Can the RNA found in our cells tell us if we can beat cancer?

This study examined whether levels of microRNA-21 could predict the patient response to chemo-radiotherapy delivered before they had surgery.

Almost a third of colorectal cancer is rectal cancer. The treatment for this cancer which has started to spread is a combination of chemotherapy, radiotherapy (known as chemo-radiotherapy) and surgery. 

Radiotherapy uses high-energy radiation to kill cancer cells by damaging their DNA while chemotherapy uses a combination of drugs to kill the cancer cells.
This chemo-radiotherapy has been shown in other studies to work better when given before surgery.
However, more than 50% of patients do not respond to this treatment. This can delay their surgery.

The current study examined whether microRNA-21 levels could predict patient response to chemo-radiotherapy delivered prior to surgery.

The records of 92 rectal adenocarcinoma patients who underwent chemo-radiotherapy before surgery were examined in this study. In each patient the cancer had started to spread from its original site but had not reached other organs. Each patient received 5-fluoracil (Efudex) or capecitabine (Xeloda) chemotherapy and underwent surgery 6-8 weeks following treatment.

MicroRNA-21 levels were raised in almost 78% of rectal cancer patients.

Lower levels of microRNA-21 were associated with a better response to treatment. Of the 56 patients who had high levels of microRNA-21, 7.2% showed a complete response to chemo-radiotherapy and 92.8% had a non-complete response. Of the 14 patients with lower levels of microRNA-21, 42.8% showed a complete response.

Patients with high levels of microRNA-21 were 9.75 times more likely to show a poor response to chemo-radiotherapy compared to those with lower levels.

The authors concluded that the levels of preoperative microRNA-21 could be used for predicting response to chemo-radiotherapy treatment.

The study would benefit from being repeated over a longer period of time and with more patients.

Discuss this article and microRNA-21 levels with your doctor.