Men around the world are more likely to get cancer than women, but why? Chinese scientists say unhealthy lifestyles and pre-existing illnesses may explain most of the discrepancy between Chinese men and women, but these differences appear to be less important when investigating why cancer affects more British men than women. The team analysed health data on nearly 135,000 Chinese people and just over 455,000 Brits, looking at 34 cancers and lifestyle factors, including smoking, heavy drinking, physical inactivity, and diet, as well as pre-existing health conditions including chronic liver disease, diabetes, and obesity. They found that, together, these factors accounted for 84% of the male - female gap in China, but just 26% among Britons. The findings suggest the factors affecting the gender gap in cancer may differ from country to country, so intervention strategies should be tailored to local populations, the authors conclude.

Because men don't go to the doctor as often. Patriarchal norms encourage men to bottle in and endure pain and symptoms. And they do until it's too late.

I remember there was a study that showed one of the best predictors for cancer survival in men was if they were married. Since spouses would encourage them to go to the doctor and get stuff checked out early and it would also help with treatment adherence.

https://ecancer.org/en/news/28017-cancer-risk-is-significantly-higher-for-adults-who-never-married-large-u-s-study-finds

The reason most men I know don't go to the doctor in USA is because it costs money and dealing with insurance is a headache if something gets discovered. Rather be dead then deal with medical bills