. The 12 participants entered remission after taking dostarlimab, a drug that helps the immune system identify tumour cells. None of the patients experienced significant side effects from the treatment, the researchers said."I believe this is the first time this has happened in the history of cancer," Dr. Luis Alberto Diaz Jr, one of the trial leaders and a medical oncologist at Memorial Sloan Kettering (MSK) Cancer Centre, told The New York Times. The results of the small trial, conducted at the MSK Cancer Center in New York City and published in the New England Journal of Medicine (NEJM), led to experts heralding it a "cause for great optimism".The 12 trial participants all had a type of bowel cancer known as "mismatch repair-deficient" that has been shown to respond poorly to chemotherapy treatment. It affects an estimated 5% to 10% of bowel cancer patients.

Researchers do not yet know if the drug will work on other kinds of bowel cancer.

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"In our study, single-agent dostarlimab was remarkably effective in mismatch repair–deficient, locally advanced rectal cancer, providing a clinical complete response in all 12 patients who have completed treatment to date," the study read. While the results were promising, Dr. Hanna Sanoff, an oncologist at the Lineberger Comprehensive Cancer Centre at the University of North Carolina, cautioned there needed to be further research before the drug replaced the stand treatment for mismatch repair-deficient bowel cancer. "While longer follow-up is needed to assess response duration, this is practice-changing for patients with [mismatch repair-deficient] locally advanced rectal cancer," Dr Diaz said in the MSK statement. 

Bowel cancer is the fourth most common cancer in the UK and the second biggest cancer killer.Nearly 43,000 people are diagnosed with bowel cancer every year in the UK. Around 268,000 people living in the UK today have been diagnosed with bowel cancer.

What are the symptoms of bowel cancer?

According to the NHS, the three main symptoms of bowel cancer are:

  • persistent blood in your poo – that happens for no obvious reason or is associated with a change in bowel habit

  • a persistent change in your bowel habit – which is usually having to poo more and your poo may also become more runny

  • persistent lower, bloating or discomfort – that's always caused by eating and may be associated with loss of appetite and weight

However, the NHS says most people with these symptoms do not have bowel cancer. Other health problems can cause similar symptoms such as a change in diet or haemorrhoids.

The NHS recommends seeing your GP if you have any of the symptoms of bowel cancer for three weeks or more.