>The old idea that cancer is less aggressive in the elderly is not entirely without merit: breast and prostate cancers tend to grow more slowly in older patients. But other types—colon and bladder cancer and certain leukemias, for example—are usually more aggressive and harder to treat.

https://www.scientificamerican.com/article/never-too-old-to-...

The article goes into some of the reasons and for that and the unique difficulties of treating geriatric cancer.