Colon or bowel cancer is the second most common cancer in Australia, with more than 16,000 cases diagnosed each year. A standard treatment for bowel cancer is a drug called Avastin, but unfortunately it doesn’t work for all patients.

Olivia Newton-John Cancer Research Institute (ONJCRI) researchers have developed a new test that may help streamline treatment for colon cancer patients by predicting whether or not they will respond to Avastin. The test would help doctors tailor treatments for individual patients and spare those patients who may benefit from the drug any side effects.

The researchers have developed what’s called a ‘biomarker’ (biological marker) that predicts whether patients will respond to the drug Avastin. Avastin works by slowing the growth of new blood vessels needed by cancer tumours to grow.

Previously, no test existed to predict whether people with the cancer would respond to the treatment or not.

“This classification test is not yet widely available in the clinic, and more testing is required to confirm these results, but nevertheless these are exciting and positive findings that could potentially change the way we select treatment for colon cancer patients in the near future,” says Dr Jennifer Mooi, medical oncologist and researcher.

Findings aired at international conference

Jennifer recently presented the findings at the European Society for Medical Oncology Congress in Madrid, Spain, which attracted around 23,000 oncology health professionals.

They were made after analysing more than 300 tumour samples from patients previously involved in the ‘MAX clinical trial’, led by Associate Professor Niall Tebbutt, who directs the Medical Oncology Unit at Austin Health. Professor Tebbutt works closely with Prof John Mariadason, Head of ONJCRI’s Oncogenic Transcription Laboratory.

Recent studies have shown that colon cancer can be divided into four “molecular subgroups” according to patterns of genes expressed in the tumour. Our research team showed that by classifying patients’ tumours in this way, two out of the four molecular subgroups of colorectal cancer respond better to Avastin.

Study part of laboratory’s drive to personalise cancer treatment

“At the moment, Avastin is given to all colon cancer patients but only a subset of patients benefits from it,” John says. “Our findings of this potential biomarker are exciting – it means we are closer to being able to select therapies more specifically for a patient with colon cancer. This will help doctors tailor treatments that are most likely to work for a particular patient and spare them from unnecessary toxicities of treatments that are unlikely to work for their cancer,” he says.

This research was sponsored by the Australian Gastrointestinal Trials Group (AGITG) and a grant from the National Health & Medical Research Council jointly awarded to John and Niall.