McGill team's discovery better predicts risk of kidney cancer recurrence

Genetic mutations in the tumours of kidney cancer patients can predict their risk of relapse, according to a new study published this week in the Journal of the American Association for Cancer Research.

An international consortium led by a team from McGill University, in collaboration with the University of Leeds in the UK, has reportedly achieved a major breakthrough in kidney cancer treatment research.

For the first time, researchers have managed to identify the genetic mutations associated with a higher risk of recurrence of the disease.

The consortium of 44 researchers from 23 institutions in Canada and Europe conducted their work over a 10-year period.

More than 900 samples of cancerous tumours taken from patients' kidneys were analyzed. Twelve genes were isolated for mutations and the patients were divided into groups according to the number of mutations present.

"All the genomic sequencing and data interpretation was done at McGill," said Dr. Yasser Riazalhosseini, who heads the genomics unit at the Montreal-affiliated Victor Phillip Dahdaleh Institute of Genomic Medicine.

As Riazalhosseini explains, the usual procedure for treating a patient with a cancerous kidney tumour is to remove it surgically if the disease has not spread elsewhere in the body.

However, "between 30 and 40 per cent of these patients eventually experience a recurrence of the disease within five years," he added. Tumours can reappear in the kidneys or elsewhere in the body and prove fatal.

"Until now, we haven't really had good biomedical markers to assess the risk of recurrence. We rely on clinical assessments and observation of the tumour, but this is not very useful," admits the researcher who hopes to help his clinical colleagues.

The researchers found that the risk of cancer recurrence increased significantly with the number of genetic mutations detected in the tumour's DNA. In summary, 90.8 per cent of patients with a single von Hippel-Lindau (VHL) gene mutation in their tumour were considered cured after five years of remission.

However, as soon as other genetic mutations are identified, the risk of relapse increases. Thus the complete remission rate after five years drops to 80.1 per cent with one additional mutation, to 68.2 per cent with two additional mutations, and to 50.7 per cent with three or more additional mutations.

PERSONALIZED TREATMENTS

With these compelling results, the researchers hope to help oncologists develop treatment plans for their patients. By being able to have their patient's tumour analyzed, doctors will be able to better assess the risk of cancer recurrence and thus establish a more aggressive or milder strategy following surgery to remove the tumour.

"Based on our risk criteria, doctors will be able to better target patients who need to be closely monitored with adjuvant therapy to prevent recurrence," said Riazalhosseini.

On the other hand, patients with a very low risk of relapse could avoid having to undergo these treatments, whose side effects can greatly affect their quality of life.

This type of sequential tumour analysis is already used for other types of cancer, such as lung and prostate cancer. According to Riazalhosseini, it may take a few more years before the practice becomes commonplace for kidney cancer.

The authors of the study point out that more than 400,000 people worldwide, including 8,100 Canadians, are diagnosed with kidney cancer each year. It is still an uncommon type of cancer, accounting for only 3.2 per cent of cancer cases in Canada, according to Statistics Canada. The prevalence of the disease is higher in men than in women.

This relative rarity partly explains the delay in research compared to other types of cancer.

"The tumours in kidney cancer are very different from one patient to another, so it was necessary to have a large sample of patients to find common elements," said the McGill researcher.

This 10-year effort allowed scientists to draw on the largest sample size in the history of kidney cancer research.

This report by The Canadian Press was first published in French on Feb. 25, 2023.