2 Patient Profile A 54-year-old high school teacher visited her family practitioner for an annual checkup. She reported no illnesses during the preceding year, felt well, and had no complaints. The hot flashes she had experienced a year ago had resolved without treatment. The physician performed a physical examination, comprising breast, pelvic (including a Papanicolaou smear), and rectal examinations; all were unremarkable. The physician recommended that the patient have a mammogram, which was scheduled for 1 week later. The results of the mammogram were not normal, and the radiologist suggested that a breast biopsy be performed. The family practitioner notified the patient of the abnormal mammogram and referred her to a surgeon, who concurred that physical examination of the breast was normal.
3 Based on the mammographic abnormality, however, the surgeon and the radiologist agreed that fine-needle aspiration (FNA) of the abnormal breast under radiologic guidance was indicated. Evaluation of the FNA specimen by a pathologist revealed cancer cells, and the patient was scheduled for further surgery the following week. In the Patient Profile, a mammogram was recommended to the patient as a screening test for breast cancer. The purpose of a mammogram is to detect breast cancer earlier in the course of the disease than would otherwise occur if the test were not performed.
4 Figure 8, a schematic representation of the course of disease over time, illustrates the possibility of detecting the presence of disease earlier using a screening test, thereby allowing for more effective treatment and prolonged survival. Inherent in this schematic diagram are two important concepts: (1) a screening test can identify individuals with a disease before the presence of disease is detected by routine diagnosis (eg, when symptoms occur), and (2) treatment at the time of detection by screening, as opposed to the time of routine diagnosis, results in an improved chance of survival.
5 Fig. 1 The natural history of a disease over time, including the preclinical stage in which a screening test can detect the presence of disease.
6 Breast cancer is a prototypical example of a progressive disease. As with most neoplasms, a breast cancer is believed to begin as a single malignant cell, which grows rapidly and forms a proliferating tumor.
- Spring '16
- Type I and type II errors, Biopsy, Screening Test