YOUR LIFESTYLE:TODAY, knowing that breast, ovarian or colon cancer runs in a family is a key piece of medical information. It can help identify high-risk individuals within that family so they can be offered screening for the early stages, or even have tissue removed before a tumour can arise, writes CLAIRE O'CONNELL
But nearly 50 years ago, the mere notion that cancer risk could be hereditary was considered fringe. “It was very different back then,” recalls medical oncologist Prof Henry Lynch, who visits Dublin this weekend for a major conference.
Now cited as the father of cancer genetics, back in 1961 Lynch was a medical intern in Nebraska who spotted a trend. “I discovered a patient who kept telling us that he was going to die of cancer because, as he stated, everyone in his family dies of cancer.”
Lynch investigated and found the family was “riddled” with the disease, but the doctors treating individual family members hadn’t joined up the dots.
“The family members were dying predominantly of colon cancer, but as I studied the family I found out that there were many other cancers that were integral genetically, including cancer of the endometrium , the ovary, the small bowel, the stomach, the pancreas and part of the urological tract,” explains Lynch, who is now professor of medicine at Creighton University.
“I put all of these together and submitted this to a genetic society and they accepted it but no one else listened to me. I was in the wilderness really.”
Lynch persisted with his theory that there was a heritable risk for this syndrome of cancers, despite the lack of interest it awoke in others. “My colleagues kept telling me I was wasting my time and I should move on to other things. But I knew. I had no doubt that this was a real phenomenon,” he says.
Then researchers in other parts of the world started to find similar familial trends, and eventually in the 1990s, mutations in particular genes were found to be at the root of the increased risks – not only for the pattern of colon and associated cancers (now known as Lynch syndrome), but also for his observations of familial breast and ovarian cancers, where it turned out that normally protective BRCA1 and BRCA2 genes weren’t working properly.
“Those gene discoveries made it legitimate, that there really was something going on,” he says. “It took it completely out of the theoretical, it was real at that point.”
And while the heritable component accounts for only about 5-10 per cent of all cancers – most tumours arise sporadically – the effect of having a familial cancer risk can be dramatic for individuals who carry such a mutation.
“Those cancers are earlier onset, about 20 or 25 years earlier than what you would expect in sporadic cancers,” explains Lynch. “They are also often bilateral, meaning in the case of hereditary breast cancer for example both breasts are more often involved, or in the case of the colon syndrome, you get multiple cancers of the colon.”
But while such cancers can take root early and grow fast, knowing that a person has inherited the familial risk factor is the start of managing it, according to Lynch.
He has been involved in developing guidelines and protocols for screening family members frequently for tumours, or even advising people to have breast, ovary or colon tissue removed as a precaution in some cases.
“As a society we really need to protect our patients because once you find one of these families, you have individuals with the strongest conceivable risk of cancer, far greater than smoking or any other cancer-causing agent,” he says.
In the past, concerns over insurance implications have held some family members back from being tested, but recent protective laws in the US and an increasing awareness mean that people in high-risk families are co-operating more, says Lynch.
However, in Ireland, there has been a low to moderate uptake of such predictive testing among families where BRCA1 or BRCA2 mutations have been found. Since counselling started here in 1998, 77 per cent of potentially affected individuals in the wider families of 29 “index cases” have not come forward for testing, according to a study published last year in the Irish Medical Journal.
Part of the issue could be a lack of communication, according to the researchers at the National Centre for Medical Genetics in Crumlin. “Specific factors which appeared to influence attendance included poor dissemination of information among families about the test,” they write.
- Prof Henry Lynch will speak at the Cancer at a Crossroads conference for healthcare professionals this weekend at the Royal College of Surgeons in Ireland. To register or for more information, call Brian Deegan at M+C Events on 01-6650300 or e-mail bdeegan@mandcgroup.ie