Can a healthy lifestyle prevent cancer? Maybe not
New research finds cancer may occur from just bad luck. In other words, lifestyle changes might help us avoid about one-third of cancer, while two-thirds of cancer types are merely the result of random DNA mutations. Does this mean practicing a healthy lifestyle is useless? Well, not exactly.
Johns Hopkins researchers say the finding has important implications for policy makers and for cancer prevention. According a statistical model develops by the scientists, approximately two-thirds of cancers are the result of stem cell division that occur randomly. Lifestyle changes can help us avoid some cancer, but for others it's "bad luck" that leads to mutations linked to cancer.
Three factors studied
The Hopkins researchers wanted to find out how lifestyle, environment and heredity factor into the development of cancer.They developed a statistical model based o n how many times stem cells divide during a person's lifetime. During cell division DNA can mutate, which is a "mistake" that can lead to cancer the researchers explain.
Cancer, according to the report, may be just the result of "bad luck". "Cancer-free longevity in people exposed to cancer-causing agents, such as tobacco, is often attributed to their 'good genes,' but the truth is that most of them simply had good luck," said Bert Vogelstein, M.D., the Clayton Professor of Oncology at the Johns Hopkins University School of Medicine. When you add poor lifestyle habits the risk of cancer increases, Vogelstein added in a recent press release.
The study, published January 2, 2014 in Science , suggests a person's risk of cancer can be
explained by the number of stem cell divisions a person undergoes. The "bad luck" factor relates to whether DNA mutates or behaves normally when cells divide.
Fewer stem cell divisions linked to lower cancer risk in mice
When the researchers looked at colon cancer incidence in mice that have fewer stem cell divisions, they noted the incidence of this type of cancer is lower than in humans whose colon stem cells divide frequently.
"We found that the types of cancer that had higher risk than predicted by the number of stem cell divisions were precisely the ones you'd expect, including lung cancer, which is linked to smoking; skin cancer, linked to sun exposure; and forms of cancers associated with hereditary syndromes," says Vogelstein.
Not included in the study were breast and prostate cancer due to lack of reliable literature about stem cell division rates in breast and prostate tissue.
The finding showed you can increase your risk of cancer by smoking and other poor lifestyle habits, but Vogelstein and co-researcher Cristian Tomasetti, Ph.D., an assistant professor of oncology at the Johns Hopkins University School of Medicine and Bloomberg School of Public Health say it's mostly bad luck that leads to cancer.
What the study means is that early screening for cancer is important. Detecting cancer early leads to higher cure rates. Practicing a healthy lifestyle won't keep some cancers at bay "We should focus more resources on finding ways to detect such cancers at early, curable stages," says Tomasetti. According to the statistical model, two-thirds of cancer are cause by bad luck.
Science 2 January 2015:
Vol. 347 no. 6217 pp. 78-81