Cancer is not caused mainly by "bad luck." The authors of a recent paper based this conclusions on estimates of random cell mistakes (mutations) made during cell replication. While genetic mutations are involved in cancers, these may be caused by external and modifiable factors such as adopting a healthy lifestyle.
PositiveTip: Clear evidence supports the value of walking more, drinking water instead of sugary-beverages, substituting veggies for fatty foods, and many other simple measures that lower the risk of cancer.