Biases in Cancer Screening

Several biases may lead one to believe that screening is effective even in situations where it is not. The first of these is "lead time bias" (Figure 12.3). As shown in the figure, lead time is the time by which earlier detection advances diagnosis. If treatment is ineffective, however ("situation 2" in Figure 12.3), then the patient will die at the same time he/she would have without earlier detection ("situation 1"). The patient's "survival," measured from diagnosis, has been prolonged but the patient has not benefited. Thus, studies that compare survival between people whose cancers were

Symptoms Appear

Situation 1: Not Screened

A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

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