The consensus among researchers has long been that a sizable fraction of all cancers could be avoided, given more exercise, better diet, less excess fat tissue. This is even setting aside the matter of smoking and its significant relationship to cancer. The study here is notable for adopting a slightly different approach from most other analyses, and arriving at lower numbers when it comes to the risk of a poor lifestyle. Whether or not one concurs, it is worth bearing in mind that aging remains the greatest risk factor for cancer incidence.
Cancer is a numbers game, risk over time: the wrong mutation in the wrong place; a mutated cell failing to destroy itself; the immune system failing to save the day by destroying the errant cell; the local tissue environment dysfunctional enough to support cancerous growth of that cell. Live long enough and cancer will happen, even given rejuvenation therapies capable of restoring the immune system, damping down chronic inflammation, and addressing the other most important mechanisms relating to cancer. A comprehensive, robust cure for all cancer is a vital part of the planned future toolkit of longevity assurance treatments.