RSS feed“Is this cancer hereditary?” is a question that I am quite often asked by my patients. We know that some cancers are hereditary but the truth is, the majority of cancer arises as a result of aging. As we get older, the risk of developing a cancer increases not because we have inherited the gene but because of cumulative damage to the DNA of a cell. Eventually a damaged cell manages to persist and develop into a cancer. In some situations, a grown-up child of a parent who had colon cancer for example, develops a colon cancer himself years later. Does the survival outcome of his or her parent help to predict the survival outcome of the child with the same cancer? If the parent survived more than 10 years, does it mean that the affected child is likely to survive more than 10 years also?
The results of a recent study from the Karolinska Institutet in Stockholm, Sweden (Lancet Oncology 2007; 8: 1001 – 1006) tackling this interesting question have just been published. They analysed a population-based Swedish family database that included about 3 million families. There were more than 1 million individuals with cancer and from this they analysed the survival in the children in relation to their parental survival from cancer. They were looking for ‘good survival’, meaning living for at least 10 years beyond the diagnosis of cancer, and ‘bad survival’. The study found that children with the same cancer as a ‘bad survival’ parent (meaning dying within 10 years from diagnosis) had significantly poorer survival themselves. This link was found in breast, colorectal and prostate cancers. When they compared children with poor parental survival to those with good parental survival, the study found that there was increased risk of death from cancer in children with poor parental survival. In these children, the increased risk of death was 44% for colorectal cancer, 39% for lung cancer, 75% for breast cancer and 107% for prostate cancer.
The significance of this study, if indeed true and confirmed by other studies, would start another race in medical science where teams of researchers would search for ‘survival genes’. While waiting for the discovery of these genes, the knowledge from this Swedish study may influence the oncologist’s approach in treating and monitoring this group of patients. Perhaps in children of poor parent survival, the oncologist might suggest a longer duration of chemotherapy and closer follow-up schedules. When these survival genes are eventually discovered, we must not fool ourselves into thinking that the problem is finally solved. Why? Having the gene / genes is only part of the equation. Good or bad genes need a trigger. The trigger is what we consume, what we breathe and what we do. The search will go on.
