IARC disputes report that attributes most types of cancer to “bad luck”

the Oncology Nurse Advisor take:

Widespread media coverage has been given to a scientific study that compares the number of lifetime stem cell divisions across a wide range of tissues with lifetime cancer risk.

The study suggests that random mutations—or bad luck—are “the major contributors to cancer overall, often more important than either hereditary or external environmental factors.” The study authors argue that focusing on early detection of the disease is more significant than preventive measures.

The World Health Organization’s specialized cancer agency, the International Agency for Research on Cancer (IARC), however, disputes these findings, pointing to a serious contradiction with an extensive body of evidence as well as limitations and biases within the analysis.

Five decades of international epidemiological research demonstrates how most cancers may be prevalent in one population but not in another and that these patterns change over time. For example, colorectal cancer was once rare in Japan, but incidence has increased 4-fold in the past 20 years, an observation consistent with changes in environment and lifestyle exposures. Furthermore, IARC points out that the study emphasizes rare cancers, which make up only a small percentage of cancer cases.

The association between cell divisions and the risk of mutation and, therefore, of developing cancer, is clear; however, most cancers are strongly related to environment and lifestyle. The IARC argues that most common cancers can be prevented as evidenced by the impact of reductions in smoking leading to fewer lung cancer cases or lower rates of hepatocellular carcinoma among people vaccinated against hepatitis B virus.

Although investing in prevention measures for those cancers whose risk factors are known should continue, the IARC stresses that cancer risk should not be ascribed to bad luck.

Continuing the search for the causes of cancer is particularly important, especially in areas of the world with limited resources for facing the growing burden of cancer.