That's demonstrably false. Early screening is useful, but that's also a medical procedure.
Really what we care about is cancer deaths at a specific age AKA what % of 15 year old people die of cancer and that really has dropped. Even beyond that the absolute rate of cancer deaths in the US peaked in 1990 216 per 100k vs 2015 at 158 per 100k. Which is a massive drop even over 1950's pre screening and younger population numbers of 193 per 100k.
PS: Stomach cancer is flat out much less common because we understand a major cause now. Cervical cancer rates will similarly drop from the HPV vaccine.
Really what we care about is cancer deaths at a specific age AKA what % of 15 year old people die of cancer and that really has dropped. Even beyond that the absolute rate of cancer deaths in the US peaked in 1990 216 per 100k vs 2015 at 158 per 100k. Which is a massive drop even over 1950's pre screening and younger population numbers of 193 per 100k.
PS: Stomach cancer is flat out much less common because we understand a major cause now. Cervical cancer rates will similarly drop from the HPV vaccine.