This is true for any medical act you perform on a massive scale really. Including vaccination, supplementation, etc. Everything is a cost/benefit ratio.
Yes, and this math has been done on many of those interventions (certainly for vaccination) and the benefit holds up. That statistical base rates are problematic for cancer detection is a pretty well-understood problem.
https://sciencebasedmedicine.org/a-skeptical-look-at-screeni...
https://skepticalinquirer.org/exclusive/the_screening_test_t...
https://fivethirtyeight.com/features/the-case-against-early-...