Prevention and Screening
The ultimate goal of cancer research is to prevent the disease the way vaccination has eradicated polio and smallpox. In the absence of a definitive prevention strategy, medical science’s best efforts have been applied to finding or screening for the disease early enough so that it is virtually curable in 100% of those in whom it is found. There have been unquestioned successes, the Pap smear being the best example, as it permits the early detection and cure of cervix cancer. Some cancer screening tests that attempt to find the cancer early, before it produces symptoms and when it is curable, have had mixed success and remain controversial, like the screening tests for prostate, breast, and lung cancers.
Cancer evolves from a precancerous state to a noninvasive cancerous state to an invasive cancerous state. The greater the number of cancer cells, the greater the risk of mutation to an invasive state. The greater the number of invasive cells, the greater the risk of those invading cells escaping into the circulation. The greater the number of cells in the circulation, the greater the likelihood that some will anchor and nest in the blood vessels of another organ, creating metastases. The greater the probability of metastases, the lower the probability of cure. Following this logic, the key to success in cancer management is to find cancer before it is invasive, or if invasive, as soon as possible before it metastasizes.