For BC, if you catch it early enough it can be surgically removed it before it spreads. In that case chemo may be unwarranted but I think they are still recommending radiation and hormone therapy. Genetic testing will also reveal whether one is more or less prone to recurrence.
Also for BC and Prostate cancer, there are approved immunotherapies. For PC there is a treatment that infuses your blood with antibodies that are primed to kill all prostate cells. One would need the prostate removed first otherwise of course it will swell up as it attacks itself. But the idea is that the immunotherapy will go around and kill off any stray prostate cells that may be circulating in the body, before it metastasizes somewhere else.
No, breast cancer is not one of the cancers that progresses from small tumor to large tumor to metastasis. In many case for breast cancer, they remove it and later there is metastasis, because that happened earlier. That's why the data on screening for breast cancer is no as great as other cancers. Same with prostate cancer.
For colon cancer and cervical cancer, screening works well.
Prostate cancer is treated often with hormones which shut off testosterone which feed the prostrate cells. then with follow up targeted radiation.
My wife had breast cancer in one breast only 30 years ago, we did a double mastectomy and followed that with nothing whatsoever and she is still with me.
Mine was caught early (stage1A), but genomic testing (Prosigna or Oncotype) scored the tumor high for likelihood of distant recurrence, so I took 4 rounds chemo. Didn’t have any idea stage 1 breast cancer ever had to take chemo. It was a shock, and it was brutal. Some things will never be the same because of chemo destruction.