Early cancer detection

1. What is Primary Prevention?
Primary prevention is the preferred strategy for reducing the disease burden of cancer. When the underlying etiology of a particular malignancy accounts for a large proportion of the attributable risk and is avoidable, such as the association between tobacco use and lung cancer, a method for primary prevention is obvious.
2. What is Secondary Prevention?
Secondary prevention is distinguished from primary prevention in that it is intervention focused on altering the natural history of the disease, thus avoiding disease-related adverse outcomes. Screening for cancer is a secondary prevention strategy that contributesto morbidity and mortality reduction by either identifying and treating precursor lesions known to be predictive of eventual malignancy, thus preventing progression to invasive disease, or by diagnosing invasive disease at an early stage when treatment is more successful, thus preventing death or avoiding morbidity.
In general, cancer prognosis is better and treatment more successful if the disease is detected when still localized. This finding is not true for all cancers but for some prevalent cancers, including cancers of the skin, breast, cervix, endometrium, ovary, testis, colon and rectum, prostate, and lung, a more favorable prognosis associated with early detection has led to secondary prevention strategies. In some instances, these have been successful.
3. What is Screening?
Screening is “the application of various tests to apparently healthy individuals to sort out those who probably have risk factors or are in the early stages of specified conditions”.
In the very near term, the greatest potential to reduce deaths from cancer is early detection of occult disease (i.e., preclinical malignancies and precursor lesions that have been growing for many years). Ultimately, prevention is the preferred solution to the disease burden of cancer. Although many practical barriers must be overcome to establish true population-based screening programs, a system of organized screening holds the greatest potential for realizing the benefits of reducing the incidence rate of advanced cancers.