Study after study after study says diet and lifestyle are major factors in every deadly disease. But it's not socially acceptable to suggest that as an approach. However, having already committed the unspeakable sin and egregious faux pas, I will suggest that if cancer is a thing you fret about, you can do something to reduce your risk starting today.
This is too simple of an statement for such a complex disease, so is therefore, misleading.
If we want more substantial studies, we turn to the UK, because they have a unified health system and have a massive collection of data on the general population. Timothy Key, et. al., Oxford, wrote a great summary of attributable factors (albeit a secondary data analysis). Outside of obvious factors such as smoking, alcohol, and obesity, what you put into your body becomes less and less a probability of being a cancer factor compared to age and genetics.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190379/
>> Early case-control studies indicated that higher intakes of fruit and vegetables were associated with a lower risk of several types of cancer. But subsequent prospective studies, which are not affected by recall or selection bias, produced much weaker findings. In the 2018 World Cancer Research Fund report neither fruits nor vegetables were considered to be convincingly or probably associated with the risk of any cancer. There was suggestive evidence for protection of some cancers, and risk might increase at very low intakes. Specific components of certain fruits and vegetables might have a protective action.
>> Vegetarians eat no meat or fish and usually eat more fruit and vegetables than comparable non-vegetarians. The risk of all cancer sites combined might be slightly lower in vegetarians and vegans than in non-vegetarians, but findings for individual cancers are inconclusive.