(Montreal) Genetic mutations present in the tumors of patients with kidney cancer could predict their level of risk of relapse, reveals 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 United Kingdom, is said to have achieved a major breakthrough in research on the treatment of kidney cancer. For the first time, researchers have succeeded in identifying the genetic mutations associated with a greater risk of disease recurrence.
The consortium involving 44 researchers from 23 institutions in Canada and Europe carried out its work over a period of ten years. More than 900 samples of cancerous tumors taken from patients’ kidneys were analyzed. We isolated 12 genes to observe the presence of mutations, then the patients were divided into groups according to the number of mutations present.
“All of the genomic sequencing and data interpretation work was done at McGill,” said Dr.r Yasser Riazalhosseini who heads the genomics unit of the Victor Phillip Dahdaleh Institute of Genomic Medicine affiliated with the University of Montreal.
As explained by D.r Riazalhosseini, the usual procedure for treating a patient with a cancerous tumor in the kidney is to remove it by surgery if the disease has not spread elsewhere in the body.
However, “between 30% and 40% of these patients are possibly victims of recurrences of the disease in the following five years”, he adds. Tumors can reappear in the kidneys or elsewhere in the body and prove fatal.
“Until now we didn’t really have good biomedical markers to assess the risk of recurrence. We rely on clinical assessments and observation of the tumour, but that’s not really useful”, admits the researcher who hopes to help his clinical colleagues.
The researchers were able to observe that the risk of cancer recurrence increased significantly depending on the number of genetic mutations detected in the DNA of the tumor. In summary, 90.8% of patients whose tumor contained only one von Hippel-Lindau (VHL) gene mutation 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% with one additional mutation, to 68.2% with two additional mutations, then to 50.7% with three or more additional mutations.
Personalized treatments
On the strength of these convincing results, the researchers hope to be able to help oncologists in the development of treatment plans for their patients. By having the possibility of having their patient’s tumor analyzed, doctors will be able to better assess the risk of cancer recurrence and thus establish a more aggressive or gentler strategy following surgery to remove the tumor.
“Based on our risk criteria, physicians will be able to better target patients who need to be followed closely with adjuvant therapy to prevent a recurrence,” says Dr.r Riazalhosseini.
On the other hand, patients for whom the risk of relapse is very low could avoid having to follow these treatments, the side effects of which can greatly affect their quality of life.
This type of sequential analysis of tumors is already used for other types of cancer such as those of the lung or the prostate for example. According to the Dr Riazalhosseini, it could be a few more years before the practice becomes common in the case of kidney cancer.
The authors of the study recall that, each year, more than 400,000 people worldwide, including 8,100 Canadians, are diagnosed with kidney cancer. It is still an uncommon type of cancer when it represents only 3.2% of cancer cases in the country, 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.
“Tumors in kidney cancer are very different from one patient to another, so it was necessary to be able to count on a large sample of patients to find common elements”, observes the researcher from McGill University.
This work, spread over ten years, has enabled scientists to rely on the largest sample in the history of kidney cancer research.
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