Many families are impacted by an increased risk of cancer due to genetic changes that are often passed down from one generation to the next. A new nationwide study in Switzerland is exploring how these families manage the unique challenges arising from their hereditary cancer risk.
Approximately 45,000 people are diagnosed with cancer in Switzerland every year. Some 10 per cent of these cancers are hereditary. This means they are caused by changes in the genetic material — referred to as pathogenic mutations — that elevate the risk of tumour development. Most people who carry these mutations are unaware of it. Many of them develop cancer before age 50 and are too young to be included in standard screening programmes. We know that early detection and treatment are crucial for better outcomes. "It is therefore crucial to actively identify people with mutations so that they can be offered genetic testing and possible risk-reduction options," says Maria Katapodi from the University of Basel.
But how do we locate people with mutations? Theoretically, we could map the genetic makeup of the entire population. This would be disproportionately expensive, however. Katapodi advocates a more targeted and cost-effective approach, focusing on the fact that cancer-causing mutations are inherited and therefore more prevalent within specific families. If a genetic specialist identifies a mutation in one person, there is a 50% chance that the mutation will also be found in their mother, father, siblings or children. Depending on whether the mutation originates from the mother's or father's side, their uncles, aunts, nephews, nieces and their descendants may also carry the mutation.
Katapodi and her team at the University of Basel have been conducting this cascading search since 2016. The professor of nursing sciences has established a Switzerland-wide network for this purpose, setting up the Cascade Cohort Study that now includes more than 600 individuals from 450 families across three language regions. "We want to help families deal with the increased risk of cancer," says Katapodi with heartfelt sincerity. "We are very grateful to the Swiss Cancer Research Foundation for their generous support in enabling us to carry out our study."
Participation in the study is voluntary. Individuals fill out a detailed questionnaire on health, quality of life, preventive check-ups and instances of cancer in the family. These participants, who include both cancer patients and healthy individuals, are contributing to a valuable dataset that grows as the study continues. Katapodi and her team designed the cascade study to investigate Switzerland. Meanwhile, researchers in South Korea and Israel have set up similar studies in their own countries, making international comparisons possible.
Based on the data collected in Switzerland so far, Katapodi's team knows that around two thirds of participants advise members of their families to undergo genetic testing. Through in-depth interviews and focus group discussions, Katapodi's team has also learned that most participants would prefer to personally inform their relatives about a hereditary cancer-causing mutation and its potential impact on them. The findings suggest that instead of directly informing relatives, healthcare professionals should empower and support carriers of a cancer mutation to share this sensitive information with their families themselves.
These difficult conversations are sometimes avoided for various reasons, such as a desire to protect family members from unwelcome news. In a scientific paper, Katapodi's researchers cite the example of 40-year-old Federica, who said: "I knew that my cousin, who started the whole [genetic testing] thing, thought that she had dropped a bomb. [...] When she found out I was positive, she was scared to see me. [...] She was afraid I would be angry with her."
At the same time, many of the study's participants feel a responsibility to inform their family about the mutation and the potential increased risk of cancer. In the same paper, the researchers quote 34-year-old Sonia: "I said to myself: I have something that isn't good. How can I put it to good use?" [...] It's not pleasant or easy, but it's useful information that you need to make informed decisions. Otherwise, you'll end up saying, If only we had known this before..."
Individuals with a cancer mutation can lower their risk of developing cancer by taking specific steps, including regular and close medical screening. "Most people choose to do this," says Katapodi. Another option is to have your breasts removed as a precautionary measure, which is what the actress Angelina Jolie did. "Ultimately, each person has to decide what is right for them," Katapodi continues. 'We simply want to make sure that everyone receives the correct information. They should then be able to make an informed decision."
Project number: KFS-5293-02-2021
